maf lessons
Thread Starter
Racer
Joined: Apr 2007
Posts: 351
Likes: 0
From: washougal wash.
Allright, I'll replace the relays, and if necessary, order a new maf. It was nice to drive it a bit today though. Buying a c4 should include a year long College course in service and maintanence. Thanks again, all
Thread Starter
Racer
Joined: Apr 2007
Posts: 351
Likes: 0
From: washougal wash.
Yes, I installed a new tps today and adjusted it to .54v. 22 is gone, only showing 33 now. Shure is odd that tps and maf crapped out at the same time...I'll go see ol' Curt Warner tomorrow and get some relays form the dealer. I know I'll catch hell for this but, I'm assuming the ecm is good since it runs well without the maf? 15 years ago my '88 IROC had similar symptoms and I ignorantly replaced sensors to no avail. Looking for different outcome this time, I appriciate the help.
Team Owner
Joined: Sep 2003
Posts: 20,172
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From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
ECM/PCM are programed (chipped on early models without MAP backup) with an extra "limp home" mode that gives the computer backup default data in case of failure. The car will run like crap with the MAF disconnected on earlier models unless it is a newer model that has both a MAP & MAF combined setup.
Anyone? Anyone? Bueller?
Race Director
Joined: Aug 2000
Posts: 14,130
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Cruise-In II Veteran
Yes, I installed a new tps today and adjusted it to .54v. 22 is gone, only showing 33 now. Shure is odd that tps and maf crapped out at the same time...I'll go see ol' Curt Warner tomorrow and get some relays form the dealer. I know I'll catch hell for this but, I'm assuming the ecm is good since it runs well without the maf? 15 years ago my '88 IROC had similar symptoms and I ignorantly replaced sensors to no avail. Looking for different outcome this time, I appriciate the help.
The reason I ask,if you have a TB that is not adjusted properly for the minimum air speed,you will get a code 33.
The ecm will see an unrealistic airflow and set that code.
I had this problem with an 52 MM TB.It was not adjusted right and it took a while to figure it out. This can still happen on the stock TB if someone adjusted the screw and did not do the proper adjustments.
That is something important to check.
Team Owner
Joined: Jan 2003
Posts: 20,290
Likes: 239
From: Summerland B.C. Canada
Have you tried to clear the code 33, run it again, and check for 33 again.
If the 33 is still there after setting minimum idle and TPS idle voltage, follow the flow chart to diagnose the problem.
http://members.shaw.ca/corvette86/Code%2033.pdf
Thread Starter
Racer
Joined: Apr 2007
Posts: 351
Likes: 0
From: washougal wash.
Did you set the minimun idle along with TPS idle voltage ?
Have you tried to clear the code 33, run it again, and check for 33 again.
If the 33 is still there after setting minimum idle and TPS idle voltage, follow the flow chart to diagnose the problem.
http://members.shaw.ca/corvette86/Code%2033.pdf
Have you tried to clear the code 33, run it again, and check for 33 again.
If the 33 is still there after setting minimum idle and TPS idle voltage, follow the flow chart to diagnose the problem.
http://members.shaw.ca/corvette86/Code%2033.pdf
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
OK the 85-87 were MAF only. So where/what are the rest of L98's configuration?
So were the '88 & '89. '90 & '91 were Speed Density or MAP. LT motors eventually used a dual strategy - I thought I allready posted this.
So were the '88 & '89. '90 & '91 were Speed Density or MAP. LT motors eventually used a dual strategy - I thought I allready posted this.
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Thread Starter
Racer
Joined: Apr 2007
Posts: 351
Likes: 0
From: washougal wash.
Went to dealer this morning and picked up nu relays. The ones in there have been replaced b-4, but were the correct pn#. Cleaned the connectors, cleared the codes, plugged maf back in and......It is running perfect. no sas, 25mpg on hi-way. All seems good for today, except for the seat controls. I'll start nu post on that later. At least it's running. Thanks, C.F.
..WW
Team Owner
Joined: Sep 2003
Posts: 20,172
Likes: 672
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Went to dealer this morning and picked up nu relays. The ones in there have been replaced b-4, but were the correct pn#. Cleaned the connectors, cleared the codes, plugged maf back in and......It is running perfect. no sas, 25mpg on hi-way. All seems good for today, except for the seat controls. I'll start nu post on that later. At least it's running. Thanks, C.F.
