I have recently pruchased a neglected 1989 TransAm. It quit running one day as I was driving. Prior to this, it was hard to start.

Here is what I know:

It would flood upon initial start up. Even though it is fuel injected, if your foot touched the gas pedal prior to or during cranking, the car would immediately flood.

The car would recently start, but struggle to keep running. I would have to restart over and over. This was prior to the no start.

It will run on starting fluid. However, as soon as the can stops spraying, the car will immediately quit running.

I am getting fuel. I get 50 psi at the test valve when the key is truned on. This drifts down to about 42 or so. It will read 50 psi during cranking, also.

I get a code that says I have either a bad MAP or MAF. The reading is low voltage. I believe I have a MAF. Is this so? If so, where is it? If not, where is the MAP? Will either of these cause a fuel related no start?

What is my problem?

Thanks for any help anyone can offer.

 

When you press the throttle pedal during cranking, it actually sends the fuel system into clear flood mode. What you are describing sounds like its not getting enough fuel.

Again, a symptom of leaning out.


I think 89' was the first year of the MAP based TPI. If so, it is either unplugged, the wiring is bad, or the sensor itself is bad. This will definately cause your problem. If you have a MAF instead, the problem wont be as bad. A MAF sensor will sit in between the air cleaning unit and the rubber boot that connects to the throttle. A MAP sensor will sit on the plenum right by the fuel pressure test valve. If you have tested your fuel pressure, then you probably have moved it.

Hope this helps.

 

Thanks for the advice. I don't see any type of wires or equipment between the air cleaner and the throttle. I have a long rubber boot connecting the air cleaner and intake. Nothing in line with it. The air cleaner is round and looks like a coffee can sort of. I had a feeling I have a MAP. I know that they can be elusive. I didn't see it at the test valve on the fuel rail. I could be anywhere in the pleneum. I will find this, and work on it. If I don't see a result, I will post again. Thanks a lot.

I just wanted to note that barely touching the gas pedal prior to or during cranking, caused the flooding condition. I know about clear flood mode, but this happened even with the slighest touch. It doesn't seem possible, but the movement from getting in the car that may inadvertantly cause your food to touch the pedal, would be enough to cause the flooding condition. I didn't believe it until I experienced it.

 

I had an 89 Formula that flooded big time on me all of a sudden. Both banks, so only thing it could be was the computer. $89 replacement from Checkers fixed it. The injectors have 12v tied to one side full time, the computersupplies the ground to energize them and spray fuel. I'm thinking your puter did same thing mine did causing your flooding,then either the driver transistors in the puter gave out or the fuse in the 12v feed popped causing no fuel feed. But that's just my internet long distance (after a few Bud lights) diagnosis.

Also, the ignition module outputs a firing signal to the coil, and also to the computer so it knows to feed fuel. Outside chance this could be your issue.

http://web.camaross.com/forums/showt...light=flooding

 

I can believe the computer. I feel the flooding condition and now the no start are related. I had a computer go bad before and got all kinds of wierd codes. This car only has one code. MAP or MAF is low voltage. I am and have always suspected the computer. Now I feel better that someone else also does. First thing today I will check the MAP, then I may start directing my attention toward the computer.

Thanks

 

I beleive 91-92 were the speed-denisty years. 89 still had a MAF sensor, to my knowlege. You can look it up over on Thirdgen.org- plenty of good articles and write-ups on the differences between different years.

 

I have 2 89 irocz's and they both have MAF......If that is bad then its not going to run

 

Keep in mind that a car that is running lean will be able to sustain an idle when you are spraying started fluid in the TB, but it wouldn't affect a car that is flooded.

- Justin

 

Yep the 89 as stated is a MAF car, I do beleive though that 90 was the first MAP powered TPIs. I would also look at the ign module, I had a simular problem on mine and the ign module was it as well, but I had no codes, the MAF code may be simply something altogether different.

 

Update!!

I do have a MAF. I pulled it off the car and it appears that the whole unit has to be replaced as one piece. Now the job of convincing myself it is actually bad before I spend $150 + on this part. Is there a way to test this thing? My book tells of a way to do that if the car is running. I seems to require a high tech VOM. Mine is low tech, with no oscilloscope functions. Is there a simpler way? If not, I will just change the part...and hope that is it.

Thanks for the information up to now. It is very helpful.

 

The easy way to test for a bad MAF sensor... Remove it and see if the vehicle runs better. It should run pretty decent with it disconnected assuming it is the MAF that is bad and nothing else is wrong. This is how my GM service manual says to test for a bad MAF sensor.

 

I can't test the MAF that way, since my car won't run. Is there a way to test a MAF off the car or on a car that won't run? I tried to start the car with the MAF disconnected and no go.

 

If the MAF was your only problem, then it would start with it unplugged.

 

I agree with 91-Z28-L98 sounds like it's not getting fuel rather than too much. Chek the fuel pressure,if good check the injector fuses to make sure they are fireing.

 

Update:

It is not the MAF. I put a brand new one on, no change. I know I am getting fuel pressure, since I checked the test valve with a pressure tester. I also know that these don't tell if I am getting enough flow.

I know the injectors are not firing. The MAF was the code, but not the problem. Next suspect is what? The computer? The module? This car was hard to start, with the flooding problem prior. It quit while on the highway. It runs great on starting fluid.

Pressure is there...runs great on starting fluid...quit on the highway...MAF code, but not the problem...Injectors not firing...used to flood on initial start up...when it did run, it was getting bad gas mileage...What is all of this telling me?

How about the module next? I know on Ford the ign. module will quit suddenly and never start again. That is spark related, but if my car sends a fuel signal...

Thanks for all of the help up to now.