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84 No injector fire - Got spark by Slammed
Started on: 05-01-2015 06:24 PM
Replies: 19 (352 views)
Last post by: Slammed on 05-10-2015 06:31 PM
Slammed
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Report this Post05-01-2015 06:24 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
Still pulling my hair out

I have power to all necessary ECM pins and good grounds. If I tap the signal wire from the distributor, the ECM will run the fuel pump but will not fire the injector or blink a noid light. I am only getting 1v across the INJ terminals when cranking. 9V on the red wire while cranking, which is plenty. Same voltage on blue during crank, because it isn't grounding. Checked on an '86 that runs, 9v during crank works fine. It's like the ECM can't supply enough ground to the INJ but it has good grounds

3 different ECMs. New injector. New module. It has strong spark and puts out a reference signal.

While cranking, I get no RPM data from WinALDL. So, I can manipulate the dizzy reference and get it to cycle the pump like it sees RPM, but it shows no RPM and won't pulse the injector. This ECM was pulled from a running '85 S-10.

[This message has been edited by Slammed (edited 05-10-2015).]

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Slammed
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Report this Post05-01-2015 07:33 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ok, so I pulled the purple/white reference from the dizzy harness and tapped it to 12v. The ECM will command the fuel pump to run but no injector fire. So whatever is going on, cooked two ECMs injector circuit?

[This message has been edited by Slammed (edited 05-01-2015).]

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Gall757
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Report this Post05-01-2015 08:13 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
How do you pop the injector fuse? Bent pins in a connector? Bare wire hitting the frame? Something like that is going on.
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Slammed
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Report this Post05-01-2015 08:30 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
The ECM and INJ share the same fuse. It is no longer popping after unplugging all the connectors and replacing, which would make me think it's completely fried a wire somewhere. But, the ECM has good voltage and grounds at all the right pins. What would cross that would cut the injector driver? TPS voltage too high does fuel cutout right? Winaldl shows good base on all sensors
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phonedawgz
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Report this Post05-01-2015 08:40 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 ECM grounds the blue wire to fire the injector. Because of the resistance of the injector, when the ECM is not firing the injector, you will read 12v on both sides of the injector. I know it sounds confusing.

Think of it this way. If instead the ECM instead supplied +12v to the injector, when the ECM wasn't firing the injector you would expect to read 0V on both sides of the injector right? So basically the same thing but reversed.

Does WinALDL show RPMs during cranking? If so yes you most likely have two bad ECMs. Sounds like your injector is shorted. That or the wiring to the injector is shorted. That short caused too much current to flow and blew the injector fuse. You replaced the injector fuse but the ECM is still bad. That's my guess.

Junk yards around here sell 80s ECMs for $20 if you pull them yourself. Not sure what other cars use the 84 ECM. In the Fiero the 84 ECM does not swap with any of the other ECMs.
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Slammed
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Report this Post05-01-2015 08:41 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
Boyfriend just got home and told me there was smoke coming from the dash vents this morning on start up. I thought it smelled funny...

I'll go out and check for rpms on Winaldl. As far as no other ECMs working, I've interchanged 84-86 card type connector ECMs in the past

Any idea what the injector driver looks like on the board? I'm having a heck of a time tracing it back

[This message has been edited by Slammed (edited 05-01-2015).]

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Gall757
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Report this Post05-01-2015 09:43 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
turn off the heater fan.

http://www.fiero.nl/forum/Forum2/HTML/123929.html

[This message has been edited by Gall757 (edited 05-01-2015).]

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Slammed
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Report this Post05-01-2015 09:47 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
So this is the third ECM

When I first got the car, it already had a cooked capacitor on the IAC. Everything else worked, but the big red cap was burnt badly and the IAC did not function

Second one goes in and it's been totally fine til last night. Third one was from a running car that I had on the shelf. I have RPM on Winaldl

Fan is/was off both times it died. It also works fine. Looking at the diagram for the A/C I can't see where it would cause this type of failure

[This message has been edited by Slammed (edited 05-01-2015).]

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David Hambleton
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Report this Post05-01-2015 10:31 PM Click Here to See the Profile for David HambletonClick Here to Email David HambletonSend a Private Message to David HambletonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by phonedawgz:

In the Fiero the 84 ECM does not swap with any of the other ECMs.


