Looking for some advanced troubleshooting help...
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Looking for some advanced troubleshooting help... Ok, i have a 1972 International Scout 2. I decided about 4 years back to put a 2002 5.3l Vortec out of a Silverado into my truck, long story short, its finally all in. The computer has been reprogrammed, the anti theft software deleted. However it will not start.
It is a fuel side issue, for when we spray starting fluid directly into the engine, it will start. The fuel pump is working as intended, 60 psi, and we have pressure at the rails. It appears to be in the injectors...The injectors are not squirting fuel into the engine. Test light shows that the injectors are not getting hot. The fuse that the power is running out of however, is hot. Could the computer not have a wire hooked up correctly and it just not communicating to the injectors to fire?
Any thoughts would be much appreciated.
Joel
It is a fuel side issue, for when we spray starting fluid directly into the engine, it will start. The fuel pump is working as intended, 60 psi, and we have pressure at the rails. It appears to be in the injectors...The injectors are not squirting fuel into the engine. Test light shows that the injectors are not getting hot. The fuse that the power is running out of however, is hot. Could the computer not have a wire hooked up correctly and it just not communicating to the injectors to fire?
Any thoughts would be much appreciated.
Joel
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They dont have power at any time.
We pulled one off to check and see if it was working properly, and the test light actually completed the circuit.
The pink wire seems to be the issue. circuits 1039 and 1239 are providing power for the 2 banks of injectors. Tracing that back,those flow into the large black fuse box connector. I am not running the stock fuse box (sadly, if i would have known, i would have just gotten 1). Those wires (the pink from each injector) need to be hooked to seperate heat? (1239 and 1039) We have tried to run it with those circuits hot, but it didnt seem to change it at all.
We pulled one off to check and see if it was working properly, and the test light actually completed the circuit.
The pink wire seems to be the issue. circuits 1039 and 1239 are providing power for the 2 banks of injectors. Tracing that back,those flow into the large black fuse box connector. I am not running the stock fuse box (sadly, if i would have known, i would have just gotten 1). Those wires (the pink from each injector) need to be hooked to seperate heat? (1239 and 1039) We have tried to run it with those circuits hot, but it didnt seem to change it at all.
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more information... Ok, we've now discovered that the injectors are hot with the key on and during crank. So that indicates that the problem is in communication from the computer to tell the injectors to fire...
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Joined: Jul 2005
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From: Beebe, Arkansas
Joel, man I bet its the ground! I didn't ask if you have good grounds. When you asked on BB
Your test light will show 12v if its hooked to a good ground at the injector. But if the motors not grounded good then you won't get the 12v at the injectors while cranking hence no fuel.
Your test light will show 12v if its hooked to a good ground at the injector. But if the motors not grounded good then you won't get the 12v at the injectors while cranking hence no fuel.
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First of all, thanks for the responses, this is quite frustrating, Ive talked to Bo185 about it alot.
I pulled all the injectors last night, they looked pretty ugly, looked like we had some rust build up. We put them in cleaning fluid over night. No change this morning when we reinstalled them.
Grounds seem to be coming up alot. If the test light is showing power to the injectors with the key on, wouldnt that indicate the grounds are good? Guess im confused on that part. The block is grounded, and the block is grounded to the body, when we test for all of these, it lights up.
always appreciate the thoughts.
Joel
I pulled all the injectors last night, they looked pretty ugly, looked like we had some rust build up. We put them in cleaning fluid over night. No change this morning when we reinstalled them.
Grounds seem to be coming up alot. If the test light is showing power to the injectors with the key on, wouldnt that indicate the grounds are good? Guess im confused on that part. The block is grounded, and the block is grounded to the body, when we test for all of these, it lights up.
always appreciate the thoughts.
Joel
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I had a hopefully brilliant thought finally.
When i bought the engine, the battery ground wire was not there. I installed a generic one from the store. It is a single wire from the battery to the alternator bolt labeled 'ground'. Last year, i was tearing apart a silverado for some other random electrical connectors, and i happened upon the battery cable, i figured i'd grab it.
Now, all this talk bout grounding issues made me search for it and pull it out. It has 2 wires... I assume the first goes to the alternator bolt, same hook up I am currently running. However, where does the other go? Im looking for schematics on alldata right now, but i figured that this additional info might help.
Joel
When i bought the engine, the battery ground wire was not there. I installed a generic one from the store. It is a single wire from the battery to the alternator bolt labeled 'ground'. Last year, i was tearing apart a silverado for some other random electrical connectors, and i happened upon the battery cable, i figured i'd grab it.
Now, all this talk bout grounding issues made me search for it and pull it out. It has 2 wires... I assume the first goes to the alternator bolt, same hook up I am currently running. However, where does the other go? Im looking for schematics on alldata right now, but i figured that this additional info might help.
Joel
They are referring to the harness grounds that should be on the back of the cylinder heads. There should be grounding lugs in the harness that stick out somewhere arund where the harness meets the back of the block
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I currently do not have the odb II set up, so I cant check for codes atm.
Grounds, I did not do anything to the grounds that the engine came with. I assumed the wires were left all intact. The only ground wire that I am unsure of where it goes / not bolted on atm is the 2nd wire coming off the battery. All data didnt provide me with the location of where it is supposed to bolt to so I am unaware of where to put it. However, the cylinder heads / block / body / frame all show ground.
