Oil pressure reading 0 (but it does have pressure) - PeachParts Mercedes-Benz Forum

pawoSD · #1 09-19-2007, 11:04 AM

A little over a week ago I replaced my old dying oil pressure sender with a brand new one from Meyle. Replacement worked great immediately, 2 bar at idle, pegged to 3 right away with throttle....etc. Until this morning. Started the car up. Sat at 0. Opened the cap, sure enough, oil squirting away. So I drove to work, when I got there I wiggled the connector on the sender, no go...still dead at 0. Perhaps the connector needs service, but other than that, what could have happened. It worked last night when I shut the car down, now today its dead?

I'll have to look into the connector later, but if thats not it....could the new sender have fried?

pawoSD · #2 09-19-2007, 11:48 AM

Anyone?

#3 09-19-2007, 11:57 AM

Can you reach the contacts on the sender and see if the resistance changes with oil pressure? It's possible you received a bad sender.

rrgrassi · #4 09-19-2007, 12:07 PM

Do what Craig said, and also check the wiring to the guage and the guage itself.

Johnt49 · #5 09-19-2007, 12:56 PM

Try removing sender wire & shorting it to ground with key on. If gauge pegs, it's a bad sender. If it doesn't move, bad wiring or gauge.

pawoSD · #6 09-19-2007, 08:09 PM

Quote:

Originally Posted by Johnt49

Try removing sender wire & shorting it to ground with key on. If gauge pegs, it's a bad sender. If it doesn't move, bad wiring or gauge.

Awesome, I never even thought of that. I will try it. Thanks! They'd better give me a new sender if it is indeed bad.

I'll also check the sender itself with a multimeter and see if the resistance changes....

DZL_Damon · #7 09-19-2007, 08:23 PM

????? Mine is mechanical... whats all this about a sending unit and wires.... is this an SD thing?

kerry · #8 09-19-2007, 08:40 PM

Quote:

Originally Posted by DZL_Damon

? is this an SD thing?

Yes. Also an MB van thing.

lonewolftek · #9 09-19-2007, 10:07 PM

Yep, SDs have electrical oil pressure gauges and speedometers.

My '83 does the same thing, 0 bar reading at idle and up to 2,000 rpm, then it pegs and jitters around for a while. I know I've got good pressure, based on hooking up a mechanical gauge in place of the sender.

PawoSD, have you switched to, or are you using, synthetic oil in your SD? I noted that my gauge only started acting funny when I started using Amsoil.

pawoSD · #10 09-20-2007, 12:31 AM

Yes, I have been running Mobil 1 5w40 turbodiesel oil for about 24k now....my old sender starting acting weird around that time, I never even thought of that.

I found out tonight it is indeed the sender....I grounded the wire and the gauge pegged at 3 instantly. So that is fine. I cleaned the connectors off and tightened the crimp so it fits on the sender tightly, but didn't restart the car again to see if it'l work....I'll find out tomorrow morning. If the sender is bad (autohauzaz) better well replace it. It only lasted a week!

Perhaps I should have just gone with the (probably better) VDO sender in the first place. 2x the cost though. This one is a meyle made in France.

Do you think they are sensitive to synthetics? I can't think of why they would be.

#11 09-20-2007, 10:26 AM

Quote:

Originally Posted by pawoSD

Do you think they are sensitive to synthetics? I can't think of why they would be.

I suspect it's a coincidence, or maybe some old sludge came loose and clogged the sender. If the failure was electrical, I doubt it had anything to do with synthetics.

pawoSD · #12 09-20-2007, 11:03 AM

I ran it this morning on my way to work and it didn't budge....so its defiantley a sender issue.

Can it get clogged? I am assuming my engine is pretty clean inside...its been on synthetic for a good 24,000 miles....and the valvetrain is spotless when I open it up...so sludge at all....

Wouldn't it still give some flicker of movement if plugged though? It doesn't budge at all....completely dead at 0.

I'm going to see if I can get it exchanged....