MAF Problems after cam swap
Jun 3, 2015 | 03:21 AM
#1
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Posts: n/a
MAF Problems after cam swap
In a customers "01 1500 with a 5.3 I pulled the engine to do a cam swap and stall converter. Now I am not getting a signal from my MAF. I didn't scan it before taking I apart but it ran fine. I took a MAF off another running truck to make sure the MAF isn't bad and visually looked at the wiring and don't see any obvious signs of problems. I didn't open the loom but it doesn't look like it got crushed or any other problems.
My question is there a ground that is specific to the MAF that I my have missed or a plug(not the one on the MAF) that isn't as tight as it needs to be?
Thank for your help.
P.S. I love blackbear but I sure wish hey would return emails quicker then 3- days.
My question is there a ground that is specific to the MAF that I my have missed or a plug(not the one on the MAF) that isn't as tight as it needs to be?
Thank for your help.
P.S. I love blackbear but I sure wish hey would return emails quicker then 3- days.
Jun 3, 2015 | 02:50 PM
#3
Joined: Oct 2004
Posts: 4,985
Likes: 54
From: somewhere in TX
Check all block grounds. Then if they are all connected start checking wiring integrity in the harness in the drip loop from the drivers side valve cover to the power distribution center. These harness are notorious for developing broken wires inside the insulation in the area once disturbed. They work harden from motor movement and then once disturbed either break or get intermittent.
pink ign 12v
black/white ground
yellow maf output to pcm
tan/black IAT output to pcm
pink ign 12v
black/white ground
yellow maf output to pcm
tan/black IAT output to pcm
Last edited by 01WS6/tamu; Jun 3, 2015 at 02:59 PM.
Jun 4, 2015 | 05:04 AM
#5
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Posts: n/a
The ground that goes to the driver rear of the block apparently cam off the bolt when I put it on, but I still have 0 reading from the MAF. I don't thing there are anymore grounds but I will go over the engine bay again. How much voltage should I see at the MAF'S pink wire?
Jun 4, 2015 | 10:07 AM
#6
Joined: Nov 2001
Posts: 4,868
Likes: 16
From: Warr Acres, OK
pink wire on MAF should have +12V. Try referencing it with the MAF black wire then with the battery -. It it is not there with MAF black wire but is with battery - then you are still missing a ground. MAF +12V is sourced with ENG1 fuse and grounded with G103.
Jun 4, 2015 | 11:50 PM
#7
Joined: Oct 2004
Posts: 4,985
Likes: 54
From: somewhere in TX
MAF pink 12V KOEO
Check using a dmm from black to pink to verify power and ground at same time.
Be sure to clear codes from the pcm before wasting a lot of time on it. Once it sets a MAF code it will ignore MAF signal even once it becomes present again until it passes the clear criteria for 3 drive cycles.
Check using a dmm from black to pink to verify power and ground at same time.
Be sure to clear codes from the pcm before wasting a lot of time on it. Once it sets a MAF code it will ignore MAF signal even once it becomes present again until it passes the clear criteria for 3 drive cycles.
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Jun 5, 2015 | 04:28 AM
#8
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Good call on clearing codes!
I will make sure I have 12v and ground.
I talked to a local tuner and they were telling me it is common for the MAF plug to corrode and they regularly replace the MAF plugs? Anyone herd of this.
I am going to try the top two and then maybe dismantle the plug to see how the connectors are looking inside.
I will make sure I have 12v and ground.
I talked to a local tuner and they were telling me it is common for the MAF plug to corrode and they regularly replace the MAF plugs? Anyone herd of this.
I am going to try the top two and then maybe dismantle the plug to see how the connectors are looking inside.
Jun 5, 2015 | 09:44 AM
#9
Joined: Nov 2001
Posts: 4,868
Likes: 16
From: Warr Acres, OK
I've tuned thousands of trucks over the past 12 years and never encountered a corroded MAF connection. MAF problems I've seen have always been blown fuse, missing ground, cut wires by other tuners or dirty insides. Did you check the G103 location?