I guess I know I can...but is it user serviceable?
I have been playing around with different ways to clamp down the MAF and/or intake boot from the supercharger kit and have found a definite connection between any form of strapping it down and the engine surging/bucking symptom. The engine barely has any perceptible surge to it when it isn't strapped at all, on the other hand, strapping it with a metal hose clamp to the hard fuel lines below create an instant hard bucking symptom.

I'm thinking a vibration is being transferred to the MAF when strapped down that is otherwise buffered by the rubber boots below and above when it is not strapped. Once a rigid connection to the engine is created the vibrations are more pronounced...I'm guessing a cold solder joint or loose wire inside that little black box on the side of the MAF.

It's my theory anyway, so can I pry that little box open poke around inside and reseal it without any special tools or skills? What to seal it with?

Thanks!

 

There is nothing user servicable in it at all.

if it is affected by vibration then I would recommend swapping with a known good one and see if problem disappears.

 

If you open it up, you loose the chance of having it as a usable core. If/when you get a new MAF, you will want that extra $100.00 or so back from it.

 

Rebuilt calibration resistor:


thread

 

Well thank you guys!
Since I have a loaner LH ECU and a loaner MAF waiting at the local DHL depot to be delivered tomorrow I'll just wait until they deliver it because after looking at Kens picture I think my soldering skills aren't up to reworking a twenty year old board, I'd rather have $100 trade in value....

 

Hi Craig,
There's nothing serviceable in there, and I've never known a MAF to have a intermittant joint. Is it an original MAF ?

 

Yes, as far as I know it is.
It has the magic Murf restrictor in there and it was a bitch to get it in, I was afraid I'd split that brown ceramic or plastic looking tube when I put it in, maybe I weakened something in that respect to create an intermittent situation.

Either that or my car is truly possessed and every time it sees me try to pinpoint the problem it causes a different symptom so I'll go insane!

 

Hi Craig,
It is best if the MAF is somewhat cushioned from direct metal to metal contact. Porsche did this by rubber and plastic joins.

However the MAf is designed to withstand substantial vibration (part of my testing involves whacking it while observing output.)

You may have a bad 'un, but I doubt the slight crack in the venturi is the cause.

 

Does the MAF body need to be kept from being electrically grounded to motor/chassis?
Just musing.

 

The MAF body is grounded through the cableform, so I don't think that would be a problem.

 

Craig,

Have you tried the loaner MAF yet?

 

Yes, briefly. I've taken about four different short drives with it approximately 50 miles all together.
The surging is gone, all but an occasional stumble and I have the intake and MAF clamped down too!! Yea!!

The only thing it didn't fix is the high idle (I had plugged the ISV connector back in when I put the MAF in).
So I put the LH in after driving with the loaner MAF for awhile and the idle is still high!
So my ISV is being told to open wide by something other than the MAF or LH ECU.

Can the EZK control the ISV somehow or maybe a short in the harness so the ISV is getting constant instead of pulsed signal.... does anyone know if the ground for the ISV is the switched leg? If so then a short to ground could keep it energized couldn't it? (someone smarter than me thought of that one)
Can a bad O2 sensor cause a high idle? I think mine is good but I'm willing to try another one at this point even though the one in there is brand new. I really thought the loaner LH would stop the high idle!!

I'm going to go pull the connector off for the ISV and see if the occasional stumble goes away without the extra air the ISV is letting through. Since the default position for the ISV unplugged is slightly cracked open and that seems to be just fine for my low altitude, warm temperature environment, I may just let it go for now.

Can anyone tell me how to check the output at the ISV connector plug to see if it is sending the proper voltage?
All I can say for sure is it opens up both, the new, and the old, valve wide open, and it stays that way while the car idles even if the ISV isn't the one installed in the car! With ISV unplugged the idle with my old LH was 850...I'll let you know what it is with the loaner LH in a bit.

 

On the "occasional stumble" you refer to, if it is so slight you sometimes might miss noticing it, mine also does that when the engine is not loaded cruising at around 55 or 60 mph. (again let me stress it is not really a stumble but more like a slight hesitation, and not very frequent)

 

You need a tune. Your A/F's are prolly off, this has to be precise and I don't mean by your wide-band only. It has to achieve a certain value in small incremental rates throughout the entire powerband. Not just WOT.

 

Great news Craig...you're almost there!