Just pulled a 90 model out of a backyard...

[adrenalnjunky]

1990 super cab, 2wd, 2.9, 5speed. Truck was my wife's grandfather's - he passed 2 years ago. In 1997 he was he was told that the motor was done and needed to be replaced. This was after a new clutch @ 88k. The shop guy wrote on the receipt I dug out of the glovebox - "Multiple oil leaks. Motor needs extensive teardown or replacement. No oil found on the clutch during this work. Rear main seal looks good." Grandpa had no other engine work done - he just kept driving it.

Grandpa's son drove the truck about 2 years ago for a couple of months - the motor has a miss, and the valvetrain sounds like a diesel. It shakes pretty bad, and does like to randomly die, cold or warmed up. Brakes have some issues as well. The truck was parked in the backyard and hasn't been touched since.

fast forward to last week, my blazer ate a transmission, and I'm out of a ride. I was told i could drive the Ranger for the time being - but no one knew really how rough this motor is.

I got it running again, changed the oil, seafoamed the fuel and oil, checked coolant, checked all the basic safety stuff and start driving it some as a point a-to-b set of wheels.

So on to troubleshooting:
I'm pretty much resolved to understand that the oil leaks are just due to this motor's tendencies.

No check engine light over the past week. I do have a constant Brake warning light, and Rear Anti-lock light stays lit.

Idle is currently at 400-500 rpm. Seems low to me, and of course, pretty sure it isn't on all 6 cylinders, at least all the time. I plan on checking spark today. The back plug on passenger side looks like a fun job.

The coolant temp gauge never moves - it may move slightly after being driven a long time - I'll doublecheck on the way home from work today. Is this most likely a ECT sensor, or a sending unit issue? Anyone have a link to pics of where they are, or to an online shop manual?

I don't want to waste much, if any money throwing sensors and stuff at this truck.

Suggestions on the first routes to take after me testing plugs/spark?

 

[Spott]

Test compression too. You're looking for 100psi minimum, and no more than a 10% difference between all the cylinders.

A compression test can reveal cracks in the block or head, or a failed head gasket, or valve problems, or bad piston rings.

Also, look at each spark plug when you pull them, and note any funny colors or deposits or anything. That can reveal problems specific to each cylinder. A happy spark plug is white/tan with no deposits or damage.

Valve cover oil leaks can be fixed with good fel-pro rubber or blue-series gaskets. Once you get those fixed, you can locate other leaks further down the engine.

Of course, a basic tune-up would be good for the engine, too, considering how it was treated and how long it has been sitting.

Spott

 

[mk42gunner]

I believe in checking the simple stuff first.

The rear plug is easier to get from the wheel well than from the top. At least it was on the 91 4.0.

The thermostat could be stuck open, I had that happen on one of the rangers I had.

Check your brake fluid.

Robert

 

[adrenalnjunky]

Last night I cranked up and started pulling plug wires one at a time. Any time I pulled one on the driver side, the truck would crank, but had a very noticeable roughness and wouldn't idle hardly. But with either the front or middle plug wires removed on the passenger side, the truck didn't noticeably change how it ran (at least in the carport). I didn't feel like trying to get the rear pass plug undone to test since it was late, and that plug was hard to get to.

Today - I changed plugs, not a whole lot of difference in running or idle. Bought an inline spark tester, but haven't had a chance to use it yet.

The back pass. side plug was easily accessed thru the fender - thanks for that mk42, saved me some time.

Something I wanted to ask about - the front and middle plugs on the pass side were almost loose, and both don't screw into the head itself, but into these standoffs that are screwed into the head? I've never worked on another ranger, so I wanted to make sure that seemed right? Those were the 2 plugs I could unplug last night and not see any difference in idle or throttle response with the engine running. Here's a Pic:

to me it looks like the end of the plug wouldn't extend past the end of this thing.

 

[alwaysFlOoReD]

I've never noticed a "plug extender" like that on any of my motors I've worked on. Subscribing to learn about them.

Richard

 

[adrenalnjunky]

I sent the pic to my pop, he says they're anti-foulers for plugs. He's never used them or dealt with them either. I plan on testing spark in the morning, and removing these to see if I can smooth up the idle.

Sent from my cm_tenderloin using Tapatalk 2

 

[alwaysFlOoReD]

I can't see how they would work as anti-fouling. I think they would act more like a cold plug. A cold plug has the center electrode deeper in the porcelain and is the opposite of anti-fouling. But I've been wrong before and probably am again.
I think your idea of removing them is a good one. The gas has a better chance of sparking off if the tip of the plug is not in a cave.

Richard

 

[mk42gunner]

Glad I could help.

The anti-foulers used to be used if you had a cylinder that really burned oil. The theory was that the oil didn't get to the plug as fast to foul it out. I don't know how well they actually worked, but I never really bought into the idea.

My Dad used to tell me that going to a hotter plug worked just as well.

Robert

 

[adsm08]

The 2.9 is known for valve train noise, but what you describe of the running conditions sounds a lot like something my truck did a few years ago.

Check your timing. What happened was that mine was off almost a full tooth and the pin that holds the gear to the dis shaft was not in place allowing the timing to be "variable". This caused low power, misfires, knock, dieseling, hard starts and random, sudden stalling at all temps.

 

[adrenalnjunky]

Welp - pulled the anti-foulers out this morning, here's what they look like:

The hole on the end of this thing is only 3/16", and the electrode is 7/8" up inside it. Doesn't seem like it would help with combustion much at all.

It doesn't even look like these 2 plugs had seen fuel yet.

Pulled them out, reinstalled plugs, spark tested all 6 - all are lighting up my inline tester. (How bright is this thing supposed to be? Mine was kinda like a 12v bulb on a 6volt battery brightness)

Truck was cold from sitting all night in the 40's, but idle seems to have come up to
600-700 range and I think it is a little smoother.

I'm planning on checking fuel pressure and compression as my next steps. Then I'll move to timing if everything passes.

sound right to you guys?

 

[adsm08]

I like to keep the 2.9 idling in the 700-850 range. If it idles smoother but is still down near 600 I would still check timing. Retarded timing can lower the idle speed.

 

[alwaysFlOoReD]

Probably a good thing they weren't firing as any oil would have cooked on and ruined threads on the way out. It looks like the lower 4-5 threads were just hanging out in the cylinder collecting carbon.

Richard