Oil Sender & Surge @ 3000 rpm

Aloha from the Big Island, home of some of the most awesome 4 wheelin around!

Proud owner of an '88 V-6 with 240K+ miles on it and no squeaks or rattles! Since I usually drive my work truck (T-100) and often my '89 BMW 325is (for a change of PACE---->) on weekends, I've been a bit out of touch with the old 4Runner which my wife loves driving daily for hauling kids, dogs, etc. etc.

I've got a couple of questions:
1. I noticed that the oil pressure gauge doesn't move much, and I'm not sure when it happened, sure that my wife didn't notice it...It does rise a few needle widths above resting when it starts and I was wondering if anyone would know if I can check resistances at the sender terminal at different RPMs before I go through pulling it out and trying to screw in a pressure gauge, or buying a new one and finding out it is actually the gauge.

2. For the last 25-30K miles I noticed that often when I'm in 3rd or 4th accelerating, as the RPMs approach 3K and almost as soon as it passes that, the engine surges forward as if I'd pressed on the gas pedal harder. There is no other hesitation or speed change after that and it is not much more than a mystery, but I wonder is anyone has experinced that as well and has an answer. I thought it might be a tps issue or an afs thing, but they both seem to be within specs....

BTW, I've had pretty good luck brazing on a blob of brass welding rod on the copper terminals of the starter solenoid and then grinding them down rather than spending big $$ at the dealer for two pieces of copper.
I've also been able to weld teeth back on the driver's window regulator then grind down to get the V shape of the teeth.

Thanks in advance and glad to be here!


__________________
One Planet, One People, Please!

 

Not that I have an answer, but my '90 3.sl0w did the same thing at about 2800 rpm under moderate to hard acceleration. I always wondered about that...

 

I think all 3.0's have that surge. I've seen other people mention it. I go with it - 1st to 2nd shift at 3k-3.2k and all other shifts at 2750 to 3k. I get better gas mileage by never lugging the engine. I shoot for the RPMs to be at 2k after the shift.

We have to look up the oil pressure gauge testing procedure. I know that my 3.0 oil pressure is right around the first mark on the left at idle - goes a little above half way on the gauge while the engine is coming to temp and pretty much always stays at that first mark once the engine is up to temp for a while. Everyone says that is normal for the 3.0. I run 0w40 now since my truck just passed 160k and it seems to really like it - slightly better oil pressure.

 

Can't find anything in the factory manual about the oil pressure sender and resistence. Mine just barely registers at idle and moves to about half way across when driving. I have noticed that the pressure drops off a lot when the oil gets older, I actually use that to judge my oil changes. Maybe new oil would help, and I've also found 10W40 gives a little higher pressure. Mines a '93 3.0 with 202,000 km.

As for the power surge mine does it at 2800 rpm, it's the imaginary turbo kicking in.

 

I like that! Imaginary turbo, indeed...that IS what it feels like!
I do plan on changing the oil this weekend, tho' I have a sneaky feeling that wont help...It used to ride about half way like yours even at idle...
Thanks for the responses!

 

Aloha!The op should be (IF I rememver) 4.6 @ idle & 30+ psi @ 3000 rpm!
The surge is just normal for the 3.0, because of the Cam...!
* Good Luck *

* Harry *

 

Hey, thanks for the info! I've read some of the other posts re: low oil press. readings and it seems to be common. Somehow it still doesn't put my mind (small as it is...) at ease. Seems that less than a year and +/-10K miles ago it was reading higher, and not finding any electrical way to test the sender, I guess I'll just have to screw a mechanical gauge in and "learn the truth". Going off-road on some of these lava fields, and not checking the oil daily seems like a recipe for disaster. one small hole in the pan and by the time I (or more likely, my wife) hears any noise from the engine, there would be some damage done....

 

I think you ought to get it in and get the oil pressure checked. You don't want to spin those bearings dry. It could be that everything is so loose in your engine, the oil pump can't pump fast enough. It could also be that the sender is defective, or the pump is wearing out. Or an oil galley is getting plugged. Keep in mind, that pumps usually fail slowly...giving you time to get them fixed before they fail below your engine's tolerance level.

Get it checked...the sooner, the better.