The only wire im now worried bout is the 1020 circuit pink, 75 into the pcm, labeled as 'off/run/crank voltage' That wire currently is running to nowhere on my truck as a result of one of my computer schematics saying 75 was 'unused', however, that was from a different year 5.3. Im currently tracing out where it goes and if thats my problem.
Joel
Grounds, I did not do anything to the grounds that the engine came with. I assumed the wires were left all intact. The only ground wire that I am unsure of where it goes / not bolted on atm is the 2nd wire coming off the battery. All data didnt provide me with the location of where it is supposed to bolt to so I am unaware of where to put it. However, the cylinder heads / block / body / frame all show ground.
The only wire im now worried bout is the 1020 circuit pink, 75 into the pcm, labeled as 'off/run/crank voltage' That wire currently is running to nowhere on my truck as a result of one of my computer schematics saying 75 was 'unused', however, that was from a different year 5.3. Im currently tracing out where it goes and if thats my problem.
Joel
Last edited by dinic; Dec 28, 2008 at 07:44 PM. Reason: mistype
I've seen a lot of motors with stuck injectors. You said you soaked you're injectors, but not sure if that would clean them up.
Try putting 12v+ and ground directly to each injector and listen that the injector 'clicks'. Do this to all 8 injectors. I built a device that will pulse the injectors rapidly, and I found that tapping on each injector with end of plastic screw driver will eventually free them up. I have had this problem on many 5.3l's and a lot of LT1's I have helped with. Sometimes 5-10 minutes per injector to get them unstuck, but so far all have cleaned up and worked fine.
I put a new 2.2L in a cavalier, junkyard motor, sat for a few years, It ran for 30 minutes on 2 cylinders until the 3rd injector unstuck, and another 15 minutes and all 4 were firing then. So it may take some time.
Try putting 12v+ and ground directly to each injector and listen that the injector 'clicks'. Do this to all 8 injectors. I built a device that will pulse the injectors rapidly, and I found that tapping on each injector with end of plastic screw driver will eventually free them up. I have had this problem on many 5.3l's and a lot of LT1's I have helped with. Sometimes 5-10 minutes per injector to get them unstuck, but so far all have cleaned up and worked fine.
I put a new 2.2L in a cavalier, junkyard motor, sat for a few years, It ran for 30 minutes on 2 cylinders until the 3rd injector unstuck, and another 15 minutes and all 4 were firing then. So it may take some time.
I currently do not have the odb II set up, so I cant check for codes atm.
Grounds, I did not do anything to the grounds that the engine came with. I assumed the wires were left all intact. The only ground wire that I am unsure of where it goes / not bolted on atm is the 2nd wire coming off the battery. All data didnt provide me with the location of where it is supposed to bolt to so I am unaware of where to put it. However, the cylinder heads / block / body / frame all show ground.
The only wire im now worried bout is the 1020 circuit pink, 75 into the pcm, labeled as 'off/run/crank voltage' That wire currently is running to nowhere on my truck as a result of one of my computer schematics saying 75 was 'unused', however, that was from a different year 5.3. Im currently tracing out where it goes and if thats my problem.
Joel
Grounds, I did not do anything to the grounds that the engine came with. I assumed the wires were left all intact. The only ground wire that I am unsure of where it goes / not bolted on atm is the 2nd wire coming off the battery. All data didnt provide me with the location of where it is supposed to bolt to so I am unaware of where to put it. However, the cylinder heads / block / body / frame all show ground.
The only wire im now worried bout is the 1020 circuit pink, 75 into the pcm, labeled as 'off/run/crank voltage' That wire currently is running to nowhere on my truck as a result of one of my computer schematics saying 75 was 'unused', however, that was from a different year 5.3. Im currently tracing out where it goes and if thats my problem.
Joel
Circuit 1020 feeds the Transmission Solenoids and PCM. The fuse was located in the underdash fuseblock in the 99+ pickups. In original wiring harness, this wire runs from C100 Pin C to Underhood Fuseblock C2 - E2. Inside the fuse block, it turns around and comes back out on C2 - F2. F2 then runs to the PCM and Transmission.
I usualy try to stick to the kiss method as much as possible. It sounds to me like something overlooked in the wiring. Good luck man with it man! If it turns out to be injectors and your using the same rails/injectors as a 6.0 I have some injectors in the garage from my pull out with about 30k miles on them. You can have them for free just cover some shipping and handling! 
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From: Phoenix, AZ
it sounds like youre overlooking something simple.
the ecu controls the GROUND SIDE for injectors NOT the power. so make SURE the pink feed wires have bat voltage with key on. and DOUBLE AND TRIPLE check your grounds on the harness (where it should go to the head. i went directly to the chassis because i didnt trust aluminum to ground anything haha)
i had a similar problem when i first cranked mine and i wasnt giving the proper wires power
also, just because your test light works doesnt mean you have everything grounded properly.
the ecu controls the GROUND SIDE for injectors NOT the power. so make SURE the pink feed wires have bat voltage with key on. and DOUBLE AND TRIPLE check your grounds on the harness (where it should go to the head. i went directly to the chassis because i didnt trust aluminum to ground anything haha)
i had a similar problem when i first cranked mine and i wasnt giving the proper wires power
also, just because your test light works doesnt mean you have everything grounded properly.
