Need help with crazy AFR issue with dead spot
Need help with crazy AFR issue with dead spot
A real head scratcher that's been bugging me for some time now and I really hope someone can help.
Will try and keep this short but basically the car will shit itself when I push throttle to 48-50% onwards. Feels like fuel cuts out and I thought it may be Maf, fuel pump or Reg, then played around with PE and AE settings that made no difference. Past logs didn't really show anything out of the ordinary until I did a log over the weekend.
Looking back at the log at where the total dead spot is(when Tps hits 50+%) I could see that Commanded AFR is 25.5! And Injector Pulse Time drops to 0.00.
I can't see anywhere in TP where this would cause an AFR of 25.5.
I'm using NVRAM and cable from this site and running The 1's A6E Enhanced Code(VT V8). I'm sure these aren't the issue.
This problem happens at any RPM when TP hits above 48%, the motor bogs down until I back off the peddle. No issue when I'm gentle on the throttle and rising to high rpm's.
Screenshots below show the story. Hope someone can throw some suggestions.
Will try and keep this short but basically the car will shit itself when I push throttle to 48-50% onwards. Feels like fuel cuts out and I thought it may be Maf, fuel pump or Reg, then played around with PE and AE settings that made no difference. Past logs didn't really show anything out of the ordinary until I did a log over the weekend.
Looking back at the log at where the total dead spot is(when Tps hits 50+%) I could see that Commanded AFR is 25.5! And Injector Pulse Time drops to 0.00.
I can't see anywhere in TP where this would cause an AFR of 25.5.
I'm using NVRAM and cable from this site and running The 1's A6E Enhanced Code(VT V8). I'm sure these aren't the issue.
This problem happens at any RPM when TP hits above 48%, the motor bogs down until I back off the peddle. No issue when I'm gentle on the throttle and rising to high rpm's.
Screenshots below show the story. Hope someone can throw some suggestions.
Last edited by VTXU8 on Sat Sep 09, 2023 5:42 pm, edited 2 times in total.
- vlad01
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Re: Need help with crazy AFR issue
Looks like the wrong or broke ADX file. I had similar issues with some of the factory ADXs showing weird numbers not possible on the newer models of Holden.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Re: Need help with crazy AFR issue
Thanks vlad01.
I'll reach out to Gareth and get him to burn me a new one and see. Either way, will be good to have a backup spare.
I'll reach out to Gareth and get him to burn me a new one and see. Either way, will be good to have a backup spare.
- vlad01
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Re: Need help with crazy AFR issue
I mean the ADX loaded in tuner pro, the acquisition definition file. If the file is not the right one or has known problems, then the live dash will have screwy numbers.
This has nothing to do with the memcal.
I had a similar issue with VS manual ADX for getrag and one of the values, I think rpm or something was showing as 28,000 rpm. It was just broken with no alternatives I could use but did what I needed at the time.
This has nothing to do with the memcal.
I had a similar issue with VS manual ADX for getrag and one of the values, I think rpm or something was showing as 28,000 rpm. It was just broken with no alternatives I could use but did what I needed at the time.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Re: Need help with crazy AFR issue
Ah yes, you are right. Thanks for pointing that out.
- vlad01
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Re: Need help with crazy AFR issue
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Re: Need help with crazy AFR issue with dead spot
I tried another XDF and played back log and it still shows AFR of 25.5. It only shows this reading for milliseconds at the point where the engine seems to cut out at 50% tps. Then it goes back to 14.6:1.
- vlad01
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VR II executive - Location: Kyneton, Vic
Re: Need help with crazy AFR issue with dead spot
That's weird. I don't know much about the newer models, maybe one of the tables have 0 values in this area? The VE table equivalent or what ever it's called in the newer cars?
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.
Re: Need help with crazy AFR issue with dead spot
I've check the "injector constant" table (similar to VE). Nothing wild there. Checked all AFR and spark tables. As well as Burst knock etc.
Nothing mechanical.
New Dizzy, coil, module, leads and plugs, fuel pump and filter, TPS. And checked all wiring/earths
I have just used the PE Spreadsheet to re calculate Afr's in PE. Lowered TPS threshold to 39% from 46%(which is roughly where the problem starts) to see if it is related to PE tables not being set correctly. So now It may crap out at 39% TP Instead of 46+%.
Has to be something I've set wrong. Care runs like a dream up to that point. Will know by next weekend.
Nothing mechanical.
New Dizzy, coil, module, leads and plugs, fuel pump and filter, TPS. And checked all wiring/earths
I have just used the PE Spreadsheet to re calculate Afr's in PE. Lowered TPS threshold to 39% from 46%(which is roughly where the problem starts) to see if it is related to PE tables not being set correctly. So now It may crap out at 39% TP Instead of 46+%.
Has to be something I've set wrong. Care runs like a dream up to that point. Will know by next weekend.
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Re: Need help with crazy AFR issue with dead spot
What I see in the graph is a problem with the commanded air fuel ratio not the actual reading from a wideband. Have a close look thru your tune at that point and I'm sure you will find it.