Three weeks ago, I replaced the original ECM in my '84 with the surplus ECM from my '86.
Except for telling me to upshift into 5th gear, it's working great.

http://www.fiero.nl/forum/Forum2/HTML/135078.html

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Slammed
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Report this Post05-01-2015 11:37 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
I now have no data So, either my cable quit or it kicked the bucket

SES will still come on and it'll flash codes. Only one stored is 34
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phonedawgz
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Report this Post05-02-2015 07:40 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
Clear the crap out of your heater box before your Fiero burns like this one.



http://www.fiero.nl/forum/Forum2/HTML/123929.html

 
quote
Originally posted by Slammed:

Boyfriend just got home and told me there was smoke coming from the dash vents this morning on start up. I thought it smelled funny...

I'll go out and check for rpms on Winaldl. As far as no other ECMs working, I've interchanged 84-86 card type connector ECMs in the past

Any idea what the injector driver looks like on the board? I'm having a heck of a time tracing it back



The large cap is a varistor. It is used for over voltage protection. If you have lost it on more than one ECM, you have a problem with the charging system. What is the voltage output of the alternator?

http://www.fiero.nl/forum/Forum2/HTML/129284.html

[This message has been edited by phonedawgz (edited 05-02-2015).]

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Report this Post05-02-2015 09:48 PM Click Here to See the Profile for commerceSend a Private Message to commerceEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes, I had an overcharging alternator cook the battery and the ecm.
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Slammed
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Report this Post05-03-2015 02:54 AM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
The last ecm died before it even started. Voltage has been right below 15 with no dimming or the like. I cleared out the front today

I've had about a dozen Fieros and this is the first I'm hearing of this problem! Dangerous
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phonedawgz
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Report this Post05-03-2015 09:06 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
There is also a possibility of a high A/C component on top of your DC. I know it sounds like I am making it up but it is real. To test - put your meter on AC and read across the battery terminal with the engine running.

A weak battery can exacerbate the AC output of an alterntor problem.

[This message has been edited by phonedawgz (edited 05-03-2015).]

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Slammed
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Report this Post05-08-2015 12:49 AM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
Cleaned up all the grounds, checked all the fusible links, new ECU and still no injector fire. I am getting data again though

Voltage on the red injector wire is dropping down to 8.5v on crank. If I hook up the meter for voltage across the red and blue, I'm not even getting 2 volts. So I've got a major grounding/voltage issue. I just can't figure out where

If I tap ground to the blue wire, it'll pop the fuse

[This message has been edited by Slammed (edited 05-08-2015).]

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phonedawgz
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Report this Post05-08-2015 03:53 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
Charge your battery
Replace your injector
Rep;ace your ECM
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Slammed
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Report this Post05-08-2015 05:02 AM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
I just pulled the battery out of the tester and it's good. ECU and Injector are both new.

The voltage on crank I mentioned above is with the injector disconnected.

Thank you for the help btw. I appreciate it

[This message has been edited by Slammed (edited 05-08-2015).]

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Slammed
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Report this Post05-10-2015 04:45 AM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
Still pulling my hair out

I have power to all necessary ECM pins and good grounds. If I tap the signal wire from the distributor, the ECM will run the fuel pump but will not fire the injector or blink a noid light. I am only getting 1v across the INJ terminals when cranking. 9V on the red wire while cranking, which is plenty. Same voltage on blue during crank, because it isn't grounding. Checked on an '86 that runs, 9v during crank works fine. It's like the ECM can't supply enough ground to the INJ but it has good grounds

3 different ECMs. New injector. New module. It has strong spark and puts out a reference signal.

While cranking, I get no RPM data from WinALDL. So, I can manipulate the dizzy reference and get it to cycle the pump like it sees RPM, but it shows no RPM and won't pulse the injector. This ECM was pulled from a running '85 S-10.

[This message has been edited by Slammed (edited 05-10-2015).]

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Gall757
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Report this Post05-10-2015 12:34 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
I hate blaming everything on the ICM, but it fails in so many odd ways. Recently I read an account of the spark being good, but one bank of injectors on a V6 not firing.....and it was fixed by replacing the ICM...

And don't forget....New parts are not necessarily good parts.
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Slammed
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Report this Post05-10-2015 06:31 PM Click Here to See the Profile for SlammedClick Here to Email SlammedSend a Private Message to SlammedEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you tap the purple white wire, the injector should spray even with the ICM disconnected. It takes it out of the equation
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