NufNuffZ28

iTrader: (10)

I am helping a friend get his 88 Iroc running correctly and the wiring is horrible. Spliced and tapped wires everywhere, it runs horrible, fuel pump does NOT prime, but turns on as soon as it sees RPM(so of course it has long starts). Fuel pressure is perfect, FPR working correctly, every injector was flow matched and tested to make sure it's firing while running. I think I have the fuel side fixed minus the not priming with the key on issue. Has stock chip in it. It runs poorly and backfires through the intake like timing is way off or no fuel. No power. Idles rough until it warms up. I get codes 14, 33, , and 42..

Code 42 stays on whether the spout is connected or not and it's hard to even read timing. I think it's way off and not advancing. Need to trace the wiring, I guess.

I know 33 is a MAF code. Replaced with a known good MAF and the code stays off, but only runs marginally better.

Code 14 is new I think, but explains. The running poorly if correct. Bad CTS messes up a lot. if CTS is seen as extremely high I could see that as not needing the pump to prime.

Anyways, here are some wires I am trying to see what they are for......

1 and 2) This brown wire was in the passenger side control arm... any ideas? Part of the timing spout?

3) 2 wire plug is near the distributor and brake booster. (Pink and gray wires.)

4) this is shorted from the black and white stripe wire to a ground...... wtf

Thanks for any help!

sofakingdom

iTrader: (1)

Pink & black I'd the test connector, used at the factory to apply power to a bunch of stuff for testing, without the presence of a vehicle. Not used after the harness is installed in a car.

Black/white is ECM ground. Should be grounded to an engine casting, probably the head. Clean up the mess and ground it. That might be a major part of the problem.

No idea about the brown.

NufNuffZ28

iTrader: (10)

Thanks for the start! Testing a lot this week, so I will update with results of various tests. I hate how butchered it is(and I'm no newbie to TPI).

sofakingdom

iTrader: (1)

OK, got a chance to look it more closely.

That brown wire was probably for the knock sensor; located in the pass side block drain hole.

Using red wire to hack into ground is pretty... hyenous. Only a true genius would think of that. I'd recommend removing Stimpy's "improvement" there, repairing the original wire, and making sure all the black/white wires are hooked up to the motor properly.

I pity you. If the rest of the car is like this, it's gonna be an uphill battle to de-moron-ify it.

daferris

iTrader: (8)

For the full pump prime check the oil pressure switch just above the oil filter

OrangeBird

iTrader: (1)

The oil pressure switch does nothing for the fuel pump prime , that is a function of the ECM and fuel pump relay . In a normally functioning system , one could unplug the oil pressure switch and the pump would still prime at key on . Looking at this wiring diagram you can see that the fuel pump relay's contacts are in parallel with the fuel pump oil pressure switch , so it's an "either/or" proposition as to which runs the pump depending on whether or not there is oil pressure and when (or when not) the ECM commands the fuel pump relay .

NufNuffZ28

iTrader: (10)

Yes, the whole car is like this....

Fan is on all the time, no fuel pump prime, slow, codes 14 and 42 still(33 and 34 usually show up after some driving) Looks like it advances timing even with the spout disconnected, so I'm guessing something is hacked and bypassed? Its honestly a horrible job.

Getting the timing right did help with how it runs, but still has slow starts because of slow prime. I, too, think that's the knock sensor.


Here are some pictures so you guys can sit back and feel for me...

sofakingdom

iTrader: (1)

1. You can buy injector pigtails from any number of places, since people need them for swapping among the various connector styles. I'd suggest starting over with fresh, given how … experienced … those look.

2. That's the main power feed to the coil. Might be a good idea to clean that up.

3. Noooiiiiice… can't tell what wire it is though.

4. If that's the FP relay connector, might have something to do with why it doesn't prime. The wire colors on the connector side of the improvement look like that connector was off of a blower high-speed relay. Not that it matters a whole lot in and of itself, except that they might, or might not, have got the right wires hooked up to the right pin of the relay. The wire colors look more like that's the wiring for the MAF (misshapenly labelled "mass air flow relay", right below the ACTUAL mass air flow relay, on Orange's FSM schematic unfortunately) though. What's it plugged into?

5. The single purple wire should be the O2 sensor... not sure what the others used to be.

6. Not sure what to think there.

Knock sensor problems won't prevent priming. A prime problem is almost certainly something related to the relay; the relay itself, the ECM, the batt feed, etc. Eeeezzzy enough to check; the dk grn wire at the FP relay should go to 12V during the prime cycle and drop back to 0 afterwards, the org wire should have 12V on it at all times, and the tan/wht wire should get 12V during prime also, from the relay contacts.

NufNuffZ28

iTrader: (10)

1. You can buy injector pigtails from any number of places, since people need them for swapping among the various connector styles. I'd suggest starting over with fresh, given how … experienced … those look. Yes going to do that

2. That's the main power feed to the coil. Might be a good idea to clean that up. Yes, doing that

3. Noooiiiiice… can't tell what wire it is though. I THINK they are the grounds that were bypassed at the ECM

4. If that's the FP relay connector, might have something to do with why it doesn't prime. The wire colors on the connector side of the improvement look like that connector was off of a blower high-speed relay. Not that it matters a whole lot in and of itself, except that they might, or might not, have got the right wires hooked up to the right pin of the relay. The wire colors look more like that's the wiring for the MAF (misshapenly labelled "mass air flow relay", right below the ACTUAL mass air flow relay, on Orange's FSM schematic unfortunately) though. What's it plugged into? That is the MAF connector that plugs into the MAF

5. The single purple wire should be the O2 sensor... not sure what the others used to be. Yes, just leaks everywhere!

6. Not sure what to think there. Rear main is leaking badly

Knock sensor problems won't prevent priming. A prime problem is almost certainly something related to the relay; the relay itself, the ECM, the batt feed, etc. Eeeezzzy enough to check; the dk grn wire at the FP relay should go to 12V during the prime cycle and drop back to 0 afterwards, the org wire should have 12V on it at all times, and the tan/wht wire should get 12V during prime also, from the relay contacts. Where is the fuel pump relay located?

