injectors not firing
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From: Texas
injectors not firing
I think something is wrong with the search function here. I tried to search, but it just basically brought me to the discussion area, so I will post my problem here.
On my '83, it will start and run as long as i manually provide fuel. The injectors are not firing. I have tested the 2 L-jet computers in another car and they function fine. I have the fuel pump jumpered to remove that potential problem from the equation. I have swapped the relay and that seems to make no difference. I have power at the injector, but not 12 volts. I only have like 7.6 volts or something like that at the injectors.
I can turn the key and the car will start for a coupla seconds from , I guess, the cold start injector, but it will not stay running.
I thought that there might be a connection problem at the Central fuse panel so I cleaned the harness connection for the injectors.
Any thoughts or ideas?
On my '83, it will start and run as long as i manually provide fuel. The injectors are not firing. I have tested the 2 L-jet computers in another car and they function fine. I have the fuel pump jumpered to remove that potential problem from the equation. I have swapped the relay and that seems to make no difference. I have power at the injector, but not 12 volts. I only have like 7.6 volts or something like that at the injectors.
I can turn the key and the car will start for a coupla seconds from , I guess, the cold start injector, but it will not stay running.
I thought that there might be a connection problem at the Central fuse panel so I cleaned the harness connection for the injectors.
Any thoughts or ideas?
Rest in Peace
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From: Concord, CA
Been there! done that and it is mated to the fuel pump triggers iirc.
Will get my thread and post in a second.
https://rennlist.com/forums/928-foru...test-pass.html
Will get my thread and post in a second.
https://rennlist.com/forums/928-foru...test-pass.html
Rest in Peace
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From: Concord, CA
Bill,
After pulling all the bosch injector connectors, and replacing the cold start connector (this was almost the reason) , cleaning the contacts, then realizing the later ... both the injector relay and fuel pump relays were being fussy.
The combo of the relays not working together appeared to have caused the injectors to not fire regardless of pressure of near 50PSI.
Flooding the spider with ether cause the plugs to get stinking wet and maybe the alcohol absorbed water (?) ... so after testing the DME again, replacing the two relays ... buying a NEW DME (still in box, was threat to old DME) it fired up weak.
Then I had to correct the reversed wires on the cold start.
Carefully clean the MAF's NOX screw ... remove/wipe down and purge all the black junk in the side air pass and finally make a 15" stoli tool to re-tune the MAF.
Does it sound like I know what I am doing
She runs now and strong with good mileage.
After pulling all the bosch injector connectors, and replacing the cold start connector (this was almost the reason) , cleaning the contacts, then realizing the later ... both the injector relay and fuel pump relays were being fussy.
The combo of the relays not working together appeared to have caused the injectors to not fire regardless of pressure of near 50PSI.
Flooding the spider with ether cause the plugs to get stinking wet and maybe the alcohol absorbed water (?) ... so after testing the DME again, replacing the two relays ... buying a NEW DME (still in box, was threat to old DME) it fired up weak.
Then I had to correct the reversed wires on the cold start.
Carefully clean the MAF's NOX screw ... remove/wipe down and purge all the black junk in the side air pass and finally make a 15" stoli tool to re-tune the MAF.
Does it sound like I know what I am doing
She runs now and strong with good mileage.
Thread Starter
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Joined: Mar 2002
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From: Texas
So Andre,
You are saying that it was a combination of relays that kept your injectors from firing? I replaced the one relay. And the fuel pump is jumpered.
I read your previous thread on this and honestly, I'm still in the dark.
I am pretty sure that my problem stems from the lack of acceptable voltage, but I'm not sure why there is not acceptable voltage. Could a bad ground cause this? I am definitely not an electronics nor electrical guru.
You are saying that it was a combination of relays that kept your injectors from firing? I replaced the one relay. And the fuel pump is jumpered.
I read your previous thread on this and honestly, I'm still in the dark.
I am pretty sure that my problem stems from the lack of acceptable voltage, but I'm not sure why there is not acceptable voltage. Could a bad ground cause this? I am definitely not an electronics nor electrical guru.
Rest in Peace
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From: Concord, CA
I did the jump on the FP and still no start.
There is a fuel injector relay too and they appear to work in concert, and I am not sure why but it makes sense to not fire dry injectors.
I also reset all the grounds (brown) wires too.
There is a fuel injector relay too and they appear to work in concert, and I am not sure why but it makes sense to not fire dry injectors.
