Ok, so heres the problem. My brother has an 85 tpi trans am. When you go to start it the first time it almost never starts. Let go of the key, try again and the second time it usually will start. However even the second time it fights and groans, taking a few seconds of the starter spinning before you even hear the cylinders fire at all, then it slowly starts firing faster into something vaguely resembling an idle speed. Although, it only idles at 600 rpm much of the time (isnt that low for tpi? I wouldnt know) and always runs really rough acting like its going to die. soon as you rev it up it seems to smooth out though. One time i was driving it and the car wouldnt idle, i had to press the gas or else it would die. So even if i would let off the gas to brake the engine would die, so i had to put it in neutral and give it a little gas and brake at the same time. My brother said thats the only time it did that though. He also tells me sometimes the engine randomly dies while driving, especially if he makes a sudden turn or something. Sounds like a fuel pump to me, but he just had it replaced last year. Any ideas guys? As a side note, one cylinder always has a spark plug that is drenched in oil so it has to be replaced pretty much every oil change. The car doesnt smoke though, so its not burning the oil. Whats the deal there?

 

I can think of a couple things. It sounds most likely like a fuel pump power problem. Either the relay is shot, or it's not getting the "turn on" signal from the computer. What's happening is that you have to crank it long enough for the car to build oil pressure. Once it does, it'll send power to the fuel pump, but then will start kind of hard.

Another possibility is that your coolant temp sensor is junk and it's telling the car that it's -40* outside. That'll rich the hell out of it on startup, and if it doesn't flood it, it'll at least start hard.

But it sounds like the fuel pump isn't coming on to me. Get a digital multimeter and check the relay. I don't remember which wire is the output to the fuel pump, but you should be able to figure it out. The small green wire with the black stripe is the signal wire from the ECM. When you turn the key, you should get 12 volts on that wire and the output wire for 2 seconds, then when you crank and when the car is running, you should have 12 volts constantly. DO NOT use a test light or analog multi meter to check that green wire from the ECM. You'll cook the computer. Ask me how I know this.

If you don't have a digital multi meter, you can just swap the MAF burnoff or power relay to see what happens. If the car starts fine, you'll know that it was the relay.

 

im sorta having the same problem... sometimes when i try to start my car, it wont start unless i give it gas, and when it starts, i have to keep giving it gas or it'll die. thats SOMETIMES, other times, it'll start up REALLY low, then jump to a high rpm and then come down some... and then sometimes it starts fine. wtf is going on? lol

 

Ok, will that also explain the rough idle/the random dieing? My brother says it dies even if it has say a half tank of gas in it. I suppose the rough idle could be because it needs a tune up. And sorry to be kind of dumb, but where would I find these relays at, are they the ones under the dash? And are they labeled, if not how do I know which is which? Thanks a lot!

 

That sounds like a sticky IAC. If the iac is sticky, it'll do all of that stuff. My Vette is behaving that way now. Sometimes I start it and it wants to immediately run at 500 rpm. Other times it sticks at 2k.

 

Nope. You need to do some simple diagnostic to figure that out. You need to make sure you have adequate fuel pressure and fuel flow. Make sure you've got good spark at all plugs. Make sure you don't have any Service Engine codes, etc.

 

Could the injectors be either leaky or sticky?

 

in another post, i described how i fixed my start up problem by unscrewing the gas cap. for some unknown reason a lot of pressure builds up inside and causes my engine to act like it wants to die when i start up.... the moment i unscrew the cap, fumes come out and once it stops hissing, my car starts out perfectly fine. weird huh? anyone know why this is happening? it's becomming a constant thing now that everytime i go to start up the car, i unscrew the gas cap cuz i know it's gonna give me problems when i start up if i don't. lol

 

The fuel pump relay is located under the hood on the driver side on the firewall. there's 3 relays. When you're looking at the car, it's the one on the left. Not sure off hand which wire is which.

The problem also kind of sounds like your MAF sensor. God, you gotta love the MAF sensor (yeah, right). Hope this helps.

 

Hey, I just went out and bought a new relay for it the other day and replaced it, and it starts like a charm now! thanks guys! although, when I replaced it I only saw one relay that looked like it so thats how i assumed it was the fuel pump relay. do the relays for the MAF look different?

oh, and a while ago it was throwing some codes. now that i replaced that relay maybe it wont anymore. I'll check again when I get home.