Hi all,

Thought I would start a new thread on this issue to clean it up.

Car is an 87 Iroc Z with L98. Has a few bolt ons but pretty much stock under the hood. The car was running great for the longest time then I was blowing fuse so I had to go on a scavenger hunt to find out why and checked all the electrical connections. At around this time I started to get codes. The electrical issue turned out to be a wire in the fuse panel and was an easy fix. The codes are not so easy to get rid of. For a while I was getting a code 34 and a sometimes a code 54. 34 was pretty much constant and 54 was sporadic. Car was idling ok and when cold took a couple of times turning the key to get it to start. Never had this before. So I started checking some different things.

To date I have done tests on(I have another thirdgen that does not pull any codes so I swapped some parts to try to isolate issue)

Tested

1) Fuel pump relay
2) Fuel pressure - have afpr - more on this later
3) MAF - removed and put other one in and vice versa. No codes on other thirdgen
4) fuses - have checked all the ones that I know of.

The car is now pulling codes 33 and 54. This would suggest that it is not even seeing the MAF and it is hooked up. Sometimes it starts up and idles great no issues. Other times it starts and idles really bumpy with black smoke. Between these two different types of start ups there is a big difference in the Fuel Pressure reading on the AFPR. Adjusting it does not smooth out the idle when it is bumpy. Lastly, when the car is turned to the on postion and but not turned over, shoud the AFPR show pressure. I have never looked at it before and it isn't showing any pressure when key is just turned on.

Sorry for the lengthy message but wanted to give all the info possible to get some help as I need this car fixed by this weekend.

thanks

Scott

 

Where is Vader when you need him?? LOL

Anybody else got any thoughts on this situation, sitting here frustrated at the moment.

thanks
Scott

 

Well like was mentioned in the other post yesterday, did you find that missing wire that goes from pin "D" of the fuel pump relay to terminal "G" of the ALDL yet?

 

Trickster, do you think the 33 and 54 are related?? I would have thought them to be two separate issues.

 

One of the checks that they give you in troubleshooting the code 33 is to check the fuel pump through terminal "G" of the ALDL. So yeah, they are related in a way.

 

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Should have time tomorrow night to do some digging for the wire that belongs in D. How hard would it be to fish a new wire if I can't find it as I don't believe that it would have retracted so far that the search that I did for it yesterday would not have found it.

 

It wouldn't be that hard to run a wire there, it is a straight shot form the fuel pump relay over to the wire bundle that goes in the passenger side to the C207 connector and then to the ALDL. Look under the dash and see if there is a wire at terminal "G" of the ALDL.

 

Yeah, it would be a lot easier if the wire is already in the Engine Bay. I will start at the ALDL and see if there and then if it is trace it back from the relay to see where it goes astray. Ideally I can get that fixed tomorrow night, clear the codes and try again. See what happens then. Thanks for the help and will post progress tomorrow night.

 

Ok, so I played around with it tonight and solved the fuel pump issue. I must have plugged the harness into the wrong relay a while back when trying to find the reason that I was blowing fuses. All the harnesses are new and the wires leading to them have been done in white so I had to unwrap all the bundles and then discovered the issue. Plugged the harnesses in right and the car started right up. Therefore removed my hard starting issue and my code 54 once I cleared the codes.

I had my fingers crossed that it would pull no codes but unfortunately code 33 was still there. It is idling ok but not as smooth as it has.

Is it possible that the relay got fried by having the wrong harness plugged into it. Is it worth going to by a new relay as they are both the same and it is unlikely both are gone. If it clears it then we are good and if not then I have a spare. Unfortunately the relays out of my '89 are a different style.

The MAF is good as I swapped the two of them the other day with no change to either vehicle.

Suggestions.

thanks
Scott

 

For code 33, can I assume that the issue is electrical. I have tested the MAF, so it would be ECM, wiring issue or relays. Is this correct??

thanks
Scott

 

Some of the cars had the same relay for the FP and MAF. I'd look to the relays.

 

Yeah,

This is one of them. All the harnesses fit all the relays. That was what pulled all the codes and rough running. Now I just get a steady 33 so I think tomorrow I will go to GM and get a relay. Won't hurt to have a spare and I can test all of them with it and see if code goes away. I also need to look at the one harness that is on the MAF burn off as the wires look like they could be a little loose causing a bad connection. All goes well should be running well again by end of tomorrow.

 

All the posts that I see on Thirdgen say that the MAF power relay and the MAF burn off relay should be the same. Mine have two different part numbers and when I called the dealer he had two different part numbers as well.

The car is an 87 Iroc with 350 TPI

Let me know as I am still trying to solve my code 33 issue. It was also mentioned that the fan cooling relay uses the same part. Is this true??

thanks
Scott

 

I think Tricksters pic down on this thread is a maro. I bumped that thread as well so you may catch it. IIRC they should be the same, the problem is usually the guy looking them up. I had the hardest time trying to explain to some of those guys that there were two relays not just one. :shrug:

 

My car is different than that. My fuel pump relay is the one on the left and then burn off and then power. All the relays had been changed so they easily might not have gone on in the correct order. I pulled the cooling fan relay and swapped it out first with the burn off and it idled much nicer but still had a code. Then swapped it out with MAF power and had no light. I think I will swap them both as the burn off made it idle better and then no code. It's only $40 to do both. Thanks guys, saved me some money on this one as if I had to get a shop to trouble shoot it would have cost a fortune.

Scott