1996 Chevy Silverado mass air flow codes 101 & 102

COLOR AIR

MEMBER
1996 CHEVROLET SILVERADO
V8
2WD
AUTOMATIC
200,000 MILES

New rebuilt motor to 383. Computer reprogramed
by fast chip. 101 and 102 codes going up hill
past half throttle. Going back down hill engine
dies at bottom. Has happened 3 times. Timing
out, kicking back on starter. Move distributer
clock wise and will start. Turn motor off and put
distributer back to origanal postion and runs fine.
no other codes show up. Cleaned mass air flow
sensors, no change. Have checked for vacuum
leaks.

5 Replies

RACEFAN966

MECHANIC
5,029 POSTS

First obd 2 codes are all P-. Next how big is the cam? The computer does not like big cams.

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Saturday, November 1st, 2008 AT 12:16 AM

COLOR AIR

MEMBER
2 POSTS

Codes are P101 & P102
Not a big cam .478 intake .481 exhaust
duration 202 intake 212 exhaust
lobe separation 115
ecm programed for that cam and 383 cubic inch
Has double roller timing chain. Ruluctor wheel
had to be shimed out to clear chain. Crank sensor
only catching half of the wheel. Im thinking
problem is there. I'm not a mechanic I didn't
do the engine. I'm a bodyman this engine was
a trade for me painting a 55 chevy. 55 is done.
My truck won't run and it is my problem. Thanks
for any help.L

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Saturday, November 1st, 2008 AT 12:53 PM

RACEFAN966

MECHANIC
5,029 POSTS

Ok first that is a big cam for a computer. Who did the program? Shimming the relutor so that it is only reading part of the wheel is a problem the computer isn't seeing all of it that should be fixed first. Now why is there a double roller chain in it if it is only a daily driver? What year block was used for the build and what heads are on it? The more you can give me the better. I would go to a single roller seamless chain they are very strong and fit right so you would not need to shim the sensor. Now the timing cover is it plastic like stock or metal? The codes are P101= Mass air flow out of range and P102= air flow to low. Give me some more info so I can try to help better ok.

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Saturday, November 1st, 2008 AT 10:27 PM

COLOR AIR

MEMBER
2 POSTS

ECM programed by fastchips. Com
Out of Tulsa Ok. Recomended by Comp Cams.
I have spoke with him with my engine problem.
Said he has done many programs with my same
combination with no problems.
I am changing timing chain back to single roller this
week. I tryed 2 new stock chains and they were
both too loose, before motor was installed. Double
roller was tight so went with it.
Engine is original motor in truck. Only changes are
comp roller cam, lifters & rockers. Edelbrock short
headers for 96 chevy 350 pickup. Double roller chain,
reprogramed ecm. Truck ran fine before engine rebuild. No codes. Just down on power from
200000 miles. Timing cover is stock but shimed
out to clear double chain. That is going away
this week when I can find a tight fitting single
roller chain. Been 5 weeks and 4 mechanics trying
to fix this. If can't fix it only choice park the truck
or buy a new complete crate motor.

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Sunday, November 2nd, 2008 AT 1:42 PM

RACEFAN966

MECHANIC
5,029 POSTS

Well don't give up yet get the seamless true roller by cloyes it is single roller but very strong and I have had no problems with them fitting and being tight. Once the cam sensor is back in place then it will read right and should by all rights run right again. Fast chips is a good company do good work so I don't think that is the problem. Let me know how it goes when the sensor is back in line ok.