Fuel cutoff comes on early, but only in second gear
01-11-2011, 11:46 PM
#1
Fuel cutoff comes on early, but only in second gear Here's the full mod list:
LS6 intake, SVO 42# green-tops, Racetronix fuel pump with upgrade harness, 243 heads, patriot golds, +.020" valves, Jesel shaft-mount roller rockers, hardened 3/8" pushrods, 230/232 613/603 on 112 cam, rebuilt 346 with ARP rod bolts, LS6 PCV setup, EGR and AIR delete, LS7 clutch, C5Z torque tube, RPM level 5 T56 (MN12), rpm level 2 3.42 3-rib diff, EFI Live dyno tune with my '98 PCM
I just got the car back together and running before Thanksgiving, and then had it tuned just after Christmas (it had a cam before and ran OK on the old tune). The rev limiter on the old tune was at 6200 but the tuner raised it to 6700 with the new mods.
In first and third gear (have not tried 4th-6th) it will run up to 6700 with no problems. In second though, it hits 6300 and then acts like the fuel cutoff has been hit. I haven't messed with it to much because I don't want to ruin anything, but I let it bounce 5 or 6 times just to make sure it wasn't a miss or some other hiccup. It does it whether I'm at WOT or not, and it has done it every time I tried.
Has anybody seen this before? I'm going to see if I can borrow a data logger to see what's going on. I called the tuner and he said he'd never heard of anything like this.
LS6 intake, SVO 42# green-tops, Racetronix fuel pump with upgrade harness, 243 heads, patriot golds, +.020" valves, Jesel shaft-mount roller rockers, hardened 3/8" pushrods, 230/232 613/603 on 112 cam, rebuilt 346 with ARP rod bolts, LS6 PCV setup, EGR and AIR delete, LS7 clutch, C5Z torque tube, RPM level 5 T56 (MN12), rpm level 2 3.42 3-rib diff, EFI Live dyno tune with my '98 PCM
I just got the car back together and running before Thanksgiving, and then had it tuned just after Christmas (it had a cam before and ran OK on the old tune). The rev limiter on the old tune was at 6200 but the tuner raised it to 6700 with the new mods.
In first and third gear (have not tried 4th-6th) it will run up to 6700 with no problems. In second though, it hits 6300 and then acts like the fuel cutoff has been hit. I haven't messed with it to much because I don't want to ruin anything, but I let it bounce 5 or 6 times just to make sure it wasn't a miss or some other hiccup. It does it whether I'm at WOT or not, and it has done it every time I tried.
Has anybody seen this before? I'm going to see if I can borrow a data logger to see what's going on. I called the tuner and he said he'd never heard of anything like this.
01-17-2011, 03:27 PM
#5
The PCM doesn't know what gear you are in because there is no physical connection for gear selection - at least on my 2002's.
The only electrical connectors to a T-56 are:
Reverse Lockout solenoid
Skip Shift solenoid
Speed sensor
When I run HP Tuners logs on my T-56 cars the Trans Current Gear selector shows "1" and never moves while on my auto cars it shows whatever gear the PCM has commanded the trans to be in - or whatever gear I have forced the trans to be in manually.
The only electrical connectors to a T-56 are:
Reverse Lockout solenoid
Skip Shift solenoid
Speed sensor
When I run HP Tuners logs on my T-56 cars the Trans Current Gear selector shows "1" and never moves while on my auto cars it shows whatever gear the PCM has commanded the trans to be in - or whatever gear I have forced the trans to be in manually.
