Can't Boost....Feels like losing spark

[DSMULATOR]

**RESOLVED**

As soon as boost starts to build I feels like i just hill a brick wall. It used to only happen intermittently when it was raining and damp out but now its happening all the time. I'm def getting fuel because my WB02 shows rich and I can smell the unburnt fuel out my tail pipe (no cat). I have new Taylor race wires, BPR7s gapped to .022" and stock coils. I can test the coil resistance and voltage, but do they have to work harder under load? I am totally out of ideas. I have zero boost leaks.

 

[tbonitz301]

I would start by checking all of your wiring, and making sure all grounds are secure.

 

[DSMULATOR]

I've got an aftermarket grouding kit wired all over the engine and its worked fine for over a year. This problem used to be intermittent. I would change the spark plugs and it would go away. Now its happening every day...

 

[colonel_odem]

Exhaust leak? it almost sounds like your plugs are fouling because your wideband is 'thinking' that there is more oxygen going through the engine and is compensating with more fuel, which is being unburned since there are not enough oxy molecules to burn with that extra fuel. check any exhaust part before the O2 sensor.

 

[DSMULATOR]

The WB is in the rear 02 spot and I don't have any leaks. The front 02 sensor is getting old. It still sweeps but could it be causinng problems?

 

[colonel_odem]

Wait a second...hmmm, I don't know about the rear O2 I'm a 1g owner, but when you tune, you want the sensor to get the pre-catylized reading. and you want the sensor in the direct downstream current of your turbine, which improves the accuracy (O2 housing). You want that to be the sensor that is in control. I don't personally have a wideband or dual sensors, so if anyone wants to chime in, please do so.

 

[DSMULATOR]

You are correct, but I don't have a converter...

 

[colonel_odem]

wichever of the two sensors is telling the ecu what is going on, needs to be the closest to the turbo, the secondary is just for monitoring purposes. that one needs to be tricked to beleive that the cat is working. I was just reading on that. There is too much of a distance between the front and rear O2 sensor for the calculations to be good for the engine. The reason I am saying this, is because I belive the O2 is to blame. It could still be something else that I haven't thaught of...

 

[DSMULATOR]

When i installed the AEM WB02 last year, I took out the second sensor and put it in its location. I then got a CEL for rear 02 heater circuit malf. I plugged the sensor back in and left it in the car under the seat and the light turned off and it ran fine ever since.

I've read that the second sensor is not for fuel metering, just to make sure the cat is working properly.

 

[tbonitz301]

Your wideband is sweeping because it should be mounted in a bung 36" downstream of the turbo

 

[DSMULATOR]

The WB is not sweeping, the front 02 is. The downstream 02 sensor location is about 3ft from the turbo and the WB is reading what it should be..

 

[DSMULATOR]

Ok, I just came back from a test drive while going to get parts. It feels like it has more to do with airflow than boost pressure. I don't even get to a boost level high enough to blow the spark out even if it was weak. I can redline the motor if I'm barely on the throttle but as soon as I put my foot in it and it builds up then it breaks up. I didn't have my laptop but I will hook it up after work and take it for some runs and post logs. I really need help here...

I really want to blame the GM maf set up...mostly becauase its a chevy part on my DSM

 

[DSMULATOR]

Ita been ported and descreened. any way to test the GM units?

 

[DSMULATOR]

I took disconnected the transistor, sanded the bracket for the ground and reconnected it and its running back to normal. So don't know if it was a bad connection or bad ground. Or the transistor is bad and just by moving it around it bought me time, but its back to 23 psi with no sputtering....thanks for all your help guys.

 

[colonel_odem]

Ok, I just came back from a test drive while going to get parts. It feels like it has more to do with airflow than boost pressure. I don't even get to a boost level high enough to blow the spark out even if it was weak. I can redline the motor if I'm barely on the throttle but as soon as I put my foot in it and it builds up then it breaks up. I didn't have my laptop but I will hook it up after work and take it for some runs and post logs. I really need help here...

I really want to blame the GM maf set up...mostly becauase its a chevy part on my DSM

My car had this same thing before I blew it last year (I still need to fix it, I was married since then and had a kid $) It could be the gm MAFS/T as I too have that, but I switched out the sensor and it did the same thing. I had to feather the throttle in for it to go to the higher revs w/o falling on it's face. I changed wires, plugs, checked the coil. nothing. what had occured before this happening was that I ran through a flooded intersection, and the car acted up ever since. the only thing that I never checked was for leaks. and I never really did anything with the O2. I did log it twice, and everytime it did it, it was just crazy! everything went nuts. I recived knock like crazy. I really would like if we found this problem out that you are having.
the only thing with that MAFS, is that I read that the screen shouldn't be removed because of the air tumbling needs to be broken before it hits the sensor. I don't know how important that is or if it would be that big of a deal...

 

[colonel_odem]

, I take a long time to post stuff (I get up and go drink coffe, the wife yells at me) I just read the resolved part. Good Deal!!!

and it was your Power Transistor?