Ok so i got my car running again by tracking down the dam vacuum leak thatvi couldnt find. Now idle is still a little rough and she tries to die while reversing. A while bak when i was trying to fix the idle i played with the idne screw thing on the throttle body that u pull on to rev the engine how do i get it back to proper possitioning. I alsi changed my iac but dont know if its set properly how do i chej it andset it.

 

By the way open headers sound nice but dam fhe exhaust fumesare bad and acceleration is crap. Im taking it to have shorties installed as soon as i fix this idle issue.

 

Try this;https://www.thirdgen.org/tpimod2. I had the lower runner bolts back out on mine that created a leak also, you have to take the plenum off to tighten them.

 

its only in reverse and drive that she starts to stumble and eventualy dies. In park and neutral idle is fine.

 

Vacuum is holding solid at like 17so i know i have no leaks

 

Any codes?

 

Nope no codes. I did the whole reset thing with the paperclip anz odly now my temp guage that wouldnt budge when i turned the engine over now functions.

 

The only thing i can think of, is maybe a weak injector? You can ohm out the injectors, but i don't know what values they should be. Check some threads on here.

 

I agree. Check the injectors. I will tell you however that mine all ohmed out ok, but still weren't working right. Changed them and my problem, which sounds like your problem, went away. You've checked vacuum I see. That's good. I'm guessing you also checked fuel pressure. You did check fuel pressure didn't you?

 

I have not checked fuel pressure how do i check the fuel pressure. Wouldnt a bad injector cause bad idling even in part? i dont have any problem untill i put it in either drive or reverse even neutral is fine. But when i give it gas from a stop in drive it does stumble untill it gets moving then it is smooth

 

On another note when i did the iac adjustment by using the paper clip and unpluging the iac and setting the minimum idle it said to set it to arround 400 and my car will not idle that low anywhere under 600 and it starts trying to die and then does.

 

Your idle should come up to around 600 in drive with the IAC plug back in. You check the fuel pressure with a gauge on the schrader valve. Make sure you TPS is set at .54-.75. I personally like .65. You may even have a dirty injector?

 

You've got to remember, you were setting minimum idle, not actual idle. You're actual idle is controlled by the ECM. The ECM is usually programmed for 600rpm. If the ECM takes a dive the minimum idle setting will keep the engine from quitting. It's all part of the "limp home mode". Another thing you need to know. These engines can actually idle on as little as 4 cylinders and can sound fine doing it. Give it a little gas and life gets a little difficult. I'm not saying your car is doing that, just trying to make a point. Idle doesn't necessarily tell you what the problem is. At this point I would lean toward injectors, but I'm not an expert. Check your fuel pressure before you do anything and go from there. Keep us informed of your progress. Oh, yeah, your fuel pressure should be mid thirty ish when you turn the key to run(not start) and hold pretty steady. If it drops kinda quick at that point you can pretty much say leaky injector. Start the engine, the pressure should jump to 42-45 ish. The needle will jump around a little, just see what it averages. If this looks good, turn off the key and watch the gauge. It should hold hold steady and gradually drop. If it drops quick, same deal, leaky injector. Good luck to you.

Steve

 

Thanks i will check fuel pressure as soon as i can get a fuel pressure cheker. I did reset battery and ended up with tps and maf codes. So im going to check those i think they may be my problem. I dont think the injectors would cause the car to bog and cut as soon as i put it into gear without giving it gas or anything. As soon as it goes in gear the idle bogs down and up like twice like its trying to catch and dies out. But in park and neutral idles prety solid.

 

Now that you have codes, especially a code 33, that would help explain the "limp home mode" type condition your experiencing in drive. Now keep in mind you think all vacuum leaks are fixed, but nine times out of ten, you may still have a vacuum leak, check your throttle body shaft for excessive play, the boot between the MAF and throttle body, all vacuum lines, and any loose bolts on the plenum and runners. Like i said earlier, i had the bottom bolts on my runners back out, i had to take the plenum off to tighten them. I also had a bad throttle body. Just some things to check out, Good luck

 

Could there be a vacuum leak even though vacuum holds steady when i check it with a guage and idle doesnt speed up and slow down like it was when i had the leak

 

Yes if the boot between the MAF and throttle body is leaking and also a leak around the shaft of the throttle body. When it comes to a TPS code, check the voltage with a digital VOM meter. As for a MAF code, they can be hard to track down sometimes, because of so many variables. Always check the obvious first. On a MAF system you have a MAF sensor which is on the front of the throttle body, then you also have a MAF relay and a MAF burn off relay. I would first double check all vacuum lines and MAF boot for leaks, then maybe replace the MAF relays first. The MAF sensor is pretty expensive, $130-$500 depending on where you look.

 

Is there any way do do away with the maf?

 

[QUOTE=thegoochking;4792014]Is there any way do do away with the maf?[/ Some have went with a MAP system, but then you have to change the computer. The only other option would be going carburetor, either way you would have to do some rewiring. Once you learn the MAF, it's really a pretty forgiving system, just like all things, when it has a bug it can get frustrating to find.

 

If you haven't already, i would suggesting getting some repair manuals, ( factory G-M, Chiltons, Haynes) they all help.

 

The mechanic im talking to now tells me if it was the maf the car wouldnt start and that it sound more like torque converter lockup. I think the whole maf making the car not start at all if its bad is going a little far but i sure hope its not torque converter locking up because i dont have the money for a new torque converter install

 

Ask yourself this? How did the car drive before you had a vacuum problem. Did the tranny work O-K?

 

the tranny has always shifted smooth but it did occasionaly cut out on me at idle at lights and when reversing a couple of time by just letting the car roll back it did it. So the problem was there just not nearly as bad. if it was the maf woul it cause idle to drop and die when in gear only? im gonna check vacuum again tomorrow but im almost possitive its not vacuum related anymore the vacuum leaks i fixed stoped the problem at idle in park now its only in gear that it cuts off on me unless i give it gas to keep the idle up

 

To answer your MAF question, yes, but as i said before you also have a MAF relay, and burn off relay. They should be on the drivers side fire wall by the brake booster. They are cheaper to replace than the MAF sensor. If you suspect a MAF problem, i would start with the relays first.

 

You have to make sure you have the correct base idle. First, check your timiing. Second, check to make sure you have a good tune up. Get a good basis.

to set the idle you have to unplug the IAC.

Also, put tape over the holes on the throttle body which feed the IAC ( top and bottom)

Then you can adjust the idle screw where you need it. Once it is set, take off the tape and hook up the IAC.

As pointed out the ECU controls the idle


If it idles fine in neutral or park, and stumbles in drive or when the AC is turned on, that could be a sign of a bad IAC.

Start with the basics.

 

My iac is brand new and tested to be working.

 

The car is at the shop right now to have my headers installed and hes gonna try to track down the problem and fix it if its small or tell me what it is if its gonna be expensive

 

I'm betting he'll tell you the expensive fix. Not that all mechanics are dishonest, it's just that some are not real sharp with older EFI's with relays and sensors, most mechanics i know don't have repair manuals that go back 20-30 yrs. Anyway Good Luck

 

Cool. Just good to eliminate the basics

 

Do you have a heated O2? Does it go to closed loop.

 

This is a new post, might help. http://www.aa1car.com/library/vacleak.htm