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DOHC Starting Issues, BIG Puzzler! by Squeaky
Started on: 06-29-2013 04:17 PM
Replies: 48 (952 views)
Last post by: Erik on 08-19-2013 10:49 PM
Squeaky
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Report this Post06-29-2013 04:17 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
So I went to fire up my newly swapped 3.4L DOHC in my 87' Fiero GT and as usual it took a bit of open throttle to get started only this this time it wouldn't idle without keeping the throttle a bit open. If I let the revs drop below 2000 it would have a rough idle and rev up and down between 1-2000. My fuel pressure was set at 43.5psi but my exhaust was noticably rich.

Concerned I turned off the engine. When I went to try again it fired breifly with the same issue and then died, after that it wouldn't fire. I noticed when I put in the key my fuel relay sometimes wouldn't prime either. After checking I found that the relay was fine and that when my C203 (the clear one) conncector by my ecm was bumped or nudged that it would intermitantly engage the fuel relay. There was a tab broken on my C203 connector so perhaps it wasn't clipped together tight?

I have the C203 connector in a spot now where it wont get disturbed and now the fuel relay primes consistantly when Im put the key in. However on the fuel pressure gauge
coming off my fuel rail it'll prime to 35-ish psi and then immediatly start dropping back to zero, is that normal? There is also a strange ticking sound coming from my harness somewhere, could this be arcing? Its not the fuel relay ticking, for that I'm certain.

Prior to this the engine idled magnificently, I'm really stumped here. Any suggestions or thoughts?
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ltlfrari
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Report this Post06-30-2013 11:08 AM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
Running rich and fuel pressure drops off rapidly when pump stops. I'm, going to hazard a guess and say leaky or stuck injector.

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

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Report this Post06-30-2013 05:38 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
The only voltage high enough to arc is the spark plug voltage.

The fuel injectors do tick if you listen closely.
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Squeaky
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Report this Post06-30-2013 10:06 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
I was hoping it wasn't the pump, mind you the pump's been imersed in stabilized fuel for 3 years. I stored my car for the winter with a full tank and then gotta deal on the engine. I've referenced your swap Dave during mine, have you experienced similar issues?

I purchased my injectors from wot tech, their the refurbished used ones they sell that are spray tested, are these likely to be faulty?
The ticking I hear when the engine's off, I'm not sure if it ticks with the engine on, I can't hear it over the exhaust haha. Gotta love Spintech's!
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Report this Post07-01-2013 06:35 AM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
I have a DOHC with a 2-12" Spintech. I NEVER hear any clicking when it's running

It really does sound like a bad injector. Did you say the pump runs all of the time? It should only run for 2 seconds when you first turn the key. Fortunately, the injectors are relatively easy to pull on this motor.

------------------
1986 SE Aero coupe.

3.4 DOHC swap is complete and running, now just have to finish the rest of the car...

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ltlfrari
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Report this Post07-01-2013 08:18 AM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
I never had that problem.
The fuel rail pressure should hold once the pump turns off (will probably bleed off over a few hours but that's all) so something is letting it bleed off more quickly. If a forward direction that would be the injectors. In the revers direction the pressure regulator maybe since I don't think there's anything else in the fuel circuit to prevent a revers flow other than the regulator.

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

[This message has been edited by ltlfrari (edited 07-01-2013).]

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Report this Post07-01-2013 12:36 PM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
There should be a check valve in the pump. The one on my 99 Silverado failed and I had to crank it A LOT to start it. I put a check valve in the line after the pump (under $20) and it worked perfect for several years. Finally replaced the pump after the fuel level sender broke. I left the check valve in line and never had a problem with it.
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Squeaky
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Report this Post07-01-2013 01:44 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
The fuel pump only primes it when I put in the key, just for about a 2 seconds. Haha yeah I know, I've never heard a V6 sound quite so mean as it does with that Spintech. I purchased an injector test harness of ebay for the dohc motor, I'm gonna have to go through and test them and then go from there, wish me luck! I'll keep things posted, all I'm waiting on for this thing is paint.
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Squeaky
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Report this Post07-01-2013 06:00 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
I visited the local pick n' pull today and found two wrecked Fiero's with C203 conncector's that were in good shape, I bought one and replaced my old connector with it. My fuel relay no longer engages intermitantly when the wire's/conncector gets nudged. So its a step in the right direction! Next is the injector's/fuel valve.
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Report this Post07-02-2013 10:44 AM Click Here to See the Profile for bonaduceClick Here to Email bonaduceSend a Private Message to bonaduceEdit/Delete MessageReply w/QuoteDirect Link to This Post
I had a similiar problem with my swap, when you replaced the fuel pump, there is a little rubber hose between the pump and sender, GM calls it a dampner, they like to split after sitting in the tank for a while.

