Acceleration problems...please help me find a solution

[want-a-fast-svx]

Does the bead crush mod apply for a situation like this???Just a thought...Is your Cat, still good? ANy check engine lights?

[n00b on demand]

I was thinking about the ECU mod as well. One of the cats was cracked back in january but it was welded back. I have never gotten a constant check engine light. A few times the light has flashed and then gone away. Only twice since i bought the car back in Nov 03.

[oab_au]

Originally posted by soobiesvx93
Interesting observation tonight. As i was going up a hill i hit the gas and it again sounded like it was choking and i heard that loud growl from the intake that you hear when the pedal is pressed firmly ( i have my intake resonator out...hence the growl). It choked and then it flew...just like it always happens. Could something be wrong with the air/ fuel mixture?? ...maybe a vacuum leak? im so baffled. Also i had my exhaust gaskets changed in january and it sounds like they could be bad again. WTF is going on

Hi Mate , from what you say, it looks like the engine is staying lean when the throttle is opened. The "growl " that you hear, shows the air flow is increasing, but the engine is not responding. This would have to be either, the spark is in a retarded state, or the fuel has not increased to match the increasing air flow.

I think I would go for the fuel. The prime suspect would have to be the MAF sensor. This signals the increase air flow to the ECU, to increase the fuel injected.

Do you run a oiled air filter? Have you checked, the plug to the MAFS. The main intake tube, from the MAFS to the throttle bodies, for leaks, leaking hose connections.?

The next suspect, as the Swede Speed Master has said is the temp sensor signaling a hot temp, to lean the mixture. As you say "If you don't let it warm up, it will do it all day". This says to me that the ECU is losing a sensor reading, and is using the last reading to continue, as it will if a sensor fails.

Check the condition of the Air flow element, see if it is dirty, if so ,clean with a cotton bud soaked in fuel. Replace the Temp sensor. Cross your fingers and pray to the Suby gods.

All the best,
Harvey.

[n00b on demand]

Hmm that sounds very interesting. You make alot of sense as well. Looks like i'll have to be spending my next few paychecks to solve this problem.

[Mr. Pockets]

Originally posted by soobiesvx93
And no there is no smoke coming out of the exhaust. Only on cold mornings but that happens with every car.

To be more accurate, steam (which dissipates quickly) usually comes out of a car's exhaust on cold mornings, not smoke (which does not).

When I drove my car in winter, sometimes smoke did come from the tailpipes on startup in the morning. It smeeled heavily of fuel, and it seemed that's what it was - the ECU apparently overcompensates on startup when it's really cold out.

[n00b on demand]

Yeah steam is what i meant to say. Sorry

[n00b on demand]

bump

[n00b on demand]

Ok everyone i have a few theories on what is happening. Please let me know what you think of them. I have come to the conclusion that my problem is fuel related..being that i hear the intake growl when i hit the gas im assuming nothing is wrong with the airflow. My guess would be that the fuel injectors are extremley clogged. This could be why its running sluggish at times but still doesnt explain why the car runs beautifully when I let it warm up for about 10 minutes. It usually takes about 10 minutes for my SVX to be fully warmed up. What about the rest of you? This leads me to my next theory that the engine temp sensor is bad and needs to be replaced. Well whatever it is im not doing anything untill i get my tranny cooler installed. Then after that i will get the fuel injectors professionally cleaned and maybe a new fuel filter and new O2 sensors. Gotta take this one thing ata time. For now i will let the SVX warm up fully before taking it out and i will deal with the crappy mileage and the hesitation. But all of your input is welcomed. I need help tackling this issue!

[dcarrb]

I wouldn't think it's your fuel injectors.

dcb

[n00b on demand]

So then what would you suggest it is because i am truly stumped. A fuel problem was the only thing that i could think of being that i get crappy mileage and that if i give it some gas it wont go and then boom it takes off. Feels almost like the fuel is delayed or something. Thats why i thought it might be clogged injectors or bad fuel filter. I dont think bad O2 sensors would cause this...correct me if I am wrong. But this is a problem i'll just deal with untill i can find a fix or solution .

[dcarrb]

I'm not knowledgable in this area, but it strikes me as an engine-management sensor problem, as others have suggested. I recall you said you were getting an occasional CHECK ENGINE light. Have you tried to pull trouble codes?

dcb

[n00b on demand]

I just got a PM from someone saying they had the same problem as me and they replaced the O2 sensors and fuel filter and all is well. I am going to do the same and see what happens.

[Earthworm]

From what I recall the engine runs on a preset fuel map until warmed up. Once it's warmed up then the ECU uses all the sensors to adjust fuel accordingly.

Basically the engine isn't running optimally until it's warm and the ECU is in a "closed loop".

[n00b on demand]

could the engine temp sensor be bad and the car thinks its always cold?

[Earthworm]

If that was the case then the engine fans would be on constantly. When that sensor fails the ECU always assumes the worst.