I will look into the prime. That is my next thing to fix. I have it running great after a couple seconds. Priming would surely fix that issue.


Thanks again

sofakingdom

iTrader: (1)

FP relay is on the firewall between the brake booster and the fender. Look for a plug with the colors on Orange's schematic.

If any of your codes are MAF related ones, it may be because they got the wire sequence wrong when they spliced that blower relay connector onto the MAF wiring.

NufNuffZ28

iTrader: (10)

Yep. was thinking so as well. Thankfully my 89 52k mile car is in the garage. Checking that next.

NufNuffZ28

iTrader: (10)

Worked on it some last night. Installed a new cap/rotor and it fixed the slight knock(old cap had stripped screws so it wouldn't tighten). Found a couple grounds that weren't grounded, replaced the CTS, adjusted the timing and now the FP primes and the fan does not run non-stop!

Going to look at what codes are left after I install the new/used MAF and go from there. I am guessing somehow the timing bypass to check timing is somehow bypassed as it still advances timing unplugged and shows timing increases. Haven't looked through that yet as I only have an hour or two at the time.

Overall it now runs 100 Xs better than it did!

OrangeBird

iTrader: (1)

I could be totally wrong here , and if so I hope someone in the know can clarify ;

I thought I remember reading somewhere here that even with the timing bypass disconnected there will still be a small amount of timing deviation observed if the engine is brought above idle speed because the ICM has it's own built in (very limited) control over the timing even with the ESC connector unplugged ?

NufNuffZ28

iTrader: (10)

You may be right. at 3k I saw just over 30* IIRC

NufNuffZ28

iTrader: (10)

So, came home to crank it..... fan came on immediately . UGH. Guess I have to troubleshoot that more now(test to confirm ecm is signaling it on.. I'm thinking, since it's running much better, of wrapping up my loose ends and sending it back to the owner for now. New Maf and speedo fix are coming as well, but it's so butchered it needs a new harness...or a lot more time in it.


While it was running, this relay was clicking rapidly...almost buzzing. Anything above idle it stops that.

Its at the firewall near the brake booster.

Any help on what this relay is for?

Tuned Performance

iTrader: (92)

It’s either fp or one of the maf relays. Looking at how fried and corroded it it it took a heavy amp draw. This usually happens to the fp relay.

Tuned Performance

iTrader: (92)

sofakingdom

iTrader: (1)

It's the one for the FP relay.

Only way it could "buzz" or "click" is if the ECM is telling it to. The question then would be, why is it doing that.

Check the voltage at the dk grn / wht stripe wire while it's doing that. It should of course hold pretty steady at all times that it's being commanded; probably within a couple of tenths of a volt of batt voltage. If it seems to drop a whole bunch while it's "buzzing", put your DMM on AC instead of DC, and see if it reads anything. If it does, check the voltage at any convenient pink/black wire, and at the orange wire (the high-current batt feed that gets switched to the pump) in that connector, and see what they're reading at that time, both AC & DC. You may have an alternator prob... ummmm, opportunity for a solution.

NufNuffZ28

iTrader: (10)

Gauge shows 14-15 volts at idle, almost too much IMO. Will look into it more this weekend. I do think I am on the right track as this is the FP relay and we have pump priming issues.

I may repin or extremely clean this connection as well. It looks pretty rough. Still think I am close to finishing some details and sending it.

Thanks guys

sofakingdom

iTrader: (1)

Don't bother with the gauge. Use real instruments. Measure the voltage at those places and see at a deeper level what's going on.

Cleaning up etc. is always a good idea but it probably won't make any difference.

Tuned Performance

iTrader: (92)

For the relay you can get a 89 up fan relay pigtail from efi connection.

https://www.eficonnection.com/home/S...ssSearchForm=+

pg29

I believe this is the Fan Relay pigtail that Tuned was referring to: https://www.eficonnection.com/home/p...male-connector

You'll need to use this relay with that pigtail: https://www.eficonnection.com/home/p...40-gm-14089936

This relay/ relay connector is much nicer than the square one that came in the earlier TPI cars for the fuel pump, those one always have that corrosion like yours does right by the end of the connector.

NufNuffZ28

iTrader: (10)

Well, owner got the car for now. It stopped advancing timing and priming again. I didn't have the time at the moment to dedicate to checking the entire harness. Some tests pointed to the Ignition module, but using a known good one made no change Tan wire and white wire both tested fine per the flow chart in the manual. When it throws the 42 the fan also runs continuously. It has to be something stupid in this wiring harness somewhere. The CTS and MAF did alleviate those codes, so some progress.

FWIW the relay that should be going to the FP is not. Unplugged it and the car continues to run.

Very confusing, so I was all over the place. may try again with it in a couple months, but I kind of hope not. If I do, i will update this thread.