Twin Turbo tuning question?
up grade to a 2002 pcm.. our 2000 pcms were nutorious for fals knock. the swap is considered a upgrade for us even if all you have is minor mods. i need to do it because i have a 2000 and get all kinds of knock. the guys who have done it say there is a huge diffrence.
You need to really look at the fuel system , I had alot of trouble with mine. It started out kind of like you are describing and got worse. Pressure doesn't actually mean volume. I put an intank walbro and walbro ext, cured the problem.
I'd copy the HO table into the LO table for the time being. That way you know what advance is being set prior to the KR. I'd also take the timing really low (8*), and then move up 2* at a time until you see KR again. That way you can be sure its timing related KR rather than some other noise triping the sensors (like a dead miss).
Originally Posted by 00Z71
I had the same problem until I ugraded to an 02 computer.
Did you program it with your stock 00 vin or with a 02 vin#?
Originally Posted by TurboBerserker
I'd copy the HO table into the LO table for the time being. That way you know what advance is being set prior to the KR. I'd also take the timing really low (8*), and then move up 2* at a time until you see KR again. That way you can be sure its timing related KR rather than some other noise triping the sensors (like a dead miss).
I'm pretty sure it is not false knock. But since I know it has TR55's in it, I think it may be misfiring when it hits boost also. So I think I will try some colder plugs then try it again.
the popping is most likely misfire or just really late combustion.
Since the advance is so far retarded you're sending the combustion event out the exhaust port.
The 99+ PCM's are all the same harware, albeit they are not programmed the same. That's not your issue.
Put some real fuel in it so you KNOW it's not rattling. Remove that variable then figure out what it's really doing.
detonation has a completely different sound than popping in the exhaust. put a wide band in it and see what the fuel is doing.
Either it's so lean that it is actually registering detonation and retarding accordingly. Or it's so pig rich it's misfiring.
Since the advance is so far retarded you're sending the combustion event out the exhaust port.
The 99+ PCM's are all the same harware, albeit they are not programmed the same. That's not your issue.
Put some real fuel in it so you KNOW it's not rattling. Remove that variable then figure out what it's really doing.
detonation has a completely different sound than popping in the exhaust. put a wide band in it and see what the fuel is doing.
Either it's so lean that it is actually registering detonation and retarding accordingly. Or it's so pig rich it's misfiring.
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From: Albuquerque, NM
What are the mods to the fuel system? Did not see them listed. Also, the fuel pressure seems kinda low?!? I thought "normal" was around 58psi but that might be for the later models. Lots of the Radix guys were seeing similar issues when the fuel pressure was low AND fluctuating like that. Seems a FMU type assembly usually bumps pressure up to the mid 60's.
made a little head way. He had TR55's gapped at .060". We replaced those with TR6's gapped at .035". It took care of the misfiring. The knock retard was still showing the same on the graph, but was not followed by the popping, cutting out. I removed the pcms ability to remove timing for knock retard. It showed no knock and was not detonating were it was showing knock retard before. So I guess I have false knock.
Will replacing the pcm get rid of the false knock. Are you replacing the actual pcm with one for an 02 or just reprogramming the 00 one with a stock 02 vin program. And if you are replacing the actual pcm are you reprogramming it with an 00 program or an 02 program?
Harlan, You said the hardware is the same between the 00 and the 02, but they show different part numbers.
Thanks
Will replacing the pcm get rid of the false knock. Are you replacing the actual pcm with one for an 02 or just reprogramming the 00 one with a stock 02 vin program. And if you are replacing the actual pcm are you reprogramming it with an 00 program or an 02 program?
Harlan, You said the hardware is the same between the 00 and the 02, but they show different part numbers.
Thanks
go in the truck section or call allen at nelson performance. actualy call him he has done this many times. i think they are replacing the pcm with a 02 pcm but i dont know how they are handling the vin issue.
I finally got the truck tuned. It had several issues. It had the wrong plugs in there. That was the first major problem(TR55's @ .060 gap). This was the misfire I was feeling. After that was fixed, it still had knock retard. Up to 12 degrees. It was false knock. I replaced the pcm with an 02 pcm and programmed in an 02 vin#. It took care of most of the false knock.
After that I was finally able to finish tuning it.
It made 564RWHP & 541RWTQ. That was with the air fuel @ about 11.3:1. Only pulling to 6000 rpms. It was still pulling at that point. The truck still has stock bottom end. I think with forged pistons and hardened rod bolts I could get it up to about 620 at the rear wheels. Very impressive truck.
The owner is building a forged 6.0L for it this summer then we will see what it can really do.
I just wanted to thank everyone for their input and help.
After that I was finally able to finish tuning it.
It made 564RWHP & 541RWTQ. That was with the air fuel @ about 11.3:1. Only pulling to 6000 rpms. It was still pulling at that point. The truck still has stock bottom end. I think with forged pistons and hardened rod bolts I could get it up to about 620 at the rear wheels. Very impressive truck.
The owner is building a forged 6.0L for it this summer then we will see what it can really do.
I just wanted to thank everyone for their input and help.
Originally Posted by getsome
I had the same problem in mine that is why I told you to try the 02 setup. I am glad you got the bugs worked out. The pcm's in the 99-01 can be a bit tricky.
I appreciate the info, it helped alot.