Bad Miss under load

[boost92]

Ok, here is my problem. For the last couple weeks I have had this problem untill today when it did not go away. Whenever I start my car after letting it sit for a considerable amount of time untill up to operating temperature it would start popping and felt like somthing was holding it back. This was only in higher gears and it seemed like it was only when at about 0 vaccuum and up to any boost....after it warmed up it would go away and run smooth. Also at first start up it smokes a little white but clears up quick.
Today brought the new problem. It started off doing the same thing this morning but It never smoothed out I could barely run 10 miles per hour and would only sort of smooth out at very low RPMs. I shut the car off and came back later and started it up after it cooled and it ran fine untill i got out to the road and then it started again. Pulled the plugs and all are fouled and sooted up. smoking a tremendous amount of black smoke. Only bad sensor I know of is the 02. Any suggestions would be greatly appreciated.

Mods are :
RC 550's
Big 16G on 18 PSi
SAFCII
Hard Upper IC Pipe

Thanks for any help

 

[DSM AWD TSI]

Before you do anything, replace the 02 sensor, if that doesn't fix or help the problem, it will make it easier to find out what the problem is.

 

[97gstnick]

First and foremost I will say is to do a boost leak test. That is one of the most important things you can do.
With that being said, it sounds like the symptoms of a dead o2 sensor. The reason it runs fine when you first start it up when the motor is cool is because it is running in open loop. Open loop doesnt use the o2 data as exclusively as it does in closed loop. Once your motor reaches operating temp it attempts to go into closed loop where it ONLY pays attention to o2 data. Then the o2 dies it will read super lean, which essentially causes the ecu to spray way too much fuel. I cant remember how long it takes but I believe if your o2 doesn't cycle for a certain amount of time it would go into open loop anyway. Does your car drive bad when it reaches full temperature and then start driving better a little bit after that?

 

[boost92]

Ok here is exactly what it would do. I would start it up in the morning before leaving for work..idle surge a little bit, smoke a little white..About 30 seconds later i would back out of the drive way everything seems fines. When i get the road i would take off in first and it would be fine I would shift into second and as soon as it started to build even just a little boost it would feel like i lost all power and someone was pushing on the brakes.. Turbo would spool and rpms would stay about where they where. After it warmed up a bit this would all go away.. Now it doesnt... It is worse in every gear and it is Not drivable at all. Wont idle unless i help it a little. person behind me while i was limping it home said it was dumping black smoke. and plugs are solid black with soot. So i assume its getting fire just getting way to much fuel. The person I got the car from said it has a walbro 255 but from what I can see it still has a stock FPR which I heard will not work with a 255.

 

[rstchris]

The 1g fpr flows better than the 2g, that shouldn't be the issue, get the o2 replaced and get the fuel trims dialed in. You should also run a test light around the plug wires to see if they leak.

 

[boost92]

Sorry if this sounds dumb but how do I run a test light around the plug wires to see if they leak. Ive never heard of this.

 

[95blackGsTurbo]

Ok here is a list of the stuff you need to do. First do a boost leak test. Build one, borrow one, do whatever you need to do. Even if you don't have one it's always good to do them.
IC Pipe Tester

Next if you have the availability, get a volt meter and hook it to the signal wire and ground from your o2 sensor and make sure it is fluctuating properly. If not replace it. You can find the single wire here.
Finding the O2 Sensor Wire

Next you need to get some sort of adjustable fuel pressure regulator. You are overrunning your stock one and causing all sorts of driveability issues. Shouldn't be a big deal when just cruising but when really on the gas your A/F's are going to be very inconsistant.

Next replace the plugs, put a little seaform down in the cylinders to clean off all the carbon from running so rich and go out and drive the car. If you do all of these things you will be amazed at the power and how much better overall the car runs.

 

[boost92]

Thanks! I think I found my problem today. It just so happens that one of my I/C Hose Clamps had come off and I had a huge boost leak. When trying to change the fuel filter (which was stopped up) I crimped the fuel line so I had to cut it off. Does anyone know what size the line is? I grabbed a 3/8 from the parts store but it is too big. I am also trying to change my o2 sensor becuase it is deffinatly bad (im getting a .02 reading all the time.. and my CEL light came on and gave me code 11). I am having trouble though getting the sensor out of the housing. I took the manifold and housing off and the sensor is in there really good! Any suggestions? Thanks for all your help guys.

 

[95blackGsTurbo]

Go to your parts store and ask for an o2 sensor socket. When you installed the new one make sure to pick up some anti-seize and coat the threads in it. Try 5/16ths fuel line and make sure to get good clamps on it if you are going to be using rubber from the filter to rail.

 

[97gstnick]

Boost leak tests reign supreme. Its amazing how many times this test can answer the thousands of questions out there.

 

[boost92]

Well it seems now I have a new problem. I had to cut the fuel line off going to the bottom of the fuel filter because the head of fitting was stripped. I was not aware that the fuel lines and fittings are metric. Can anyone give me any pointers on were to find a metric fitting for this fuel filter besides Mitsu.. Autozone, Oreily's and Advance dont have any. Just standard

 

[zhjiln]

you are running too rich, ruining your spark plugs resulting in the miss under load.. ergo youve got a boost leak test to do sir...

 

[boost92]

thanks but yeah they answered that a long time ago.. All thats left now if fixing the fuel line. but no one stocks metric fittings for the fuel filter. My roommate suggested changing the fuel filter to a gm style. Im not sure if anyone has done this. Any input?

 

[95blackGsTurbo]

I would recommend getting all SS line and an inline fuel filter and SS from the filter to rail. I might not be the most cost effective way but is a nice modification to do if you plan on modifying the car anymore.

 

[boost92]

im looking for a cheap but reliable fix for this at the moment. All I need is sizes of fittings and lines if anyone knows. Thanks

 

[boost92]

Fixed and back to running again. It runs really great but Ive got this strange little blinky light show going on on one of my gauges now that i replaced the o2 sensor.....just kidding... Thanks for all your help guys +1 for dsmtuners.com