Ground Problems!

[bpatch85]

Background:
5.3L out of 2001 2wd Chevy Avalanche w/ 4L60e has been installed into an '82 CJ7 trail jeep.

Novak Adaptors programmed the PCM and modified the harness as well as supplied all hardware to mount and adapt the engine and trans into the CJ7.

All connections are made(I believe) on the harness to there appropriate locations except for the O2 sensors. No exhaust only headers.

I confirmed the injectors are getting power w/ a NOID tester and spark from the coils.

The PROBLEM that I need help w/ is that I suspect I am missing a ground somewhere. Reason being when I turn the ignition to the ON position the fuel pump does not turn on. I turn the key to start and the motor turns over but the pump never turns on and obviously doesn't fire.

However, when I connected an OBDII reader, that gets it's power by connecting directly to the battery, the pump kicks on and the engine fires and run as it should.

So with discovering this I remove the OBDII reader and back to no fuel pump running. This time I take a wire and go from the ground pin on the OBDII plug and ground it to the chassis. Once I do the the fuel pump kicks on for 2-3seconds in the "ON" positions, then start the motor and the engine fires and runs as it should. While the engine is running I remove the temporary ground and it dies.

Sorry if this is long winded but trying to give an idea of what I have going on.

So, where am I missing a ground? My head is spinning after going back to all the grounds I have installed and assuring they all are clean and have a good connection along w/ reading Brendan's website and all of the google searching.

Your help is appreciated.

Ben

[JMac11]

First of all- You are not crazy.

I had a similar issue, mounted PCM in glovebox, while i was finishing up on my Check Engine Light I kept hearing an electrical arc, the light would go on and off. I ran a jumper ground to the PCM case and solved that issue. I am not sure, but I have read that if the PCM has had a short in its life, that this is a symptom. I need mine reprogrammed and but I am running, just not great.

[BR3W CITY]

There is an internal case ground for the PCM. You can tell if its the culprit by simply grounding the ECM case right to metal and seeing if anything changes.

When your OBDII scanner is plugged in, are all your scans reading correctly?

[bpatch85]

Posted via Mobile Device

[bpatch85]

I checked the PCM case with an ohm meter and it appeared to be grounded. I had also tried grounding the PCM case with a wire to the chassis with no luck just to try. (Actually this had been done a few days ago with the same thought that the PCM case needs a ground)

I contacted Novak and they stated a couple things.

First, check and/or bypass the park neutral safety switch. He stated that if this switch was bad then it would not allow the motor to run. I'm not certain how these work in that I don't know what it disables to prevent startup in gear.

The other is that he asked if my CEL was wired. I didn't realize it at the time that it had been wired for the use of one by Novak. Once I did locate the 2 wires and mentioned that they were unhooked Novak stated that this also needed to be wired and that it is possible this could be a culprit. 🤔

I'm going to research the PNS switch and see what I need to do with it and I'll pick up a light tonise for the CEL.

When the OBDII was hooked up we only found one code. That was MIL code.

Any other thoughts or ideas on what to do next?
Posted via Mobile Device

[ls1nova71]

No offence, but a lot of what this Novak place is telling you seems to be just run around so they don't have to admit messing up the harness. You DO NOT need a check engine light for the engine to run, my car has been running for going on 17 years without it. Also, the neutral safety switch just keeps the starter from working, not the engine from running, meaning, if the ignition is on, and you put power to the starter, it will start no mater what gear position its in. It really sounds to me like they missed a ground wire in the harness somewhere. That being said, the only way you're going to find it would be to pull the harness covering off and go through it, there's no way that can be done over the internet. But, since you know that adding the ground to the ALDL makes it run, the easiest thing to do would be to splice a ground from the ground coming out the back of the ALDL connector and put it to a good ground location, preferably on the back of the head with the other grounds. A lot of the grounds in the LS harness are tied together, so essentially you would be just adding another ground spot to a circuit that currently isn't grounded.

[bpatch85]

Originally Posted by ls1nova71

No offence, but a lot of what this Novak place is telling you seems to be just run around so they don't have to admit messing up the harness. You DO NOT need a check engine light for the engine to run, my car has been running for going on 17 years without it. Also, the neutral safety switch just keeps the starter from working, not the engine from running, meaning, if the ignition is on, and you put power to the starter, it will start no mater what gear position its in. It really sounds to me like they missed a ground wire in the harness somewhere. That being said, the only way you're going to find it would be to pull the harness covering off and go through it, there's no way that can be done over the internet. But, since you know that adding the ground to the ALDL makes it run, the easiest thing to do would be to splice a ground from the ground coming out the back of the ALDL connector and put it to a good ground location, preferably on the back of the head with the other grounds. A lot of the grounds in the LS harness are tied together, so essentially you would be just adding another ground spot to a circuit that currently isn't grounded.

Novak stated that I need to jumper the relay for the PNS. I'm illiterate when it comes to figuring out this wiring but Im not sure that is correct.

I had my hesitations about the CEL as well. I can't see how that plays a role. I spelled out to them everything I have going on. I'm going to give them another call to try one more time just try. Probably end up no where but what the hell its just time spent right?!

As for adding the ground. I was worried that this wasn't appropriate or correct. Again I'm not the most knowledgeable with this wiring but my concern was that this ground it being substantial enough for use over time. Believe me, this was my first thought when I figured all of this out but out of principle I wanted to find the "right" fix. The way it was intended to work from Novak. Anyways, as long as there won't be any future problems with running that new ground to the block I will probably be doing that if I don't get anywhere.
Posted via Mobile Device

[solidaxel]

Interesting!

[binford]

I will assume you have a ground from the battery - to the frame, to the body, and to the engine. Plus you already grounded the ECM case.
Double check that the connectors are good. I use "star" washers to bite into the metal for a good connection.

One could use an ohm meter to see if you have ground for each pin on the ECM connector that should be tied to ground.

http://lt1swap.com/1999-02pcmpinouts.pdf

[bpatch85]

Ok, sorry for the delay in response. A more important vehicle became a priority for repairs and I lost track of getting back in here with my results.

Talked to Novak and they out me in touch with the head of the wiring department. After going through a few things over the phone to confirm all was how it should be the guy stated that the way they assemble the harness for a setup like mine has changed. Rason being, and he admitted to this, was that they had ran into this problem before. He admitted that it was possible that a ground was missed as it had happened before on the old harness layout and the guy from Novak took responsibility. They offered to go through the harness and make any repairs for free if I would send it back. But since I really didn't want to disassmble what I have done he said the next best thing to do would be to add my own ground that would allow the system to run correctly. So that's what I did!

Thanks for the input and knowledge you guys shared and helping me reassure that I wasn't completely crazy with this problem.
Posted via Mobile Device