mx6roadster

ok.. I'm Beating a dead horse here but please help. I have an 85 vette and my mods are as follows

355 4 Bolt Main, Dart 202,160 Heads, 490 Lift Comp Cams with Roller Lifters and Rockers, Accel Lower Intake and Runners, Ported Upper Intake, 58mm BBK TB, Accel 24LB Fuel Injectors, Walbro 255 LPH Fuel Pump, Hypertech Coil Cap and Rotor, MSD 6al ignition and 8mm Wires with AC Delco Plugs gapped at .035, B&M Shift Kit, K&N Air Filter with Straight Inlet Tube (no accordion) and Cold Air Intake, MAF Screens removed , TB coolant bypass, AIR system removed and Bypass pulley installed, TCI Torque Converter (not sure on stall)

Ok I never got this engine running quite right yet.. I was having a Problems in the thottle all over the Rpm band , mainly Full throttle was a big hole;( I was chasing a fuel problem from surging throttle while test driving. I fixed it and discovered that my lack of power was not fixed so I took out the old Air Filter and the engine seemed much happier so I took it down the street and something flew in the MAF and broke the wire.;( I have three other MAFs from previous engine testing and I can't get the others to work... I am getting a surging idle from 400 to 1200 rpm and when i put it in gear it stalls. Like the ECM does not agree with this MAF

Old Maf didn't do this but I never really got that working right in the first place .

0280213002/14081243 are the numbers on my original MAF and I have one other with the same exact numbers. (I have tried MAF cleaner on all)

And the other two are these numbers

0280213004/14094712
0280213009/10055877

I have no Vacuum Leaks, Timing is at 6 degrees BTDC , TPS is at .054 , Cleaned and reset IAC. Please make sense of my MAF confusion!!!

I would trade all three of these MAF's for one that works , and If that doesn't sound like my problem.....what could it be?

89onlyZ51

The MAF's with part #'s ending in 712 and 877 are for 86+ TPI cars. The 85 MAF's were digital and not interchangeable. Assuming your ECU is the original then, the MAF's for '86+ will not work. When you use the (assumed) non-broken '85 MAF, are you getting a check engine light and any trouble codes?

mx6roadster

nah....no trouble codes at all..........but isn't that always the case. its funny that all three act exactly the same even though two of them are not for 1985 ecm's . Makes me think something else is wrong but at the same time I did not have this new problem before i was forced to swap MAF's.

tequilaboy

Some conflicting info to stir the pot:

The 870 ecm schematics that I can find show the MAF signal on pin B11. Pin B11 is an analog input.

The digital maf input is pin B6.

From this information, I'm inclined to believe that the 85 MAFs are analog, contrary to popular belief.

mx6roadster

I'm not scan tool and schematic savy....but is that even possible and how does that help or hurt my problem?? i'm so confused on what to check or do next to better this situation. I think I need a known good 85 MAF to rule out that as a problem. The other thing I was reading on this forum about people with surging idles was checking for sticking EGR's but I think that would be a idling only problem. Mine when put into drive or reverse stalls....and in park almost stalls when fan kicks on. I'm 99% percent sure it is the MAF not compling with ecm.

Is anyone selling a MAF for cheap or swap for others I have. I dunno If they are good cause my car is an 85 ;( I can't sell something If I don't know if it's good or not and I'm not in position to dump a **** load of money for a new one on a hunch that it may or may not be the problem. ;( ;( ;(


Maybe I'll swap for carb if this keeps up