c5 w/trans issues
10-07-2014, 09:36 AM
#1
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c5 w/trans issues So I bought this c5 from a guy dirt cheap, so I kinda expected problems just don't know if its a tune or tranny issue. The car will go to rev limit b4 shifting and when cruising it goes in and out of lockup.......Did some searching and checked MAF. It was bad so I changed it and now issue seems worse. The car is a H/C/I c5 the guy I bought it from said it just had a tune but the MAF was broke at the connector and if they missed that who knows what else is wrong?.........any help would be greatly appreciated.
10-07-2014, 05:46 PM
#3
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If the MAF was broken at the connector, then the PCM was running in SD (Speed Density) mode. Installing a new MAF and fixing the connector put the PCM back into its "normal" MAF mode. Since you say this made it run worse, this indicates the MAF table was never optimized for the H/C/I.
As bbond105 said, find a COMPETENT tuner and you should be good.
As bbond105 said, find a COMPETENT tuner and you should be good.
10-08-2014, 07:46 AM
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I wish I lived in a area w a competent tuner around unfortunately I do not..........Now with that being said I have hptuners but I am not at very proficient w it yet. I hear a lot of horror stories abt mail order tunes, The nearest tuner is over 100 miles away and now the car wont upshift to third. seems like the trans doesn't engage until over 4k rpms. I know that I need to start w the MAF problem before I can go anywhere else. How do you find out which mode the car is in? MAF or SD? should start there I guess.
10-08-2014, 08:41 AM
#5
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I have used two mail order tunes from Vengeance Racing, (http://vengeanceracing.net/). While I do admit the tune most likely is not extracting the most out of my setup. The car does run and shift good with no drivability issues.
At least that would get you in the ball park and then you can make little tweaks to fine tune it. I don’t know if they lock their tune or not, be sure to ask.
At least that would get you in the ball park and then you can make little tweaks to fine tune it. I don’t know if they lock their tune or not, be sure to ask.
10-08-2014, 09:09 AM
#6
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Disconnecting the MAF will put you into SD mode. (I think open-loop too, e.g. no feedback from O2 sensors, which might also be bad.) It will give you a MIL light, but that can be tuned off.
This forum has a good tuning section and HP Tuners has their own forum. Just search there for how to disconnect the MAF without the MIL light.
Two good books by Greg Banish can teach you a lot too. Search his name on Amazon; only $17 each.
I enjoy tuning, but I have spent 40+ years with computers and electronics.
This forum has a good tuning section and HP Tuners has their own forum. Just search there for how to disconnect the MAF without the MIL light.
Two good books by Greg Banish can teach you a lot too. Search his name on Amazon; only $17 each.
I enjoy tuning, but I have spent 40+ years with computers and electronics.