PDA

View Full Version : Cut out issue


Gaboon
10-09-2011, 02:56 PM
87 shelby charger converted to TII with a relentless Perf logic two bar map.

Over boost completely removed.

This cut out issue, I have been chasing for two years now and has prevented me from racing. The last time I raced, I blew my intake manifold up during a nitrous run because the car cut out and filled the intake with NOS, once it fired again, it sounded leke a twelve gage going off in front of me.
Pump gas, I run max of 17 lbs.
This seems to happen only in fourth gear when I step on it from a slow cruise and always at 5200 rpm Under or over that mark it seems fine.
If I run through the gears,second, third into and through fourth it won,t happen.
I have changed the hep, map and my TPS (voltage at WOT is 4.5 volts (no codes)

Any ideas would be appreciated.

Joe
turbovanmanČ
10-09-2011, 02:59 PM
Check the SDS and bypass the Baro sensor, leave it hooked but run the vacuum line straight to the MAP. I had the same issue for years and found it by a fluke.
Gaboon
10-09-2011, 03:02 PM
I'm having a brain fart here, what's the SDS?
turbovanmanČ
10-09-2011, 03:06 PM
Speed Distance Sensor, ;)
Gaboon
10-09-2011, 03:14 PM
Doh!
Actually, I'm almost certain the SDS is good. I replaced it not too long ago and a few times over the years. The car will stall at every stop when it goes bad.
I'll bypass the baro and see how it runs. I'll be back.
Gaboon
10-09-2011, 03:31 PM
Bypassed it, same darn thing! Any other ideas?
turbovanmanČ
10-09-2011, 03:39 PM
Ok, sounds good. I've also had bad wiring coming off the SDS too.
cordes
10-09-2011, 04:53 PM
It's pretty easy to check the SDS wiring by testing for continuity while spinning the gear.

I had a similar problem to yours, but the cutout was always at 6PSI. We finally determined that some of the connections in the wiring harness were bad enough to cause it when there was more current flowing through it rather than just me testing it with the volt meter. I knew there were a couple of bad spots, but when I pulled the whole harness even I was shocked by how bad it really was. Lots of hidden problems in there.

That being said, there's a big difference in the condition of your car and mine.
Gaboon
10-09-2011, 09:20 PM
Ok, sounds good. I've also had bad wiring coming off the SDS too.

I'll get under the car tomorrow and check the wires. At the very least, I'll clean the connections. Thanks for the help.


It's pretty easy to check the SDS wiring by testing for continuity while spinning the gear.

I had a similar problem to yours, but the cutout was always at 6PSI. We finally determined that some of the connections in the wiring harness were bad enough to cause it when there was more current flowing through it rather than just me testing it with the volt meter. I knew there were a couple of bad spots, but when I pulled the whole harness even I was shocked by how bad it really was. Lots of hidden problems in there.

That being said, there's a big difference in the condition of your car and mine.

I'll begin to go through the wiring to see if I find any issues. Even though the car's never seen bad weather, it's still old and could use a good once over.


If anyone has any other ideas, please feel free to post em.


Thanks,


Joey