Go Back   LS1TECH > LS1-LS2-LS3-LS6-LS7 PERFORMANCE > Conversions & Hybrids
Sign in using an external account
Register Forgot Password?
Search

Conversions & Hybrids
LSX Engines in Non-LSX Vehicles
Sponsored by
Don Hardy Race Cars

LS1 swap in Porsche backfire need help

Reply
 
Thread Tools Search this Thread
Old 01-23-2010, 11:30 PM   #1
Teching In
Garage is empty, add now
 
Trader Rating: 0
Join Date: Nov 2009
Posts: 2
Default LS1 swap in Porsche backfire need help

I am wrapping up my LS1 swap into a Porsche 944 Turbo. On the dyno today we are having a backfire at 4500 rpm's.

The car idles & runs well but at 4500 we get the backfire. On the dyno o2 was 12 to 1 at WOT so it shouldnít be a tuning issue. I was told to check for bad grounds. Any ideas?
rmj951 is offline   Reply With Quote
Old 01-24-2010, 12:34 AM   #2
Launching!
Garage is empty, add now
 
Trader Rating: 1
Join Date: Jul 2009
Location: Rosedale, Indiana
Posts: 294
Send a message via Yahoo to remauto1187
Default

Ignition coil breaking down, spark plug wire.

I bet its not a bad distributor cap!
remauto1187 is offline   Reply With Quote
Old 01-24-2010, 08:03 AM   #3
rao
TECH Resident
Garage is empty, add now
 
rao's Avatar
 
Trader Rating: 15
Join Date: Dec 2005
Location: Naperville, IL
Posts: 960
Default

+1 on spark plug wires.
__________________
Rob

Current - 1998 BMW 540i LS2 Stroker/T56 Build Thread
Old - 1992 BMW 325i LS2 Stroker/T56
Older - 1995 BMW M3 LS2 Stroker/T56
rao is offline   Reply With Quote
Old 01-24-2010, 11:50 AM   #4
Launching!
Garage is empty, add now
 
Trader Rating: 1
Join Date: Oct 2007
Location: Germany
Posts: 274
Default

Backfire through the exhaust or intake?
fast400 is offline   Reply With Quote
Old 01-24-2010, 12:30 PM   #5
TECH Resident
1970 Chevrolet Malibu
My Garage
 
Bowtie70SS's Avatar
 
Trader Rating: 10
Join Date: Oct 2005
Location: Cincinnati, Ohio
Posts: 948
Default

What about a bad valve spring? If it is broken near the bottom end it might not present itself until higher rpms.
__________________
2004 CTS-V
2003 Silverado SS LQ9
1970 AMC Rebel Machine
My never ending 70 LS2 Chevelle build thread http://ls1tech.com/forums/conversion...lba-toast.html
Bowtie70SS is offline   Reply With Quote
Old 01-24-2010, 05:30 PM   #6
Teching In
Garage is empty, add now
 
Trader Rating: 0
Join Date: Nov 2009
Posts: 2
Default

We installed brand new wires & valve springs.
rmj951 is offline   Reply With Quote
Old 01-24-2010, 05:38 PM   #7
TECH Resident
1970 Chevrolet Malibu
My Garage
 
Bowtie70SS's Avatar
 
Trader Rating: 10
Join Date: Oct 2005
Location: Cincinnati, Ohio
Posts: 948
Default

Maybe you have a bad fuel injector? What about your fuel and timing tables. Something could be goofed up there?
__________________
2004 CTS-V
2003 Silverado SS LQ9
1970 AMC Rebel Machine
My never ending 70 LS2 Chevelle build thread http://ls1tech.com/forums/conversion...lba-toast.html
Bowtie70SS is offline   Reply With Quote
Old 01-24-2010, 05:38 PM
LS1Tech
Pontiac Firebird




Paid Advertisement
Reply


Tags
1992, 4500, 944, backfire, backfires, backfiring, bad, bumper, causing, coil, conversion, front, ls1, ls2, porsche, s2, spoiler, swap


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off



Join Ls1Tech

All times are GMT -5. The time now is 10:42 AM.


Powered by vBulletin® Version 3.8.7 AC1
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Advertising - Terms of Service - Privacy Statement - JOBS
Emails & Contact Details