problem when at WOT

bleeatch · May 20, 2004

i have a pretty much stock 89 GT (cobra intake mani and cold air is all) and lately when i get on it, well anytime the gas pedal is over 3/4 the way pressed, my car all of a sudden feels like im driving against 500mph wind, the RPMs still go up i just have no power and dont take off like before. Also after driving for a while i can start to smell gas, and the car tends to ping alot at half throttle. please help me find whats gone bad. thanks

bleeatch · May 20, 2004

anyone?

astronut1885 · May 20, 2004

Sounds like a fuel system problem to me. Check your pump, injectors, regualtor, all of that. If it's pinging, then it's running really lean, and it might be running super lean at WOT. That's my best guess.

CivicEater · May 20, 2004

Sounds clutch to me since the RPMS are rising......

astronut1885 · May 20, 2004

clutch won't cause pinging, or a bogging semsation, it'll just rev straight to the limiter.

87'GTstang · May 20, 2004

I second the fuel system, sounds like your engine is gasping for fuel. What about if you gradually accelerate and slowly floor the pedal (as in over time versus instantaneous)?

Another theory is since you said you smell gas, then maybe you have a fuel system leak. When you floor it, the fuel raises pressure enough to cause a leak somewhere, but the mixture is sent up because you floor it and you have a lot more air going into the engine but because you have the fuel leak you are in trun running lean which causes the pinging......too far-fetched?

ninety15.0 · May 21, 2004

I am having the SAME EXACT problem! i have been trying to figure it out for like four weeks now, and i have gotten no where. This is what i did: Pulled codes, just to see if anything is comming up, nothin. Checked entire EGR system (valve, solenoid, connections). Full tune up, plugs wires cap rotor pcv fuel filter, cleaned K&N MAF and TB. none of that stuff worked. So i checked fuel pressure and vacuum, and both were fine. Although i didnt have a guage mounted in the car to see what happened under load at WOT, so it could still be fuel! then i removed and cleaned IAC, and checked the TPS voltage throughout entire pedal travel. both were fine! as of now i have run out of ideas, so im gonna have to bring it to my mechanic and see what he comes up with. good luck man tell me if u find the answer!

87'GTstang · May 21, 2004

ninety15.0 said:
I am having the SAME EXACT problem! i have been trying to figure it out for like four weeks now, and i have gotten no where. This is what i did: Pulled codes, just to see if anything is comming up, nothin. Checked entire EGR system (valve, solenoid, connections). Full tune up, plugs wires cap rotor pcv fuel filter, cleaned K&N MAF and TB. none of that stuff worked. So i checked fuel pressure and vacuum, and both were fine. Although i didnt have a guage mounted in the car to see what happened under load at WOT, so it could still be fuel! then i removed and cleaned IAC, and checked the TPS voltage throughout entire pedal travel. both were fine! as of now i have run out of ideas, so im gonna have to bring it to my mechanic and see what he comes up with. good luck man tell me if u find the answer!

Did you ever check the WOT relay I posted in your thread?

ninety15.0 · May 21, 2004

Yes i did check that....thanks for reminding me about that. haha i have checked soo much crap i think i have forgotten some stuff i have done. The ground and voltage were both fine on the WOT relay! i cant figure this thing out!

bleeatch · May 21, 2004

87'GTstang said:
I second the fuel system, sounds like your engine is gasping for fuel. What about if you gradually accelerate and slowly floor the pedal (as in over time versus instantaneous)?

Another theory is since you said you smell gas, then maybe you have a fuel system leak. When you floor it, the fuel raises pressure enough to cause a leak somewhere, but the mixture is sent up because you floor it and you have a lot more air going into the engine but because you have the fuel leak you are in trun running lean which causes the pinging......too far-fetched?

when i gradually accelerate its fine, i could take it to redline if i wanted to, its just when i stomp on it. thats a good point about the fuel leak, ill look over the fuel lines tomarrow.

jtstang89 · May 21, 2004

Same thing happens to me, just not all the time...its really weird. I ran a diagnostic test and the codes that I got were concerning the EGR valve positioning sensor, and my o2 sensors. Would the sensors come up just because I gutted my cats...Or do I need to replace them?...also, a friend of mine had the same problem with his '92 F-150. He solved the problem by replacing he Throttle positioning sensor, so I could be that....sorry I couldn't help much, but If anyone has any input on the O2 sensors, I would really appreciate it (especailly if it can help me get over 16 mpg again!).

