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My car has been acting funny at low throttle levels, it sounds like it's backfiring out of the intake and has no power with minimal throttle. If i give it over 50% throttle it picks up and goes pretty normal; and once it's warmed up it drives more normal, but still does backfire out the intake a bit.
I'm throwing codes 32,33, and 34. Which two of those are for the maf sensor, I think that's my problem, and I know a guy who will give my his 88 maf for cheap if it will work. I've read on some posts that it will work and some that it wont, does anyone have an idea if it will?
Hi
I have a 88 MAF on my 85 vette it runs fine, the 85 had an analogue maf the 86 onward have digital mafs.
Google the numbers on the maf sensor and it will show what year it is for.I have been running the later maf without a problem, no codes either and the vette runs great
I've had an '88 maf in my '85 now for 7-8 years, no problem. This issue has been kicked around a lot on here and there are a lot of knowledgable people here but sometimes they are just wrong. If expertise in the matter means anything, the person who told me it was okay to run the '88 was none other than Gordon Killebrew, and that was in a face to face conversation with him.
alright, well I got the 88 maf today, i tried it and it's not working right. It idles super low, below 500 rpm. Once i accelerate it seems responsive and drives normally. Finally when I give it WOT it doesn't really pick up speed, it just seems hesitant or like my power is capped, and kinda backfires and stumbles. It also seems to run super rich, it reeks of rich exhaust and my fuel economy gauge is saying really bad gas mileage.
The symptoms you describe sound like what I experienced when the maf connector wasn't seated properly. I'm going to ask the obvious, please don't take offense, did you remember to plug it back in?
If it improves, it could be the MAF burnoff module, or the MAF which you already replaced.
I have a MAF from my 85, but I was experiencing the same problems you state, so I just drove it with the MAF unplugged. Probably attributed to my car rocking a head gasket and leading to my engine build, but I was sick of it running like **** and just wanted to drive it. The engine was old and had seen much better days anyways. With the new engine I am going to be running a 85/87 hybrid setup, utilizing the MAF burnoff relays like the 86+ MAF cars.
yep, i didn't forget to plug it in, I even double checked haha. Although the 88 maf has been sitting around at the guys house for a few years, so maybe the wire in the sensor or the prongs in the connector got nasty.
I'll try pulling off the connector and seeing how it drives, I only unplugged it and revved it in neutral, it seemed to backfire and have an inconsistent idle, but i didn't actually drive it.
Pwnage,what is the 85/87 hybrid, are you referring to just the maf sensor stuff?
I ruined my original 1987 BOSCH MAF while porting it out myself.
Broke the thin platinum wire.
Used a 1985 MAF on my 87 vert for 2 years.
Ran good but not quite the same.
Felt like less power much of the time.
No other changes made other than the installing the 1985 MAF.
Like ignition timing was being retarded 15 or 20 degrees.
Installed a 1988 MAF on my car a few months back.
Runs very strong.
Especially off the line.
More than I ever recall with my original 87.
I left the 1988 MAF stock with both screens intact.
Just wiped the entire housing clean with a damp rag.
Subject of 1985, 1986-1987, 1988-1989 BOSCH HOTWIRE C4 & F- body MAF's needs more scientific style research done.
With a laboratory grade Techtronics digital storage oscilloscope.
The best oscilloscope I ever used while still in college studying electronics tech.
Don't own that oscilloscope.
Looking for 1 to buy yet without costing $2K.
Cost was $15k something in 1987 I recall for that Techtronics Oscilloscope.
Dead on accuracy.
I suspect the BIN files were programmed in matched to each of 3 separate style C4 TPI style BOSCH MAF's.
I am no computer programming expert like others here on C4.
Electronics TTL circuits I recall much of.
I have a AAS in Electronics Technology too.
At least 2 OP AMPS (operational amp) circuits inside of those BOSCH MAF's.
Likely a signal converter & conditioner also.
Brian R.
Last edited by 87 vette 81 big girl; 10-06-2011 at 01:57 AM.
yep, i didn't forget to plug it in, I even double checked haha. Although the 88 maf has been sitting around at the guys house for a few years, so maybe the wire in the sensor or the prongs in the connector got nasty.
I'll try pulling off the connector and seeing how it drives, I only unplugged it and revved it in neutral, it seemed to backfire and have an inconsistent idle, but i didn't actually drive it.
Pwnage,what is the 85/87 hybrid, are you referring to just the maf sensor stuff?
The 1985 cars used a special one year only "burnoff module" to power the maf and supply the burnoff function. 86+ years used a more reliable relay system. With my car, I bought an 87 harness, and sent it to Jims Performance to make it compatible with my 85's charging system/dash. It is going to use the burnoff relay system used on the 86+ cars. So its a half 85 and half 87 harness. Sorry for the confusion.
I remember when I was having an issue similar to this I would open the hood, and it would be running rough, but when I would drop the hood, it would clear up. Eventually I got a FSM and traced it to the burnoff module. When it was running rough, the slightest tap on the box would make it clear up and run great. It is not a reliable system, IMO.
