[cdygibson]

on my 88 civic when its cold outside... like under 30 my car is realy hard to start i have to pump the gas to get it to start an hold it at like 3 grand till it warms up or it stalls. i am getting the throttle angle code an i was told that the throttle postition senser would make the car do this. tell me what you think an what i should do.

thanks
cody

 

['9445]

If you're getting a throttle angle code, I'd start there. That's a pretty essential input to the ECU. The CRX service manual says the throttle cable is the first thing to check for "frequent stalling when cold" though. If it's DPFI, there's a vacuum activated thing (controlled by the ECU) that's supposed to close what honda calls the "tandem valve" but anybody else would call a choke. DPFI and MPFI both use another valve (EACV) controlled by the ECU to boost the idle when cold, if that isn't working you'd have no fast idle.

 

[toxiclows]

I have the intake and all stuff that was bolted onto it if you need parts. . . the throttle body ( dpfi unit ) is gone though. . .. i can drop it off if you want. . .

Chris

 

[ZeniceguyCRX]

sounds like the coolant temp sending sensor on the head. change that first

 

['9445]

sounds like the coolant temp sending sensor on the head. change that first

Yeah this could cause no fast idle too. If you have a meter you can check the TW sensor, it should have resistance 200-400 ohms when the car is warmed up. When cold it should be over 1000 ohms (5000 ohms at 0F).

 

[bobski]

If it's DPFI, there's a vacuum activated thing (controlled by the ECU) that's supposed to close what honda calls the "tandem valve" but anybody else would call a choke.

Actually, it's spring loaded closed unless the ECU activates the associated control solenoid, and even then it's dependant on the level of vacuum on the engine side of the plate. I wouldn't call it a choke... Chokes are designed to decrease air flow and increase intake vacuum, resulting in higher fuel flow and a richer mixture. If you look at the shape of the plate, it deflects air over the nozzle of the main fuel injector. It's there to help evenly mix the air and fuel, not alter the air/fuel ratio.

 

['9445]

If it's DPFI, there's a vacuum activated thing (controlled by the ECU) that's supposed to close what honda calls the "tandem valve" but anybody else would call a choke.

Actually, it's spring loaded closed unless the ECU activates the associated control solenoid, and even then it's dependant on the level of vacuum on the engine side of the plate. I wouldn't call it a choke... Chokes are designed to decrease air flow and increase intake vacuum, resulting in higher fuel flow and a richer mixture. If you look at the shape of the plate, it deflects air over the nozzle of the main fuel injector. It's there to help evenly mix the air and fuel, not alter the air/fuel ratio.

OK ... I have never looked at a DPFI intake closely, was just going by the diagram in the service manual, which showed a second plate above the throttle, but the drawing is very generic. Kind of sounds like it shouldn't affect starting all that much unless it's really cold outside. Is this another reason DPFI sucks, because this thing is partly closed a lot of the time?

 

[bobski]

Kind of sounds like it shouldn't affect starting all that much unless it's really cold outside.

Unless the plate is jammed and a foreign object is blocking the opening around the fuel injector, it shouldn't prevent starting.

Is this another reason DPFI sucks, because this thing is partly closed a lot of the time?

Likely. You could hold the plate open with a zip-tie on the armature to see if it has an effect on performance, idle quality or fuel economy.