Lean? Spark blowout? Belt slip? Unsure

[justinsstang]

2014 Paxton car. Torquebooster 3.33 pulley 9.7psi wastegate spring. 93 octane. Manual trans.

At 6k+ RPM the car creeps up from 10.8 to 11.2-11.4 AFR. Lund said this isn't lean, but wanted to share what all I see anyways. What it's doing is, at the 6k+ RPM, it starts cutting out and jerking around.

I thought it was lean, so I swapped out a kenne bell boost a pump for a JMS bap. I thought it was cured for a while, but I believe now I was just getting lucky as its doing it again.

So I know it's not the boost a pump.

I don't know what heavy belt slipping feels like, so I can't say if that's it or not. I did notice very light dusting a while back when I checked the back of my Paxton, but it wasn't much at all, and I didn't notice anything funky that. So is this what belt slip feels like? Maybe the cold weather just isn't letting the belt grip the pulley (20-40 degrees outside depending on the day so far in Illinois the past week).

Another thing which Lund said it could be is spark blowout. My plugs are gapped at .032. He said try taking it down to .028 and seeing what happens. Haven't done it yet, but I'm about to (just told me yesterday while I was at work).

Any other ideas, anyone experience this before and solve it, etc etc?

Considering selling the car and I have someone interested willing to put a deposit on it for me to hold it until they have time to come see it, but I won't sell the car like this. Any information is greatly appreciated.

 

[Jumpmaster2015]

Vacuum leak perhaps? The first thing I thought is maybe unmetered air is getting into the system, but Id imagine the tune would compensate by adding more fuel. In my experience cutting out and jerking is usually air related.

 

[92fiveohfox]

Check all connections for a boost leak. Is the bucking just at wot or are you talking about part throttle?

 

[Jumpmaster2015]

Check all connections for a boost leak. Is the bucking just at wot or are you talking about part throttle?

This too. Check the simple things first.

 

[Blazer707@TBR]

I've felt some bad spark blowout and what you are describing is what I have felt before. what plugs are you running? And try and take it down to .028 like lund suggested. That is what fixed the problem I've felt before.

 

[AKDMB]

I would say check the plugs as well

 

[cb900f]

2014 Paxton car. Torquebooster 3.33 pulley 9.7psi wastegate spring. 93 octane. Manual trans.

At 6k+ RPM the car creeps up from 10.8 to 11.2-11.4 AFR. Lund said this isn't lean, but wanted to share what all I see anyways. What it's doing is, at the 6k+ RPM, it starts cutting out and jerking around.

I thought it was lean, so I swapped out a kenne bell boost a pump for a JMS bap. I thought it was cured for a while, but I believe now I was just getting lucky as its doing it again.

So I know it's not the boost a pump.

I don't know what heavy belt slipping feels like, so I can't say if that's it or not. I did notice very light dusting a while back when I checked the back of my Paxton, but it wasn't much at all, and I didn't notice anything funky that. So is this what belt slip feels like? Maybe the cold weather just isn't letting the belt grip the pulley (20-40 degrees outside depending on the day so far in Illinois the past week).

Another thing which Lund said it could be is spark blowout. My plugs are gapped at .032. He said try taking it down to .028 and seeing what happens. Haven't done it yet, but I'm about to (just told me yesterday while I was at work).

Any other ideas, anyone experience this before and solve it, etc etc?

Considering selling the car and I have someone interested willing to put a deposit on it for me to hold it until they have time to come see it, but I won't sell the car like this. Any information is greatly appreciated.

Datalog tells all. If MAF flow doesn't stay proportional to RPM then you got belt slip.

 

[justinsstang]

Check all connections for a boost leak. Is the bucking just at wot or are you talking about part throttle?

By boost leak do you mean vacuum leak?

There's only one vacuum line you have to run with the paxton kit and that's the blow off valve line. Just T'd in to the brake booster and ran it to the bov. Don't think that'd be it.

And yes this is only at WOT above 6k ish rpm.

 

[92fiveohfox]

By boost leak do you mean vacuum leak?

There's only one vacuum line you have to run with the paxton kit and that's the blow off valve line. Just T'd in to the brake booster and ran it to the bov. Don't think that'd be it.

And yes this is only at WOT above 6k ish rpm.

I mean one of the pipe connections is not tight and letting air escape. Like cb900f said, data log it.

 

[gimmie11s]

1. Replace plugs with brisk or the NGK gapped at .028
2. Perform boost leak test. Go to hardware store and buy 4" plumbing cap from plumbing section. Pull off intake tube and Install cap. Add air to system and listen for leaks.
3. Verify boost pressure on gauge at 6k+ rpm.


11.2 is not lean. Something else is going on.

 

[bmoney50]

I had spark blow out issues at .32 when I upped the boost. Have you changed boost levels?

 

[justinsstang]

Not really upped the boost per-say. I had the 3.6 pulley on and have the NGK 6510 plugs gapped at .032. Swapped to 3.33 pulley and 9.7psi wastegate spring. Still gapped at .032. That's probably what up. I'll datalog it anyhow, and the highest it got was 11.4 which I thought was lean.

 

[justinsstang]

It finally did it during a datalog for me! I looked at it and sent it to lund as well, it's a misfire. Plugs need regapped or possibly new ones. They are the NGK 6510 with 8500ish miles on them. If I need new ones they sure didn't last very long lol. I did run torco 3-4 times though, might have something to do with it.

 

[kcobra]

Stupid question but have you logged knock to see if the car is pulling timing? This you feel big time!

 

[kcobra]

I run torco all the time with zero issues.

 

[Aaron@JPCRacing]

It does sound like you have some spark blowout. Especially with the AFR leaning up some when it starts acting up (which typically shows signs of a miss).

I would take the plugs all the way down to .025 and see how it reacts.

 

[justinsstang]

I dropped it to .028, problem solved! Ran better last night than it ever has since I installed the torque booster, amazing.