Alright,

My car is running very rich at idle and someone who drove behind me said it smelled strongly like gas. I've been having an issue with rough idle/stalling when I start the car that lasts about 30 seconds and then goes away. It seems like the car is partially flooded. Sometimes I have to give it WOT while cranking to get it to start (usually only when hot). Also, this problem started around the same time I noticed my accelerated warm-up stopped working. It still comes on sometimes (usually when the car starts up perfectally) - but not every cold start like it should.

I've replaced the FPR and the car holds 31-32 psi of fuel pressure at idle.

I just replaced the plugs and tested to make sure that they are sparking.

The double throttle control appears to be working properly.

MAP sensor is plugged in.

While replacing the FPR I pulled the secondary fuel rail up and ran the fuel pump, no fuel leaked out.

There are no engine codes at this time.

Ideas would be great. Thanks,
-Charlie

 

i had a somewhat similar problem when i first bought my car. turned out to be the thermoswitch. im not sure why that would cause a rich condition and flooding, but once it was replaced the car ran fine.

are you stock?

 

Thanks for the reply. Are you referring to the thermoswitch that turns the fans on?

Yes, mostly stock. I have a downpipe and catback.

-Charlie

 

mine has similar conditions...smells like fuel on start up, not strongly but its def there...curious

 

The thermoSWITCH will not affect this. The thermoSENSOR (air intake or water) will!

 

Around the same time I started having starting/idling issues I noticed that my AWS stopped working every time - so, I'm convinced it is related.

I just tested the AWS solenoid valve with an ohm meter and it read 13.3-13.5. The factory manual says that it should be 9.3-11.3.

Would this valve going bad cause any of my other isses? (rich, poor idle, stalling, ect)?

Thanks,
-Charlie

 

IIRC, yes.

 

One thing that is worrying me... before I go spend $200 or however much a new AWS valve costs, is that there are no engine codes. Do solenoid valves go bad without throwing codes sometimes?

-Charlie

 

All the AWS does is by-pass air and jack your idle speed way up to pre-heat the cats.

If I had to pick something I would go with the water temp sensor. That sensor is pretty important until the O2 sensor warms up, enriching the mixture for start up.

 

Well the AWS solenoid is working properly. This problem occurs no matter what the engine temperature is. The double throttle control works properly, isn't that controlled by the water temp sensor?

-Charlie

 

Leaky fuel injector?

 

I'm starting to suspect the PVC line that runs to the oil filler neck. The hose is very hard and does not make a good seal around the nipple coming off the oil neck.

It seems like the valve is setup so that it lets pressure out of the intake manifold into the oil system until the pressure in the oil system is greater than the pressure in the intake manifold, then at this point it closes the valve off. Is this correct?

-Charlie

 

Scratch that - I don't think that a boost leak out the PVC would cause my idle problems. It looks like the check valve closes when the intake manifold pressure is negative as it is when idleing anyway.

As far as a leaky fuel injector, I know it isn't a secondary injector but it is possible that is a primary one. When I was testing fuel pressure I did notice a rapid drop once the pump turned off. I thought it may have been because I didn't use hose clamps on all the lines to the gauge, but I'll try it again and see.

-Charlie

 

the pcv check vakve will draw from the oil filler neck but not allow boost to the oil neck. one way arrow going towards the intake. if the aws valve failed for whatever reason or the air tract for it is plugged and you start the car out of gear it will bog and die because the ecu is injecting fuel like the rpm's will go to 3,000 even if they are not. it is not a feedback system. faults if open or shorted not if non functional. fuel drop off is a problem. crimp the feed and the return lines behind the gague so the gague and the injectors are pressurized together. clamp the lines, turn off the pump and see if the pressure drops. if it does the fpr, fpd or an injector is leaking. check the fpr by pulling the vac line and seeing if it has fuel in it

 

Well even with good clamps the fuel system doesn't hold pressure long after turning off the ignition. I'm going through the FSM and it says to test the fuel pump hold pressure... It says to plug one end and check the pressure but doesn't say anything about letting it sit to see if it holds pressure. The max pressure is within spec, but once the ignition is off the pressure drops pretty quick, is this normal?

mad7, my valve was installed so that pressure could be vented from the manifold to the oil neck, and not the other way around. Judging by the shape that the hoses are formed to, it has been like this for a while. Would this cause problems with idle and running too rich?

-Charlie

 

Alright, I did a pressure test and clamped the main fuel line (between the gauge and pump) before shutting off the ignition and the pressure dropped just as fast. So, I guess it is a fuel injector leaking? Would ohming the injectors tell me anything or is the only way to know by pulling them?

-Charlie

 

Would a fuel injector leak intermittently, or stop leaking once the engine is hot?

My engine lacks power, hesitates or stumbles under light load and backfires below 3,000 rpm only when it is warming up, but runs great when cold and fully hot.

 

Injector electrical resistance won't tell you anything about whether it'll leak. Leaking is a mechanical problem (bad seat seal, spring, etc.) I think you'll have to pull them.

 

I just did an ohm test on the air intake thermosensor and the fuel thermosensor and they checked out ok. I guess its time to pull the primar injectors.

-Charlie

 

you need to clamp the return line also for the fuel leak down to be accurate. then pull the vac line from the fuel pressure regulator. should be np from underneath especially if you have a dp. the oil thing is not a big deal just turn the valve around so that you cannot blow through it to the oil fill neck. sounds like you may be pulling the injectors to have a better look soon.

 

Well, I pulled out both fuel rails today and hooked them into the lines. With the pump running I didn't see any fuel come out of any of them. However, the primary injectors were both wet when I pulled them out and the secondarys were bone dry. This could be because I pulled off the secondary rail yesterday and didn't pull the primary until today? I haven't run the car for a few days, would gas still be on the tips of the injectors?

Thanks,
-Charlie

 

My Fuel System Tests Out Fine, But When Accelerating The Injectors Dump Fuel In The Midrange. What Could Be Causing This, Its Like An 80 Hp Difference From What It Should Be Running. I Have Been Testing This Problem For A Year And Have Not Been Able To Fix The Problem, Pettit Could Not Find The Fix Either.

 

yeah, sorry... i got that mixed up.

 

Davew, When I Was At Pettit Racing Trying To Sort Out My Car He Said That My Fuel Pressures Tested Out Great. Then He Said That He Benched The Injectors, This Means That He Basically Checked Resistance, Correct? If So This Means That I Could Still Have A Problem With My Injectors. They Were Flowed And Matched Last Year When I Had The Motor Rebuilt. Ever Since The Car Has Not Ran Correctly. With The Wolf 3d Computer We Were Able To Pull The Fuel Back While On The Dyno And I Made Mid 320 Hp To The Wheels At 12.5 Lbs. So Im Really Anxious To Fix This Damn Car....... Thanks For Any Help...

 

Is there a way to test the thermoSENSOR? I have the same issue of the car running pig rich at first start up and the rest of the day its fine....