MAF question

[gunablue]

Hello,

I'm getting error code 23 along with codes 22,15, and 17. I just had an engine with 85k installed last week. My mechanic used all of the old parts from my old engine that he could. He said that he noticed that one of the tubes from the MAF was sealed shut. I have taken a picture of the tube in question, as well as the canister it's coming from. The tube is coming from the bottom of the cannister. I disconnect the maf and reconnected it and my check engine light went off. When I took it out for a drive the c/e light went off and the car drove DRASTICALLY better. Before I had little power below 3k rpms, but for a brief period it ran like a raped ape. Now it's back to the way it was. My question is should this tube be sealed shut like it is and if not, where does it go? Should I replace my MAF sensor?

OH one more thing, would the maf sensor failure cause the other codes?

Please help!! I've spent more money in this car than I'm going to admit to and the other half is about ready to divorce me over this!!

http://public.fotki.com/solrwind/our_ca ... ube_1.html

[gunablue]

here's the second picture

http://public.fotki.com/solrwind/our_ca ... tube1.html[/url]

[vrg3]

That canister is not the MAF sensor. It's the wastegate control solenoid. If your mechanic called it the MAF I would seriously question his competence to work on your car.

Look at this page to see where the hoses go:

http://www.graphics.cornell.edu/~v/vacuum/

It looks like someone may have done one of those "vacuum bypass" mods on this car. It's not good for the turbo or the engine but it won't kill it if you don't spend too much time accelerating hard at part throttle.

Did you clear your codes to see which ones came back? If your injectors really are misbehaving you need to resolve that.

[gunablue]

the first time I didn't count things right and got the wrong codes. I'm going to reset the ECU tomorrow and see what codes I get then. Is there a way to reverse this vacuum bypass mod?

I'm trying to see if I can resolve this myself as it would be much cheaper and I'm tired of dealing with mechanics!!!

Also, should I not drive the car until I get this resolved? I don't want to damage anything.

[vrg3]

To get the vacuum stuff back as it was, just follow that diagram.

You should be okay driving the car, at least in terms of the vacuum hose thing. Depending on where the boost control hose is going, you should realize that accelerating at part throttle may be somewhat harder on the turbo and throttle than stock. You should probably buy a boost gauge in order to keep an eye on manifold pressure.

[gunablue]

I unplugged the MAF sensor and plugged it back in last night. I then took the car for a drive and it drove great. The check engine light went off and everything. A few minute into the drive it comes back on and it goes back to performing the way it has been. I then turn a corner and it gets better again with the check engine light on.....subsequently followed by the same habit returning a few seconds later. Today before I came to work I unplugged it again. The only difference this time is that the car sat all night. At first it drove great, and then performance again returned to abnormal, but no check engine light. Would the MAF sensor cause the codes I mentioned in my first post? Is it also possible for the MAF sensor to fail and me not get a code and just have the symptoms that I do? I don't have much power below 3k rpms...it comes on gradually.

Will reconnecting the wastegate control solenoid fix the lack of power under 3k rpm? If anyone is near my area, please let me know as any help that you could offer would be greatly appreciated (I also have some parts from my old turbo engine that I could trade in exchange for helping me fix the bugs in this one!!)

Also from the diagram, I can't tell which one is the wastegate control solenoid. Is it the one marked pressure exchange solenoid? pardon me for asking so many questions, but my mechanic hasn't called me back yet and I don't know anyone with a Leg turbo locally that I can look at.

[vrg3]

Why do you believe so strongly that your problem is with the MAF sensor?

Unplugging and reconnecting the MAF sensor shouldn't have any effect unless the connector is faulty.

Are you certain you're talking about the MAF sensor? The aluminum-bodied cylinder, about 3 inches in diameter, attached to the air filter housing?

You cleared the codes, right? Which codes came back?

The boost control solenoid is the wastegate control solenoid. Connecting it correctly probably won't fix your problem of having too little power at low engine speeds.

[gunablue]

I was thinking the MAF only because of the codes that I pulled yesterday. I overslept this am and didn't get a chance to pull the codes yet.

The aluminum bodied cylinder is where I unplugged the wire from each time. I'll let the car sit overnight tonight and get up early tomorrow and disconnect the negative terminal like it says to do on the printout that I have and then see what codes I get.

I appreciate your help vrg. Maybe this weekend I'll check all of the vacuum lines in case once is disconnected or cracked. At this point it can't hurt. I don't know what else to do....

I'm not sure if I should take it back to the guy that installed the engine. Seems like he should have picked up on this problem when he test drove the car.

[vrg3]

Well, the codes you pulled also indicated trouble with injectors 2 and 4.

If your mechanic called the wastegate control solenoid the MAF sensor, my advice is don't go back to him.

Can you tell if the engine is misfiring when it's misbehaving?

When you disconnect the negative battery terminal also press the brake pedal for 30 seconds. That'll help purge any residual charge in bypass capacitors.

[gunablue]

He said that he replaced injector #4 with one from my old engine as it threw a code for it.

The engine doesn't seem to be misfiring when it's misbehaving.there's just no power below 3000 rpms. I accelerate, but the revs don't increase as quickly as they should....like something is missing from the equation.

It idles a bit high which is another issue with it. When first started it goes up to 2k rpms and eventually drops down to 700. I figured ok, maybe because it's cold. But even after it's warm whenever I come to a stop the rpms are at 1200 so it feels like I have the accelerator and brake on at the same time even though I don't. My old engine did none of these things. When I put it into N or P after driving it, the rms go up to about 1700 for about 30 seconds or so and then drop to 700.

I tried the negative battery cable and brake thing and the light never went off. I held the brake pedal for 30 seconds. Should the car be cold when I do this? I did it twice yesterday just to make sure I didn't do anything wrong. The second time I did it, I even held the brake pedal for a minute.

My mechanic called me back earlier and told me to bring him the wiring harness from the old engine and he'd swap them over in hopes that it helps. I have another mechanic that does great work, but the last time he had my car he had it for almost 3 months......see why I'm stressed?

[vrg3]

It shouldn't matter whether or not the car is warm.

If the light remained then that means the ECU was actively detecting the trouble. You have to pull the code.

If your idle is unpredictably high maybe your IAC valve isn't working right. A malfunctioning IAC valve could also leak some boost which might make your car slowing than it should be at low speeds when it's off boost.