badabing

If the MAF is dirty or otherwise malfunctioning to the point where the engine runs in "limp mode" (boost limited to .5 bar) would it throw a code that could be read with an OBDII scanner. If not, is there another piece of diangnostic equipment that would be able to test for a bad MAF, as I have access to quite a bit of sophisticated diagnostic testers.

911/Q45

There are several codes that can be tripped by a bad MAF sensor. Unfortunately, some of them don't decode to that problem. Best test is to swap with a known good sensor and see if the problem goes away.

badabing

what if you have no codes at all?

Acropora

I've had a bad MAF w/ no codes. Put a new one in and it ran like a top.

911/Q45

These things are old enough that replacing the MAF sensor isn't really wasted money even if it isn't bad yet.

TheOtherEric

Hook up a Durametric, and log RPM and MAF. Go for a drive and go full throttle in 3rd gear. The Durametric should read ballpark 1100 to 1300 kg/hr at 6000 rpm. This is how I confirmed my MAF was reading properly.

TheOtherEric

Oh, another thought -- one of the TSBs give a value for MAF at idle and at like 2500 rpm at standstill. So you can hook up a durametric or scantool or hammer and do that measurement without even going anywhere. But if it's a flaky MAF or just crapping out at higher air flows, this technique won't identify it.

badabing

I guess my real question is, is there a definitive way to tell if the engine is operating in "limp mode"? i took her out for the first time yesterday and it felt like i was driving with the handbrake up or like i was dragging an anchor. some schmo it a modded VW GTi gave me a run for my money

badabing

sorry to be pain. i did a lot pf searching on here and the internet. can't seem to find a definitive answer if there is a sure way to tell if the engine is in limp mode. any ideas?

JBL930

Your engine light would be on for a start, is it?

Felix

There are some faults that will trigger a code but not a CEL - a disconnected IAT sensor comes to mind. Get the codes checked - if the ECU isn't storing any codes then it doesn't think there's a problem. That doesn't mean there isn't - just not a fault condition that the ECU is told to look for.

badabing

thanks phelix, for your help here and all your contributions through out the forum............i routinely see your advice posted everywhere..ok enough butt kissing lol

anway, there is no CEL and no codes. i did have a and CEL and a code before because i forgot to connect the Intake temp sensor in the intercooler, but have since reconnected it, cleared codes using OBD II scanner and driven at least 100 miles.

what do you recommend i do now. should i just break down and take it to the (gulp) dealer? mind you its not the money i'm concerned about (well a little concerned) but i honestly believe that most dealers do not know what they are doing when it comes to issues like these. that being said, if it is advised that i seek professional assistance, can anyone recommend a tech in the NY/NJ area?

TheOtherEric

Then why don't you hook it up to a Durametric or Hammer and see what's wrong?

badabing

i said i had access to them but i don't necessarily know how to use them or which one to use? lol

if anyone knows what to use and the procedure, let me know.