legacycentral bbs

So what exactly is the Atmospheric Pressure Sensor, were is it, and what does it do?

Is that part of the waste gate solenoid? Is that what messures atmospheric pressure? (hmm, does that question sound as dumb to you as it does to me?)

Also, I was checking for vacuum leaks and my engine was running real smooth. I was spraying fuel injection cleaner here and there on all the vacuum hoses i could see and nothing. So I started disconnecting some here and htere to see how it affected the car.

I disconnected the hose that goes from the wastegate solenoid to the manifold a couple times. Would that trip the code? I didn't actually check it before I did all this, so I don't know if I tripped it before or after my vacuum check.

So...any thoughts? Would this help explain my 17.5+ times?

-Ryan

Ok so it isnt he atmospheric pressure sensor it is the:

Pressure sensor and pressure exchange solenoid valve. (since I have a turbo).

So it sounds like I may need to get a MBC, eh?

Any reason why this might also affect idle??

It shouldn't affect idle.

This page explains what the two parts are, as well as giving an alternative to the OEM parts in case you need to replace one or both:

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

How can I test them? Will a MBC replace this whole unit, or would I still need of of the two peices as well?

These parts are separate from the boost control solenoid. An aftermarket boost controller has nothing to do with them.

To test the pressure exchange solenoid:
- Check that the yellow-with-red-stripe wire coming to it has +12v on it when the ignition is on.
- Measure the resistance across its terminals; it should be about 40 ohms, give or take.
- Put the ECU in test mode (connect the green connectors) and put the ignition in the ON position. You should be able to hear or feel it clicking on and off.
- If you want to be really really sure, blow air into the outlet (the nipple labeled "hose to sensor" at the top of that web page). When the solenoid is not powered, the air should come out the nipple labeled "hose to manifold." When it is powered, it should come out the filter.

To test the pressure sensor:
- Check that the 5-volt reference wire and the ground wire are getting +5v and have continuity to ground, respectively, when the ignition is on.
- Check that you measure roughly 2.6 volts at the signal wire when the ignition is on but the engine's not running.
- To be really sure, power it with a 5-volt power supply (that page says which wire is which), and apply pressure and vacuum and verify that the output follows the equation at this page: http://www.graphics.cornell.edu/~v/fcd/

It occurs to me -- you say you disconnected the hose from the wastegate solenoid to the manifold. There is no such solenoid; do you mean the pressure exchange solenoid?

If you did, and you didn't correctly hook the hose back up, then, yes, that could certainly cause this code to be thrown.

Have you tried just clearing the code?

I haven't cleared the codes yet. I wanted to see what you guys had to say first. The hose I disconnected was the hose that says "goes to manifold" (from the Pressure exchange Solenoid) on your site. I disconnected it, while the car was running, at the solenoid, and also did it at the manifold (seperate times). When I was disconnected from the solenoid I sprayed the quickest lightest spray of fuel injector cleaner in there. I don't know if that was a good Idea or a bad one, but I figured it would just go to the manifold and shouldn't bother anything. The engine stumbled for a slight second and then was back to normal.

So disconnecting that thing while the engine is running can flip the code?

That may be it then. I'll clear the codes and see if it comes back.

Well I cleared the codes by doing the driving meathod and connecting the wires. I then checked hte codes and i already had the purge solenoid again. (35) I drove around a while in D-check mode and nothing came up. So maybe I flipped it by accident. We'll just have to drive it around and see. I was a bit excited to figure something out. oh well. I'll just watch it and see what happens.

Yes, disconnecting that while the engine is running can flip the code. When the ECU tries to sample barometric pressure and finds it exactly the same as manifold pressure, it assumes the pressure exchange solenoid isn't working.

Well that is good and bad to know. It's nice to know those things are still working, but I was pretty excited to hopefully find an answer.

I know exactly what you mean.

So the vacuum leak search yielded nothing? You sprayed all around the intake tubing, all the vacuum hoses (refer to http://www.graphics.cornell.edu/~v/vacuum/ for a list), around the brake booster body, around the base of the intake manifold?

I've only done this test with starting fluid, not fuel injection cleaner. Starting fluid makes the engine run smoother and at a higher speed when it gets ingested. You say the cleaner made the engine stumble... that might be harder to detect than an increase in idle speed, so you might want to try it again with an aerosol can of starting fluid.

Sounds good. Thanks for the tip. I'll try that this weekend.

Either i'm really bad at finding vacuum leaks, or my car doesn't have any. I couldn't find any leaks. I took starter fluid and sprayed it down the leangth of all the vacuum lines I could find. i couldn't get too precise down by the intake gaskets so I just pointed and shot. Of course that got starter fluid all over but I know fluid was down there near the gasket. My engine idle never raised a smigen.

I hope you mean starting fluid...

If you really sprayed all around all the intake stuff and it didn't do anything, then you probably don't have a vacuum leak.

vrg3 wrote:I hope you mean starting fluid...
.

Here we go again!

hehe, yes, startING fluid.