I'm at the end of my rope with the '88! Update x2

[5speedz34]

I KNOW THIS IS A LONG READ BUT THANKS FOR YOUR HELP.

 

Let me give brief a background on the car. I bought my 88 2.8 5speed back from Kevin. When I got it it had a bad ICM. So I got a junkyard ICM and coils.

 

The guy that owned before Kevin and I swapped a 89 2.8 into it on the existing 88 wiring. Of course the 89 was a auto motor so it didn't have the air pump. If you want to search some of the posts he made about it his name on here was nerfbars.

 

Well when I got the car back it wouldn't accelerate over 2500k in any gear. When I swapped the ICM and coils over this took care of that problem.

 

Since then I've been trying to diagnose whats wrong with this thing.

 

So far I've replaced the

ECM (this was on a whim, hoping it would solve my problems)

2-wire coolant sender by the LIM

Cleaned out the TB and did the O-ring

Changed the oil

New plugs and wires

Knock sensor and I reconnected it

Cleaned out Coolant level sensor

 

Ok, so here is what the car is doing. At any time wether the car is hot or cold it has some kind of hesistation. It also only does this in gear, and when it is accelertaing. This hesistation can go from a a small bucking or chug to full blown shuddering of the whole car(damn engine mounts ). When it does it bad, which is most of the time, I loose all power and I can't go anywhere. Usually I need up putting the clutch in when it does this and try to shift into another gear. It is throwing a 43 (knock sensor) and a 45 (running rich condition) and I have a low coolant light. I had orginally thought that the car was retarding the timing due to a bad knock sensor and thats where it was getting it's running rich condition.

 

Well, I bought a new knock sensor and went to replace it and the fucking wiring was cut! So I went and bought heat shrinking splice connects and re connected the wire and it still gave me the code 43. I went ahead and replaced the knock same code again, at this point I was like WTF mate? FWIW: The base of the crank sensor was cracked where it meets the block. I don't know if that matters.

 

 

At this point I really didn't know what to do all it could be is my wiring was bad, and I'm not the greatest at wiring either. Whats the best way to connect those two wires?

 

So I thought the low coolant light might be because of a dirty sensor. I pulled the coolant level sensor off at the rad. and cleaned it. The fucker was dirty! I tried getting as much of the scale off the sensor as I could. I put it back in and I'm still getting the low coolant light!!!! ARGH. I might try rubbing alchohol or should I just get a new sensor. I also grounded the pins on the plug to make sure it wasn't the wiring/or ECM. I might try to clear the codes and ground the harness again.

 

The reason I was doing this was because, I was thinking that the sensor was making the ECM think that it was in a closed loop or something and retarding the timing setting off the running rich condition.

 

This is where I'm at right now and I really just don't know what the hell to do, as it stands I can't drive the car. And I'm stuck driving my dads truck, and my rents are on my ass.

 

FWIW: The harness if fucked on this car. If I wanted to swap over harness' what would I need to find? Would a auto 2.8 work and then wire in the 5speed stuff or what?

 

 

THANKS ALOT GUYS I KNOW THIS WAS A LONG READ.

[5speedz34]

It's nice to see people have responded so quickly!

 

Anyways, I grounded the Coolant light in hopes it would clear out code 45 and it didn't. So this really didn't do anything for me. The car smells like it is definatly running rich but it has an exhaust leak coming from the cat area where a straight pipe was put in with clamps.

 

Also the car has a really loopy idle, when it's cold it idles at about 1200 and then after sitting for 5 minutes comes down to 900 but shoots around the whole time, there is also times where it shoots down to 100 and then pops back up. TPS? Would a vacuum leak cause this?

 

EDIT: The crank sensor is broken a little bit at the block, is it worth replacing it?

 

 

PLEASE HELP ME OUT THOUGH.

[Brian P]

 

Also the car has a really loopy idle, when it's cold it idles at about 1200 and then after sitting for 5 minutes comes down to 900 but shoots around the whole time, there is also times where it shoots down to 100 and then pops back up. Would a vacuum leak cause this?

 

yes it can. A bad intake gasket can do that as well.