HISSIN50 · May 21, 2004

IIRC, the puter does not use lambda sensor input at WOT....
i think that is directed at the post above me, but with so many folks asking stuff on one thread, i cant keep it straight.

good luck to all.

astronut1885 · May 21, 2004

O2 sensors don't have any effect at WOT. There could be ignition problems which are causing you to run rich at WOT, but the pinging wouldn't jive with that. What's your timing set at? If you have a volt reader, check your TPS, it should go from .99 volts closed to around 4.00 volts open. Do this by turning the key on, and testing the voltage while opening and closing the TB. Your fuel pump could also be on it's way out, my old GT had this problem right before it died. Are you sure it's detonating at part throttle? Maybe it's something else. Detonation sounds like loud static, or like marbles in your motor, but either way it's really freaking loud and you know it's happening for sure.

bleeatch · May 21, 2004

yeah i know for sure is detonation, it only does it when the car has been running a while and its the middle of the day and hot out. my timing is at 10* and im running 89 octane (it still acts the same way with 91 octane) I can smell fuel too, so you think that a small leak in the fuel lines would cause the loss of power and also causing me to run lean and ping, like 87'GTStang mentioned? or maybe my fuel pump is goin out? ill do a fuel pressure test this weekend, what should my psi be?

astronut1885 · May 21, 2004

around 38 I think, but it won't show a bogus pump because the car won't be running at WOT.

GTRocks · May 21, 2004

I'm betting you have a dirty MAF. If you have a CAI, I'll double the odds!

Pull the MAF off and look inside. At the top there is another small circle housing that has two small wires inside it. They have a tendency over time to pick up impurities in the air. These small wires are essentially resistors that tell the computer how much air you are pulling in, and that data is used to calculate how much fuel to mix in. Take a Q-tip and some carb cleaner. Spray the Q-tip with the cleaner and GENTLY clean those two wires. Just rub them gently and be amazed at the crud that comes off of them. Put it all back together and smile at the 25 hp you just gained!

87'GTstang · May 21, 2004

GTRocks said:
I'm betting you have a dirty MAF. If you have a CAI, I'll double the odds!

Pull the MAF off and look inside. At the top there is another small circle housing that has two small wires inside it. They have a tendency over time to pick up impurities in the air. These small wires are essentially resistors that tell the computer how much air you are pulling in, and that data is used to calculate how much fuel to mix in. Take a Q-tip and some carb cleaner. Spray the Q-tip with the cleaner and GENTLY clean those two wires. Just rub them gently and be amazed at the crud that comes off of them. Put it all back together and smile at the 25 hp you just gained!

Wish I had MAF

No offense, but 25 hp, i'm not thinking that drastic.

bleeatch · May 21, 2004

alright ill try that when i get home tonight. does it have to be carb cleaner? i heard rubbing alcohol will work

HISSIN50 · May 22, 2004

electrical contact cleaner works....and if you do use something to touch the wire, be VERY careful. i would not have the guts to touch it, but you folks are braver than i am.
good luck.

GTRocks · May 22, 2004

What's the alternative? Leave the car running like crap? It's not hard, but just don't go in there like Hercules. Be gentle, rub lightly and you shouldn't have any problems. You can use about any cleaner that won't leave a deposit. You want something that will evaporate. Alcohol should also work. You want something that will lift oil deposits, particularly if you have a CAI. When these wires get really gummed up, they really get you bogged down. I think 25 hp is conservative. I got beat off the line by a LeBaron. That's when I knew I had a problem!! That was followed soon thereafter by backfiring under WOT.

I cleaned the MAF and **SHAZAM**

Still looking for that LeBaron!

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