dan
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Report this Post07-02-2013 01:58 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Good to know Dan! I'll have to drop the tank and have a look. What is the purpose of the dampner?
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Report this Post07-02-2013 03:58 PM Click Here to See the Profile for bonaduceClick Here to Email bonaduceSend a Private Message to bonaduceEdit/Delete MessageReply w/QuoteDirect Link to This Post
it is just to connect the pump to the sending unit.
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Report this Post07-02-2013 09:55 PM Click Here to See the Profile for Steven SnyderClick Here to visit Steven Snyder's HomePageClick Here to Email Steven SnyderSend a Private Message to Steven SnyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
If the C203 terminals are corroded (and they all are by now since our cars are so old), the fuel injector voltage can drop low enough to not allow them to open at low idle. Replacing the C203 with a junkyard connector doesn't usually help because they are corroded too.

I had this problem years ago and chased it for months. Fixed it by repinning the c203. I think you can get everything you need from phonedawgz, except maybe the crimping tool. //www.fiero.nl/forum/Forum2/HTML/128971.html
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Report this Post07-03-2013 03:31 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
That makes sense Steve. Although splicing in the C203 connector I stole from the junk yard car did fix the inconsistant engagment of my fuel relay, the engine still doesn't fire. Regardless thats a cheap and easy enough repair,and I know that my local Napa stocks a HUGE variety of gm pins. I'm gonna start with that and then go from there. Here's the game-plan:

Re-pin my C203 connector
Test my injectors
Drop fuel tank and check the dampner and possibly replace pump

Hopefully along the way I stumble accross the issue and don't have to drop the tank but thats the jist of what I plan on doing so I can hopefully solve this issue. I'll get cracking on it this weekend. Any other suggestions or ideas?

Also Steve I should let you know your DOHC was the inspiration for my engine bay scheme, I hope to post pictures soon!
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Report this Post07-03-2013 06:26 PM Click Here to See the Profile for sspeedstreetClick Here to Email sspeedstreetSend a Private Message to sspeedstreetEdit/Delete MessageReply w/QuoteDirect Link to This Post
I struggled getting mine to start as well. It ended up being something I never expected. It wasn't getting fuel into the cylinders. I could hear the injectors and it had fuel pressure. Shoot some ether into the intake and it would roar to life (for a second). The injectors were a set for the 1997 3.4 DOHC (I had read they were quieter) mounted on the fuel rail NEW from GM. I finally pulled them out and took them to a local injector service to get them checked out. He ran them through the cleaning cycle and then mount them for test. Nothing. They clicked, but no spray. He kept bumping up the pressure til at 80psi they broke loose. After that they performed fine at 40psi. Apparently they were just stuck from sitting on the shelf.

------------------
1988 GT, 5-speed, white, beechwood leather, 3.4 DOHC crate motor with Getrag 5-speed. C.A.R.B. legal. Corvette power steering, Boxster wheels and 12" brakes. Then on to the F40 installation.

[This message has been edited by sspeedstreet (edited 07-03-2013).]

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Report this Post07-03-2013 09:20 PM Click Here to See the Profile for Steven SnyderClick Here to visit Steven Snyder's HomePageClick Here to Email Steven SnyderSend a Private Message to Steven SnyderEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Squeaky:
Also Steve I should let you know your DOHC was the inspiration for my engine bay scheme, I hope to post pictures soon!


Nice! I can't wait to see it.
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Report this Post07-04-2013 12:59 AM Click Here to See the Profile for SourmugSend a Private Message to SourmugEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hope you get you issues worked out.

Looking forward to seeing some pictures.

Nolan
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Report this Post07-12-2013 08:41 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
edit

[This message has been edited by Squeaky (edited 07-12-2013).]