 

But when you're ready to call it quits, I'll buy it off you and I'll get it going

[99RegalGS]

I would start out by testing the Knock sensor output at the ECM for the code 43. According to my chiltons it's pin 11 in the PCM connector A. There should be 0VAC with KOEO. Now to check the output of the sensor have someone watch the multimeter while you tap the block near the sensor with something hard. Still KOEO. There should be a small voltage (less than 1VAC) coming out of the sensor.

 

I would almost just replace the crank sensor if I was able to. Espically if it's cracked anywhere.

 

Also have you checked the O2 sensor at all? There should be a fluctuating voltage (between 50mv-950mV) coming from it once it's hot.

 

The Coolant level sensor shouldn't have any affect on how the engine runs.

 

And yes you can make a 2.8 Auto harness work. You'll just need to find out which wires you need to connect to your Trans.

 

Hope this helps a little

[gp90se]

lets start with basics, cleaned the IAC and run starting fluid around the lower intake/plenum/vaccum hoses. go thru the wiring and see if anything else has been cut. I *think*an auto wiring harness will work without a problem, just leave the TCC plug dangling. tryed swapping out the ICM for a known good 1?

 

good luck

[5speedz34]

Thanks alot guys.

 

This is really what I wanted, if anyone else has any advice please post it!

 

I have the service manual, but I wasn't to point of where I was to test out the stuff with a multimeter.

 

Right now I have to get ready for work, and I'll see what I can do about this tommorow.

 

Thanks!

[Aaron]

Sorry Tony wish I could help more.

 

But at least the Z34 ran when you bought it

[GOT2B GM]

My g/f drives an 87 Z24 with the 2.8 MPFI and 282. We had a problem with it earlier this year similar to yours. It would idle ok, and rev freely under no load, (clutch in or in neutral) but it was a total different story while driving. It would be ok until about 3K - 3500 rpm where it would stutter or even buck, depending on how hard you were into the throttle. You either had to shift up, or let off the gas. The fastest you could get the car to go was like 90 km/h (55 mph).

 

I started with changing the fuel filter, and checking the fuel pressure, which was fine. It had plugs, wires and coil packs that were all less than 6 months old, and a ICM which tested good at the parts store, so I didn't touch that stuff.

 

At this point, I was at a loss at what to check next, so I took it down to the garage around the corner from my house. Only 1 hr of labor later, they diagnosed the problem. I had over 5x the amount of backpressure I was supposed to have. (they have a back pressure gauge that threads into the O2 sensor hole) They told me it was more than likely a clogged cat.

 

So I borrowed a sawzall from work, and cut the cat out, and took it for a rip Damn, it was loud, but that was the problem. So I went out and bought a new stainless Magnaflow cat, clamped her in, and its been working great since.

 

Hope that helps, sorry its soooo long.

 

Good luck getting her fixed.

 

EDIT: Oh yeah, and it was also throwing a code 45 (rich exhaust) like yours.

[slick]

As I told you on the phone about 1 hour ago: Intake Gaskets.

 

And, as for the crank sensor, definately replace that.

[Aaron]

So Tony, this is what you should do, in order:

 

1) Replace CAT

2) Replace intake gaskets

3) Make sure the MAP sensor is plugged in and working

4) Replace crank sensor

[THe_DeTAiL3R]

Did you clean the IAC properly? My 2.8 always got gunked up I cleaned it about twice a year. Hopefully that would help with the idling problem.

[93CutlassSupreme]

To all those who can't read, (Aaron), there is no cat on this car. It also has a newer Turbo muffler. Exhaust restriction isn't the problem on this car.

 

 

I'd replace the coolant level sensor. I see you didn't replace the O2 sensor; it may be giving a false rich exhaust reading. The crank sensor is probably broken if it is cracked; I'd replace it.

[GOT2B GM]

Ok well I didn't see ANYWHERE in his post that the car didn't have a cat.

[gp90se]

....but it has an exhaust leak coming from the cat area where a straight pipe was put in with clamps.

