98blktrans

Hey Everyone,

So a quick backstory on my 98 Trans Am Ls1 Auto no engine mods. Got the vehicle from a buddy of mine about 3 years ago who had it sitting in a field for 4 years. The car had a trans leak and wouldn't start along with body issues.

Once I got the vehicle I dropped the tank and put a racetronix hot wire kit with fuel pump. Once I got everything bolted back up the car fired up like a champ. Once I confirmed it turned on I gave a nice tune up to include plugs, MSD wires, fuel filter, air filter and oil change. After all of this, the car would start with ease and purr like a kitten. The car continued to sit in my driveway for about 2 years as there was still the transmission leak that I needed to figure out along with severe interior/exterior issues. So I would fire it up every now and then and let it idle for 20-30 mins or so at a time.

Fast forward to recently. I went to crank it up and it started fine. I tried to give it some gas then it would choke out on me. I thought the fuel was low so added some, still did the same. Didn't think much of it. Another day came and I went to start it. This time it was hesitating to stay on. So I discovered the bellow had a nice tear. I replaced the bellow and while it did a little better and would stay on, I could not give it gas otherwise it would choke and sputter.

At this point the car would idle fine so I assumed it was the MAF or perhaps a TPS. Since the car would idle fine I let it run while I searched for that transmission leak, which is now fixed! *Disclaimer* While jacking the vehicle up, water fell from atop the gas tank. Not sure how it got there but the car was sitting on an incline for several months and of course it rained pretty hard here during that time. Pressed on with doing a trans filter change. Everything was good to go so now back to the throttle issue. I took the car for a spin through the neighborhood and unless I attempted to press the gas more than a 1/4 of the way it did really good.

So I did a number of things, cleaned the MAF and IAC, no dice. Tried resetting the PCM via removing the fuses and disconnecting the battery, nothing. I replaced the ENG SYS fuse along with a couple of others. So I went and got a new MAF from Autozone which didn't work. At this point the car was struggling to stay on.

The SES light was on which initially threw codes P0108 MAP, P0123 TPS and P0131 O2 sensor. I cleared the codes since I figured one may have led to the other so I gave it a fresh start. Turned the car on which it struggled but stayed on long enough to throw another code. Then it died.

It once again threw the P0108 code MAP sensor circuit high voltage. As I went to the car to see how ridiculous the MAP would be to remove I felt hoses crumble in my hand. Yep, you guessed it, PCV system was completely trashed. So I did what i've read on here and made one from 3/8 hose, T's and L's. Went to turn on, nothing.

At this point I'm at a loss. The car will crank and crank with starting for a second then shutting down. It will no longer at least start and idle like it used to. I pulled the rear line of the fuel filter to see if gas was coming through and yea it poured on me. I know the fuel pump is working as I can hear it. One thing I will mention is that I assumed the fuel rails would have some fuel release after all this time if I pressed the nipple in, but nothing happened. I have not hooked up a fuel pressure gauge yet since I don't have one but will try and pick one up.

Any ideas of where to begin with this one?? Sorry for the long post but I wanted to be sure I got it all out there.
Thanks guys, as they say, "First time caller, long time listener."

98blktrans

The car does have 225K miles so if I need to chase a wire or maybe clogged cats let me know.

qweedqwag

Fuel pressure: Check it.

98blktrans

To make sure i'm checking correctly, I would hook up the gauge then crank and watch the gauge? What should it read at cranking?

bammax

Hopefully you weren't running it with 2 year old gas. That's a big no no since the gas turns to varnish after that long.

98blktrans

After I did the fuel pump, which was about 3 years ago, I had completely dropped the tank and cleaned it out and put fresh gas. Since then I would run for a while at a time which I had to put new gas here and there. There's a possibility the fuel may have been old, but the fuel that came from the line when i disconnected from fuel filter seemed to be clean. Let's say the fuel was no good, what am I looking at here? Thanks.

RPM WS6

iTrader: (3)

~2 year old gas that was continually refreshed isn't necessarily a major problem, especially if it was treated with stabilizer and/or other additives for preservation during that period. Whether the tank was kept full/near full (less air = less humidity in the tank) is also a factor, in addition to storage conditions and climate.

But, overall, based on the mileage and history of the car, I wouldn't be surprised if several injectors were functioning poorly (or, now, not at all). Odd that you didn't get any misfire codes if there was an issue with fuel starvation, but if fuel pressure checks OK at the rail then injectors might be part of the problem. But it sounds like you could be dealing with several problems based on those various codes and crumbling vacuum lines and such. Those codes could also be related to some wiring harness issues from sitting in that field (rodents, etc.), maybe it was passable for quite some time after you bought it but marginal wires or compromised connections might have gotten worse from heat cycling and/or vibration during the various idling periods in your driveway, etc. Between the high mileage, poor storage conditions, various codes, and repairs/diagnostic info thus far, there are a lot of variables here.

98blktrans

Appreciate the responses. So an update; I went and put a gallon of premium 93 fuel just to rule out the no gas issue. Hooked up the fuel pressure test kit and the results are as follows:

When turning the key to on (fuel pump priming) the gauge read between 8-10 psi for a few seconds then dropped to 0 once done. While cranking the pressure stayed at 10 psi to include the slight second the car begins to turn on. Any ideas here?

RPM WS6

iTrader: (3)

Sounds like you have found the main problem then: inadequate fuel pressure at the rail. The question is, why? Could be a partial blockage (though the immediate drop to 0 after shut down would indicate no restriction on backflow, which there actually should be, but that's still no guaranty that there isn't a partial blockage somewhere), could be a wiring issue, a problem with the new pump, or a problem with fuel draw at the tank.

98blktrans

Would pulling the line from behind fuel filter and priming to see if fuel dumps eliminate the need to drop the tank again? This 98 tank was not fun to drop alone in my driveway.

bammax

Maf sensor needs to be cleaned and check the internal wires for breaks and then check the wiring harness that plugs into it.

TPS is fairly cheap, but check the wiring harness first.

O2 code is drivers front and that'll effect the idle once warmed up. Stick with acdelco for best results.

Fuel pressure is low because either the pump isn't pumping, or it's pulling air, or there's a leak somewhere between the pump and where you're testing or there's a blockage that's limiting the flow to the front. In any situation you want to measure pressure from as close to the pump as you can get and work your way forward until the pressure drops to localize the problem area. If it's low right out of the pump then it's obvious where the problem is.

After that entire list I wouldn't be surprised if mice ate the main wiring harness and you're just seeing the symptoms of broken wires. Mice like cars parked for long periods.

98blktrans

98blktrans

If anyone happens to stumble upon this, it turned out to be a hole in the flex fuel tube running from the fuel pump to the sending unit inside the tank. Parts are on order so hopefully that was my only problem. I now need a Fuel Pressure regulator housing since I blew the o-rings out of mine...