i have a 99 sl1 that has an intermittent lack of power issue. it has a manual trans. and when shifting into 3rd gear typically and sometimes 4th on a cold start the car will go nowhere when giving it gas. i have to down shift and bring up the rpms to get it to move. now if i let the car idle for 5 minutes or so it has no issues. this happens any time the car sits for 15 20 mins or longer or has a chance to cool off a little. i have an oil leak from the head gasket that i am currently fixing and also did a compression and leak down test prior to the gasket that resulted in low compression in the number 2 and 3 cylinders (85 psi) 140psi at number 1 and 195psi at number 4. the leak down resulted that the valves were possible not sealing on the eshaust side and when pulled apart they were pitted a little bit. to end this story...i replaced the valves, stem seals, ground the valve seats and replaced head gasket but still have the same issue. where do i go from here? anyone?

 

Let me see if I understand you correctly -- when the car is cold, you put it in gear and let out the clutch and it won't go anywhere, but if the car is warm, it works OK -- is that right?

 

what are the compression readings post head gasket replacement?

 

OceanArcher: No, when this happens the car is already in motion. lets say i take off from a stand still, get through 1st and 2nd gear but then when i shift into 3rd gear, let out on the clutch so it engages, and apply the throttle, the car bogs down and has no power at all. i can put it on the the deck and nothing happens. it isnt until i downshift to bring the rpms up that i can get any sort of throttle response from it.

Derf: I will be gettin a post reading this week. i didnt have time once i finished the head gasket. but i will post them later this week.

Thanks to the both of you.

 

Post head gasket compression readings: cyl 1: 175; cyl 2 177; cyl 3: 182; cyl 4: 179 ( all went up but cyl 4 came down from initial readings. thought that was odd)

The head gasket took care of the low compression and oil leak but the drivability issue still occurs. I found out also that the ect gauge should read at around the half way mark when fully hot but mine only reads at the 1/4 mark. My initial thought was the ect sensor fault but it reads ok so my next plan of action is the t-stat. The only other part i would like to check out is the fuel filter but have yet to buy it cause its a little pricey seein how the fuel regualtor is built into it and i also have not checked just to see what comes out of it either. what do ya think?

 

sounds like you're running kinda rich. Don't forget these cars run open loop for a short time after startup, so it may only be in open loop mode that the car is misbehaving. Once it goes into closed loop operation and runs everything off the feedback from all of the sensors, it partially corrects for things--like adjusting the fuel trim.

The thermostat being stuck open would indeed make your car run cooler as you noted, and the ects, if measuring correctly, would indicate to the PCM that the car hasn't warmed up yet and will keep the fuel mix richer than it would normally be.

Suppose it's worth a try.

 

yeah a friend actually mentioned to me to monitor the fuel trim. i will take care of the t-stat, and monitor the loop status and fuel trim then get back to you on my findings. thanks a ton