Ok,
I am trying to diagnose a problem I am having with my car. First of all, I have a 1994 FD Automatic. My only mods are downpipe and k&n drop in filter. Second, let me describe the symptoms I am having. When I first start the car, say inthe morning, and I let it set there and idle up to normal operating temperature. I then take off and my car is amazing.........enormous boost and pulls very strong, then once i get to the first stop sign/light and come to a completes stop and take off again, I have very little to no boost. I have a very faint smell of fuel coming from the engine bay and when slowing down or letting off the gas im getting a backfiring noise. I have changed the plugs, checked for vacuum leaks and changed plug wires. What else could this be? It appears that its something either affected by temperature (cause i have one run with full boost) or something being loaded up with fuel (hence the backfiring and fuel smell). My car is not throwing and engine codes. I did notice that I had a wire loose for a sensor on the fron side of the thermostat housing. I have found this to be a "water thermoswitch" for the AUTo TRANNY. Could this be my problem? If this switch was bad would it throw a engine code? I am in dire need of a remedy for this problem.

Any help is very appreciated!

-Cody

 

describe the backfire noise? like a pop or a deep hum?

 

its a loud popping noise.

 

check map sencor

 

bump

 

Check the map sensor.

Anyways that thermo-switch will run the fans 100% of the time if it has an open (which it sounds like yours does). It will not affect boost unless you had an additional electrical load unit issue.

Anytime you faintly smell fuel, you shouldn't be driving a car which has a furnace under the hood.

 

When you say "not throwing codes" do you mean that your check engine light is not on, or did you actually go and try to pull a code out of the ECU?

It really sounds like a thermo sensor problem to me. But then again, the fuel smell worries me. Is the smell strong in the engine comparmtment?

Check for codes and reset the ECU.

-bill

 

ok after doing somelooking around the engine i noticed the check valve for the purge control was backwards (arrow pointing away from UIM)........could this be my problem?

=Cody

 

ok i switched the direction of this check valve mentioned earlier. Problem Solved. The car is amazing! Damn check valves.