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Discussion Starter · #1 ·
When I start my 85 CJ7 w/258 and 36,000 orignal miles it has great oil pressure (60psi) after it gets to operating temp it only shows about 2-3 psi at idle and about 18-19psi at 55mph. I am running 20w50 I live in houston 50 to 75 is the current outside temp. The gauge is new. What can I do to raise the pressure at operating temp (both at idle and crusing speed) new pump? If so High out put or high volume or is there another/easyer answer???
Thanks a bunch

 
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Discussion Starter · #2 ·
First, if your using to orginal gauge, don't overreact! They are very dependent on ground and read spuratic. Trust me I have on. You might consider using a manual type gage instead. Also, you should have 10 psi for every 100 rpm as a rule. If you have that then you should be OK. Hope this helps.Ken

 

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Other than your idle pressure ......it seems about right. Typical would be 10-13 warm idle 18-22 road speed and 38-42 cold start (or somewhere close to that)........but the internal pressure relief is about 58 psi. I have a high volume pump and that's where it peaks out.....cold start and at road speed. You've got the worst of both worlds.......high cold pressure and no hot pressure......check the sender and guage. Those two conditions just don't add up. If you can push enough volume to hit 60 psi.......you should be able to maintain 15 at idle. Then again ......I'd ditch the 20-50 for 10w-30.....at least until it hit REAL hot weather......maybe then you would not hit the 60psi mark at cold start.......not that this will help with this problem.....but it would maybe give more believable readings at cold start (like the typical 38-42). A high volume pump is not commonly recommended nor is a high pressure pump. With the high volume your idle, "at speed", and cold start pressures would definitely increase -with the high pressure, which is usually just stiffer relief springs, your idle pressure should remain about the same but you'll get higher pressure the faster you go.

GeeAea


Figures don't lie ....... but liars sure do figure.
 
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Discussion Starter · #5 ·
Sorry I forgot to mention that the gauge is new and a mechanical one with the line coming right out of the side of the engine,next to the bell shaped sender that was for the electric gauge. Also I am trying to sell this jeep to use the money else where and get another project. and the low pressure looks bad to prospective buyers......HELP

 

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You didn't mention any sounds out of it at idle. With that kind of oil pressure at idle ......I'd expect it to be a little noisy. If it's quiet......I'd still suspect that the gauge was faulty.

GeeAea


Figures don't lie ....... but liars sure do figure.
 
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Discussion Starter · #8 ·
First, I'm not sure your numbers are an actual indication of your oil pressure. You mentioned a new gauge, how about the sending unit? If you put a new one in, DON'T use teflon tape or anything else on the threads.

Perhaps try another gauge/sender combo -- anything to establish that those numbers are actually correct before launching off on new oil pump, etc.

You could also have gunk built up inside the sender and/or its passage.

John

'80 CJ7
'84 CJ7
'76 Scout
NRA Life
Join the NRA!!
 
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Discussion Starter · #9 ·
The sending unit is non functional a fitting is coming out of the side of the eng block with 2 holes 1 has the bell shaped sender and the other is the tube going to the gauge

 
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Discussion Starter · #10 ·
welp this is what happened on to my 1988 wrangler with the 258, the oil pressure since i got it read past 80, soi got a new sending unit put it on and it worked for about 2 hours then it read 80, so i got another one and before i put it in i looked at where it screwed in and it was really gross, so i got some carb cleaner and sprayed it in the whole and got a small stiff paint brush and poked around in there and got all the crap out of it and sprayed it with some more carb cleaner until i thought it was really clean, its been running for 4 months now no probs.

(\/)ikey
1988 Wrangler Laredo 4.2L w/5spd Manual
1995 Wrangler 2.5L w/ 5spd Manual-dixie horn
 
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Discussion Starter · #11 ·
So, its a mechanical gauge? Complete with tiny hose to gauge? At this stage, with the sender out of the picture, I'd suspect hose or the gauge has crud in it. Have you checked this?

John

'80 CJ7
'84 CJ7
'76 Scout
NRA Life
Join the NRA!!
 

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Probally crap in the lines BUT.......
This is'nt a discount store sun/suntune guage is it?
I've had REALLY bad luck with them!
If it is get a SW or something as good , not cheap but there on the money!

85'CJ7 258 4" runnin33's
 
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Discussion Starter · #13 ·
Have not checked the line will clean that out and recheck. Also will get a friends mechanical gauge(hand held)and try that also
Thanks

 
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