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Squeaky
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Report this Post07-30-2013 11:13 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sorry gents, the pennock's picture uploader is having difficulty with my computer so I've been having trouble uploading pics.

However I'm back from vacation and have gone ahead again with fixing my issue. Turns out it was my adjustable fuel pressure regulator that was leaking causing my fuel pressure in the rail to drop. I've since ditched my external adjustable fuel pressure regulator set-up (it was a universal regulator) and gone back to a stock DOHC fuel rail. Now it holds pressure and only drops a few psi when left for an extended period of time.
Also my fuel pump primes the rail consistantly after changing out and splicing in a newer C203 connector.

But its now just only turning over, not starting. The starter will crank the motor but it doesn't want to fire. I know my injectors are fine and I know that the fuel rail has fuel (it reads 33 psi, I'm assuming its reading that low because of the residual air in the fuel lines/rail that I installed). I'm gonna check and see if I'm getting spark next.

Although in my infinite wisdom I noticed after I put in the new fuel rail that I forgot to disconnect my battery... By fogetting to disconnect the battery could the electronics have locked something out?

I also checked my fusebox underneath my dash and none of the fuses are blown, lastly I tried starting it with the help spraying a bit of fuel into the tb.

All arrow's seem to be pointing at me not getting spark but I'm not sure. My mind is slowly turning to mush just thinking about it. Any thoughts, experiences or suggestions?

Once again much appreciated!!
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Squeaky
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Report this Post07-30-2013 11:18 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post

Squeaky

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Oh I've also noticed my tach is getting power as the gauge's needle hovers and trickles about the zero mark which seems right to me if its just the starter turning over the motor without firing.

Thought I'd mention that because I've heard that if the tach needle show's no signs of moving during cranking over then it could potentially be a bad icm or crankshaft positoning sensor. Although I don't think thats the case as the needles behavior like I described above seems normal given the situation.
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Report this Post07-31-2013 11:35 AM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Bump...
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Report this Post07-31-2013 12:06 PM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
Pull the plugs and check for spark. Then check for power to the ICM, ICM grounding and all of that stuff.

------------------
1986 SE Aero coupe.

3.4 DOHC swap is complete and running, now just have to finish the rest of the car...

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Report this Post07-31-2013 12:22 PM Click Here to See the Profile for aaronkochClick Here to Email aaronkochSend a Private Message to aaronkochEdit/Delete MessageReply w/QuoteDirect Link to This Post
When Joe (Fieroking) was first getting into the 3.4 DOHC swaps, he ran into a weird issue with the crank or cam sensor wiring. Something about the wiring needing to be twisted or shielded, then the polarity was backwards in the book. I remember him fighting the same thing for quite a while, and once he swapped polarity of the sensor wiring, BOOM, engine ran like a raped ape and still does.

Sorry I can't remember exactly which sensor, just the gist of it. Good luck getting it sorted out!

------------------


Build thread for my 88 + 3800NA swap

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Report this Post07-31-2013 01:01 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Will do guy's!!

Tonight I'm gonna pull the plugs and test each of them for spark, that seems like a logical start. Thanks Aaron! I know that from researching some previous threads that the sensor will likely be the crank sensor but I will take a look at the camshaft positioning sensor as well.

Also do you know if Fieroking's DOHC was running fine prior to switching polarity, or was this something he found before he first started it? Mine at one point was running fine, this all happened rather quickly.

Thanks again to everyone for their help so far, I'm new to wrenching on fuel injection so your help is much appreciated! Anymore suggestions or thoughts/opinions are welcomed.

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Report this Post07-31-2013 02:14 PM Click Here to See the Profile for aaronkochClick Here to Email aaronkochSend a Private Message to aaronkochEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Squeaky:

Will do guy's!!

Tonight I'm gonna pull the plugs and test each of them for spark, that seems like a logical start. Thanks Aaron! I know that from researching some previous threads that the sensor will likely be the crank sensor but I will take a look at the camshaft positioning sensor as well.

Also do you know if Fieroking's DOHC was running fine prior to switching polarity, or was this something he found before he first started it? Mine at one point was running fine, this all happened rather quickly.

Thanks again to everyone for their help so far, I'm new to wrenching on fuel injection so your help is much appreciated! Anymore suggestions or thoughts/opinions are welcomed.


