Need help with my lt1, can't figure out whats wrong

**Mike510** · 10-29-2010, 10:57 PM

So I have a 1994 z28 6 speed and for some reason the car runs like complete crap on first start, a lot of missing and doesnt wanna get up to speed very well at all and its very rough. But then after about maybe around 30 minutes of driving, it smooths itself out and runs normal. Thas why I don't think its the opti cuz why would it not work and then all of the sudden work? Can someone let me know what I should try?

**JaycenK** · 10-30-2010, 09:46 AM

I would look for codes first even if you don't have a check engine light. Then I would start looking at sensor values. start testing the TPS, look at the air temp sensor, look at the IAC motor, clean the MAF with MAF cleaner, pull a plug to check them and then look at ignition. Typically if it's ignition related it wont get better when it gets warm.

**Mike510** · 10-30-2010, 10:37 AM

Ok cool, I'll check those out. Is there any way it could be a plug wire? I was thinking it might be getting hot,expanding, than working somewhat. Its just a pain getting to them and looking.

**Mike510** · 10-30-2010, 10:38 AM

oh and btw, no check engine light. AND one more thing. One time we had the MAF on backwards and then my dad cleaned the wires in the MAF lightly with a q-tip and I read never to touch them, could it be bad?

**Smittro** · 10-31-2010, 06:23 AM

Originally Posted by Mike510

oh and btw, no check engine light. AND one more thing. One time we had the MAF on backwards and then my dad cleaned the wires in the MAF lightly with a q-tip and I read never to touch them, could it be bad?

Umm yes it I'd say it could.. MAF elements should never be touched but the proper (CRC Maf cleaner) spray cleaner and let to just dry...

**Mike510** · 11-04-2010, 07:40 PM

I've also noticed that when its running bad it smells like somethings burning, what could that be?

**Smittro** · 11-04-2010, 07:49 PM

Originally Posted by Mike510

I've also noticed that when its running bad it smells like somethings burning, what could that be?

What does it smell like.. Oil, coolant (sweet smell), rubber, etc,etc.?

**TLS_Addict** · 11-08-2010, 01:37 PM

Wouldnt be the opti, at least I dont think so. Does it miss up top under WOT or have a hiccup? If so than possibly.

Not sure what it could be. The MAF could be it but I am doubting it because the problem is not all the time, only on start up and when the engine is cold.

Do yourself a favor. Change the fuel filter, air filter, change your plugs, check your wires (might have a short somewhere), and clean the hell out of your TB if need be. Mine had NEVER been cleaned and it took some work but I got all the gunk out of it. That helped 100%. I also replaced the opti and the water pump though too.

What year is it? I have a stock air lid from a 94. Its not a lot of hp but it gives a "little" and it sounds meaner....lol It is NOT the one with all the vents in it. There were two different ones used. Here is a pic of mine.

**JaycenK** · 11-08-2010, 08:01 PM

Test the IAC

**Mike510** · 11-11-2010, 01:33 AM

its kind of like a light jerk sometimes through all rpm's and I can tell I don't have full power, it feels like its holding back. I could hear it too but the burning smell seems like its coming from the exhuast but idk...

**Mike510** · 11-11-2010, 01:34 AM

Originally Posted by TLS_Addict

Wouldnt be the opti, at least I dont think so. Does it miss up top under WOT or have a hiccup? If so than possibly.

Not sure what it could be. The MAF could be it but I am doubting it because the problem is not all the time, only on start up and when the engine is cold.

Do yourself a favor. Change the fuel filter, air filter, change your plugs, check your wires (might have a short somewhere), and clean the hell out of your TB if need be. Mine had NEVER been cleaned and it took some work but I got all the gunk out of it. That helped 100%. I also replaced the opti and the water pump though too.

What year is it? I have a stock air lid from a 94. Its not a lot of hp but it gives a "little" and it sounds meaner....lol It is NOT the one with all the vents in it. There were two different ones used. Here is a pic of mine.

Ive never seen that lid before, I have a 94. Mine looked different.

**TLS_Addict** · 11-11-2010, 08:33 AM

Mike, its another version they had. I cant even find where to get this one though in reproduction or anything.

This one has an opening about 4" by 6" in the center. My other friend had a 95 and his had the one with vents all over the top of it. I would cut it anyway and call it a day.

**Mike510** · 11-19-2010, 02:34 PM

Ok so theres something else I've noticed today. I heard a ticking noise coming from the bottom of the car and today when I was driving, it drove like crap but the last three blocks or so to my house it ran fine and when I pulled over I didnt hear the click anymore...what could that be?

**kensz28** · 12-04-2010, 07:22 AM

Sell it and buy a honda.......................

**Bad Co.** · 12-06-2010, 08:44 PM

I had a 94 formula a few years ago that was doing the exact samething. I took it to a local mechanic and he said i had a cracked/warped head. I was not satisfied with that diagnosis so i took it to the pontiac dealership. $200 later it ended up being a injector plug. One of the wires had broke and just was barely hanging in there. Moral of the story; check all your injector plugs and wires.

**johnward643** · 12-25-2010, 08:36 PM

Originally Posted by JaycenK

Test the IAC

How would you go about testing the IAC?

**fbodyNATION** · 01-22-2011, 09:39 PM

Originally Posted by kensz28

Sell it and buy a honda.......................

y would u tell this man do do something DUMB like that??? u cant be serious

**Smittro** · 01-22-2011, 09:59 PM

Originally Posted by johnward643

How would you go about testing the IAC?

Pitch it and buy a new one...

For the price,, not worth the effort..

It will run without an IAC sensor.. Prolly have a wandering idle tho..

OP:

Sounds like the PCM is bad to me.

Possibly in limp mode..

Have it scanned..

Just my .02

**Black18Ice** · 01-27-2011, 09:10 PM

All I know is I kept putting off the opti, because I didn't want it to be it...and it was the opti. Sometimes it is just easier to replace it.

**Mike510** · 01-29-2011, 09:35 AM

It turned out I think my problem was the rubber from the TB was cracked and letting air inside. I wrapped electrical tape on it for now and its working a lot better.