maf reading high g/s. cammed engine

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dilly

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	maf reading high g/s. cammed engine « on: March 03, 2019, 08:33:04 PM »

buddy has a cammed 12v vr6 (AFP)
stock engine other than a mildly built head due to bending valves. it has 276 cams and HD springs
runs like shit. I let him try my giac ecu but nothing changed
what i did notice is that the maf at idle was reading 6-7g/s which from my experience is way too high considering my stock vr runs at about ~3

maf is good

what i am assuming is that one of the maf tables need to be tweaked/scaled due to the increased amount of air being sucked in

correct me if i am wrong and if you have insight i would appreciate the info
thank you


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nyet

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	Re: maf reading high g/s. cammed engine « Reply #1 on: March 03, 2019, 08:42:39 PM »

Quote from: dirtnasty on March 03, 2019, 08:33:04 PM

what i am assuming is that one of the maf tables need to be tweaked/scaled due to the increased amount of air being sucked in

What? No. Why on earth would you change the MAF tables unless you changed the housing or sensor?


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dilly

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	Re: maf reading high g/s. cammed engine « Reply #2 on: March 03, 2019, 08:59:40 PM »

Quote from: nyet on March 03, 2019, 08:42:39 PM

What? No. Why on earth would you change the MAF tables unless you changed the housing or sensor?

i don't know
that is why i am asking


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dilly

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	Re: maf reading high g/s. cammed engine « Reply #3 on: March 03, 2019, 09:59:22 PM »

anyone have experience with cammed engines beit 2.7/8, vr, 1.8t etc wit this issue?
just want it to run correctly


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BlackT

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	Re: maf reading high g/s. cammed engine « Reply #4 on: March 04, 2019, 12:05:51 AM »

That is a amount of air that engine sucks in at idle,you can't do anything. The MAF and ECU are paired?


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nyet

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	Re: maf reading high g/s. cammed engine « Reply #5 on: March 04, 2019, 12:19:30 AM »

trims, logs, dtc, etc.

Just going by g/s is pointless.


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Blazius

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	Re: maf reading high g/s. cammed engine « Reply #6 on: March 04, 2019, 01:55:41 AM »

Usually cammed long duration engines require a tiny bit more fuel to get them to idle properly. But personally I think the tractor sound is pretty good Tongue

it just depends if its going to stall when when you are about to take off then you need to fix it.


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_nameless

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	Re: maf reading high g/s. cammed engine « Reply #7 on: March 04, 2019, 06:38:14 AM »

Does the car have stock fueling, and maf? If so it should idle without issues. I have awp injectors in mine with a homemade mk3 short runner on my afp running corn juce with zero issues. I'd think you have a hardware issue


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_nameless

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	Re: maf reading high g/s. cammed engine « Reply #8 on: March 04, 2019, 06:49:38 AM »

https://youtu.be/dKBsGB7tDnQ


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dilly

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	Re: maf reading high g/s. cammed engine « Reply #9 on: March 04, 2019, 08:31:58 AM »

Quote from: BlackT on March 04, 2019, 12:05:51 AM

That is a amount of air that engine sucks in at idle,you can't do anything. The MAF and ECU are paired?

yes they are paired

Quote from: nyet on March 04, 2019, 12:19:30 AM

trims, logs, dtc, etc.

Just going by g/s is pointless.

trims were jumping around +8 to +25 not holding steady
p1141 Load Calculation Cross Check Range/Performance

Quote from: Blazius on March 04, 2019, 01:55:41 AM

Usually cammed long duration engines require a tiny bit more fuel to get them to idle properly. But personally I think the tractor sound is pretty good Tongue

it just depends if its going to stall when when you are about to take off then you need to fix it.

it does stall when coming back down to idle and throttle response it more than trash. it takes a second for it to react to pressing the pedal

Quote from: Marty on March 04, 2019, 06:38:14 AM

everything is stock except for the cams and springs


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dilly

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	Re: maf reading high g/s. cammed engine « Reply #10 on: March 04, 2019, 12:50:07 PM »

also he just told me that it has a 9lb flywheel


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nyet

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	Re: maf reading high g/s. cammed engine « Reply #11 on: March 04, 2019, 02:51:27 PM »

Quote from: dirtnasty on March 04, 2019, 08:31:58 AM

yes they are pairedtrims were jumping around +8 to +25 not holding steady

Doen't make much sense for the MAF to read high yet run lean.

Something is very very wrong with the setup.


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dilly

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	Re: maf reading high g/s. cammed engine « Reply #12 on: March 04, 2019, 05:08:41 PM »

Quote from: nyet on March 04, 2019, 02:51:27 PM

Doen't make much sense for the MAF to read high yet run lean.

Something is very very wrong with the setup.

Okay I will look into it further
Might be an injector issue

Odd thing is that it doesn’t break up or anything

Once it catches itself it revs fine throughout the rev range but once it comes down to idle, that’s when it stalls or reallllly struggles to stay alive


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nyet

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	Re: maf reading high g/s. cammed engine « Reply #13 on: March 04, 2019, 05:13:40 PM »

Could be a vac leak, but i'd expect that to have low MAF readings and run lean.


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BlackT

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	Re: maf reading high g/s. cammed engine « Reply #14 on: March 04, 2019, 10:31:30 PM »

What values are of vaccum in intake manifold. Does anything break the engine, like bad altenator/AC compresor or something like that?


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