I also reset all the grounds (brown) wires too.
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Thread Starter
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From: Texas
Not yet, but I will do that after I get back home. I am trying to get ideas to work on while I am without anything to do on any of the other cars and away from the situation. Not likely that I got a bad relay from the box, but anything is possible
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From: Johnson City, TN
You never know. I got a bad headlight relay from the box last year.
The other thing to consider is the alarm system. It supposedly disables the fuel pump on the 84 US. And, I think it also interupts power to the injectors for US cars, utilizing somehow the alarm relay that is fitted only to US 84 cars with alarms. It does this in a diffferent way than on the ROW 84 cars, which have a different ignition system and apparently don't have an alarm relay. If you want to read further, try the Electrical Training document on the CD's, about 2/3 through the document. There also a couple ways to jumper the alarm at the Z plug, depending on whether you remove the actual alarm box deep behind the glove box (as I did), or if you temporarily jumper it. WSM has some information on the temp jumper. Alan helped me with Alarm disabling a while back, but search is down.
The alarm box is full of 80's style circuits, so it is not inconceivable that a problem with that box is resulting in an atypical failure. Happened to me, but my car must have been struck by lightening or something, as f-d up as it was. Of course, everyone will now chime-in to stick with the basics, and I agree. But keep the alarm stuff in the back of your mind, John.
The other thing to consider is the alarm system. It supposedly disables the fuel pump on the 84 US. And, I think it also interupts power to the injectors for US cars, utilizing somehow the alarm relay that is fitted only to US 84 cars with alarms. It does this in a diffferent way than on the ROW 84 cars, which have a different ignition system and apparently don't have an alarm relay. If you want to read further, try the Electrical Training document on the CD's, about 2/3 through the document. There also a couple ways to jumper the alarm at the Z plug, depending on whether you remove the actual alarm box deep behind the glove box (as I did), or if you temporarily jumper it. WSM has some information on the temp jumper. Alan helped me with Alarm disabling a while back, but search is down.
The alarm box is full of 80's style circuits, so it is not inconceivable that a problem with that box is resulting in an atypical failure. Happened to me, but my car must have been struck by lightening or something, as f-d up as it was. Of course, everyone will now chime-in to stick with the basics, and I agree. But keep the alarm stuff in the back of your mind, John.
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From: Rep of Texas, N NM, Rockies, SoCal
I looked at this problem briefly a few months ago. It does have power to the injector plugs but it's very low. It should be a solid 12V and he's only getting a bit over 8. If there is an alarm system that stops the fuel flow, I would think it would disable the circuit altogether. If there is a way to remove the alarm circuit from the car without disabling the car, that would be the best thing to do.
I'm out of town and don't have the prints handy but I recall a sheet with the 'immobilizer' on it. Still, having only 8V at the pins of the injector sounds like a large resistive drain somwhere in the harness.
When I get back to town, I'll go over and have another look, and we'll get the CIS car going too.
I'm out of town and don't have the prints handy but I recall a sheet with the 'immobilizer' on it. Still, having only 8V at the pins of the injector sounds like a large resistive drain somwhere in the harness.
When I get back to town, I'll go over and have another look, and we'll get the CIS car going too.
Thread Starter
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Joined: Mar 2002
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From: Texas
Doc, I'm out of town right now also. You come over and get both cars running . I WILL supply the beer. Name your brand.
Namasgt- the fitting worked like a champ. I now got to find the correct fitting to match up to THAT fitting.
Namasgt- the fitting worked like a champ. I now got to find the correct fitting to match up to THAT fitting.
Thread Starter
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Joined: Mar 2002
Posts: 6,121
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From: Texas
Dr. Bob,
I clenaed the connection at the battery ( the smaller wire that doesn't go to the starter) and that was it!!
I now got 12 volts at the injectors (12.8 actually) Namsgts was there with me and the car started but ran like doo doo. I pulled the injectors and will clean them and back flush them. Reseat and give it a go. Thanks loads for the heads up on that solution!!
Doc Mirror. Still fighting the CIS. Beer is calling you.
I clenaed the connection at the battery ( the smaller wire that doesn't go to the starter) and that was it!!
I now got 12 volts at the injectors (12.8 actually) Namsgts was there with me and the car started but ran like doo doo. I pulled the injectors and will clean them and back flush them. Reseat and give it a go. Thanks loads for the heads up on that solution!!
Doc Mirror. Still fighting the CIS. Beer is calling you.
