Isuzu Trooper Owners Club UK™

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

Has anyone tried adjusting the oil pressure on the 3.1 engine, am bellow 30psi when hot, and drops to about 5 at idle, I have tried a range of different oils, it is on tractor lube currently (20w50) this has not raised the oil pressure at all but it does smell interesting.
it has covered just over 138k miles, from the state it was in when i got it, it has not been looked after but i have always changed the oil at least every 4 months.
This is not a new issue, and has been running round quite happily for the last 2 years no probs but am about to take her out of service for a body swap and resolve a few other issues and this would be a good time to get to those hard to reach areas.

Google · Sponsor

griffter · Posted: Tue May 07, 2013 19:37 Post subject:

if its a 3.1 put some proper semi 10/40 in it then see how it is

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

Did try it on 10w40 to start with, it was low so i put the heavier oil in, thought being a light comercial engine it might have an adjustable pressure releif valve

TrooperDan · Posted: Tue May 07, 2013 21:47 Post subject:

tip

Put all the electrical items on (lights, heaters etc) and see if oil pressure needle goes up a bit. if so it may need a new sender unit
_________________
www.independentisuzu.co.uk

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

Will check it out tomoz when its hot, thanks for that.

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

hmm, so cruising with the gauge showing a steady 30psi, holding the wheel with my knees i switched both the lights and fan at the same time, hit a pothole and ended up in the *beep*...
no didnt, the needle dropped and then went back to 30psi where it had been, i have a spare monty at home, if the probe is easy to get to i may swap them latter but i think it was just the alternator fluctuating with the added load, maybe a handfull of sawdust will bring it back up?

griffter · Posted: Wed May 08, 2013 14:20 Post subject:

as a comparison when hot my 3.1 td at idle is about 1.9 kg/cm2 or in real money 28 psi ish when cold more like 40 psi at idle

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

you have both been very help full, I do have a manual, but it was 99p on the bay and doesnt have a lubrication section, found the sender on the easy side of the engine behind the fuel pump, ill swap it latter, am curious tho, the sender bolts onto what looks like a "T" or does that nut hold the prv in place? would be really helpful if someone could recommend a good engine manual in case i have to start measuring oil pump end float

Gribble · Posted: Wed May 08, 2013 19:02 Post subject:

The prv's not really adjustable on a 3.1 , you need to put a direct reading gauge in to see what you have then think about how to fix it .

Usual cause of low oil presuure is worn mains - check the crank for lift .
_________________
2 New Troopers !

omega63 · Posted: Wed May 08, 2013 22:11 Post subject:

My Monterey from cold at idle is 90 psi approx. going down to 35 psi approx. when red hot Rolling Eyes

, running on mineral engine oil 15w/40 Fuch its the same oil as we put in the TX1 black cabs using the Nissan 2.7 normal aspirated engine. It does say in the hand book that this is the middle of the range oil grade for our climate here in the UK, i was thinking of going to fully synthetic oil like 10w/40 next oil change Rolling Eyes

....

eithan h · Posted: Wed May 08, 2013 23:28 Post subject:

the gauge on the dash isn't the best thing for giving you the correct oil pressure, put a proper gauge where the sender goes and get a real reading

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

I tried the sender off the monty, readings were no better so plumbed in a calibrated gauge ( 1/8 27 ntp thread if anyone is interested ) and i have good oil px, when warm its no lower than 30psi at idle and tops 80 at 2500rpm so I either have two dodgy senders a faulty gauge or dodgy wiring (with the sender unplugged dial reads full scale so any wiring defect would probly show as an over reading)
I am very happy knowing the px is good, and great full for your advice, however a little upset with myself for running it on tractor oil for last year or so when it didnt really need it.
I have another set of filters, will give it an early service and put some sensible oil back in it this w/e

Cheers
James

Gribble · Posted: Thu May 09, 2013 18:13 Post subject:

You have a high resistance in your engine earth lead to cause this oi rekons .

With a mulit meter set on ohms see what you get between the battery - and the engine block near the oil pressure sensor. Positive lead off for this test .
_________________
2 New Troopers !

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

Now that i know the engine has good px i will go ahead with body swap and see if it is any good with the gauge in the monty, for the sake of technical debate lets say sender and gauge are fine, with the engine running i unplug the sender ( which only has one wire so must just alter the resistance to earth) and the gauge goes to 110 psi-max, so with an increase in resistance in the earth side it would reed high not low, i did just check by putting a jump lead from engine to the negative terminal and no change.
I also found some pucker manuals online for free, there is a link on clubisuzu, will put a link to the link when im back at my desk

Jimmydoo · * Joined: 01 Jun 2011 Posts: 17 Location: lincolnshire

Now that i know the engine has good px i will go ahead with body swap and see if it is any good with the gauge in the monty, for the sake of technical debate lets say sender and gauge are fine, with the engine running i unplug the sender ( which only has one wire so must just alter the resistance to earth) and the gauge goes to 110 psi-max, so with an increase in resistance in the earth side it would reed high not low, i did just check by putting a jump lead from engine to the negative terminal and no change.
I also found some pucker manuals online for free, there is a link on clubisuzu, will put a link to the link when im back at my desk