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This car has the B18A1 engine with 198,000 miles. It is all stock and burns some oil. It will start and run ok until the normal operating temperature is reached then it acts like an unruly teenager or a spoiled brat 2 year old. After sitting at a red light for a couple of minutes the car wants to stumble and stall instead of accelerating normally. If I manipulate the gas pedal just right I can prevent the car from stalling and proceed down the road. I checked the fuel pressure and it read 30 PSI when the key is turned on and also when it idles. When I open the throttle the fuel pressure rises to 40 PSI. When I disconnect the vacuum line to the fuel pressure regulator the fuel pressure also rises to 40 PSI. I removed the throttle body and cleaned it with carburetor cleaner and reinstalled. I sprayed carb cleaner all around the vacuum lines, intake manifold gasket and throttle body gasket but found no leaks. I measured the throttle position sensor with an ohmmeter while opening the throttle plate slowly. It was linear throughout its range with no dead spots. I removed the idle air control valve and cleaned the dirty screen with carb cleaner and then reinstalled. I opened the fast idle thermo valve and adjusted the inner washer fully clockwise and resealed. Then I bled the cooling system. I checked to see if there were any codes stored in the computer but found none. What should I check next?
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Thanks again guys for all the assistance. I checked for codes in the computer and found only one which was code 6. This code is for the engine coolant temperature sensor. I must have induced this code on 11-10-2011 when I disconnected the electrical connector from the sensor to connect the ohmmeter while the engine was running. I removed the negative cable from the battery terminal for a few seconds and reconnected it to erase the code. I will continue to check for codes on a daily basis. I could not find an EGR valve on this car which has a manual transaxle. I think that some automatics have this valve. To answer the question. After I have stopped at a red light I will manipulate the gas pedal and try to increase the RPM’s above 1000 if I do this sucessfully the car won’t stall so I guess the magic number is about 1000 RPM’s. Keep those suggestions coming, I will try to check anything that you think might be causing this problem.
Does it want to stall in all gears with it being a manual trans?
I would be looking at a possible clutch issue. I would check the cluctch free play and the linkage/hydraulics to make sure everything is adjust correctly. It could be that your pressure plate is not releasing fully.
It is true that the manual trans engine does not use an EGR. As for the code it’s a pretty important one and can reak havoc on the fuel mix so if you have pluged it back in to the CORRECT spot you should be good, if memory serves there are 2 similar connectors there and if you mix them up it will cause problems with the fuel mixture. One connector is for the fan switch the other is for coolant temp, you can identify which goes where by looking at the color of the connector and the color of the sensor, match up the like colors and you should be hooked up correctly.
Your problem was exactly like the one I had on my ’89 Honda Prelude Si. I could open the throttle when the engine was cold and the engine would accelerate normally. While driving, power and acceleration were normal while the engine was cold. But once the engine reached operating temp I had to feather the accelerator pedal at stop lights to keep it going and it would be hard to start if I failed. Power good if I could get going again and keep the RPM up.
Eric says to stick to the basics so I started checking plug wires, coil, and plugs. Lo and behold, I replaced the Denso plugs with NGK plugs and that fixed the problem. One of the old plug’s electrode and lower portion was brown. The other three showed evidence of carbon fouling, a symptom of rich running. I installed the old set 37,000 miles and 7-1/2 years ago.
I still can’t figure out why the stumbling problem would appear at low RPM/idle but only when the engine warmed up. I replaced the EACV with one from a junk yard 39 months ago but did not recheck now. The Fast Idle Vale is good. Vacuum at idle when cold and valve closed (no vacuum) when engine warm.
Nor can I understand why the stalling problem arose after just letting the car sit all last winter. It ran fine until the winter came but in the spring it wouldn’t start until I bled the cooling system. But even when I could start it again there was this odd problem of stumbling and stalling at operating temp.
However, there’s no denying that now after plug replace acceleration is smooth whether engine is cold or warm. No more dying at stop lights.
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