LTFTs low at idle, high while cruising
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Teching In
Joined: Dec 2017
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From: Russia
LTFTs low at idle, high while cruising Hi all,
I have a 2004 5.3 engine swapped into a wrangler. Engine is stock. Intake is basically open element filter to 4" pipe to a 90-degree
elbow. Exhaust is LS3 manifolds to 2.5" pipe to Y-pipe to 3" pipe and muffler (no cats). The tune is stock aside from small stuff
like fans, VATS, DFCO etc.
Idles and drives fine, but LTFTs are about -10 at idle and +10 while cruising at 2400 rpm. Up to +18 on heavy acceleration.
LTFTs are almost the same on bank 1 and bank 2 (+-2%), so it doesn't look like an exhaust leak. Cleaned MAF, no effect.
Got the injectors cleaned and checked, they are good as new. O2 sensors are new ACDelco 213-1702. Fuel pressure is 59-60 psi.
Does that look like a symptom of some common issue? Can it be because I'm running non-stock intake and exhaust?
I have a 2004 5.3 engine swapped into a wrangler. Engine is stock. Intake is basically open element filter to 4" pipe to a 90-degree
elbow. Exhaust is LS3 manifolds to 2.5" pipe to Y-pipe to 3" pipe and muffler (no cats). The tune is stock aside from small stuff
like fans, VATS, DFCO etc.
Idles and drives fine, but LTFTs are about -10 at idle and +10 while cruising at 2400 rpm. Up to +18 on heavy acceleration.
LTFTs are almost the same on bank 1 and bank 2 (+-2%), so it doesn't look like an exhaust leak. Cleaned MAF, no effect.
Got the injectors cleaned and checked, they are good as new. O2 sensors are new ACDelco 213-1702. Fuel pressure is 59-60 psi.
Does that look like a symptom of some common issue? Can it be because I'm running non-stock intake and exhaust?
Joined: Aug 2007
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From: Turnin' Wrenches Infractions: 005
Im not sure what youre asking. These cars arent like 0 trim stock. Trimming like that is normal on an untuned vehicle. IF its tuned (and its similar weather to when it was tuned) then i would say someone doesnt know what theyre doing. But for a stock car the tunes are basically garbage, getting worse as soon as you modify anything.
Thread Starter
Teching In
Joined: Dec 2017
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From: Russia
I'm running an OEM MAF, but it is not from the same donor as the engine. The engine is from a 2004 suburban and my MAF is from a 2003 tahoe.
Here's a log I recorded a couple of weeks ago (highway cruising around 7:15).
Here's a log I recorded a couple of weeks ago (highway cruising around 7:15).
Thread Starter
Teching In
Joined: Dec 2017
Posts: 14
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From: Russia
Im not sure what youre asking. These cars arent like 0 trim stock. Trimming like that is normal on an untuned vehicle. IF its tuned (and its similar weather to when it was tuned) then i would say someone doesnt know what theyre doing. But for a stock car the tunes are basically garbage, getting worse as soon as you modify anything.
Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
They can get wacky. Also, wideband readings tend to be way off what you are expecting also.
Ok so looking at the log, it seems pretty normal except a few things. At one point it is commanding 16.0 AFR, which i dont like. Fuel trimming looks decent then there are areas where it does act kinda wacky for short periods but they seem to be near areas of throttle transitions and stuff....but yeah the fact that it spikes into the 20s doesnt seem completely normal, though disregard if its after a throttle lift and the o2s are pinging lean.
Ok so looking at the log, it seems pretty normal except a few things. At one point it is commanding 16.0 AFR, which i dont like. Fuel trimming looks decent then there are areas where it does act kinda wacky for short periods but they seem to be near areas of throttle transitions and stuff....but yeah the fact that it spikes into the 20s doesnt seem completely normal, though disregard if its after a throttle lift and the o2s are pinging lean.
Last edited by 01ssreda4; Dec 26, 2017 at 07:55 AM.
Thread Starter
Teching In
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From: Russia
Thanks, I missed that in the logs. I did some more logging and it seems that sometimes commanded AFR changes to 16.0 for about 25 seconds and then changes to 13.6 for another 25 seconds. From what I've been able to find it is the cat test that can't be disabled in P59 PCM.
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Thanks, I missed that in the logs. I did some more logging and it seems that sometimes commanded AFR changes to 16.0 for about 25 seconds and then changes to 13.6 for another 25 seconds. From what I've been able to find it is the cat test that can't be disabled in P59 PCM.
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From: Monroe,NY
Thanks, I missed that in the logs. I did some more logging and it seems that sometimes commanded AFR changes to 16.0 for about 25 seconds and then changes to 13.6 for another 25 seconds. From what I've been able to find it is the cat test that can't be disabled in P59 PCM.
Looking at your log all your part throttle ST trims look fine except for a couple areas in the higher rpms. I couldn't see wideband on my scanner. You could straighten that out with a tune no problem.
Thread Starter
Teching In
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From: Russia
Was the commanded 16.0 while you were out of the throttle? Could be DFCO.
Looking at your log all your part throttle ST trims look fine except for a couple areas in the higher rpms. I couldn't see wideband on my scanner. You could straighten that out with a tune no problem.
Looking at your log all your part throttle ST trims look fine except for a couple areas in the higher rpms. I couldn't see wideband on my scanner. You could straighten that out with a tune no problem.