1994 to 1995 Harness Discrepancies

[zdav28]

I'm not really good at the ohms measuring and what not, but according to this pic on Shbox's website, it says the ohms should be about 8000...




Here's another link
http://shbox.com/1/4th_gen_tech2.html#opti_test

I beleive this is the COIL. Mine has 78k ohms. I would consider that good. However everything I've read checks the voltage going to the ICM, or the grounding to the PCM/ICM, wiring to the ICM, but not the actual ICM. I'm going to try Kragen today. Just thought there was some way to test the correct resistence on the ICM.

[zdav28]

go to this link click diagram #1 and #3. #1 has ground wire pines going to PCM. #3 has all the ignition circuits. To check grounds put lead on battery +12 the - lead on pcm pins if you measure +12 then you have a good ground. there are 3-4 (don't remember) ground connections by icm mount stud. one is also a 1/4" braided wire that other end connects to frame by ABS unit.
http://shbox.com/1/4th_gen_tech2.html#1995_pcm_wiring

I used these schmatics to check each wire in the harness. Yes I did find some opens, injector #1 wire insulation was so brittle, I put liquid insulation on them and electrical tape. Since I had everything off I decided to check the alternator, coil, ICM, and PCM. Each so far has checked out but I can't get the ICM checked.

[zdav28]

If you didn't have voltage to the PCM then when you turn the key into the on position you wouldn't hear the fuel pump even turn on.

I've never heared the pump.
Maybe I should have intro'ed as NEW OLD FAT DEAF GUY.
Wondering if the reason I had pressure was from using the pump primer to dump whatever fuel was in the tank, then using it again to prime the pump with fresh fuel. How long would the pressure remain at 40 psi? Wouldn't it eventually bleed down?

Guys,
I really apreciate all the help, advise, and quick responces. Never having worked on a car newer than 79, aside from brakes and maint. These things can be mind boggling at first. But I'm learning, thanks to you all. Pretty amazing, as I've learned from reading here how you can change the whole characteristics of your ride but just tuning the computer.
Thanks - off to Kragen now........

[Phantom409]

That is what we are here for

[zdav28]

Kragen can't check it either.

[meissen]

Let's start back at the basics.

1994 Z28 car with a 1995 motor/trans/PCM
1995 engine harness
Crank but no spark
42lbs fuel pressure
#2 injector does not blink with noid lights
PCM when used on another car fires right up

You said you've never heard the pump but if you're getting 42lb of pressure that you were able to measure, then you have fuel... enough to start it, atleast.

I think your biggest symptom is the #2 injector not blinking. Was it ONLY the #2 injector that didn't blink or were there any others that weren't working with the noid lights?

And I know - stupid question but have you checked the fuses? We had another guy on here that was totally at a loss on why his car wouldn't start and we went over to his house to help him out. Sure enough - one of the injector fuses was blown so the car wouldn't start.

[98blackbeauty]

I've never heared the pump.
Maybe I should have intro'ed as NEW OLD FAT DEAF GUY.
Wondering if the reason I had pressure was from using the pump primer to dump whatever fuel was in the tank, then using it again to prime the pump with fresh fuel. How long would the pressure remain at 40 psi? Wouldn't it eventually bleed down?

Guys,
I really apreciate all the help, advise, and quick responces. Never having worked on a car newer than 79, aside from brakes and maint. These things can be mind boggling at first. But I'm learning, thanks to you all. Pretty amazing, as I've learned from reading here how you can change the whole characteristics of your ride but just tuning the computer.
Thanks - off to Kragen now........

Do you have a pressure gauge or did you just rent one? the sequence of the fuel pump is when you key ign on there is a 2-3 sec prime cycle then when you key ign to start pump comes back on to deliver fuel with engine running. That said there is a check valve in the pump that maintains pressure between prime and start.
to be sure pump is ok I would 1. put meter on tst plug for pump on right fender well. you will see +12v for 2-3 sec with key on then +12 volts while cranking. 2. if voltage there put pressure gauge on schrader valve and do same test and check pressure for both cycles.
If you have fuel pressure then pump working go back to no spark even though you didn't hear it. I understand because I am old fat deaf man too.LOL
Did you check the grounds in the earlier post I sent? there are 3-4 of them and I know that seems redundant but the PCM supplies a ground through the engine harness to various assemblies to complete the circuit ie; the icm. there for, when you meter some thing you grd is on battry and your probe will read +12 or required voltage, but unit won't be working because the suppied ground not there.
Hope this helps just trying to review stuff youve done but might have missed something.

