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Misfire after build.

JerzNick

JerzNick

SE Level Member
I finally finished the build. Installed the following mods:

XP-Cam
CompCam Lifters
Ported Gen 3
Ported TB
Ported Heads
AutoLite 104's
3.25 Pulley
Speed Daddy Headers
Wideband o2

Started it up and it idled perfectly! Opened HP Tuners and started Scanning while I drove for a half hour or so. Without boost the car seems to drive pretty good. The instant I make the slightest boost, it starts to misfire. Not only can I hear it in the exhaust but HPT sais "multiple random misfire". Again, it only seems to happen when throttle is 50% or more... I tried APP606's to see if the plugs would make a difference but to no avail. any ideas???

Thanks in advance
 


Yes...you are. Otherwise it'll often log a multiple misfire and run like crap.

Nick.. look at the how to setup an HPT file in the tuning section stickies and fix that stuff as well.
 
JerzNick said:
I finally finished the build. Installed the following mods:

XP-Cam
CompCam Lifters
Ported Gen 3
Ported TB
Ported Heads
AutoLite 104's
3.25 Pulley
Speed Daddy Headers
Wideband o2

Started it up and it idled perfectly! Opened HP Tuners and started Scanning while I drove for a half hour or so. Without boost the car seems to drive pretty good. The instant I make the slightest boost, it starts to misfire. Not only can I hear it in the exhaust but HPT sais "multiple random misfire". Again, it only seems to happen when throttle is 50% or more... I tried APP606's to see if the plugs would make a difference but to no avail. any ideas???

Thanks in advance
Click to expand...

Your build sheet looks.... identical to mine. lol
 
88formula said:
Your build sheet looks.... identical to mine. lol
Click to expand...

lol, And how is yours running?

I followed Bill's advice and turned off misfire/egr reporting but now I'm getting a knocking sound from my motor :\

I think it's coming from the supercharger, I need a mech stethoscope!
 


BillBoost37 said:
Yes...you are. Otherwise it'll often log a multiple misfire and run like crap.

Nick.. look at the how to setup an HPT file in the tuning section stickies and fix that stuff as well.
Click to expand...

Followed both hpt guides Bill, nothing was mentioned about turning off those codes. Once I turned em off, it ran great for about 20 minutes then a knocking sound :th_depressed:

Sounds kind of like the s/c rotors clacking... weird.
 
Just pulled it today. Needs new bearings and seal... Fuggin money pit :/


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Mine is not put back together yet. Have a long ways to go.
94ABE6DB-0D40-4292-BF81-DA0F328A8634-2420-0000049AC46C4F61.jpg
 


BillBoost37 said:
That's an hour away from being in a car..
Click to expand...

Check out my build thread, I got a little more too it then your typical L67 powered car. Plus I still need to buy bigger injectors, WBS fuel rails, fuel pump, and buy+install a shift kit while the cradle is removed from the car. Then once that is all said and done, and I have the motor reattached to the cradle I then have to fabricate a complete custom header back exhaust. Doesnt help I can hardly find the motivation to work on my car anymore... OH and I forgot to mention once it is all put back together I have to buy a wideband, and HPT then tune it myself. It will be quite the adventure!
 


Eek that doesn't sound to good .
Flex plate could be cracked hopefully.
Also sounds like my car . You don't wanna hear what's wrong with mine ..
Again
 
I'm getting very aggravated with this car. Every time I fix or replace something. Another piece goes bad. Wtf?!


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