It may be that the '88 maf has a broken wire inside of it, but try cleaning the contacts first. It may very well be that an '85 maf in a newer engine will not let that engine perform as well since the '85 is a dinosaur. GK and I did not discuss that, we only discussed upgrading an '85 to an '88. I have no issues whatsoever using the newer maf but like Pwnage says, the burnoff module is a poor system. I have already changed mine once and I have a spare just in case. I saw a new one somewhere the other day and they were asking $1300+ for it! If I were faced with needing one I would do something like Pwnage did and eliminate the burnoff module.
It may be that the '88 maf has a broken wire inside of it, but try cleaning the contacts first. It may very well be that an '85 maf in a newer engine will not let that engine perform as well since the '85 is a dinosaur. GK and I did not discuss that, we only discussed upgrading an '85 to an '88. I have no issues whatsoever using the newer maf but like Pwnage says, the burnoff module is a poor system. I have already changed mine once and I have a spare just in case. I saw a new one somewhere the other day and they were asking $1300+ for it! If I were faced with needing one I would do something like Pwnage did and eliminate the burnoff module.
Before spending that much money on a new GM MAF sensor consider going to a Blowerworks maf like I did on my 89 Corvette..These use a Ford Mustang MAF blade type sensor that can be perchased for around $100.00 if they ever go bad. One of the nice things about this unit is if the sensor ever goes bad you don't have to replace the whole thing, you just replace the blade sensor that goes into the aluminum tube with 2 screws.You also don't have to worry about the MAF burn off module anymore, the new unit eliminates there use..The whole unit including the housing, new plug, and instructions is $299.00 for the smooth tube with sensor or $399.00 for the tube with L98 adapter plus the Bin files for your car.The cheapest I have ever seen a new GM Bosch maf is $799.00, and that's if you can find one...WW
Go to the site below and click on "GM L98 MAF Sensor"
It may be that the '88 maf has a broken wire inside of it, but try cleaning the contacts first. It may very well be that an '85 maf in a newer engine will not let that engine perform as well since the '85 is a dinosaur. GK and I did not discuss that, we only discussed upgrading an '85 to an '88. I have no issues whatsoever using the newer maf but like Pwnage says, the burnoff module is a poor system. I have already changed mine once and I have a spare just in case. I saw a new one somewhere the other day and they were asking $1300+ for it! If I were faced with needing one I would do something like Pwnage did and eliminate the burnoff module.
I have the 85 BOSCH MAF Sensor yet Chuck.
I will hang onto it in case You need it.
Its de-screened by me.
But the housing I did not port.
Came off a '85 C4 You brought in at "V2V" when I 1st met You & Jason.
Not worth $1300 to me. ??
Crazy.
Need an all original low mileage ZR-1 rear diff assembly.
Factory installed batwing be awesome too.
Not for me.
For a special C4 ZR-1 Racecar that runs a very cool & fast flying American Road Race.
90 miles flat out.
I would appreciate if You & Jason keep an eye out for 1 or if another wrecked C4 ZR-1 comes in.
Year is not important.
Just from a ZR-1.
The $$$ is good to take it off your & Jason's hands.
Brian R.
Last edited by 87 vette 81 big girl; 10-06-2011 at 08:17 AM.
Thanks for the offer on the maf but I think I would switch to speed density if I ever needed one. I have tuned port on my dd El Camino too, it is run by an Accel Gen 6 system and is speed density. I'm not crazy about the Accel unit but I do like the speed density. I'm not going after wrecked Vettes any more, too darn old to be crawling all over underneath a wrecked Vette looking for solid places to tie it down.
i acquired an 88 maf from a forum member based on reading these threads, my 85 did not take well to the 88 maf , if it could throw up i think it would have...just my input and experience
I ruined my original 1987 BOSCH MAF while porting it out myself.
Broke the thin platinum wire.
Used a 1985 MAF on my 87 vert for 2 years.
Ran good but not quite the same.
Felt like less power much of the time.
No other changes made other than the installing the 1985 MAF.
Like ignition timing was being retarded 15 or 20 degrees.
Installed a 1988 MAF on my car a few months back.
Runs very strong.
Especially off the line.
More than I ever recall with my original 87.
I left the 1988 MAF stock with both screens intact.
Just wiped the entire housing clean with a damp rag.
Subject of 1985, 1986-1987, 1988-1989 BOSCH HOTWIRE C4 & F- body MAF's needs more scientific style research done.
With a laboratory grade Techtronics digital storage oscilloscope.
The best oscilloscope I ever used while still in college studying electronics tech.
Don't own that oscilloscope.
Looking for 1 to buy yet without costing $2K.
Cost was $15k something in 1987 I recall for that Techtronics Oscilloscope.
Dead on accuracy.
10-02-2011, 01:27 PM
85 and 88 maf interchangeability
