Car dies at high rpm’s Please help
04-30-2018, 08:13 PM
#1
Launching!
Thread Starter
iTrader: (119)
Join Date: May 2008
Location: Jefferson City, MO
Posts: 220
Likes: 0
Received 0 Likes
on
0 Posts
Car dies at high rpm’s Please help Help Please
in my 70 Chevelle not a new swap I did this swap 12 years ago
When spraying nitrous my car back fires out exhaust and kills the motor??? Last Thursday it started doing this on motor also without nitrous EVERY time for the last year it was only on N20 now on motor also.
I have not made a successful nitrous pass with this new motor had in over a year
383 LS1,11.5 compression,93 octane,ported 243 heads,br7ef plugs .028 gap,nitrous outlet LS6 money maker spray bar
I have used this intake successfully with old motor for several years with old ls1 cam only and lots of spray no problems.
Runs great on motor now
Things I have changed chasing this problem over the last year 3 sets of spark plugs,3 different sets of complete coil packs,different plug wires,I upgraded the complete fuel system front to back,Changed out new solenoids,all new nitrous lines,bypassed the nos mini 2 progressive to a bang button solenoids grounded straight to the head power comes straight to battery positive junction verified 13.5 volts at the push button during an attempt nitrous pass volts stayed the same,battery ground goes straight to block and another cable from block to frame ,sent the intake off to nitrous outlet to go through it and redo it,I have tried 2 completely different tunes I’m at 20 degrees on 100 shot trying to fix problem,this back fire out exhaust has never messed up a plug or anything just shuts the motor off it’s very loud pops a couple times.This weekend I also went through the complete wiring harness thinking it was ground so I checked everything,changed cam and crank sensor,wired fuel pump straight to battery to test with no difference,ground to new bare metal spot on frame. Afr is good up until it dies
Any ideas where the problem might be ??
in my 70 Chevelle not a new swap I did this swap 12 years ago
When spraying nitrous my car back fires out exhaust and kills the motor??? Last Thursday it started doing this on motor also without nitrous EVERY time for the last year it was only on N20 now on motor also.
I have not made a successful nitrous pass with this new motor had in over a year
383 LS1,11.5 compression,93 octane,ported 243 heads,br7ef plugs .028 gap,nitrous outlet LS6 money maker spray bar
I have used this intake successfully with old motor for several years with old ls1 cam only and lots of spray no problems.
Runs great on motor now
Things I have changed chasing this problem over the last year 3 sets of spark plugs,3 different sets of complete coil packs,different plug wires,I upgraded the complete fuel system front to back,Changed out new solenoids,all new nitrous lines,bypassed the nos mini 2 progressive to a bang button solenoids grounded straight to the head power comes straight to battery positive junction verified 13.5 volts at the push button during an attempt nitrous pass volts stayed the same,battery ground goes straight to block and another cable from block to frame ,sent the intake off to nitrous outlet to go through it and redo it,I have tried 2 completely different tunes I’m at 20 degrees on 100 shot trying to fix problem,this back fire out exhaust has never messed up a plug or anything just shuts the motor off it’s very loud pops a couple times.This weekend I also went through the complete wiring harness thinking it was ground so I checked everything,changed cam and crank sensor,wired fuel pump straight to battery to test with no difference,ground to new bare metal spot on frame. Afr is good up until it dies
Any ideas where the problem might be ??
05-01-2018, 12:39 PM
#4
I'd start with check volts at high rpm's. Plenty to read about it on tech here. Spinning alternator a little to fast maybe which might be ok on motor alone but then add in the load of the solenoids and othe n2o related things might be enough to make it cut out.
05-01-2018, 03:34 PM
#5
Have you done a leak down on it?
06-07-2018, 10:59 PM
#7
Launching!
Thread Starter
iTrader: (119)
Join Date: May 2008
Location: Jefferson City, MO
Posts: 220
Likes: 0
Received 0 Likes
on
0 Posts
About a month ago car started dieing on motor N/A now was every time it hit high rpm,i found a bad pin for #6 coil where it plugs in fixed that now its so random when it dies on the motor only now 1 in 6-10 times,makes me not want to spray it since its doing it even on motor now 
Trending Topics
06-08-2018, 09:44 AM
#8
TECH Senior Member
Did any of the above posts help your situation at all? This is the first post since your first in this thread.
08-11-2018, 06:57 PM
#13
TECH Senior Member
Not doubting you Hio, how does that happen?? Learning....
08-11-2018, 07:18 PM
#14
10 Second Club
iTrader: (8)
I guess from not proper damping. Seen it happen twice. Once on my own car. It typically happenes on abrupt rpm type changes. Like after a gear change or on full clutch engagement. Mskes the car stutter.
i could see it being more prevalent on a faster car or nitrous car than it was the bolt on stuff i fool with mostly. It also gets continually worse like 70ls1chevelle seems to be displaying.
worth a try to change the balancer imo.
i could see it being more prevalent on a faster car or nitrous car than it was the bolt on stuff i fool with mostly. It also gets continually worse like 70ls1chevelle seems to be displaying.
worth a try to change the balancer imo.