Oil pressure gauge

[PAT.BMW]

OK, I'm new to the forum and have looked all over but can't find any discussion on this, but my oil pressure gauge sucks! I have a 2001 7.3 and when it's hot it takes a good 10-20 seconds for oil pressure to register then it jumps from nothing to normal for another 5-10 seconds, when it's cold it's fine. My 2002 F-550 has almost instant oil pressure anytime. In checking the system over I was shocked to find out the oil sending unit is nothing more than an on/off switch and the gauge is nothing more than an idiot lamp with a pointer than a true reading of oil pressure. The dealer said this is normal for the gauge to take this long to read, if so why is it only on this truck?

 

[Ford_Forgotton]

The oil pressure sending unit is a pressure sensitive element, and the pressure sensor may be going bad. Or you could have a bad/loose wire going to it.

Or, you really do have low oil pressure when the engine is hot.

The only way to really tell would be to install a REAL oil pressure guage and watch for any differences between a cold start and a hot start, and the delay in pressure build up.

Like I said, It could be as simple as the sensor going flaky, or as bad as the low pressure pump taking a crap.

 

[PAT.BMW]

There is a little more to the story, I did replace the sending unit and that made the problem worse, flickering oil PSI with the old sending unit went to no PSI at idle with a new Ford part. I replaced it again with a generic part from NAPA and it's back to the origianl problem I had with the origianal part. My next step was to install a real gauge and see whats really going on. What pressure should I see at idle?

 

[maniac]

There is a little more to the story, I did replace the sending unit and that made the problem worse, flickering oil PSI with the old sending unit went to no PSI at idle with a new Ford part. I replaced it again with a generic part from NAPA and it's back to the origianl problem I had with the origianal part. My next step was to install a real gauge and see whats really going on. What pressure should I see at idle?

I have a "real" gauge, I see 30 at idle 60 running down the road.

 

[PAT.BMW]

I have a "real" gauge, I see 30 at idle 60 running down the road.

HMMM, I have 10 at idle on cold start and then after driving for 30 minutes it drops to 7 it idle in gear, but have 55-60 PSI at freeway speeds.

Oil pump ?

 

[maniac]

When its cold outside I can pin the gauge at 100, once it warms up, 200 degrees water temp, it stays right at 55 to 60.On the highway.
I run Mobil Delvac 1300 since it was new.

I would put in a "real" gauge and double check yours first.

I put mine into the fitting right next to the oil filter on the block.

 

[PAT.BMW]

OK,

With a real gauge my highway psi is great, but drops to only 5-7 psi when at idle, which seems too low but I can't find what the spec is. Sooo I'm thinking I going to need;

1) an oil pump...best case
2) main bearings
3) engine...worst case

I'm open for ideas, oil pump/bearing magic mystery goo in a can etc...

 

[maniac]

How many miles on this?

If it was the oil pump you wouldn't have any pressure or very low all the time.

I don't think the mains would be gone either.

What does it idle at? maybe idle set too low.

 

[PAT.BMW]

How many miles on this?

If it was the oil pump you wouldn't have any pressure or very low all the time.

I don't think the mains would be gone either.

What does it idle at? maybe idle set too low.

It has 94k on it, idle is around 700 according to the factory tach, but it does not start to build oil pressure until around 1100-1200 rpms. The local dealer informed me there are 2 oil pumps, a low pressure and high pressure, isn't the high pressure pump used for fuel delivery to the injectors? The parts guy at the counter did not know.

 

[Tbar]

Oil pressure at 2000 rpm.


Tbar