I am having some problems when my car gets above 4000 rpms. It seems to run OK, but as soon as it hit 4k, my wideband starts dipping into the 11s and when 4500-5000 comes around it goes into the 10s. All the time while this is happening, my boost gauge it not showing any boost but my fuel pressure is right on 60 psi. The engine also starts cutting out and losing power. I have my pulleys set to max out my F1, and it was making 10-15lbs of boost on the dyno with a belt that was too long. I switched to a shorter belt, and it did run ok as far as I remember (this was a while back) after I put the shorter belt on, but I developed a hole in my intercooler. I have since replaced the cooler and have not had any luck since.

I pressure tested my system for boost leaks when I installed the fmic and tested it all the way to 22 psi and besides the 90 degree elbow looking like it was going to pop at any time, everything else checked ok. I tested the system again yesterday and found no leaks.

I pulled the plugs, and they all looked decent. The strap was kind of a light color, but not quite white. It was far from tan or brown, more of a galvanized metallic look. The electrode was brown and the insulator did look white. I went through several plug diagnosis guides and the closest one to mine that I found was:

http://www.globaldenso.com/PLUG/basi...ages/p1-13.jpg

Case 3
· Loss of power when running at high speed or under high load
· Piston breakdown



[Appearance]
The insulator leg section is scorched extremely white with small black deposits. Rapid electrode wear.
[Results]
Loss of power when running at high speed or under high load.
[Cause]
Spark plug incorrectly tightened, engine cooling problem, ignition timing too early, spark plug heat range too low, severely abnormal combustion

My car was also tuned in September so the air was cooler. It was tuned on 93 octane, but I put some 100-104 unleaded race gas in it trying to eliminate possibilities. I think Alan told me that the total timing was set on 18 degrees. I have been running TR6 plugs gapped at .035, but I went to a BP7EFS to see if it affected anything and it did not.

It seems like it has to be a problem with the boost, or lack of. I can not imagine my belt slipping, as I have the SDCE tensioner and the Reichard Racing blower pulley.

Since the initial tune, I have also switched from a M6 to a A3.

Sorry this is so long, but I like bringing in as many details as I can.

Is there anything you guys think I should look at? This is really beginning to frustrate me. I have only really been able to race my car once since last April. All these little gremlins keep popping up.

Please Help

 

Are you logging any of these events? Cutting out could be a few things, knocking/detonation could be occuring when this happens.

Don't see why it wouldn't build boost, RR pulleys are hard on belts if not set up right. Look for belt dust anywhere along the belt track. On the s/c brackets, pulleys, s/c face..everywhere.

Intake/vacuum leak? Maybe?

I feel ya tho, gremlins like these suck *****. I'm damn near in the same boat.
J

 

Haven't had a chance to log anything yet. I am waiting on a buddy to get his HP Tuners back.

There is some dust, but I my manual tension pulley is so close to a mounting bolt spacer that I think the belt was rubbing on the spacer at one time.

I am starting to wonder about the belt slipping though. I had a Napa belt on there to dyno, and I ordered another one from Pep Boys and they ordered a Dayco poly v belt. I have run that brand on my car before, but I am not sure how good it is for a FI application, especially for the speeds of a blower. I am thinking of putting the old belt that was too long back on there to see if anything changes.

Anyone else have any suggestions?

 

No boost on a RPM vs PE tune will be very rich and should cut out. I'd concentrate on getting the boost back. Do the easy stuff first...new belt,etc.....does it build boost at lower rpms?

 

Well, I was driving around tonight and started to play with it to see what it would do. I went to the floor with it and it seemed to be ok. I have had a couple of instances when my engine was sputtering and trying to die after I take off from a red light. I also remembered that my idle has been moving aroung a little here and there. I think it may be my O2 sensors. It seemed like I ran it up before without any problems when I was checking my boost. Now all the sudden it starts running like crap.

 

The same thing happened to me before i got the SDCE setup. I was running the stock 8 rib ATI tension setup trying to run 11-12psi and at 6000 RPM my A/F starts going downward towards 10's and the car stops making power (losing over 100rwhp compared to a prevoius 8psi run). We tried leaning out the setup, but nothing changed. It turned out to be major belt slippage even though we saw a little bit of dust. So on the final run we tensioned the belt more until the idler pulley bolt got bent and stuck in the J bracket. After that i got the SDCE tension setup and it fixed the problem.

I bet its a belt slipping problem because going rich all of the sudden is a indicator of belt slippage. When you have the belt slipping your car is still pumping the fuel needed for the boost that should be there, but now with belt slippage there no air to work with all the extra fuel added via the PE table (if you are still running a MAF) so you go into a rich condition.