We were on the dyno today trying to get every thing set up right . W/M injection , boost control ,and start to tune it . While getting the W/M injection adjusted right , we started getting a misfire in the # 2 cyl. It would come and go , so we thought in might be the W/M . It went away for a few runs and came back just as we were going to do tuning . This time it didnt go away . We changed out the coil pack and then put new plugs in it . Still misfires . Then all of a sudden it went away again , and hasnt come back again . We had already spent a full day on it and Money started to play into it and I want to see if any one would know where to look , or any idea what it could be . We thought it might be an injector going bad , but after it cleared up ....we are stumped . Any help out there ?

 

c'mon boog just buy a porsche and be done w/ it...

 

Chit ...Im broke . I cant afford a cup of coffee right now . lol

We did give up on the boost control idea , and put back on the 3.12 pulley . We're pretty sure it will not break the head gasket seal again with the W/M injection and L19's

 

Oh , by the way . We never once got a code other than the normal P300

 

how did you know the #2 cylinder was misfiring if all you got was the multimisfire code?

 

Shop had a SnapOn OBDII . He could turn off and on any injector while it was idling . We also unplugged the coil and it didnt have any effect . We left the plug in and connected the coil pack to another plug and it fired normally

 

I took the car out tonight and it was misfiring and the CEL light came on . It cleared up and ran fine for a few minutes and started again . This time the CEL blinked 10 times and stayed on . One other time it blinked 5 times . I got home to read the codes and got the normal P0300 . But under that was [ XX ] then a rectangle box next to the X's . Any idea's ???????????

 

oh ok, that really kinda sucks that it didn't give you a P302 code then instead of a P300 - making you work for it

I've had it blink on me two different times. Once it blinked then stayed on, the other time it did that process like 4 times on the highway - was really worried. Went to Autozone, read the code and had 2 P300 codes. Cleared them and eventually it returned back to normal (which is constantly on for my car - probably cams and flywheel?)

 

Bad injector in that hole?

 

The [ XX Box ] under the P0300 code is what I'd like to figure out

I dont think a bad injector would act the way it is . Misfire for a while , then run perfect , then misfire again . I'm thinkingg it may be a short in the signal to the injector , or the signal to the coil pack . When ever it does it , it goes real lean

 

Maybe an injector malfunction issue. They can act up, periodically.
Thats the only other thing I can think of, since you said you already swapped coils and plugs.

Try swapping that injector to another cylinder, and see if the misfire shifts to the new cylinder.

 

Im going to go over the wiring first and see if I can find a short . Then I'll dig in and pull the plenum and swap injectors around .

 

Went out and played with the car today . Wasnt to thrilled about it , it was 100 degree's out and the garage wasnt much cooler .

But I found the problem...the injector clip wasnt pushed down all the way on the injector . A install problem ...and Im going to see if the shop will finish the tune for no charge . Well actually Im going to demand it . I was charge for several hours of shop time , 2 coil packs , and a set of plugs . **** happens and Im happy I found it with out to much trouble . But they should make it right with me . Car runs much better , even better when it wasnt misfiring . It also explains why my A/F gauge [ drivers side ]was always leaner than his brand new inovate A/F [ in the X pipe ]. The injector was never firing at full strength .

 

hey booger, glad to read that everything cleared up for your Z--you have to admit, pretty easy solution--too bad they all weren't like that.

My Z just threw the P0300 code this afternoon. I hooked up a scanner and read that there were two P0300 codes. (one of them was the real MIL (malfunction indicator light), the other was "pending"). The P0300 stays "pending" (does not enable the "SES" light) until it happens multiple times. Anyways, enough of that silly information...

I'm wondering why my Z threw this code. It's been terribly hot, 107 degrees all day on the pavement...and I do kinda remember the engine skipping ever-so-slightly when I was WOT (near redline) last night...It may have also misfired once or twice when I had my 22 runs at the dragstrip last week. Today's heat could have driven that "pending" code into a MIL...

So, I cleared the code, took the car for a nice run, and it remained off--I checked for "pending" codes and it found none.

I don't know what other information I could provide other than I have everything that came with the JWT TT kit installed on my car.

Peace!

 

Most guys with the return fuel system and bigger injectors , get the P0300 . I will continue to get that and Im not worried about it . Going Friday to finish the tune . Shop is going to take care of me on that .