Blow-through MAF problems, need suggestions.

Well, as I described in this thread in the 4th post down:

http://web.camaross.com/forums/showthread.php?t=384420&page=2&pp=15

I am having problems with the MAF reading incorrectly on the pressure side. It had been located in the intake pipe as the Vortech S-Trim was originally designed to.

Like my post says in that thread, I believed the bypass valve to be creating turbulence right in front of the MAF, possibly throwing its readings off. I moved the MAF to the pipe that leads from the intercooler up to the throttle body in a straight section of the piping about halfway between the cooler and the TB. The bypass valve stayed over in the pipe from the blower to the intercooler. Its still doing the same thing. It will read fine at idle and WOT, but anything above 1,500 RPM's and the readings start jumping up and down just like you'd see with the O2 sensor readings.

I just don't get this. I've done some searching on here and found that most people who have moved their MAFs to the pressurized side have had no problems at all. It read everything correctly before moving it to the pressurized side. Before I moved it away from the bypass valve, I took the blower belt off and it ran perfectly. The MAF was reading exactly like it should. I put the belt back on and it runs like trash again.

I'm running a stock MAF with the screen still in it. And yes, I verified that it is facing the correct direction in the airstream.

Anyone with any help or suggestions....it would be appreciated. I really don't want to move the MAF back in front of the blower....

Any turbulence is negligible if venting before the MAF...as you may have found out after moving the MAF closer to the throttle body (which IS a good idea due to possible leaks). The FMI seems to be the thing that changed things.

OK, I just tried an MAF known to be good from a friend's car and it does the same thing.

I unhooked the outlet pipe from the intercooler to check the flow of air through the intercooler itself. It seems to be coming out of there in a steady stream...doesn't seem to be blocked and pulsated out of there.

This really has me confused. I found someone who had this same problem and posted about it last year, I sent him a PM but he hasn't been on this board in awhile. There has to be someone else out there who has had this problem though....

Maybe try running just the MAF to see if runs ok NA.

How much hp you running at the wheels?

Maybe try running just the MAF to see if runs ok NA.

Already did....it runs perfectly N/A....aside from it adding a lot of fuel if I go much over 3,000 RPMs. :D The MAF acts and reads just like it should without the blower belt on.

How much hp you running at the wheels?

Not certain at this point. A lot, probably. :D

I've been thinking that maybe the 12 psi pulley I'm running is pushing more air than the little Bosch bypass valve can release from the intake piping while its not supposed to be creating boost (at cruising). And maybe this is producing too much pressure in the intake piping while the throttle plates are still mostly closed, possibly creating turbulence in the piping, causing the MAF to read badly?

Just throwing out ideas. I'm not an engineer...I've only got a business degree. :D Anyone any comments....suggestions?

I've had mine on the pressure side for years with no problems. I do have my a good distance between my BOV and the MAF though. I would have though a bad MAF but, since you have tried that I would try the MAF connector/connections. Did you butt splice the MAF wires earlier? Maybe while you are scanning it and watching the MAF reading tap on the MAF and pull on the connectors to see if you see anything fishy.

I've had mine on the pressure side for years with no problems. I do have my a good distance between my BOV and the MAF though. I would have though a bad MAF but, since you have tried that I would try the MAF connector/connections. Did you butt splice the MAF wires earlier? Maybe while you are scanning it and watching the MAF reading tap on the MAF and pull on the connectors to see if you see anything fishy.

How much PSI are you running? What BOV?

I've never had a problem with the MAF extension wiring before. It is spliced, soldered, and heat shrinked. I put it in convoluted tubing and moved it away from the coil wire and control module wiring to try to reduce any possible interference.

My maf wiring is bad right now and needs redone, is there a place with a decent price on the maf connector. Dealer told me $30 and Pep boys had some for $25. Was is the name of the better bosch valve, is it the 114 or 115? What do they cost? I think I have a surge at 1500-1800 rpm caused by mine factory one.

crap jeff just saw that was you. :D

Got that painting do yet?

I was running 10psi with the Procharger bypass valve for a couple of years. I'm running a turbo with a Megasonic blow-off now at 12 psi.

Have you rtried turning the sensor 90* in the pipe? Sometimes reclocking can solve this type of problem
Mike

I found the problem, for those who may be curious.

Advice: If you're running a 12 psi pulley on your Vortech, don't move the MAF to the pressure side unless you've got a bigger bypass valve than just the Bosch one! :D

I drilled another hole in the intake tubing, just in front of the intercooler, big enough to fit another bypass valve into. Started it up, tested it out with Datamaster and everything looks good. The intake piping was jammed up so badly with air at cruising RPMs....it had nowhere to go because the blower would keep pumping the air and the bypass valve couldn't release enough of that air to help.

Anyone have a Bosch bypass valve lying around that could be sold to me? PM me if you do. Even if you don't have one, if you could suggest a supplier that has them, I'd be grateful. I Googled the Bosch part number (0280142102) and found one place selling them for $100, but I'm not spending that much on just one of these little plastic things.

Thanks!

This info was given to me in a prior post.


Ask in a VW or Audi dealer: they cost about $30 new.
The older valve was a little weak, the new ones are better.
New valve:
Bosch part number: 0280 142 108
Audi part number: 034 145 710 C


Also, Vortech said a new one from them is $65.

-Scott.