It ran, but not well. If yours was running ok before, this may not be the problem.

------------------


Build thread for my 88 + 3800NA swap

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Report this Post08-01-2013 07:14 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
So here's an update:

Checked for spark and there was none, took a little journey underneath my dash to the fuse box and discovered that my 5 amp fuse for my left bank of injectors was blown... I'm gonna continue later. Tonight's my Grandma's 85th, so the Fiero can wait.
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Report this Post08-02-2013 07:32 AM Click Here to See the Profile for tesmith66Send a Private Message to tesmith66Edit/Delete MessageReply w/QuoteDirect Link to This Post
That fuse has nothing to do with ignition. Sounds like you either have wiring issues or you knocked that fuse out when you swapped fuel rails. Replace the fuse and test all others while you are in there, then check all of your grounds- especially the ignition. The bracket that holds the ICM and coil packs MUST be well grounded to the engine.

------------------
1986 SE Aero coupe.

3.4 DOHC swap is complete and running, now just have to finish the rest of the car...

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Report this Post08-02-2013 03:58 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Its gotta be grounding out somewhere, I don't think switching out the fuel rail was the direct cause of it blowing my fuse. Prior to all this when my engine ran it blew the same fuse, I replaced it and she fired up and ran good... Then it didn't run at all which brings us to now haha.
Up in Canada its a holiday on Monday so after camping I'm gonna explore more into my icm and trace my wires on that one injector bay.
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Report this Post08-06-2013 11:05 AM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Just an Update:

So I'm still dealing with two issues: The first being no spark and the second being my injector fuse that keeps blowing.

I tested my ICM last night for 12V with the key turned to on and got nothing, before doing so I made certain it was grounded to the block. I suppose that could mean a bad ICM which would really suck because its brand new. My spark plug wire's weren't attached to the coils while I did this but that shouldn't matter, correct?

I have a brand new crank sensor but before I replace it I wanna check if my crank sensor if bad, does anybody know which pins on the C203 connector run to the crank sensor? Mine is an 87'.
Electronics are totally not my forte so forgive me if this is a 'dumb' question but if my crank sensor is in fact bad, would that result in there being no voltage with key-on at my ICM?

I also was chasing my issue with having the left-bay injector's fuse that keeps blowing. I unplugged the injector harness from the injectors and put in a new 5 amp fuse. Before In starting looking more into the harness itself I wanted to make sure it wasn't just and injector shorting out. With the injectors unplugged the fuse still blew immediately when I put it in, thus confirming that somewhere within the harness my injector wires are grounding out. This issue I'm not as concerned about, the fix should be easy just finding where to fix it is tedious.

Meanwhile I'll keep on chippin' away!
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Report this Post08-06-2013 11:32 AM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Squeaky:

Just an Update:

So I'm still dealing with two issues: The first being no spark and the second being my injector fuse that keeps blowing.

I tested my ICM last night for 12V with the key turned to on and got nothing, before doing so I made certain it was grounded to the block. I suppose that could mean a bad ICM which would really suck because its brand new. My spark plug wire's weren't attached to the coils while I did this but that shouldn't matter, correct?


The stock Fiero wiring has the ignition system getting power off of C500 E3. Did you wire your harness the same? If so then power TO (not from) the ICM should run from C500 E3 to the ICM. If you have no power to the ICM, the ICM won't work. So before playing with your crank pick up get power to your ICM. By the way the power that runs to C500 Pin E3 isn't fused. When I make my harnesses I put a fuse there. GM used a fusible link in SOME of the Fieros.

 
quote
I have a brand new crank sensor but before I replace it I wanna check if my crank sensor if bad, does anybody know which pins on the C203 connector run to the crank sensor? Mine is an 87'.


Depending on the year there are one or two crank sensors on the DOHC. The one in the middle of the block always runs to the ICM. If you have the second at the crank pulley that runs to the ECM/PCM. Neither runs to C203

 
quote
Electronics are totally not my forte so forgive me if this is a 'dumb' question but if my crank sensor is in fact bad, would that result in there being no voltage with key-on at my ICM?


