Light miss/hesitation at full boost.

[punkrocker00406]

Hi, I have a 90 TSi. Engine is stock, Stock 14b. Mods include all emissions removed (blocked off EGR Valve, charcoal canister removed, no catalytic converter.) Hacked air can, Hallman MBC set to 15 psi, 255lph fuel pump, AFPR set to 38psi base fuel pressure, 8mm spark plug wires that are under a year old, new plugs. Now on to my issue, most of the the time at full boost it has a small miss. I have a data logger but am not real sure what to look for in the readings other then knock being bad . So heres the reading I got in a 3rd gear pull on 94 octane pump gas. I am getting a high knock reading. The knock reading in this pull went from 0 to 5 to 22 to 21 to 14. I will give the read outs when i was getting the knock count of 22.

RPM... 4656
INJP... 19.19ms
KNOCK... 22
02-R... 0.85v
TPS.. 99.6%
INJD... 74.2%
TIMA... 15 degrees
02-F... 2.08v
MAFS... 1603.9Hz

So obviously I'm getting bad knock. Which is probably the root of my problem, but considering I'm running 94 octane pump gas which to my knowledge should be good enuff for 15psi out of a stock 14b, what can be causing my knock. Also, are thoes other readings normal? Like i said i dont know anything about where the 02 reading or any of that should be under full boost. Thanks

 

[punkrocker00406]

That is understandable. BUT, I have been running this set up for some time now with good results, this just started happening out of the blue, leading me to believe something is screwed up. Know what I mean?

 

[punkrocker00406]

Not as far as I know. The previous owner bought it and broke a shift fork and parked it. Then i came along and bought it, I'm not sure about the owner before that. When i bought the car a little over a year ago it had 93,xxx on it and I just turned 100,000 2 days ago. Do you know of any way to test the coil packs to see if that is my issue? I defenitly dont have the money to spend on the wrong part.

 

[punkrocker00406]

Well when it first started having this problem it had the same ngk bpr6es that were in it when i bought it. I had my dad buy plugs for me because i was busy, which was a mistake because he bought bosch platinums. Which I know i shouldn't really use them, but i put them in any way and the problem was still there. As of right now the bosch platinums only have 400 or so miles on them.

 

[punkrocker00406]

Thanks for your advise Mikuda, If any one else has any other ideas i would love to hear them!

 

[punkrocker00406]

Ok , I put NGK BPR6ES's in. Gapped them to .28. The missing is much harder to notice now, but there is still some present. I didnt have my data logger with me but tomorrow i will log a 3rd gear pull again and see how much knock i am getting now. But about the plugs i took out today. All 4 are pretty white. My uncle said in his opinion he thinks that means its running lean. Is this true? If this is true what could cause this considering i have a 255lph fuel pump and afpr? Like i said at the beginning of this thread, I am on a stock 14b at 15psi on 94 octane pump gas. Please help. Thanks!

 

[bacalhau16]

All white does mean that its running lean. Try turning up the fuel pressure a little bit. That may help. One or more of your injectors may also not be flowing well. Not sure how keen people are in using an injector cleaner on DSMs, but taking them out and cleaning them isnt all that hard either.

 

[punkrocker00406]

I actually had that thought run through my mind about cleaning the injectors, but all 4 plugs are equally white, wouldnt you think if it was dirty injectors it would be one or 2 of them. What are the odds that all 4 injectors would be plugged the same amount and all 4 cyls. would run equally lean. Am i right in thinking this?

 

[PitBullDsm]

8mm spark plug wires that are under a year old, new plugs.

WOT Miss - Not Spark Plugs/Wires!

You should at least test the wires, as this is a common problem when they fatigue.

 

[punkrocker00406]

Bad spark plug wires can really cause it to run lean and have knock?

 

[punkrocker00406]

Only reason im asking is because i have had a plug wire leak on me before. To the point to where that cylinder would stop firing completely. And that is not what kind of miss i am having right now. Know what i mean?

 

[Rob10_99]

Your plugs shouldn't be all white.
The ceramic should look fairly white/ceramic like.
The gap should be .28(or less)
The ground part of the plug should be the only metal part thats white, and it should stop at the base of the threaded area.
If your clueless I suppose I could pull a plug and take a pic for you, I'm sure my 7's havent overheated on my B16g pile in my garage.

Most important is that the gap isnt too big, bigger the gap the more resistance the spark has.
And that means the easier it is for it to jump somewhere else, a cause of high rpm missing.

 

[punkrocker00406]

Like i said. I gapped them to .28. And the side electrode (the part that the spark arks to) is the part that is white.

 

[PitBullDsm]

Only reason im asking is because i have had a plug wire leak on me before. To the point to where that cylinder would stop firing completely. And that is not what kind of miss i am having right now. Know what i mean?

Yeah, I misunderstood. Bad wires wouldn't cause knock and a lean AFR

 

[punkrocker00406]

Any one else have any ideas on why i would be running lean?

 

[punkrocker00406]

Ya mine whines like that also, I just looked over the vfaq on how to do the rewire. When i get a couple extra bucks ill look into buying one of these relays and wire ill need. I havent replaced the fuel filter, ill look into that also.

 

[punkrocker00406]

Could this possibly be a timing issue?

 

[punkrocker00406]

Do you really think thats gonna make a difference for me fame? Im on a stock 14b at 15psi. and i JUST put new BPR6ES's in 2 days ago.
Also I would like to add that i ran my car almost out of gas today and put a half tank of 93 octane in (which is what i ALWAYS run) and i did 2 more 3rd gear logs and between the two the higest knock count i got was 9. So i think i may have had a bad batch of gas, but i still think i might be running a little lean.

 

[punkrocker00406]

Hey guys, heres a few updates. I installed a new fuel filter and WOW was the old one clogged. I also installed a new pcv valve just for the hell of it. After changing the fuel filter my fuel pressure shot up 20psi so i readjusted the AFPR back down to 40psi base pressure. I checked my ignition timing via VFAQ instructions. It was off 4 degrees, so i corrected that. Went out and logged a few pulls and my knock is all over the place still! This is what my most recent log looked like at the point of highest knock.

RPM - 4437
INJP - 18.17ms
KNCK - 21
02 - .87v
TPS - 99.6%
INJD - 67.1
TIMA - 14 degrees
MAFS - 1522.1 Hz

Can any one tell me anything from thoes readings? Keep in mind that is the stock o2 sensor not a wideband. Anyone please! Thanks

 

[punkrocker00406]

Bump - No one can tell me anything from these readings? Sorry for being impatient.