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I have a 2003 Tahoe with built 6.0 and turbo kit im having a problem where the car pulls until it reaches 6300 rpm it feels like its misfiring with no pops or bang or its hitting a rev limiter but in the tune its been raised till 6700rpm and the problem still occurs so the car wont reach the shift point which has been set 6500rpm it will stay in the 6300rpm range and do the misfiring shit.
please if someone can chime in and help.:oAttachment 97291Attachment 97292
You do have abuse mode set to 6,000rpm for whatever reason. Set that to 8,000rpm. You have other weird settings in there for some stuff but try that first.
I have a C4 Corvette I tune that has this issue too. 0411 ecu swap on the LT1 and almost like clockwork it will act like it hits a rev limiter at 6100-6300 rpm. Rev limit was set to 7500 (forged pistons, forged crank, and H-beam rods). I never figured the issue out so hopefully someone has some input here.
I will change it and try to see if it will solve the problem ill keep you updatedQuote:
Originally Posted by 5FDP
Is this happening when in the boost at 6500rpm but not when out of boost? If it's happening in boost but not out of boost I have the following thoughts. If it happening not in boost...then ignore the following.
Not sure if you have swapped injectors or not, but keep in mind, at higher RPMs there is less time the injector can pulse to inject fuel. While it might be able to keep up and lower RPMs, those higher rpms leave very little time for injection. Perhaps a larger injector is needed? Take a look at your injector pulse time (INJ B1 or INJ B2) in your scanner. Take 6500 rev/min multiply by 1min/60s and then invert it to get sec/rev => 0.009sec/rev. Then multiply that by 2 because the came spins half the speed of the crank. So that's only 18ms for the injector to be able to inject all it needs to at that rpm. At lower rpms (let's say 3250rpm) you have 36ms for injection and most stock injectors can probably handle that. If your INJ B1 or INJ B2 are trying to inject longer than the valve it open, then your injector is not large enough. I ran into this when I turbo'd my little ecotec motor. Injectors were maxing out before I got above 5k with boost. Went from 45# to 60# injectors and it solved the issue. Just a thought.....
Quote:
Originally Posted by four_by_nut
The car has a set of ID 1050x injectors so theres plenty of room left and fuel pressure is good.
I have set the abuse mode to 8,000rpm with no difference still the same?Quote:
Originally Posted by 5FDP
Did you pull the plugs?
What plugs are they and what gap are you running?
thinking in spark plug gap too, how much boost running?
The plugs which im using is NGK tr7 gaped to .22 .Quote:
Originally Posted by 5FDP
This problem happens even when its on low boost like 7 psi :)
code?
trans abuse?
2101 code?
No codes or REP it feels like its rev limiting at 6300rpm so i checked everything with no luck.Quote:
Originally Posted by lukearmstrong1990
Trans abuse is disables as you can see in the tune ^^
Minor input. Your shift RPM's are very close to your shift MPH's. It will only shift full throttle when both are met. I would shift based on rpm, so lower your WOT shift MPH so they don't both go true at the same time.
Also, I noticed that your INJ B2 really falls while INJ B1 stays and levels off. At some points they differ by 25%, that is a lot. Not sure why.
I just had a Silverado SS that did the same thing. It was almost like a rev limiter at 6200-6300. We changed valve springs and injectors and plugs and plug wires and coils. Long story short, we replaced the crank sensor and that fixed it. It never had a DTC at all.
Tried that with no luck :)Quote:
Originally Posted by pknowles
Crank sensor has been changed with no difference I'm doubting the reluctor wheel where the crankshaft had 58x and been changed to 24x.Quote:
Originally Posted by kevin87turbot
Exact same thing here. 2001 Corvette. Mostly stock with headers. 6300 rpm pops like a rev limiter. Only full throttle because of normal delay in shift but can reproduce every single time by just putting shifter in any gear and light throttle up to 6K to 6,300. Anyone find a cure yet? I was going to lowering WOT shift speeds down to get the trans to shift a little earlier so it does not hit 6K so hard.
I found the issue the car was valve floating baaad i changed valve spring and the car is mint :)
I was just going to say, sounds like a valve float issue.Quote:
Originally Posted by tahoels1
Check this. Found my issue on the Corvette. May help you too.
https://forum.hptuners.com/showthrea...ht=rev+limiter
I was having that same problem, I lowered mph in 1st to 2nd shifting. I was hitting 6000rpm sometimes before I was hitting the scheduled mph shift so it wasn?t shifting as soon as I lowered mph all was well. FYI I lowered 2nd to 3rd also but it was mostly the 1st to 2nd where this was happening. Good luck