260E W124 oil pressure problems.

[cjkuhn]

Good Day.

i recently got a mercedes 260e 1988 w124 little over 350k on the clock
i started by giving the engine a service replacing all the fluids and filters but
a few days ago the fuel pressure gauge just stopped working so i took out the oil pressure sensor and replaced it with an oem one but the gauge still did not respond i then thought that it might be the gauge itself took out the cluster and swapped with one from a friends car (same model and engine) but still no joy.
i then went and tested all the wiring all of them seem to be fine.

anyone got any suggestions as to what else might be the problem as not even my brother in law who's owned about ten of these knows

thank you.

 

[grober]

this might help?
Untitled Document

 

[cjkuhn]

this might help?
Untitled Document

Not really considering the parts of the manuals i need have been replaced by the belt drive unit.

but thanks have found some info i needed for other problems

 

[grober]

belt drive unit?
NOW I UNDERSTAND--- WEBSITE PROBLEM ---SORRY

TRY THIS DOWNLOAD http://modtech.us/w201-mercedes-shop-manual.html

 

[cjkuhn]

will it help with a w124?

 

[grober]

Its the same engine and much of the technology was shared at the time.

 

[cjkuhn]

Its the same engine and much of the technology was shared at the time.

ok so i tried everything in the manual and what some local mechanics suggested but still no luck

 

[balge]

Looks like it has to be wiring fault if it's not the sensor or the gauge, and if the other gauges work most likely between the cluster and the sensor?
cheers

 

[cjkuhn]

Looks like it has to be wiring fault if it's not the sensor or the gauge, and if the other gauges work most likely between the cluster and the sensor?
cheers

thanks but I've already tested the wiring and all tested out ok.

my neighbor suggested i check the pressure relief valve his old diesel truck did almost the same and the valve was stuck might as well check it considering that some of the timing chain guides broke apart (all have been replaced.

 

[carat 3.6]

thanks but I've already tested the wiring and all tested out ok.

my neighbor suggested i check the pressure relief valve his old diesel truck did almost the same and the valve was stuck might as well check it considering that some of the timing chain guides broke apart (all have been replaced.

It wont be the relief valve, that's a wiring problem you've got. Run the wire that goes to the pressure switch to an earth, then see what the gauge does.

 

[cjkuhn]

It wont be the relief valve, that's a wiring problem you've got. Run the wire that goes to the pressure switch to an earth, then see what the gauge does.

did as you suggested when i placed the wire on ground the gauge responded

 

[carat 3.6]

did as you suggested when i placed the wire on ground the gauge responded

In that case the sender unit is faulty (or you have 0 oil pressure, which I doubt very much).

 

[balge]

How do you test an oil pressure sender - PeachParts Mercedes ShopForum

Post 6 gives resistance values for the sender

 

[cjkuhn]

In that case the sender unit is faulty (or you have 0 oil pressure, which I doubt very much).

the sender was replaced by new oem sender so i doubt that a brand new sender from mercedes will be faulty

 

[balge]

If you have any reason to suspect the pressure release valve that should be a priority - I would have thought even if it failed wide open there would be enough pressure to show something on the gauge - can't have flow without pressure

I've had new stuff fail out of the box, even prestige brands. Stuff fails sometimes, I would test anything suspect just to be sure.

 

[carat 3.6]

the sender was replaced by new oem sender so i doubt that a brand new sender from mercedes will be faulty

It can happen, as balge has said above. You've proved the gauge and wiring are good, so that leaves the sensor or an engine with no oil pressure. If it has got no oil pressure the engine will sound very rattly, and soon stop...

 

[cjkuhn]

alas after buying 5 sensors it turned out to be a circuit that shorted within the cluster

should have looked there first could have spare some money