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914World.com _ 914World Garage _ Air Pressure Sensor

Posted by: Headrage Jan 5 2005, 06:22 PM

Are these things supposed to hold a vacuum? My car was running pretty well when I pulled it out but I seem to remember seeing something on how to test.

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Posted by: Bleyseng Jan 5 2005, 06:58 PM

Take a vacuum tester and pump up to 15hg and wait 5 minutes. After 5 min is it still holding 15hg or how much has it leaked down???

Geoff

Posted by: jr91472 Jan 5 2005, 07:01 PM

suck on it and then see if it will hold your tongue (you know, like a straw) IPB Image ..........no really...it will at least tell you if the diaphram is intact.

flame on.....

Posted by: Bleyseng Jan 5 2005, 07:07 PM

You can't suck enough to tell!! unless, shoot I won't go there.....

Geoff IPB Image

Posted by: SLITS Jan 5 2005, 07:16 PM

See PBanders site on the D-Jet System.

I thought it was pump to 20 and then time the bleed down.....something like no more than 2" per minute.

Posted by: Headrage Jan 5 2005, 07:51 PM

I did suck on it and couldn't even get a vacuum. Maybe it takes more suction than I can give (probably a good thing around here). I hope it's not bad.

Posted by: Headrage Jan 5 2005, 08:22 PM

I couldn't get the PBanders page to load but I found this on Rennlist. It says to blow into the sensor. IPB Image

Pressure Sensor

Located at a bracket near the battery, the pressure sensor is the single most important sensor in the fuel injection system. Consisting of an iron core surrounded by
a pair of coils, mechanically connected to a thin metal diaphragm, this sensor measures the pressure at the intake air distributor relative to the ambient pressure
(that is, it can correct for changes in altitude).
It can fail in several ways. The coils can develop an electrical fault, or the diaphragm can leak. A defective sensor will often result in a very rich running condition.
However, I have seen one fault resulting in the mixture becoming so lean that the engine wouldn't run. The coils can be tested by measuring the resistance between
terminals #7 & # 15 (should be about 90 ohms) and between #8 & #10 (should be about 350 ohms). You can try blowing into the sensor to test the diaphragm.
Although they carry different part numbers, the only difference between the 1.7L and 2.0L pressure sensors is calibration. I will describe how you can change this
yourself later on.

Posted by: Cap'n Krusty Jan 5 2005, 08:26 PM

" 'Blow' is a figure of speech", he said. And, in this case, it won't tell you much. Gotta pull vacuum on it. You should be able to suck on it through a tight fitting hose, and stopper it with your tongue. If you can't pull any vacuum, it's likely toast.

Posted by: Bleyseng Jan 5 2005, 08:38 PM

You can pull a really weak vacuum on it with sucking on it but if the diaphram is cracked then it will seem to hold a vacuum.
Test it with a mittyvac like I said to 15hg to find out. We test them at 15hg cuz thats what you are supposed to pull at idle. It should hold that for 5 minutes without bleeding down. If it does bleed down its got big problems.
I have fixed/repaired about 20 of those darn things for 2.0l motors.

Geoff

Posted by: Headrage Jan 5 2005, 09:45 PM

I'll try and get one of our instrumentation techs to test it tomorrow. I'll report on the results.

Posted by: DJsRepS Jan 6 2005, 05:10 AM

If you pull vac by mouth and cap it by toung and cant get it to hold your toung with the vac you made its toast. If it does hold your toung then buy the Mightyvac and do a real test. Tool at Sears or Flaps $25-$45. Good for checking the vac adv on the dist as well.

Posted by: Bleyseng Jan 6 2005, 12:35 PM

pic of the test

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Posted by: Headrage Jan 6 2005, 12:46 PM

Thanks a ton, I think its done. When I suck on it I can hear air going through it. IPB Image Just another freekin cost.

Posted by: SLITS Jan 6 2005, 01:14 PM

http://members.rennlist.com/pbanders/DJetParts.htm

http://members.rennlist.com/pbanders/manifold_pressure_sensor.htm

Posted by: Headrage Jan 6 2005, 01:38 PM

Thanks for the link Ron. I'm sure it's bad. Someone has been playing with it as well. The seal for the adjustment is gone as well as the cover.

Posted by: SLITS Jan 6 2005, 01:43 PM

Links work perfectly for me.

If the seal is gone off the adjustment screw, someone has screwed with it.

Which one do you need or should I ask what Bosch OEM is on yours?

Posted by: Headrage Jan 6 2005, 02:05 PM

P/N: 0280100043

Posted by: Bleyseng Jan 6 2005, 02:17 PM

is it still riveted together or screwed??

Posted by: Headrage Jan 6 2005, 02:23 PM

Still got the rivets in it.

Posted by: Bleyseng Jan 6 2005, 03:44 PM

Well, my bets the diaphram is cracked then.

Geoff

Posted by: DJsRepS Jan 6 2005, 06:12 PM

Ive got a good one from a junkyard 7yrs ago. It is the wrong pn for my car. I will look at the #'s for you.

Posted by: DonTraver Jan 6 2005, 07:08 PM

I think we scored a couple of those today, call Mike (Dr. Evil)

Later, Don