1G break up at WOT yet good AFR's

[buhay6]

Ok I'm having a problem lately with my 1g breaking up under WOT and only WOT. I have a innovate LC1 installed to show me what my AFR's are and it seems to be very accurate. What my cars doing is it'll go rich under full boost (running waste gate pressure) I'll see mostly 9.9-10.9 AFR's at WOT and it'll start to break up, accel slow and then gradually start pulling like its supposed to. If I go less then WOT like say 50-75% throttle it'll be totally fine pull nice and I'll see proper AFR's 11.5 ish with no break up/ knock.
My off of boost AFR readings go between 14.7-15.4 is when I'm just cruising.
Ok I found another problem I seem to be loosing boost into my engine, like its coming out of my catch can breather what would cause this? my compression not a all bad and I've deleted the PCV because I've had this problem before.
1-140 2-154 3-154 4-153

mechanical timing's all good bang on so I'm thinking possible ignition problems, MAF, or ECU?
Anyone have the info on resistance testing for the coil packs and MAF (1g)
Any and all suggestions welcome!!
This should be my last problem before I start installing my go fast bits I've piled up.

 

[Talonman86096]

Check your plugs and wires?

 

[buhay6]

spark plugs are brand new but the wires are older.

 

[hotrodssnova]

What gap are the plugs? Afr on a stock 1g are stupid rich, like you are seeing. Plug wires or gap would be my guess. Pcv valve closes under boost iirc.
Sounds like crankcase pressure if you're blowing oil out the breather. Has your dipstick popped out yet?

 

[briansmith]

Yes. Too rich up top. Mitsu set the stock fuel tables Uber rich to keep from knock when the car new back in the 90's incase the owner used crappy fuel this was to keep a safety margin and keep from warranty claims in case the owner actually ran the car. Some from of tuning is needed to get those afr's in check. And stop fouling plugs. My max allowed afr is set to a 10.5:1 in my six bolt swapped 2g this is just a starting point and as soon as I get some good track times I expect to lean them out a hair more

 

[buhay6]

Bit of an update, turbo just let go completely smoke blowing every where.
Spark plugs are set to service manual specified gap. I deleted the PCV because a brand new PCV failed on me with in a week so I figured why not just by pass it and go directly to the intake snorkel and be done with it. Found the plug on the t-stat housing fit perfectly in place of the nipple in the 1g intake mani.
My dip stick has yet to pop out, I was going through a lot of seals for awhile (rear main, front main, cam seals etc) before I found out that a bad PCV was letting boost by and pressuring up the crank case blowing my seals etc.

I don't have a way of tuning at this time but am looking at ECMlink in the near near future. I have been able to get 30 mpg highway so I'm hoping I can increase it to 35 with a good tune.

 

[bmxfelon420]

Did you cap off the PCV port on the intake? Just checking.

 

[inthemidst]

I don't know if the oil/smoke from turbo can cause the wideband to read incorrectly someone add to this if its a fact.

 

[buhay6]

Did you cap off the PCV port on the intake? Just checking.

yes of course I did, I used the plug you find on the t-stat housing (grabbed from a spare housing I had) its the same thread pitch and size as the nipple threaded into the intake mani. I then took a spare BOV vacuum line and ran it from the PCV to the intake snorkel.

I don't know if the oil/smoke from turbo can cause the wideband to read incorrectly someone add to this if its a fact.

It shouldn't affect the readings I don't think, but it could possibly fry the sensor from what I've heard.
I think I'll send Justin a PM and ask if its possible to have a boost leak through the turbo oil seal, I just rebuilt the turbo 1k km ago but on original assembly I didn't realize until after that there were two different style thrust collars. Thinking me having to take the assembly apart and change out stuff might have compromised the seal.

 

[J'sDSM2]

There are a lot of factors since the turbo was about to break but it sounds like a possible knock issue. Did you have a larger turbo?

 

[buhay6]

I just had a ported 14b, I know it didn't do it on my old 14b which had a bad compressor housing gasket. I'm pulling the turbo tonight and going to swap on my old centre section install the compressor seal from my blown one onto it and run a few more blt's see if I'm still getting pressure built up in the crank case.

 

[oneslowwdsm]

You should def try gapping those plugs closer. It sounds exactly like spark blow out. I had the same issue on my old 16g setup at only 23psi it would start breaking up mid pull. Its easy to do and at least you know thats not the issue if it does the same thing.

 

[buhay6]

K i'll give it a try and knock the gaps a little closer.