 

[DaveFromColorado]

sounds like an injector or two may be sticking open causing an overly rich condition in a couple cylinders, this will allow for free revs and a lopy idle, but will cause a foul out condition under hard acceleration. This will also cause the O2 sensor to see too much unburned fuel (what you can smell in the exhaust) and lean out the rest of the engine, causing the knock tripping the knock sensor, retarding the timing causing that major bucking you've been feeling - I'd pull all your injectors and have 'em tested, there's a couple places folks on here have recomended, a quick search will help ya find them - otherwise you can go collect a set of injectors from the junkyard and have those tested/cleaned and replace all 6 at the same time ... depends on how much down-time you want with the car.

 

--Dave.

[Aaron]

Retarded ignition timing will not cause bucking or roughness in any way, shape, or form. In fact, the only result of retarded timing is a SEVERE loss of power.

[GP1138]

Retarded ignition timing will not cause bucking or roughness in any way, shape, or form. In fact, the only result of retarded timing is a SEVERE loss of power.

 

Sounds like the knock sensor is still fucked.

[5speedz34]

Thanks for all the responses.

 

I'm really busy tonight and I get back with you guys tommorow.

 

About the wiring, all together there is the air pump thats not plugged in and a plug on the ac compressor and 2 wires are off the starter. And there are half dozen wires that are spliced, cut or hacked. So I think my first thing is to swap harness'.

 

What ones will work, honestly I'm going to look for a 5speed harness first.

 

Would only a 2.8 one work since they have the other (non-digital?) style EGR? I really don't want to splice.

 

Thanks

Tony

[gp90se]

88 and 89 all came with vacuum EGR valves, and I think a few 90s. The wires from a digital egr dont match up to a vacuum egr, so splicing wouldnt be straight foward. My regal has a 3.1/4t60 and vacuum egr, and I have the vacuum hose blocked off. purrs at idle and accellerates very smoothly.

 

Go grab an 88-89 harness (auto if thats all you can find, and put it on, shouldnt take more then 3-4 hours and might make all these issues vanish.

[5speedz34]

88 and 89 all came with vacuum EGR valves, and I think a few 90s. The wires from a digital egr dont match up to a vacuum egr, so splicing wouldnt be straight foward. My regal has a 3.1/4t60 and vacuum egr, and I have the vacuum hose blocked off. purrs at idle and accellerates very smoothly.

 

 

Go grab an 88-89 harness (auto if thats all you can find, and put it on, shouldnt take more then 3-4 hours and might make all these issues vanish.

 

Yeah, cuz I was looking at some flow charts in the service manual, and it seems like alot has to do with ground and what not and I the wiring is really fucked up on this thing.

 

Case in point

 

 

^knock sensor plug

 

 

Notice the alt wiring?

 

Yeah everything is like this on this car.

[gp90se]

BEAUTIFUL!!!!

 

I had a wire like that on my 3.1 (alternator to battery) because I was to lazy to swap out a bad wire. but that harness is fubard. hardest thing 2 remove is the grounds and a couple plastic clips, but before diagnocing any other issues, get a new harness in there.

[5speedz34]

BEAUTIFUL!!!!

 

I had a wire like that on my 3.1 (alternator to battery) because I was to lazy to swap out a bad wire. but that harness is fubard. hardest thing 2 remove is the grounds and a couple plastic clips, but before diagnocing any other issues, get a new harness in there.

 

Great!

 

Is there any difference between a Canadian and American harness?

 

Cuz I might be able to get one from Kuntzie.

[1990lumina]

Would this air pump have anything to do with it running rich??? I really have no idea what it's purpose is other then emissions maybe?? I know my RX-7 has a pump that pumps air right into the cataletic converters and it's supposed to clean up the emissions......however you say you have no cat...I dunno..

[gp90se]

I doubt theres a difference, but its GM, so who knows lol

[Brian P]

BEAUTIFUL!!!!

 

I had a wire like that on my 3.1 (alternator to battery) because I was to lazy to swap out a bad wire. but that harness is fubard. hardest thing 2 remove is the grounds and a couple plastic clips, but before diagnocing any other issues, get a new harness in there.

 

Great!

 

Is there any difference between a Canadian and American harness?

 

Cuz I might be able to get one from Kuntzie.

 

other than being upside down, no unless any DRL wiring passes thru there.