John1987formula

I have a 1987 Firebird Formula with 19K original miles. It has the 305 PFI V8 with a 5 speed manual transmission. The car sat for a few years at a time over the last ten years. I have two problems currently that I am trying to solve. The first problem is a starting problem. The car will only start if the battery charger has been on the car and the battery is fully charged.

After the car starts it usually starts again but if it sits for more than twenty minutes it will not start. The lights come on but when you turn the key nothing happens. Occasionally it will click and then it will start. I have installed several new batteries and something is draining them down within a few days of installation.

My second problem is that there is a slight miss in the engine. The hood shakes and there is a puh puh sound at idle after the car runs for a few minutes. There is a slight hesitation too when accelerating. The idle speed seemed to change as well especially after starting up and coming to stop signs. I changed the spark plugs since they have been in the car for about ten years even though they only had about 4K miles on them. I also changed the plug wires since I am pretty sure they were original. I purchased the car with 15K original documented miles on it from the original owner. I also changed the cap and rotor as well. I changed the IAC valve. It was in pretty bad shape and it corrected the idle speed problem.

I disconnected the MAF sensor wire per the factory shop manual trouble shooting guide and the motor smoothed out. There was a rotten egg smell after the car ran for a minute or two but it went away after I reconnected the MAF sensor. I took out the MAF sensor and cleaned it with MAF sensor cleaner. The miss is still there.

The MAF sensor looked new even though it is 28 years old. There are no codes showing up other than a code 34 after I disconnected the MAF sensor. After I reconnected the MAF sensor the code disappeared. The only code now is a code 12 which is normal according to the manual.

I connected a vacuum gauge inline with the intake manifold and I am getting a steady 19-20 inches of vacuum.

I put some Lucus Fuel System Cleaner in the gas tank with some fuel stabilizer thinking it may have been gummed up from sitting so long. I have run about half of the tank since filling it up.

I am not sure if I should change the MAF sensor or the relay for the power or burn off for that circuit or check the TPS or fuel injectors next? Has anyone had any experience with this problem?

-srs-

Check the voltage with the car running. If it only starts after a full charge, your alt may not be charging. You can test for a parasitic drain by disconnecting the ground when you park it. With only 19k on it, you likely don;t drive it often enough for that to be a big hassle. The under hood lights are notorious battery killers...I used to build them for GM back in the day. The car doesn't happen to have an alarm does it? They can also be a drain if wired poorly.

As far as the miss goes, ohm out your injectors. They don't like to sit. I had several go bad on my 37k Z28 that was a garage queen for 15 years.

bigal55

iTrader: (1)

Car sitting so long, need to replace fuel filter, cap and rotor beside the plugs and wires you have already changed. Basically, a general tune up to start with. Is the gas in the tank old? Many problems with the original Multec injectors as reported by many members. Might think about changing those out if your problems persist after the tune up and you have used up that old gas. BTW, putting fuel stabilizer in after the fact will not do any good, need to do that before car sits for a period of time. HTH!

85Special

I'll second the spark plug wires. Mine sat for 12 years, I cleaned it up gave it a tune up but had it in my mind that the wires were brand new before it went in storage. Pulled my hair out for a week trying to figure out why it was falling all over itself at idle. Changed the wires and she smoothed out a lot, eventually had to replace injectors too. Went southbay for them, noisy but great. I set my rockers live after replacing the cam, I was having a hell of a time telling rocker knock from fuel injector noise. I called southbay about the problem and they told me that was normal but they would be happy to go back through the injectors if I wanted to send them back. I finally did get the rockers set and wondered about the injectors for a week or so. They never missed a beat, a year and a half later and still no trouble, and I would recommend them to anyone.

85Special

Crap sorry did not see you replaced the wires already... The MAF is a problem, if the sensor is truly bad finding a replacement is a small nightmare. Cardone is a joke and most other part manufacturers have dropped them. Basically orileys was the last I knew of that sold a new unit and they don't anymore. Summit has an adjustable MAF I have not tried but expect to drop $350. But going round and round with cardone I was fed up trying to keep the car original and went with an EBL computer and dumped the damn MAF system. Well worth the $500 ish I dropped on the computer. Took mabe an hour to do the computer swap, just be sure to have the tools to do the job. I used a weather pack tool kit from summit, it's 3 screwdriver like tools for assembling the connectors, they worked great for releasing the pins in the ECM connector. Plus our cars use those connectors anyway so it's a nice little set to hang on to.

Bad gas could still be a problem. Fuel stabilizer is for keeping fresh gas fresh. It won't do a thing to old gas. I would have recommended octane booster and sea foam injector cleaner. Lucas is great stuff but its oil based where sea foam is a solvent. Best advice I could give is burn that tank as close to empty as possible and fill up with premium gas, preferably at chevron or another "A" grade gas 91 or 92 octane.

Johnny*G

John, were you ever able to solve your problem? I'm having a similar issue and found a vacuum leak but that's it. injectors ohm out ok. Ignition new. Was curious about the MAF. I thought about purchasing one and plugging it in for diag purposes.

John87Formula

I had to create a new profile due to pass word issues. I put in a new MAF sensor and it improved the idle by about 90%. The first replacement I put in actually made the car run worse. I ended up putting in a factory used part I bought from Hawks Third gen. They had one for $75.