Druck pressure?

[FenderGuy]

My druck pressure was at 5 before and I just noticed when I was about to turn it off, it is around 3 or 4, when I rev the engine it goes around to 4 and 5???? whats the deal?

[rusnak]

that's the car's mojo meter, bay-bayyy

[2002M3Drew]

It is supposed to do that...the needle always jumps when you rev the engine. Pressures in the 3-5 range are good.

[Jeff Alton]

Druck is pressure......

The faster you rev the engine, the more pressure the pump builds.

At operating temp you should see 4 bar at 5000rpm, that is the factory spec. Noted p-car mechanics/experts recomend you see between 10psi and 1 bar per thousand rpm also....

Cheers

[FenderGuy]

Ok guys thanks for the replies...i also called my mechanic.. my druck pressure guage was always at 5, which I thought was normal..so thats why I was like what the heck was going...last night was the first time i had seen the needle go between 3 and 5

[sig_a]

Druck (Deutsche for Pressure) should be 1 bar at idle. If your needle doesn't drop all the way down to 1 bar at idle, either the druck/press gauge or the oil pressure sender unit is faulty. Assuming it does not drop to 1 bar at idle, the sender is probably dirty or bad. If the needle's range seems limited from 3 bar to 5 bar, you can tap lightly on the sender while the car is at idle and observe the gauge from the rear window. Continuous and repeated slight tapping will sometimes result in the needle slowly moving down to 1 bar at about 850 RPM or idle speed. This worked for me. My guess is that there was blockage in the sender, and the repeated tapping broke it loose. All that said, a new sender unit would permanently fix the problem.

[masraum]

Originally posted by FenderGuy
Ok guys thanks for the replies...i also called my mechanic.. my druck pressure guage was always at 5, which I thought was normal..so thats why I was like what the heck was going...last night was the first time i had seen the needle go between 3 and 5

Chances are that means that the sender is bad or the connection is bad. The normal behavior is something like this

engine cold
idle pressure 3bar rev it up to 5bar

engine warm/hot
idle pressure 1 - 1.5 bar
as you rev 1 bar per 1000 rpm until you get to 4.5 bar or so.

When the sender went bad in my car the gauge went to 5 almost all of the time except when the engine was completely warm/hot and then it might drop to 3.5bar at idle.

Again, bad sender or bad connection/ground.

[FenderGuy]

Steve and all pelicans,

Thank you for your replies I learn something new everyday with this kick a$$ car lol ..

My druck was always at 5 even at start up and when it warmed up..

I observed this at start up today

engine cold
idle pressure at 4bar

engine warm/hot
still at 4bar but I rev it stays at 5 bar...

Mechanics didnt even notice that the druck was at 5 all the time and they replaced the engine

[kwm]

Originally posted by FenderGuy
Ok guys thanks for the replies...i also called my mechanic.. my druck pressure guage was always at 5, which I thought was normal..so thats why I was like what the heck was going...last night was the first time i had seen the needle go between 3 and 5

When you called your mechanic did he tell you to hurry up and bring it in for a engine rebuild?

[FenderGuy]

Originally posted by kwm
When you called your mechanic did he tell you to hurry up and bring it in for a engine rebuild?

No they told me to bring in for a turbo upgrade

[sig_a]

Before you go to the expense of replacing the oil pressure sender, which is about $150 for the part, try repeated tapping. My sender still works after this DIY fix and it's been working correctly since last summer.

[FenderGuy]

Originally posted by sig_a
Before you go to the expense of replacing the oil pressure sender, which is about $150 for the part, try repeated tapping. My sender still works after this DIY fix and it's been working correctly since last summer.

When I get home from work I'll clean the connectors and tap the bugger...thanks for the tip

[DW SD]

Also, if you disconnect the wire at the sender (and don't ground it), it should read full tilt on the gauge. If you ground the line to the engine it would read full tilt on the other end of the range. That would verify that your wiring and gauge work properly. If that doesn't happen I'd trouble shoot the gauge or wiring.

