89 Z24 2.8L e-test help...fuel staying rich!

[chainsawsuspiria]

It is a GM dealership. He tried a couple of scanners. He enters all the basic stuff, then it says to look at the engine light to see if it flashes the 12 code. The fan kicks in and the code flashes. He punched a few more buttons and that's when it read "no data".

I'm going to have them check the Pressure Regulator, and the Cold Start Injector(since you mentioned it). I looked up the cold start injector on the autozone site and it's listed for my car.

Another thing. I did a quick search here at the forum for ECM. I was reading most of them and came across some posts that said the ECM for this car is well known for having problems.


Is the fuel pressure regulator hard to install? I looked at it(next to the injectors, on the right side...right?) and it looks relatively easy to change.

[chainsawsuspiria]

I haven't had anything done yet(pressure regulator, etc...), I was wondering if anyone could answer me why codes 44 and 45 are the only ones flashing. It just seems weird to me.

[BlazerLT]

Fairly simple really, the fuel pressure regulator is not regulating the fuel properly and is letting too much or not enough fuel into the injection system.

[chainsawsuspiria]

So simply put, once a new fuel pressure regulator is installed, everything should balance out.

As I mentioned before, when I put a new one on, do I have to put anything on the threads so it doesn't leak(thread lock; teflon tape; etc...)? Does it have to be torqued to anything specific? Or just tightened and then turn a fraction more?

I would like to do this soon because I love my car and I don't want anything to worsen in the coming months. The funny thing is that it runs great.

Thanks again you guys. Not to rush you guys but if I could get a quick reply, it would be very much appreciated...I'd like to do this tomorrow or saturday.


Added: From a search online - if I get codes 44 and 45 at the same time, it says that it's a faulty O2 sensor circuit.

I'll do the fuel pressure regulator first, but if it is the circuit, how do I fix that?

[Fireplug]

A rich running engine will eat o2 sensors.
I still dont like the idea of no data from the ecm. And think that problem should be fixed first. It just might be the main cause of the rich problem and we are chasing a ghost and not the true problem

[chainsawsuspiria]

I know exactly what you're saying. I just want to fix the cheaper things first. Fuel pressure regulator $100 vs ECM $400.

If the fuel pressure regulator is the problem, it's only a hundred dollars. If it still runs rich, I'll take it back and have them put the new ECM in.

[chainsawsuspiria]

Today I was driving around. I got some gas and went to the store. When I came out of the store and started the car, it was idling all over the place. Then it would stall. It restarts fine, I put it into reverse, then it dies. Restarted and backed up, put it in drive, then it was idling rough again. As it revved up, the car jumped forward.

It did that all the way home...at red lights. Didn't happen while driving.

So I took the groceries inside and came back out, on my way to the mechanic. It started right up and nothing happened...no stalling. It ran fan.

So I get to the shop and explain to them what happened. I let the car idle for a bit(still rich by the way). When I put it into drive, then back into park, the idling was all over and then it stalled.

I'm gonna have them do a fuel pressure test and possibly have them change the fuel pressure regulator.

Also, Should I still go ahead and take it to the other shop and have them put in a new ECM? The downside is that it will be about $440.

[BlazerLT]

try one thing first and then more to the other.

Don't start changing 6 things at the same time.

[Fireplug]

man you are spending a ton of cash on this problem guessing and just throwing parts at it.
If you still are not getting any ecm data you MUST FIX THAT PROBLEM FIRST. you can throw a entire new engine at this problem and still have it because you dont know whats going on with out the engine data if its wiring or bad ecm have a GM Tech who know what he is doing test your car for this problem

[Cam7]

Go to a salvage yard I got mine for $25 US and had to change the prom. Not hard to do. Fuel pressure regulator could be bad hard to tell unless a pessure test is done. Could be a bad Injector since 44 is comming up. Injectors should read 11 to 12.5 ohms. Like Fire said dont throw parts at it very costly.

[chainsawsuspiria]

I did get a used computer. The guy also took his out of his car and it was doing the same thing.

Anyways, I got a new EGR at the dealers cost(with a year warranty). I put it on and everything seems normal, the two screws that are holding the tube on were tight as hell).

I did a fuel pressure test and the pressure was fine. The scanner has the numbers going between 100 and 900, instead of it staying at 900 like before. And it switches between open loop and closed loop now.

I mentioned before that when I revved it up to a steady 2000 RPM that it would start to idle rough and somewhat puff. Well, that's not happening anymore either.

I'll keep everyone informed if anything else happens.

Added: Now my horn seems to be messing up. A year or so ago, someone tried stealing my car and ripped open the steering column. The guy I know at the dealer had one so I went to his house and he put it on. Every so often, when I do use it, it will honk once/twice and then there's a buzzing under the steering column. A wire? Could a connection be dirty?

[Dave 1955]

Hello there. I am new to this site and have been reading all of the problems you were having with your Z 24. I too have the same problem. I have a 1988 Chevrolet Cavalier Z 24 convertible manual transmission. I have replaced fuel pump fuel pump relay injectors fuel pressure regulator Exhaust converter engine computer oxygen sensor map sensor airflow sensor throttle position sensor idle air control valve coil packs ignition control module etc.… I have not change the EGR valve, is this still working for your car? My car is missing at 2000 RPMs and every so often while driving it shuts off and starts jerking, the manifolds are looking hot so that's why I thought it was the converter. I am at my wits end with my car. It only has 54,000 miles on it. Please help, it would be greatly appreciated. I am trying to get an EGR valve now, it is very difficult to find one for my car because it has a manual transmission. Thank you in advance

I also have checked all my grounds, and exchange some of those new parts at the auto parts store because I thought maybe they were bad. The car has not changed at all through the entire process of swapping these parts.

[777stickman]

Hello to you also and welcome to AF. Did you notice that this thread is 14 years old? Most likely the OP will not respond. With that said it seems the EGR cured his issue. Hope it cures yours also.