OK,,, I give up - Page 3 - PeachParts Mercedes-Benz Forum

brookspw · #31 08-08-2009, 01:54 PM

Quote:

Originally Posted by brookspw

Ok, now I'll check the ohms.

Ohms are fine.

Left the car running. Car had been running smooth as silk. Went back out there and the idle is surging. Regen valve is clicking like a drum roll...so, that evidently is not the problem.

Now, on, I guess to track down vacuum leak, or actuator or air flow meter.

Seems like it runs very smooth until fully heated up then surges.

Arthur Dalton · #32 08-08-2009, 02:01 PM

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You have only determined that the solinoid pintle is working..you have not determined if the flow is correct.
Take the vac hose going to the canister off when the vavle is pulsing and put you finger on the port of the valve..does it have pulsing suction??

If yes, then unplug the connector..does the valve shut OFF ?
If NO to either , it is full of crap and needs to be cleaned.
That is why my early post said to check flow.

brookspw · #33 08-08-2009, 02:04 PM

Quote:

Originally Posted by Arthur Dalton

< >>

You have only determined that the solinoid pintle is working..you have not determined if the flow is correct.
Take the vac hose going to the canister off when the vavle is pulsing and put you finger on the port of the valve..does it have pulsing suction??

If yes, then unplug the connector..does the valve shut OFF ?
If NO to either , it is full of crap and needs to be cleaned.
That is why my early post said to check flow.

Ok, I will do this. But...flow is good and clear when I connect it to the battery when I had it out of the car.

Arthur Dalton · #34 08-08-2009, 02:08 PM

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I am not concerned with it being clear..I am concerned if it CLOSES...cuz if it DOES NOT , then it will fit your condition...get it ?????????????????????

Dirt can hold it open and you then have an interior VAV LEAK.....and a vac leak will cause your condition...

brookspw · #35 08-08-2009, 04:20 PM

Quote:

Originally Posted by Arthur Dalton

< __________________
>>
You have only determined that the solinoid pintle is working..you have not determined if the flow is correct.
Take the vac hose going to the canister off when the vavle is pulsing and put you finger on the port of the valve..does it have pulsing suction??

If yes, then unplug the connector..does the valve shut OFF ?
If NO to either , it is full of crap and needs to be cleaned.
That is why my early post said to check flow.
I am not concerned with it being clear..I am concerned if it CLOSES...cuz if it DOES NOT , then it will fit your condition...get it ?????????????????????

Dirt can hold it open and you then have an interior VAV LEAK.....and a vac leak will cause your condition...

Arthur, I really appreciate your help. Have a little patience, I do not know these cars like the back of my hand like you do.

Ok, let me make sure I'm understanding what you are suggesting.

1. When the valve DOES start it's pulsing open and closed, take the vac hose off (the one on the "from" end of the directional arrow -- toward the front of the car, the smaller of the two valve inlets). See if I actually have a pulsing (on/off) vacuum going INTO the valve. I should have the pulsing vacuum.
2. If it does pulse, then take power away which SHOULD make the vacuum stop, correct (since no power = closed valve)? If it does stop, then the valve is working correctly. If it doesn't then something is keeping the valve somewhat open even though the electronics are saying that it should be closed.

Am I understanding your directions? In #1 -- am I looking at the correct side of the valve to check the vacuum? In #2, am I understanding your conclusion?

Thanks.

Arthur Dalton · #36 08-08-2009, 04:28 PM

Correct.

You do not want a valve that does not close when there is no power to it...if that was what they wanted , they would not have a valve there to begin with. They would have just run a vac line to the canister.

Sorry for being short with you ,but your responces are with a.. "Yeah, BUT...." and you want Specifics...like I was NOT specific ????

I was very specific.
The reason they PULSE the vac from the canister is b/c if the engine just got a big gulp of air from the canister from a wide open purge, it would upset the A/F mixture of the engine, just like a VACUUM LEAK..so , they meter it in small pulses/doses ..that is what the frequency of the pulses are for...and they vary according to the load conditions of the ECU criteria and feedback of the mapping.
The pulses are what you feel in the valve, but just cuz you feel the sol. pulsing the actuating pintle pin DOES NOT mean the valve SEAT is shutting OFF vac when it is not getting a signal...that's all I was trying to tell you and I thought I made that clear.
Ever turn a faucet OFF , but water still leaks out...same deal, except in this case , it can effect the A/F mix to the engine just like you had a vac leak...which you may have.
I just wanted to let you know you had not diagnosed the Purge as OK correctly just cuz you could feel it pulse ..that is only part of the test for purge [ as my very first post states] You must then check flow OPEN/CLOSED. Regardless of the pulsing ....it can be pulsing all day long and not be doing what it is designed to do.[ control/meter vac flow on/off using a predetermined frequency/Htz signal]
The 3 sections to purge system are ECU demand signal to solinoid coil of purge, [ OK/OHMED] actuation of pin by solinoid, [OK/ Feel] and valve seat open/closing for vac flow when pin actuates. [ Not tested] That's it.............you have verified the first two, and now if you verify the flow test, you have eliminated or confirmed the Purge as the cause of your condition and if then verified, I suggest you look elsewhere.

brookspw · #37 08-08-2009, 05:23 PM

Ok. That valve is evidently working as it should.

When pulsing, I took the hose off and I do get a pulsing vacuum, off/on. With power disconnected I get NO vacuum whatsoever.

The other suggested issues are a vacuum leak somewhere, mass air flow meter (new one put in 4 months ago), and throttle actuator (replaced 4 months ago with a salvage part, same #, from a 96 model. It was cleaned very well inside and wiring looked fine.

This started after head gasket r/r so I'm leaning vacuum leak somewhere before replacing those parts again. The large tubes to intake and intake gasket were also mentioned as possible culprits in the vacuum leak scenario.

Thanks for the help and expertise. If you have a suggestion on isolating the vacuum leak that would certainly be welcomed.

Arthur Dalton · #38 08-08-2009, 05:28 PM

My first check for your condition would have been the FP regulator daiphragm port for fuel leakage into intake,

brookspw · #39 08-10-2009, 09:07 AM

Quote:

Originally Posted by Arthur Dalton

My first check for your condition would have been the FP regulator daiphragm port for fuel leakage into intake,

Checked it cold and hot. Pulled vac tube while running. Detected no fuel at all, solid vacuum, though didn't notice it running any different with vac tube on or off.

I'm going to reset my computer, run it, and have codes pulled.