[Phantom409]

Check your fuses but if you have good fuses and the injectors still aren't working then you need to check the Opti and make sure it's got pwr because the injectors get there signal from the Opti.

Make sure your pump is working also.

[98blackbeauty]

went back and read through the post from the beginning, do you still have original engine? the ICM on that engine should be compatible with your new engine. Try and the one that was on the 94.

[zdav28]

I'm going to go back through and troubleshoot from the beginning. I just screwed the gauge on, yes the KOEOff. But I didn't hear the pump, I did when I cleaned it out, and primed it. Just wonder how long the pressure would maintain before bleed down.

I use the ground on the harness, group of ground wires on the COIL/ICM bolt.

Checked all the fuses, in the engine compartment. I'm going to check the cabin fuses, just in case.

I have a football game tomorrow, and varsity friday nite. so I won't get time to go through this again till late Sat. or Sun.

I'll try and get some pic's up also. Everybody have a great weekend.

[98blackbeauty]

Just wondering how you made out.

[zdav28]

Hey Everyone,

I haven't touched her in a while.
I hate when life gets in the way of the things we enjoy.
All my married friends told me not to, but I did.
They told me not to have kids, she'll get fat.
We did, she didn't.
The American Dream, buy a house, with a big yard.
Now I have to fix it, and mow the dam grass, and it doesn't go dormant here, just keeps growing. @#*& Kalifornia, sun all the time.
Buy a car, now I have 7 plus the power and sail boats.
Before those kids, we'd go sailing every weekend, now never.
Who maintains those? Guess........
And those little people who came to live here? Braces, football, shoes, and don't have a girl, clothes, clothes, clothes, dance competitions, oh yeah and shoes.
Anyone have a cloning machine available?
Wait a minute, I do enjoy this. So basically more important things I enjoy have taken up my time.
I'll make some time this weekend and post.

[zdav28]

OK,
Made some time, bought a NOID lite kite from Harbor Frieght. Really nice, 11pc NOID LITE w remote fiber optic cable 20.00, and a fuel injection pump tester, 17.00.

So I'm not getting any fuel pressure, grnd is good, not 12v to grey wire, checked pump relay, gnd is good, 12v on pink wire, .45v on grn from PCM.

I'm going to jumper the pump primer wire, and see if i get any signal to the NOID lite. I don't think it will damage anything. Read somewhere someone had the same problem, turned out to be his ignition switch, and this was one of the steps he used to DIAG. his problem.

Have any ideas as to what else might be wrong, that I'm not getting voltage to the pump relay from PCM?

[meissen]

Alright Dave - now we have something to work with.

Grey wire goes from the fuel pump relay through the vehicle to a large connector that's behind the rear seats to go through the floorpan. From the exterior, it goes from the floor pan by the rear end to the fuel pump.


Pump Relay:
Grey: To the fuel pump and also splits to go to the fuel pump primer in the engine bay by the PCM and AC/heater box.
Pink: 12v from #5 fuse on the interior fuse block
Dark Green/White: From the PCM, it goes through the grommet on the passenger side firewall to a plug behind the passenger kick panel. C220, cavity J. From that plug, it goes to the fuel pump relay.
Black/White: From the fuel pump relay to C210 (same location as C220) cavity B and then to ground.


For Dark Green/White wire -
Key in the "ON" position: You'll have 12v for 2 seconds and then you'll have 0 voltage
Engine running car started: You'll have constant 12v


Can you confirm you get 12v during the first 2 seconds of the key being put into the "on" position - this should be the fuel pump prime when you first turn the key on.

[zdav28]

I get 0v with Key Off. Key on no crank, 0.14v on grn/wht wire. It doesn't drop in 2 sec.