Engine/Transmission (1998.5 - 2002) Need Help-Truck Dies

[RedneckRam]

I'm new to the forum, and I have a problem. Wondering if anyone else has experienced this one.

With Comp on 5x5 and throttle wide open, I can go through all the gears holding each gear to 2700 rpm truck runs fine. But when I hold any gear to 2700 or thereabouts and I engage the clutch and let the rpm fall back to idle truck dies most of the time or runs rough. If I re-engage the clutch and bring the rpm's back up when it's running rough the motor will smooth out. If I re-engage the clutch when the motor dies and put it in a lower gear while coasting motor will restart. With comp on 3x5, I cannot get the truck to die, but it will start to run rough after throttle has been wide open and clutch is engaged. With the comp off, the symptoms are the same as with it on 3x5 but so slight they're almost unnoticeable.

About a week ago the truck started to stumble under acceleration with comp on 5x5, and since it was gradually worsening I replaced the VP44. This helped with the acceleration stumble but didn't fix the problem on the deceleration side. I reset the APPS and replaced the 150's with my 100 horse injectors. Also drained the fuel tank, replaced filters on FASS and had codes checked. No stored or active codes showed up.

I'm debating replacing the cam shaft sensor next. Any suggestions would be appreciated.



RedneckRam

 

[AKAMAC]

Welcome aboard SS,

Have you made sure that you don't have an air leak on the supply side of the fass system? Can you check the pressure at the schrader valve on the VP? If these are not out of spec, I would suspect the return line from the VP44.

Mike

 

[Allnew2Me]

I have heard that the standard Edge Comp will defuel at 2700 RPM. That may be what you are feeling. If it cuts fuel it may stumble even if you are backing to idle. As far as I understand it, the Drag Comp will continue fueling past that RPM, that is the only difference between the two. It is said that the comp can be reflashed into a drag if you send it back to Edge.

 

[RedneckRam]

I did check the FASS fuel pickup line and discovered the quick-connect at the tank was loose. I removed the quickconnect link and hooked it up directly, and tightened it down well. That didn't help. I also checked all the clamps on all the fuel lines from the FASS to the VP44. Doesn't seem to be any air in the lines. My fuel pressure guage is hooked inline 6" before the VP44, and runs 15 lbs. at an idle. With comp on 5x5 and wide open throttle it will drop to 9. 5 lbs. I hooked up a second guage at FASS, it showed 15. 5 lbs at an idle. But i wasn't able to check it at wide open throttle.

I agree that part of what I'm feeling as far as stumble could be the fuel shutoff at 2700 with the comp, but why won't the truck return to a smooth idle after hitting those rpm's.

I forgot to mention in the first post that I also took the Superchip out of my wife's 99' and tried it without the comp installed. Results were the same as with the comp on 3x5.

 

[Double J]

I agree that part of what I'm feeling as far as stumble could be the fuel shutoff at 2700 with the comp, but why won't the truck return to a smooth idle after hitting those rpm's.

Have you tried removing the Comp all together (leave the superchip off as well) and see if you still have a problem in that RPM range? Since it's doing it around the 2700rpm defuel point I'd try that first... still sounds kinda of strange though, the truck should still hold an idle. Did it just recently start doing this? The reason I ask is because I had some stalling issues with my auto soon after installing larger injectors and switching over to winter blend diesel. I had to get a TSB flash done to prevent it from dieing every time I dropped it into gear. Not sure how or if this would affect a stick though.

 

[RedneckRam]

I have tried it with out either but it still starts to stumble slightly when returning to an idle after a hard pull. I have also noticed that it really started with the colder weather and #1 diesel. I have also cleaned the IAT sensor it was pretty dirty after running the exhoust brake alot.

 

[Double J]

Hopefully someone that has had this problem in a 6-speed will chime in.....

 

[RedneckRam]

Double J, I talked to the guys at Quik Kard in Wasilla. The diesel at Tesoro and other fuel stations is #1 diesel, good to -60F. Quik Kard has #1 AND a winter blend of #2, which is only good to -10F. Tomorrow I'm thinking I'll pump off my tank into the wife's truck and top off with the #2. See if that affects it at all. I also shimmed the FASS to 18psi at an idle and now the truck only drops to 11 psi under wide open throttle. I've read a lot on here about reliability issues with the FASS and the problems some people are having. I see you have a RASP, how do you like it? I've been debating leaving FASS in place and hooking up a RASP for better reliability. Any one have any thoughts?... ... .

 

[Double J]

I also shimmed the FASS to 18psi at an idle and now the truck only drops to 11 psi under wide open throttle. I've read a lot on here about reliability issues with the FASS and the problems some people are having. I see you have a RASP, how do you like it? I've been debating leaving FASS in place and hooking up a RASP for better reliability. Any one have any thoughts?... ... .

To be perfectly honest, if the FASS isn't giving you any problems I'd leave it. The RASP sure is a nice peice though and used in conjuction with a FASS would be :--) one hell of a set-up. I've got a buddy who runs a stand alone FASS (AK Ram) who seems to be fairly happy with his... . even though he does have some RASP envy :-laf