Running rich until fully warmed up?

[TsiFwd96]

My 2g(6-bolted) has started running completely rich (DSMLink reads 1.1v) till it warms up after driving for some time. Air/Fuel gauge is all the way rich and when warming up it almost lights up the whole gauge. If I rev the engine and let off the gas it will read down to .98v for a second. I changed the coolant temp sensor and nothing changed. Any ideas or things to check for? It was running fine before and all of a sudden this just started happening. DSMLink setting are the same, I already checked the FPR's vaccum line, no visible sign of o2 sensor shorting out, no CEL's are thrown. Injectors are 660's and a 255 fuel pump.

 

[crunchymilk]

Do you have an FPR for your 255? Are you venting your BOV?

 

[andymoraitis]

Please fill out your vehicle profile. We can't diagnose what's wrong if we don't have a baseline of what's installed.

Thanks,

Andy

 

[nightspeed87]

i do believe our cars are suppose to run rich until it reaches operating temperature of about 185-195 but maybe not as rich as yours suggesting. my a/f ratio gauge does that too everyonce in a while, it could just be something with the gauge, but i dont really trust what it says not very accurate, but if you have link you shuold be able to sort out your issues.

 

[drewvr4]

yea its the cold idle thing...most people have the problem with the idle surging...one of the reason for that is the fiav on the throttle body...i noticed mine doing the same thing

 

[TsiFwd96]

I don't have an aftermarket FPR and I'm venting my BOV back in.

So it sounds like maybe the FIAV? Any tests I could do? Or does anyone think it's more likely to be something else? I thank everyone for their input/suggestions.

 

[TsiFwd96]

Oh, and my idle isn't surging.

 

[drewvr4]

if your not running a fpr with a 255 thats your problem...the stock one works up to a 190 then you need to get another

 

[TsiFwd96]

I've been running the stock FPR for years without problems. What's a good one to buy and how do you set them to the right pressure?

 

[andymoraitis]

You may think you've been running the stock FPR on a 255 without problems, but what aren't seeing is that your base fuel pressure is likely 8-10 psi on the heavy side. This washes fuel past the rings, dilutes the oil and makes your motor run like a dog.

A good kit is the Aeromotive push lock setup from:

http://www.importevolution.com

Make sure you buy a liquid filled gauge and re-set your pressure to the correct base (43 with the vacuum line off).

Cheers,

Andy

P.S. Thanks for updating your profile but you didn't list any tuning device. Please tell me you're not running 660 injectors with nothing to control them. If you don't you'll need more than an FPR to deal with your overly rich tune.

 

[drewvr4]

ahh he beat me to it...what he said ^

 

[slipstream808]

No, no, he has a DSMLink (his first post). What are the O2 volts reading on it? Are they cycling at all?

 

[slipstream808]

Oh yeah, and what are your STFT, and LTFT's like? If you are getting FPR overrun, then you should be seeing STFT and LTFT Lo in the VERY negative after your car gets to it's learn mode (175 degrees I think).

But 02 should start cycling almost right after startup.

 

[TsiFwd96]

O2 readings are 1.1v and does not cycle until after driven for at least 10 minutes or so. I'm waiting on an aftermarket FPR. I'm still not sure that it's the whole cause of it all, but it's better to put an aftermarket one on there anyway.

 

[JeCliPz]

I don't see that anyone has suggested this, and feel free to disagree with me, but your o2 sensor is heated and, if it has gone bad, could possibly be giving an inaccurate reading until the car has warmed up. Also, I had the same problem once and found that I just had a leak in my IC piping, causing A/F ratio to run rich.

 

[andymoraitis]

A failing O2 will usually read lean and dump excess fuel, but an O2 that cycles very slowly could indeed be on it's way out. What concerns me are the Denso 660's as these are notorious for having inconsistent flow rates. I bought a set and had them flow tested. The rates were between 700-720 and it would have been extremely difficult to get a consistent tune from them. Add that to the 255 runing on the stock FPR and it's a messy situation at best.

 

[nightspeed87]

to be honest my 190 overruns the stock fpr and i didnt think it would when i bought it... Its a walbro "highpressure" 190... ( Yea i didnt know they made highpressured 190s either till i found this one ) and maybe that could be the over run reason because its highpressured, but it makes the exhaust pop if i rev it up high and let it rev down by itself, and you can smell gas flowing out the exhaust as it revs down by itself....( You have to go by the exhaust to smell it, its not to the extreme because you wont see black smoke or anything coming out, just a scent of gas ) So yea im eventually going to get a afpr too.

 

[DarkSwatCobra]

hmm...you cant be dumping all that much if ## not seeing black smoke...

 

[FORMONTOYA]

You can actually be running quite rich and never see any black smoke at all. Of course the tip will be coated in black.