Nope. 12v to your ICM is required for it to work. The crank sensor has nothing to do with the 12v getting to your ICM.

 
quote
I also was chasing my issue with having the left-bay injector's fuse that keeps blowing. I unplugged the injector harness from the injectors and put in a new 5 amp fuse. Before In starting looking more into the harness itself I wanted to make sure it wasn't just and injector shorting out. With the injectors unplugged the fuse still blew immediately when I put it in, thus confirming that somewhere within the harness my injector wires are grounding out. This issue I'm not as concerned about, the fix should be easy just finding where to fix it is tedious.


Any chance you have the ICM being powered by the INJ (2)? fuse? If so a 5A fuse is way too small for that.

By 'left bay' do you mean the front bank? Any idea how your harness is wired? Usually when I wire a harness I put all the injectors on one fuse and all the other powered things in the engine bay on the other.

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Report this Post08-06-2013 12:08 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by phonedawgz: The stock Fiero wiring has the ignition system getting power off of C500 E3. Did you wire your harness the same? If so then power TO (not from) the ICM should run from C500 E3 to the ICM. If you have no power to the ICM, the ICM won't work. So before playing with your crank pick up get power to your ICM. By the way the power that runs to C500 Pin E3 isn't fused. When I make my harnesses I put a fuse there. GM used a fusible link in SOME of the Fieros.


I can't tell you much about how the harness is wired, I had it done by Erik here on the forum 2 years ago. I put my fiero harness in a box, shipped it off and in a month's time I had a DOHC/Fiero harness returned back... Kinda wishing now I would've taken the plunge and built my own, at least that way I could've learned a thing or two.
However thats good info, and I can tell you that mine has a fusible link. Not sure if GM or Erik put it there. When I arrive home this evening I'll start by checking to make sure that I have power running from my C500 E3 TO my ICM and then start going from there.

 
quote
Originally posted by phonedawgz: Depending on the year there are one or two crank sensors on the DOHC. The one in the middle of the block always runs to the ICM. If you have the second at the crank pulley that runs to the ECM/PCM. Neither runs to C203.


My DOHC engine is a 93', I have only the one crank sensor going in the side of the block near the alternator.

 
quote
Originally posted by phonedawgz: Nope. 12v to your ICM is required for it to work. The crank sensor has nothing to do with the 12v getting to your ICM.


Good to know!

 
quote
Originally posted by phonedawgz: Any chance you have the ICM being powered by the INJ (2)? fuse? If so a 5A fuse is way too small for that.

By 'left bay' do you mean the front bank? Any idea how your harness is wired? Usually when I wire a harness I put all the injectors on one fuse and all the other powered things in the engine bay on the other..


Yes thats correct, its the front or 'left bay' thats giving me issues. Anything's possible I guess haha, the location of the 5 amp fuse that keeps blowing is labeled "TBI INJ1" //www.fiero.nl/forum/A...00421-2-099195.html. So I don't think that the ICM is being powered by that fuse, unless I'm missing something here...
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phonedawgz
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Report this Post08-06-2013 12:28 PM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Check to see what looses +12 on it's pink when the INJ1 fuse is out. Heated O2 (if you have one), Evap Solenoid, Automatic Transmission, MAF
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Report this Post08-06-2013 01:02 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Will do!
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Report this Post08-07-2013 11:03 AM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Update:

So I quickly checked this morning before work to see if my ICM was getting its 12V of power from the C500 connector by slidning a paper clip past the power wire that goes to my ICM and down to the pin then tested it with my multi-meter... And I got nothing. I tired with key's turned to on and with it turned off.

There's a fusible link down the wire but I tested at the C500 connector so even if it is bad I should still be reading power at the connector, correct? Lastly could that just be a result of not having my injector fuse installed?

More to come this evening!
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Report this Post08-09-2013 10:54 AM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Alright so I started at the fusebox where my 5 amp injector fuse kept blowing and followed the wire back to my C203 connector, I unplugged my C203 connector and popped in a fuse and then turned the key. The fuse didn't blow so I know my problem is further back down the harness.

I plugged my C203 harness back in and sure enough the fuse blew, so I visually inspected my wires after the C203 and followed them up and through the firewall without seeing any signs of damage.
The injector wire I was chasing once past the firewall goes to the DOHC C100 connector (I think its the C100 connector, there's 2. One has grey housing and the other is black, I'm talking about the black one). That connector plugs then into my injector harness.

