Newbie: 85 3.2 looking at MAF conversion options.

[kbken62]

I have a very rich running 85 3.2. In my past I converted similar AFM barn door to Miller Performance MAF which is off a cobra. This was on my BMW S14 motor.

In any case instead of going down the path of trying to fix/tune my AFM, I'd like to hear about options for an MAF upgrade.

Hopefully it will pass the strict California smog tests.

Thanks,
Ken


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[kuehl]

Ken,

There have been quite a few aftermarket MAF systems over the years.
In terms of quality and perfection look into Sal's systems.
Sal Carceller MAF

Most impressive is Sal's support.

[dyerkes]

+1 on Sal's MAF solution

[J-Mac]

Sal's solution is great. But I don't believe that it will pass Ca smog visual.

[Quicksilver]

If you have a running rich problem then throwing a modification at it isn't a solution. (except for lightening your pocket book.)

None of the MAF systems will be California legal. California requires an obscene quantity of money to get a CARB exemption for an engine modifying part. There isn't a large enough market to ever make a profit after California as taken their 6 digits of $$$$. If you have a MAF in California you just need to cross your fingers and hope the smog station doesn't notice or swap back the stock parts.

Fix your problem before thinking about modifying the car otherwise you will never have a good baseline to work from.

-----
Just a point about that damn near bomb proof, reliable, barn door AFM that people seem to hate on: It Is Not A Restriction On A 3.2 With Stock Internals!

Bruce Anderson and Jerry Woods were asked to test the AutoAuthority MAF and on the dyno they found it was good for a 5 HP loss. In fact it was referred to it as a "cash flow device". They pointed out that without opening up the motor there was zero power to be found in the intake but there was 20 HP to be found in the exhaust.
If you don't know who Jerry Woods is you need to read up on Porsche racing. He is one of the best aircooled Porsche race engine builder in the world. The quantity of things he developed for 935 in the late 70s and 80s is legendary.

If you are set on an MAF the real place it would shine is where you are dealing with serious altitude change. If you live in the Rockies and if you want to run Pikes Peak the MAF would be a great idea. If you are a hobbyist and you are messing with the engine management the MAF is an obvious choice.

IF you still want to do an MAF there is only one choice. Go for Sal's. He actually works with people and is still trying to make everything he touches better.

[kyngfish]

Hi - on my 86, my MAF is turned pretty close to all the way rich - funny thing is, using my wideband, my idle shows up as slightly LEAN at idle. Under Load, the O2 Sensor and Motronic take over, and I'm stoic.

Pretty sure mine is almost all the way rich to hide a vacuum leak which I am currently chasing down. I know people say that if you remove your oil cap and the idle stumbles you're fine on the vac, but I'm 100% certain I have one, because I've found a leak that I need to fix - and the oil cap trick will still cause a stumble. I think because it may depend on the size of the leak.

Anyway - less experienced than a lot of these guys, but those are my 2 cents.

EDIT: I just realized I didn't make a point here - point is - I agree with Quicksilver - fix your running rich problem first - you may be hiding a vacuum leak.

[kbken62]

Thanks for the input. I am checking all lines and hunting new parts for suspect hoses. I will have all new on the car shortly. However, if I have to rebuild or replace the AFM, I'd prefer a MAF, from past experience on a built BMW.

I'll update after I get some new hoses and gaskets and a bit more testing.

And yes, California sucks with post 75 cars.




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[DaveMcKenz]

Hi Ken,
Running rich doesn't sound like a vacuum leak. To me it sounds like a faulty sensor. Could be O2 sensor or cylinder head temp sensor. If either is dead, the fuel injection brain thinks the car is cold or is running lean. Either condition will lead to running rich. BTW how are you measuring AFR's?
I would recommend fixing the stock system within reason before trying to modify it. I worked with Sal on my injectors, and he insisted that I perfect my stock system before installing his injectors and custom chip.
Just my two cents.
Good luck with your car.
Dave

[kyngfish]

Originally Posted by DaveMcKenz

Hi Ken,
Running rich doesn't sound like a vacuum leak. To me it sounds like a faulty sensor. Could be O2 sensor or cylinder head temp sensor. If either is dead, the fuel injection brain thinks the car is cold or is running lean.
Dave

Probably good advice to ohm the sensors. Not hard to replace. That said, depending on if it was a preexisting issue before he bought the car, someone could have turned the AFM rich to hide a leak.

[kbken62]

Originally Posted by DaveMcKenz

Hi Ken,
Running rich doesn't sound like a vacuum leak. To me it sounds like a faulty sensor. Could be O2 sensor or cylinder head temp sensor. If either is dead, the fuel injection brain thinks the car is cold or is running lean. Either condition will lead to running rich. BTW how are you measuring AFR's?
I would recommend fixing the stock system within reason before trying to modify it. I worked with Sal on my injectors, and he insisted that I perfect my stock system before installing his injectors and custom chip.
Just my two cents.
Good luck with your car.
Dave

Thanks Dave,

New O2 sensor. Not sure about head temp sensor, so I'll have to look into that. I don't have a meter for AFR, and have to take to shop to get checked.

I'm wanting to renew any older or worn parts as a matter of course that I do with all my cars.

I found a crack in the gasket from where the air box meets the AFM, but doubt that would cause a problem.

Also noticed when I open the oil filler cap the car idle changes and stumbles quite a bit. Not sure why that happens, but will read more.

Thanks again,
Ken


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[DaveMcKenz]

That's an idea Kingfish. Someone tweaked the AFM rich to mask an air leak which has since been fixed. Possible.
I recently replaced my O2 sensor with a new Bosch (on my 928) and the new one was dead too. You might try running your car with the O2 sensor connected and disconnected to see if there is any difference. If not, it might cast suspicion on the O2 sensor.
Pulling the oil cap while idling should cause a stumble and then return to idle, maybe a little slower. That's good.
Dave

[ben parrish]

How do you know it's running rich?
What are the symptoms causing you to think it's rich?

[kyngfish]

Originally Posted by kbken62

Also noticed when I open the oil filler cap the car idle changes and stumbles quite a bit. Not sure why that happens, but will read

The stumble is supposed to happen. When you open the cap you're introducing a large vac leak which causes the stumble. So that's good.

Test your cylinder head sensor with a voltmeter. There are a set of three plugs over the driver's side of the engine in a metal bracket. The top one is the CHT. Unplug and test the connection to the right (left side is the harness not the sensor).

Ohm readings depend on engine/ambient temp. I would test when engine is cold.

[kbken62]

Originally Posted by ben parrish

How do you know it's running rich?

What are the symptoms causing you to think it's rich?

Ben,

Initially just smells rich and the confirmed when it fail California smog test.

Thanks,
Ken


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[kbken62]

My Smog test results.


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