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3.4 engine swap/rebuild started twice and not again... by Blacksheep
Started on: 07-30-2012 11:35 PM
Replies: 13 (545 views)
Last post by: lou_dias on 03-25-2014 07:40 AM
Blacksheep
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Report this Post07-30-2012 11:35 PM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sorry this is kind of a double post, I kind of posted about this in my build thread as well but there may be some that don't pay much attention to those threads.

Anyways, I got the engine put together and wired up this last weekend, its a 3400 using the Fiero heads, intake, timing cover, alternator, ac compressor, and a 7730 ECM (reprogrammed by Darth Fiero), and DIS. After we got it put in the car Sunday we pulled the fuel pump fuse and my brother hooked up something he made to watch the spark and injector pulses on his laptop as it was trying to start, everything seemed to be working so we unhooked the thing he made plugged the injectors back in and put the fuse for the fuel pump back in and started it. Oil pressure went to about 60 on the gauge when it was cranking. (we may have forgot to put the cap over the thermostat back on.......)


I turned the car off then cause its idle went straight to 2500 rpm. We started it up a second time to see if the idle would go back down and let it run about twice as long before shutting it off, it still idled at 2500 rpm. After that we checked for things that were unpluged and it turns out we forgot to plug in vacuum line that goes to the break booster so that's probably why it was idling so fast. We also noticed the plug going to the throttle position sensor was broke but it was just the round plastic piece around one of the plugs, it was still making contact so we tried to start it again now that the break booster line was hooked up but it wouldn't start. So we unplugged the line, still wouldn't start so we plugged it back in. Switched the plastic part on the throttle position sensor plug to a newer non broke one, still wont start. We hooked the thing my brother made up again, same readings as we were got at the start. Pulled a spark plug and grounded it to the block as we tried to start it, it sparked. We removed the bolt I was using to plug the hole for the cold start injector and put a rag around below, there didn't seem to be much pressure behind it, and we tried to start it to see if it was pumping fuel thru there, it was. I put a jumper between pin A and B to check and see if there was any codes, the fan came on and the light just flashed 12. We decided to leave it there yesterday and get a fuel pressure tester today.
So today I went down there again with a fuel pressure tester and hooked it up to that valve right above where the fuel lines come into the rail, it was at 0psi when I hooked it up, turned the key on and the pump ran for the normal 2 sec or so and pressure went up to about 45 and seemed to stay there. Tried to start the car again, didn't start. Pulled the spark plugs out of the rear three cylinders and hooked up the compression tester, all three read just above 150, all three spark plugs looked the same as well. Fuel pressure dropped slightly as I tried to start it, but stayed above 40. Video of me trying to start it with the fuel pressure and compression tester gauges hooked up, what the gauge reads at the begining of the video (40-45) is where the pressure was at about 5-10min from the last time the pump ran.


Compression tester:


Spark Plug:



So any ideas on why it is not starting now? Only things I can think of atm are injectors not actually working correctly (fuel not getting into the engine correctly) or getting spark but at the wrong time now for some reason, both of which I guess are possible but seem kind of weird that it would start and run the first two times then all of a sudden no more. Any ideas on what to test next?

[This message has been edited by Blacksheep (edited 07-30-2012).]

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n7vrz
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Report this Post07-31-2012 02:16 AM Click Here to See the Profile for n7vrzClick Here to Email n7vrzSend a Private Message to n7vrzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Are you getting spark at the plugs?
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Blacksheep
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Report this Post07-31-2012 03:01 AM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by n7vrz:

Are you getting spark at the plugs?


I believe so, hooked a timing light up to each of the wires Sunday and it was flashing, pulled a couple of the rear plugs Sunday as well and watched them spark. I didn't try the ones I pulled again on Monday cause I was there by myself and that makes it kind of hard to turn the key and hold the plugs

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n7vrz
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Report this Post07-31-2012 03:07 AM Click Here to See the Profile for n7vrzClick Here to Email n7vrzSend a Private Message to n7vrzEdit/Delete MessageReply w/QuoteDirect Link to This Post
Rereading thru your post I see were you said you removed a bolt you were using to plug the cold start injector. Did you completely remove the cold start injector? Or have you reinstalled it?
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Blacksheep
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Report this Post07-31-2012 03:12 AM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
Its completely removed, there is a freeze plug blocking the hole where it was in the lower intake and a bolt with the old washer/gasket thing on it up on the fuel rail. I believe the cold start injector is not supposed to be needed with the 7730 ECM and that it is supposed to be removed.
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Blacksheep
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Report this Post07-31-2012 05:12 PM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
So, n7vrzs post asking about the cold start injector got me thinking, the 7730 doesn't need it because the ECM I believe fires the main injectors to add the extra fuel and to know if the engine is cold it would use the ECM temp sensor which is right below the coolant waterfall I created when I first started it without the cap on......

So I sprayed a tiny bit of starting fluid in the intake and it started but the ses light came on right away, code 15 (Coolant sensor - high voltage)

So does what I came up with make any sense or am I completely off? Either way I'm off to find another coolant sensor.
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sardonyx247
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Report this Post07-31-2012 08:43 PM Click Here to See the Profile for sardonyx247Click Here to visit sardonyx247's HomePageClick Here to Email sardonyx247Send a Private Message to sardonyx247Edit/Delete MessageReply w/QuoteDirect Link to This Post
A bad temp sensor would deff casuse it to not start. Check the wireing and plug for the temp sensor.
BTW the cold start injector only worked when it is REALLY cold out. and no not needed for the 7730.
Also keep in mind sometimes it won't want to idle right untill you drive it above 24mph to reset the IAC so the ECM knows where it is.


edit to add, use a timing light to see where you are, I see you had DIS added and not everyone knows how to program it right.

