stlFD

I've posted recently about my hesitation problem and haven't been able to fix the problem. I get a severe hesitation at anything over light throttle in any gear, but if I give it light throttle and let it rev up to 4500 rpm, I can get full boost. Basically, the car runs fine over 4500 rpm. I checked tps voltages and it is fine. My relevant new parts are as follows:

plugs and wires
injectors cleaned by RC
o2 sensor
water thermosensor
egr valve
knock sensor
fuel filter
pulsation damper

I got an idea today that my knock sensor may be the problem. I am running on an engine with bad o-rings so when I start up the engine pops a little while burning off the coolant in the engine. (before I get flamed, my new rebuild is coming in this week. I'm driving the car sparingly) Could the knock sensor be causing my engine to cut timing or fuel or whatever even after the coolant is burned off and the engine is warm? Also the car runs rich. Any other suggestions would help. Thanks

dgeesaman

iTrader: (7)

It's probably not the knock sensor if it's new. I was going to say injectors but you have that already done. Given what you said about 4500rpm being the difference, I'd say it's a primary boost problem.

Do you have a boost gauge installed? If so, is this problem only happening when you're above 0psi and under 4500?

Dave

Mahjik

iTrader: (1)

Does the hesitation go away when the car warms up or is it there all the time?

stlFD

The hesitation is there all the time. I didn't mean that I think the knock sensor may be bad, I just thought that if the ecu interprets the coolant burning off as knock after I start the car, maybe it would affect the way the car runs after it warms up. I thought that the knock sensor would only retard timing temporarily when the engine knocks, but I could be wrong. What solenoids operate at light load up to 4500 rpm? I'll check to make sure, but I believe that the hesitation does only occur above 0 psi and under 4500 rpm. Once it's above 4500, I can give it more throttle and boost rises quickly.

Also, can anyone tell me if a PFC will allow me to monitor solenoid operation? I may jump the gun and buy one if it will help me diagnose this problem.

Oh yeah, I also replaced the check valves with viton ones from Dale Clark

1QWIK7

iTrader: (33)

I have a similar problem to this.

If i dont warm up the car much, the car will buck to a point where i have to pull over because the car basically doesnt want to move. So i have to let it idle on the side of the road til the water temp reads about 110F, then i can start rolling and the car will clear up.

But then one time i warmed up the car to about 110F and the car drove fine, drove about 8 blocks to the pizzeria, shut the car off which was at 125F when i shut down. Came back 10 minutes later and heatsoak raised the temp to about 185F. I idled for about 20 seconds, then started to drive off. The car bucked in first gear and thank god there was a red light, i stopped and let it idle. When the light turned green, the bucking cleared.

At first i thought it was a TPS issue but now this happened when it the car was warmed up as well. Usually clears after a couple of minutes upon initial bucking. The bucking doesnt stay with me for the entire drive. Usually upon startup as i assume after my short trip from the pizza place.

My question is, could this be the thermosensor being faulty? Doesnt it tell the ECU if the car is warmed up or not making it force more fuel into the engine? Maybe im running really rich when im bucking, when i idle on the side for a while, it clears up.

DOes that make sense?