Assuming full tilt (zero and 5+ bars) is reached on the gauge through the previous test, focus in on the sender itself. This same simple test will work for all of the resistance based senders / gauges (temp, oil level, oil pressure, fuel level, etc.) In other words, resistance varies at the sender as it goes through its operating range and the gauge measure the difference in current flow (due to resistance).

Good luck,

Doug

[FenderGuy]

Ok the tapping didn't fix the problem, instead its down to 3 at start up now.. Grounds are out of whack ...
thinking the sender is bad...


did a search on replacing the unit, it is really that hard to do? it seems like a lot of work just to take the sender off...i know not to use a crow bar...

[dshepp806]

BIG NO on the crowsfoot!!!!

SAVE YOURSELF!!

Doyle

[sig_a]

[QUOTE]Originally posted by FenderGuy
[B]Ok the tapping didn't fix the problem, instead its down to 3 at start up now.. Grounds are out of whack ...
thinking the sender is bad...


Do you mean the range is now between 5 and 3, where it had ranged between 5 and 4, and is now 3 at start-up idle? If that's the case, keep tapping since a fully warmed-up engine at idle would produce about 1 to 1.5 bar. I had the same experience where tapping was slowly moving the needle from 4 to 3 to 2 and then finally 1. Also, I noticed the needle would bounce slightly with each tap. I tapped it at least 500 times over the course of days. It was if the tapping was dislodging something stuck in the oil feed line. So unless you want to spend about $300 having someone replace it, don't give up the tapping technique just yet. Also pulling the wire should pin the needle at 5+.

Also, crows foot removal is tight especially if your car has AC. The base of the sender is threaded into the aluminum casing. Possible to damage if not done correctly.

[KCPSG]

I don't recall the part being that expensive...you just need to be careful removing the old sender. Definitely a DIY type of job......tons of threads about it.

[FenderGuy]

[QUOTE]Originally posted by sig_a
[B]

Originally posted by FenderGuy
Ok the tapping didn't fix the problem, instead its down to 3 at start up now.. Grounds are out of whack ...
thinking the sender is bad...


Do you mean the range is now between 5 and 3, where it had ranged between 5 and 4, and is now 3 at start-up idle? If that's the case, keep tapping since a fully warmed-up engine at idle would produce about 1 to 1.5 bar. I had the same experience where tapping was slowly moving the needle from 4 to 3 to 2 and then finally 1. Also, I noticed the needle would bounce slightly with each tap. I tapped it at least 500 times over the course of days. It was if the tapping was dislodging something stuck in the oil feed line. So unless you want to spend about $300 having someone replace it, don't give up the tapping technique just yet. Also pulling the wire should pin the needle at 5+.

Also, crows foot removal is tight especially if your car has AC. The base of the sender is threaded into the aluminum casing. Possible to damage if not done correctly.

Everyone who is not aware of the druck pressure should take a lesson from me and not learn the hard way. When I got the car the druck pressure was always at 5, I thought this was normal. It wasn't untill last week that the pressure had dropped down to 4 and would go to 5 when I reved the engine. Of course I got worried and called the mechanic the next day, who informed me that that the druck pressure should be at 1bar at start and when full warmed should be at 3 to 5. Had I known this before, maybe it would have saved my last engine when the piston ring failed. Had I known the pressure had dropped, I would have towed it to the shop and had them look at it.


Since tapping it it has moved down to 3 even at start up, sometimes it gets stuck at 3 and then moves to 4...I will continue to tap it, just 400 more taps to go

The part itself is cheap but even with the ac out it looks like a pain the a$$ to replace. Had I also know it wasnt normal to be at 5 all the time, I would have had it replaced when they put in the engine.

[rnln]

haha... reading this thread, now I know that my druck press has been bad since day one, that I thought it was good (always at 5). It worked for several days at the beginning of the cold season this year, I thought it was bad (moving around 3 on freeway) :lol:

BTW, someone mentioned $150. I sae PP is selling 84-89 for only $85.

[myfast911]

When you called your mechanic did he tell you to hurry up and bring it in for a engine rebuild?
if you knew his mechanic you wold not laugh.that is what he he would say. $ 9000.00 valve job