------------------
"DRIVE IT LIKE A FIERO"
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'87Blue GT 3.4L Swap Completed!!!!!!!! Boosted!!!!!!!
^^^^ Now in the Construction Zone^^^^
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[This message has been edited by sardonyx247 (edited 07-31-2012).]

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Blacksheep
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Report this Post07-31-2012 08:46 PM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
Changed the temp sensor and reset the ecm, code 15 went away but it still won't start unless I give it a bit of starting fluid. Once it starts it seems to keep running, idle is about 1200, but after a few sec ses light comes on and I get a code 21 now (tps - high voltage). I don't have a new tps sensor sitting around to try tho. Would the tps cause it to not want to start but let it idle? Are the codes the 7730 gives even the same?
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Blacksheep
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Report this Post07-31-2012 09:33 PM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
New video, this one is it starting and idling (about 1500 rpm) after adding a cap full of gas to the intake.
I think the whining is the alternator.
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Blacksheep
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Report this Post07-31-2012 10:02 PM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
Also pulled one of the spark plugs again, it was pretty black this time (soot, not oil)


So, bad tps? From the sound of things I was reading about the tps it sounded like it shouldn't even be running at all if its shot, but maybe with the 7730 its a bit different? Or I was just reading the stuff about the tps wrong.

Timing off causing this? I don't have q good timing light here, my brother took his stuff with him, I could borrow one tomorrow, but the timing plate with the marks on it is gone, it was broke so with the DIS I didn't think I needed it so I left it off.......
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phonedawgz
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Report this Post08-01-2012 12:23 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
Unplug your TPS and see if it will start.

If your TPS is wired wrong, or is defective such that the ECM thinks the throttle is at WOT, the ECM will not pulse the injectors. This is the 'flood clear mode'.

Since plugging in your TPS was something that happened just before the engine stopped starting, try unplugging it and see what happens.

-----------
This also makes it look like the ECM is seeing the TPS at WOT.


 
quote
Originally posted by Blacksheep:

Changed the temp sensor and reset the ecm, code 15 went away but it still won't start unless I give it a bit of starting fluid. Once it starts it seems to keep running, idle is about 1200, but after a few sec ses light comes on and I get a code 21 now (tps - high voltage). I don't have a new tps sensor sitting around to try tho. Would the tps cause it to not want to start but let it idle? Are the codes the 7730 gives even the same?


Any chance either the tang is not engaging the throttle correctly? Having the black and gray wires reversed on the TPS connector, or it's wiring could also do it.

[This message has been edited by phonedawgz (edited 08-01-2012).]

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Blacksheep
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Report this Post08-01-2012 02:53 AM Click Here to See the Profile for BlacksheepClick Here to Email BlacksheepSend a Private Message to BlacksheepEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by phonedawgz:

Unplug your TPS and see if it will start.



So I went to go see if this would work, I had unplugged my ECM earlier to take it back home with me so I could pull the cover off and look at the chip inside to make sure nothing was melted for some reason (not sure why I didn't just check it at the shop), so I plugged the ECM back in, plugged the positive battery cable back in, unplugged the TPS and tried to start it. It started right away. So I thought great, Ill plug it back in and take another video of it not starting when its plugged in, but starting once its unplugged.... It didn't quite happen that way:


After I reset the ECM again, because running it with that unplugged set the SES light (as expected), I started it a few more times and added a bit of water/antifreeze to work a bit of air out of the system, it started fine each time and no error codes anymore.
I had unplugged and plugged the TPS sensor a few times when it was giving me errors so I don't think that is what did it (although I never did try to start the car with the TPS unplugged). I had checked the plugs going into the ECM before, none of them had come loose. I've also been removing the positive battery cable each night when I was done. Only other thing that was different was when I brought the ECM home I pulled the chip/prom/whatever its called out to get a better look at it and then put it back in, maybe somehow it had worked its way loose a little bit or had some dust on it? I don't really know.

Anyway, in case anyone is interested this is how the wires in my TPS are



------------------------------------------
Also, oil pressure seemed a bit high but after doing a search for "high oil pressure" on the forums it seems its pretty normal, I imagine it will go down a bit once I let the engine get warmed up and it gets broke in. I'm using normal (not synthetic) 5w30 with some break-in oil additive.
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Report this Post03-11-2013 01:04 PM Click Here to See the Profile for meego123Click Here to Email meego123Send a Private Message to meego123Edit/Delete MessageReply w/QuoteDirect Link to This Post
Very interesting thread. Found it very informative. So am curious to know if you got everything buttoned up and how the car is running now? And also how it compares now to when it had the 2.8?

Did you check further into the sooty spark plug or if it was running rich?

Also someone made the comment either in your engine swap thread or the original thread "3400, why top swap??" that brought me to your threads (I looked back but couldnt find it) about only two of the three holes in the bracket that bolts to the head lining up with the 2.8 head. They said you would have to drill the head for the third bolt or just use two. Did you run into this problem with your swap?


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[This message has been edited by meego123 (edited 03-11-2013).]

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lou_dias
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Report this Post03-25-2014 07:40 AM Click Here to See the Profile for lou_diasClick Here to Email lou_diasSend a Private Message to lou_diasEdit/Delete MessageReply w/QuoteDirect Link to This Post
sometimes you may have to reverse the wires on the tps...it may think you are at WOT and not enable the IAC to let the motor idle...
hooking up a scan tool such as a laptop with an ALDL cable and TunerPro RT will tell you this...

[This message has been edited by lou_dias (edited 03-25-2014).]

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