MAFS trouble...

metalman

Registered User
My car has been acting up for months, you might have seen other threads, rough idle, stalling at red lights, low vacuum, etc. Yesterday I pull the plug to the MAFS while the car was bucking and running rough on me in the driveway. It immediatly smoothed out. The RPMS rose to about 1000, vacuum was up to about 18in, and I drove it around the block and my car had some ~~~ to it! So, I thought it was a bad MAFS (PRO-M 75mm for 30lbs inj.) So I swapped it out with an identicle MAFS (thanks, Z) but still the same exactly symptoms.

Could it be the plug or the wiring itself? What is the maf connected to....directly to the computer?

I'd appreciate any help on this matter, thanks!

Metalman
 
metalman said:
My car has been acting up for months, you might have seen other threads, rough idle, stalling at red lights, low vacuum, etc. Yesterday I pull the plug to the MAFS while the car was bucking and running rough on me in the driveway. It immediatly smoothed out. The RPMS rose to about 1000, vacuum was up to about 18in, and I drove it around the block and my car had some ~~~ to it! So, I thought it was a bad MAFS (PRO-M 75mm for 30lbs inj.) So I swapped it out with an identicle MAFS (thanks, Z) but still the same exactly symptoms.

Could it be the plug or the wiring itself? What is the maf connected to....directly to the computer?

I'd appreciate any help on this matter, thanks!

Metalman

According to the EVTM I have, 2 wires (Tan/Lightblue and Darkblue/Orange) go to the computer, 1 goes to the inertia switch (Red) and the last to ground (Black/Lightgreen). I have no idea where to check on that one, hopefully this helps some.
 
i feel your $ loss

I have a 35th ann. that is doing the same thing. my car starts surging at low rpm and idle only. I just put a new maf on it because i too got it to stop surging by pulling the maf plug. i myself was wrong. $150 wrong. I don't know why the check engine light doesn't come on when surging occurs. It has correct fuel pressure even under boost. It's not fuel. this is my daily driver and i have to pull over to shut down and restart about 3 times in just 4 miles. someone has to know something. let us know before we lean out and blow. help!!!
 
I have some wiring schematics. I'll do what I can to check them out. I'll probably try to find where the ground goes first. Maybe it's a bad ground?
Thanks, MN12SC35th

So, until I figure out the problem should I leave it plug in and fight the roughness or unplug it to run smooth? But unplugging it leans out the car, right?

Anyone else have experience with this problem?

BTW while this is happening I had my rear passenger caliper decide to pop of the bracket 2 days ago, while I was driving :eek: The bolts on the back of the pin loosen up, I lost my break pads and the brass brakeline bent a bit. It also scored the inside of my wheel. Thank God no permanent damage. I bought a new pin and bolt, new pads, screwed the caliper back in and rebent the brakeline in place. All is well now...phew...only if I can fix this MAF issue...
 
metalman,

i just went thru the exact same problem- it's not your maf. after I ruled out the other sensors (dis, coil pack, crank and cam sensors, harmonic balancer, fuel pump) on my car, and tracing the wires for short outs/grounding issues, my EEC was the culprit. Installed a new one, and she runs to perfection with the original maf. If yours is a '90, and it has the original EEC, replace it man. I'm telling you, i've already done all the foot work on this. there are guys that will say the EEC not likely to go bad- but i'll tell you if it's the original ford unit, it's bad (15+year old unit). If it's a reman unit, then it's iffy- i don't know if that one will need replacing. It will be marked on the box if it is a reman unit or a ford original. I've had 4 other sc's that DID NOT have driveability issues, and they all had reman EEC's except for the one i just bought, which had an original ford EEC. This '90 SC i have now started out having very bad driveability issues with the original ford eec, exactly like yours is having and unplugging the maf did the exact same thing yours did.

replace the EEC (assuming you have a good engine- no burt valves, bent rods, etc..).

got mine from ecudirect.com- don't fool around with this, you'll be looking for the problem forever and eventually wanting to part out your car.
 
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DUDE!
Thanks for the suggestion. I will definatley check out the EEC. It definatley makes sense though. After 3 MAFS, and thank God I didn't actually buy three MAFS. A friend let me borrow a couple of his to check the problem out. They are just on loan :)

If it's not the maf, then it' got to be the wiring or what it's connected too. It wouldn't the be the wires to the inertia switch, maybe the ground...but unlikely. The wires to the EEC seem like the likely culprit? We'll see...

Thanks again, Hytork
 
metalman said:
DUDE!
Thanks for the suggestion. I will definatley check out the EEC. It definatley makes sense though. After 3 MAFS, and thank God I didn't actually buy three MAFS. A friend let me borrow a couple of his to check the problem out. They are just on loan :)

If it's not the maf, then it' got to be the wiring or what it's connected too. It wouldn't the be the wires to the inertia switch, maybe the ground...but unlikely. The wires to the EEC seem like the likely culprit? We'll see...

Thanks again, Hytork
Man, i know how you feel. I was pulling my hair out, and i actually got to the point of calling the guy that sold me the car thinking he was scamming me (it ran good just until i got home with it). But i got down to checking/tracing the maf wires and looking for shorts and frayed wires touching things they are not supposed to. didn't find anything out of place. after all that, it kept pulling the same trouble code over and over again (code 66) on 3 different mafs, and it would never clear out of the computer. then it dawned on me that 3 mafs could not possibly all go bad at the same time- the eec was bad.

i really love my SC for now. i hope i can get a few trouble free years out of this thing. i've done it before.
 
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