6.0 runs and quits - Page 2 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Wildkarde · 03-31-2018, 01:19 AM

The only GM computers that don't default to low octane tables when the MAF is failed are the ones used in LS2 and LS7 applications. There's nothing wrong with running speed density if you need to because you are flowing too much airflow for your MAF sensor to handle or have a really monster cam, but just unplugging the MAF sensor is a terrible way to do it. Honestly going straight SD should be a last resort, the car will run better in most applications with the MAF. Especially E38/E67 Gen 4 stuff that rely even less on SD normally.

Not only are you running the low octane spark table, most of the LS engines including all of the gen 4 stuff has the IAT sensor included with the MAF sensor. The IAT sensor is a big part of airflow calcs when running speed density.

While your engine may run smoothly with the MAF unplugged dave, that doesn't mean it's running at anywhere near its peak. GM's VE tables, especially the virtual VE tables used in the E38/E67 computers are known to be fairly rich. This is a safety issue since things like clogged airfilters heavily effect the accuracy of SD, and while the narrowband O2's can correct this at idle/part throttle they are no help during PE. And rich is at least safe, or least until you get so rich you start washing cylinders down.

Wildkarde · 04-01-2018, 04:41 AM

yeah, you definitely need to get the exhaust buttoned up before you can really dig into this. open collectors will be hitting the O2's with tons of air making the computer think the engine is crazy lean.

4x4k30 · 04-19-2018, 07:58 PM

Quote:

Originally Posted by Wildkarde

yeah, you definitely need to get the exhaust buttoned up before you can really dig into this. open collectors will be hitting the O2's with tons of air making the computer think the engine is crazy lean.

I got the exhaust hooked up and I have been driving it all week and it still will not run with the maf hooked up . it runs ok with it not hooked up but it has low power . I keep getting a p0102 code maf low circuit I have checked all the wiring and found nothing . I checked the pvc its seems fine too and I cant find any vacuum leakes I don't know what else to do

Wildkarde · 04-19-2018, 08:42 PM

How did you check for vacuum leaks? The best way I have found is to lightly spritz carb cleaner around all the areas that can leak and listen for the engine rpm to spike. Gotta check all the vacuum hoses, the throttle body, the intake gaskets at the heads (known to leak on these motors), and all the air intake between the throttle body and Maf sensor.

If you are confident you don't ahve any vacuum leaks and the wiring is good you really need access to either a scan tool that can read real time data to check MAF hertz or a DMM that can read frequency. If you go the DMM route this is a good tutorial on how to do it. http://easyautodiagnostics.com/gm/3....sensor-tests-1

03-31-2018, 01:19 AM	#1
Wildkarde Registered User Join Date: Mar 2018 Location: Ardmore Posts: 100	Re: 6.0 runs and quits The only GM computers that don't default to low octane tables when the MAF is failed are the ones used in LS2 and LS7 applications. There's nothing wrong with running speed density if you need to because you are flowing too much airflow for your MAF sensor to handle or have a really monster cam, but just unplugging the MAF sensor is a terrible way to do it. Honestly going straight SD should be a last resort, the car will run better in most applications with the MAF. Especially E38/E67 Gen 4 stuff that rely even less on SD normally. Not only are you running the low octane spark table, most of the LS engines including all of the gen 4 stuff has the IAT sensor included with the MAF sensor. The IAT sensor is a big part of airflow calcs when running speed density. While your engine may run smoothly with the MAF unplugged dave, that doesn't mean it's running at anywhere near its peak. GM's VE tables, especially the virtual VE tables used in the E38/E67 computers are known to be fairly rich. This is a safety issue since things like clogged airfilters heavily effect the accuracy of SD, and while the narrowband O2's can correct this at idle/part throttle they are no help during PE. And rich is at least safe, or least until you get so rich you start washing cylinders down.

04-01-2018, 04:41 AM	#2
Wildkarde Registered User Join Date: Mar 2018 Location: Ardmore Posts: 100	Re: 6.0 runs and quits yeah, you definitely need to get the exhaust buttoned up before you can really dig into this. open collectors will be hitting the O2's with tons of air making the computer think the engine is crazy lean.

04-19-2018, 08:42 PM	#4
Wildkarde Registered User Join Date: Mar 2018 Location: Ardmore Posts: 100	Re: 6.0 runs and quits How did you check for vacuum leaks? The best way I have found is to lightly spritz carb cleaner around all the areas that can leak and listen for the engine rpm to spike. Gotta check all the vacuum hoses, the throttle body, the intake gaskets at the heads (known to leak on these motors), and all the air intake between the throttle body and Maf sensor. If you are confident you don't ahve any vacuum leaks and the wiring is good you really need access to either a scan tool that can read real time data to check MAF hertz or a DMM that can read frequency. If you go the DMM route this is a good tutorial on how to do it. http://easyautodiagnostics.com/gm/3....sensor-tests-1



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