se93

When i start my car (fully cold) fast idle speed is really slow increasing rpm's and seems to not be right. Usually, most hondas will start up (fully cold) and initial cold, fast idle speed will increase rpms rapidly. In my car, it starts and seems to not want to increase. It gradually does, and when warm runs with no problems. Is this a possible symptom of a bad engine coolant temp sensor? I get no check engine lights and car runs well, with the exception of on some occasions, the engine will shut down when coming close to a stop. Is it coincidence, but these situations have all started ever since i converted from automatic to manual transmissions.

Anyone have any suggestions?

BTW: When i converted to manual, we started to have problems with maintaining sufficient fuel volume levels. I got a walbro 255lph fuel pump along with an AEM fuel rail and regulator. I currently have fuel pressure at 34 psi at idle. I am running a chipped ecu, but at the moment am using the factory settings chip.

Jarrad_r6

I wonder if it has to do with the weighted fly wheel. It seems to me that the ECU may control the engine differently. It seems that with the extra moment of inertia it may require more fuel to spin the engine up faster. If the ECU still thinks that it is running a automatic I wonder if it isn't adding enough fuel fast enough. It seems like like the ECU should continue to adjust the fuel mixture until which would explain why it eventually gets to the proper idle speed. That may also be related to the engine dying. The extra rotational energy could make the ECU try to slow down the engine faster by shutting off the fuel to the point that it finally dies.

This is all being pulled out of my a$$, so let me know what you find out. Did you swap the ECU? Does anyone know what the differnce is, if any, between the auto/manual ECU?

Jarrad

se93

Jarrad

I replaced my chipped ecu and put in a stock JDM H22 MT ecu in its place. I also had the fuel pressure decreased from 36 psi to 32 psi before cold starting the car today. I saw that there was a pretty noticeable improvement in the cold idle speed and its way of behaving. Seemed to function more freely and with better and quicker acceleration at cold idle. I know that the honda service manual says that the H22 works well with 24-31 psi at idle. I had it at 40 psi and have gone down to 32 psi at the moment. Maybe too much fuel pressure at idle for the h22 considering that it uses this range of fuel pressure at idle. I can also say that with the stock ecu, my engine did not shut down even once when coming to a stop as it does with the chipped ecu. I used the chipped ecu with the stock/spoon program and had the same problems. I can say though that the spoon program is very good at reving those rpms in gear. They flow and move in a flash. I do not think the flywheel has anything to do because fuel volume is now stable with the addition of the fuel pump, regulator and fuel rail. With this first test with the stock ecu, it seems that maybe my chipped ecu is part of the problem. I am suspecting that the engine coolant temp sensor is not working as it should since the symptoms as mentioned in the honda shop manual point towards this sensor.

What do you Jarad and anyone else think of this?

se93

Jarrad

I replaced my chipped ecu and put in a stock JDM H22 MT ecu in its place. I also had the fuel pressure decreased from 36 psi to 32 psi before cold starting the car today. I saw that there was a pretty noticeable improvement in the cold idle speed and its way of behaving. Seemed to function more freely and with better and quicker acceleration at cold idle. I know that the honda service manual says that the H22 works well with 24-31 psi at idle. I had it at 40 psi and have gone down to 32 psi at the moment. Maybe too much fuel pressure at idle for the h22 considering that it uses this range of fuel pressure at idle. I can also say that with the stock ecu, my engine did not shut down even once when coming to a stop as it does with the chipped ecu. I used the chipped ecu with the stock/spoon program and had the same problems. I can say though that the spoon program is very good at reving those rpms in gear. They flow and move in a flash. I do not think the flywheel has anything to do because fuel volume is now stable with the addition of the fuel pump, regulator and fuel rail. With this first test with the stock ecu, it seems that maybe my chipped ecu is part of the problem. I am suspecting that the engine coolant temp sensor is not working as it should since the symptoms as mentioned in the honda shop manual point towards this sensor.

What do you Jarad and anyone else think of this?

Jarrad_r6

I guess I should have read your sig