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Old 05-22-2012, 03:03 AM   #1
Scooby Newbie
Member#: 276321
Join Date: Mar 2011
Default full boost stuttering jecs maf fix

Trying to get this beast going and been running into a few problems


Ya that maf sucked. Swapped in a known bad jecs maf from work (intermittently cutting out) and she fired right up. Engine responded great and took off no problems. So I went back to the wreckers and exchanged the maf for a different one.
New problem, throttle wasn't as responsive and WOT/full boost I was getting some stutters. It would accelerate but didn'thave any punch and erraticly roughly every second to 2 seconds it would miss. The whole car would lurch momentarily then go, 2 seconds later it would do it again. All in all even at idle the car just felt laggy.
Pulled the plugs and they were all white hot. Checked over the whole fuel sytem and everything checked fine. Fuel pressure was in specs but was concerned with flow under full boost. Replaced the 3 year old Walbro pump for a recently bought brand new Walbro. Also replaced the coil pack and wires as well. Stuttering continued.
Went to town and checked all ground and connectors in the fuel system. Everything checked out.
What the heck might as well check the maf. Compared the output voltage while car was running for both mafs, current and the nfg one. Nfg was a little higher. Installed the nfg maf and throttle response was noticeably sharper.
Checked resistances on terminals of mafs while unplugged from the harness. NFG maf was .2 of an ohm lower.
So I figured the exchanged maf had a higher resistance and was telling the computer that less air was going in than what was actually going in.
WTH might as well take that little box apart, I'm gonna return it anyway.

Wish I had pics

-took a small screwdriver and sliced all the silicone up on all four corners of the square black plastic cover on the jecs maf.
-pried up the black plastic cover.
-there was a copper cover underneath that, pried that up too.
-underneath there was 2 circuit boards half layered on top of each other
-noticed on a couple spots on the top circuit board and across the external connector connections there was this black ****. Almost like that black silicone used to seal the cover melted in there.
-sprayed it down with some electrical contact cleaner and black sploches stayed. Scrubbed them lightly with a tooth brush to no avail. Pulled out the carb clean and the lower board looked like it was melting the protective layer off. Scrubbed the black spots quickly and they came off. Doused the whole unit with more contact cleaner and blew lightly on it with the air line.
-installed the copper plate and hot glued the black plastic cover back down.

Plugged it in fired it up and noticed a drastic difference. Smoother idle and sharper throttle response. Took it for a burn and it pulled smoothly.....until I blew my faaaakin intercooler hose off again....but that problem is for another day.
Hopefully someone uses this as a reference some day
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