I then unplugged my injector harness and plugged in another 5 amp fuse and went to turn the key, and once again it blew.

Based on that I'm guessing the wire is somehow damaged and grounding out somwhere between where it comes out of the firewall and where it plugs into my C100 connector. I'm also wondering if maybe thats where the 'ticking' sound was coming from like I mentioned in the first post.

More to come at the end of this weekend!
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Report this Post08-09-2013 11:35 AM Click Here to See the Profile for carbonSend a Private Message to carbonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Squeaky:

Alright so I started at the fusebox where my 5 amp injector fuse kept blowing and followed the wire back to my C203 connector, I unplugged my C203 connector and popped in a fuse and then turned the key. The fuse didn't blow so I know my problem is further back down the harness.

I plugged my C203 harness back in and sure enough the fuse blew, so I visually inspected my wires after the C203 and followed them up and through the firewall without seeing any signs of damage.
The injector wire I was chasing once past the firewall goes to the DOHC C100 connector (I think its the C100 connector, there's 2. One has grey housing and the other is black, I'm talking about the black one). That connector plugs then into my injector harness.

I then unplugged my injector harness and plugged in another 5 amp fuse and went to turn the key, and once again it blew.

Based on that I'm guessing the wire is somehow damaged and grounding out somwhere between where it comes out of the firewall and where it plugs into my C100 connector. I'm also wondering if maybe thats where the 'ticking' sound was coming from like I mentioned in the first post.

More to come at the end of this weekend!


Yay for troubleshooting. While problems suck... finding the real source without throwing parts at the car can be extremely satisfying!
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Report this Post08-13-2013 02:41 AM Click Here to See the Profile for ErikClick Here to Email ErikSend a Private Message to ErikEdit/Delete MessageReply w/QuoteDirect Link to This Post
You should run a 10 amp fuse on TBI INJ 1 and TBI INJ 2. I typically run the DIS off of the TBI INJ 1 and the injectors on TBI INJ 2 when I build a harness.
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Report this Post08-13-2013 02:57 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Haha will do, I actually just e-mailed you with regards to that. Thanks Erik I'll try that out when I get home and I'll let you know how it goes.
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Report this Post08-15-2013 10:19 PM Click Here to See the Profile for SqueakyClick Here to Email SqueakySend a Private Message to SqueakyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Erik:

You should run a 10 amp fuse on TBI INJ 1 and TBI INJ 2. I typically run the DIS off of the TBI INJ 1 and the injectors on TBI INJ 2 when I build a harness.


Plugged in 10 amp fuses into both injector slots in the fusebox and immediatly the TBI INJ 1 fuse blew. I'm wondering if I should maybe just drop the engine to get a better look, this is really quite disheartening. Getting back to the e-mail I sent you Erik, could you elaborate on some of my questions?

I still believe for the fuse to all of a sudden start blowing consistantly must mean that somewhere I have a short or its grounding out. With your expertise can you think of anywhere to check while I'm chasing wires?

I'm at a loss here boys


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Report this Post08-16-2013 02:45 AM Click Here to See the Profile for ErikClick Here to Email ErikSend a Private Message to ErikEdit/Delete MessageReply w/QuoteDirect Link to This Post
The fuse that's blowing most likely goes to your DIS. Disconnect the C203 connector . Take the multimeter and test for continuity at pin J on the C203 connector with the other probe at pin B ( pink/ black wire) of your 2 pin connector that plugs into the DIS/ICM. Make sure it's unplugged from the DIS. If that checks out then we know that the TBI INJ 1 powers the DIS. Then from that point touch a probe on pin J of the C203 and leave the two pin connector unplugged from the DIS and take the other probe and touch it to ground and check for continuity. If it does check out then it shorting somewhere along the wire. If not then somethings up with your ICM. After the fuse blows you could turn the ignition key switch to the on position and check to see if the DIS pin B is getting 12 V as well. If it is then it's running off another circuit. Several of the wiring harnesses that I have built power the DIS off of the C500 @ E3 pin. This test is to confirm that your DIS is running off of the TBI INJ 1 circuit that's blowing the fuse. Once we determine what TBI INJ 1 powers then we can move from there.
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