Checking/increasing torque on AT

[happycloud]

I have an 87 4wd AT. This is my second van - the other was an 86 2wd AT. I noticed that this one has considerably less power than the other. I di realize that this is a smaller engine but I am wondering if I have another issue.

I recently aquired it and after a tuneu took it on a long drive. After about 600 miles I started losing torque and hearing a loud clicking sound. After checkig I saw that it had almost ran out of oil in dip stick. This means it used maybe 1-2 quarts during that 600 miles! The van doesnt leak oil nor is there any smoke coming out. One of the things I noticed was that the lack of oil was directly related to an almost complete lack of torque - I could only go 25 on the hwy.

Any idea what the issue might be as far as oil being used up and could that issue result in a low overall torque even when oil is topped up?

[Burntboot]

Losing power due to low oil is VERY bad, don't drive the poor thing till you sort it out.

As to not seeing any smoke, its hard to see when you're driving, even if it leaves a blue trail, the perspective just isn't right.
If you really want to know if she's burning the oil, have a friend follow you at night and stand on it hard, highway on-ramps are good places to try this.

As it is new to you, start with a good crankcase flush, lots of threads and lots of products out there, seafoam won't cause damage like some products (diesel oil/atf/varsol)
You should also pay attention to the colour of the oil, should stay the colour of honey for a LONG time, if it turns black soon, then you'll know you have a blow-by issue.

The other thing to look at would be the PCV valve, if its stuck in the "open" position, it sill suck oil vapour into the intake all day long.

Other causes are possible, but those would be the top 2.

By the way, your 87 is the same displacement/engine that your 86 had, the 4WD is a heavier beast, but shouldn't be overly noticeable, in the grand scheme of things.

BB

[happycloud]

Okay I will look at these things. Thank you. I didn't know that my engines power to the tranny was related to oil level until the other day. I could hear the engine rev but was not going anywhere. I was kinda hoping that there would be that one thing that would fix my oil usage and torque at the same time

[happycloud]

I should add in case its possibly relevant that my oil light (the little yellow one) comes on and off randomly (oil pressure stays normal except in that episode) and the engine light also comes on and off and blinks 11. I have not solved that yet.

Do you know where I can find info on testing the PCV valve for a 4ye? Looked through the van manual and on this forum but not really finding the right thing.

[Burntboot]

I suspect you have multiple problems going on simultaneously (common situation with "new" vehicles)

Low oil would only cause a loss of power if the engine was starting to seize.
I missed the part where you said the lack of torque continued after adding engine oil, this almost completely eliminates the possibility the 2 things are related.

Sounds a lot more like a transmission problem, especially if the engine is revving freely but not transmitting power to the wheels.
Have you checked the transmission fluid level and condition?

If the CEL is coming on and while driving, something is up for sure, (these things will log codes without ever tripping the light).
When you say the CEL blinks 11x, that is with a jumper wire in the diagnostic connector, right?
I believe code 11 is addressed in the archives but my memory fails me on the details and my manual won't help as 88's have different codes.

I have had bad luck with A/M PCV valves so I always get mine from Toyota (they're not expensive), while your there, may as well grab the grommet it mounts in.
(It will most likely crumble when you remove the valve)
As to testing, it should rattle when you shake it and you should only be able to blow through it one way.
In your situation, I would just replace it, it eliminates one more part of the equation.

The oil level sensor (yellow light) can be finicky.
When you see that light, check the oil, you'll know soon enough if its accurate or not.
Pressure senders are notorious for showing low pressure at idle, but usually indicate fine once off idle.
The fact that your seeing low pressure at the same time as low level warnings is worrisome and needs to be investigated. (see line 2)
I would resist driving it until you sort out the basic issues, you don't want to do unnecessary damage.

BB

[happycloud]

Thanks - I wasnt super clear on the torque. So when it just lost power it was due to low oil. Filling it up put it back in a "normal - I can go 80 but it takes me a while" mode. I was questioning it all because I had at the time no idea my movement to the tranny was related to oil - taking the oil useage, flicking light etc I started wondering if a component of some kind was perhaps not working as it should. THe tranny oil is fine. I also upon purchased gave it some oil changes, added some good cleaners/additives for engine, gas and AT (forget the name but came recommended by an ex toy mech).

I will go ahead and get the PCV changed and go from there.

[happycloud]

Ok.. I replaced the PCV valve but no diff. The last one looked clean and rattled.

I did a compression test and have 115, 135, 135, 135lbs so #1 is a little low.

I pulled my plugs -they have 1200 miles on them. They all look a bit oily on the threads but not too sure what to tell from them. #1 plug looks same as the others with exception of #2 which was cleaner but I think I had a slightly loose cable.

I noticed that my exhaust had some leakage around where it screws to manifold - we took it off a while back and someone said to just put sealant but clearly it needed the original compression rings which I added. Putting my hand right around that part I still feel some wind but I dont think its coming from the joint - maybe slightly above? I cant quite see what is going on there.

It gives it a tiny extra humph but I am still dealing witht this crazy oil useage.

To reiterate... The van drives ok but has less power than my old one did which had more miles. Even bare bone empty its a dog going up any hills. Slapping the gas a few times to get it to switch gears 2x does help but it just doesnt feel quite right. I did have to mess with the throttle cable as it was shifting super high before (still roflroflroflroflty power) - I can't adjust it to factory as it doesnt have any of the expected markings but I did manage to get it to shift at lower rpm.

It uses a quart per 500 miles about. It got low twice - just loses torque - engine revs but car doesnt move much more than 20mph on flat. Doesnt heat up really. I know now not to drive more than a 100m before adding oils so wont happen again but clearly a problem.

I cant imagine that a little lower pressure on #1 is the root of the issue - the oil on all the plugs might indicate something else but not sure where to look.

Attaching plug pics - the one I hold by itself is #1, otherwise they are held with #4 on left hand side.

Thanks for insights.

[IronViking]

I have noticed that ALL my 2wd vans have had lots more power and speed compared to my 4x4 vans. I just got a 2wd 5 speed van a few days ago and it totally blows the doors off of my current 4x4. My 4x4 also burns thru quite a bit of oil. I run royal purple synthetic to keep things lubed and incase I run it too low.

[Burntboot]

My manual is currently AWOL, so this is from memory, but compression readings should be on the order of about 180-185# across the board, and with a variation of no more than 15# between cylinders.
Given that you have compression readings of 135# would either indicate a big problem or that the compression test was done incorrectly.

For the record, a compression test is done with the throttle held wide open and (preferably) a warm engine.
I usually crank about 6 times, most important that the number of cranks is the same for each cylinder and the pressure should come up family quick.
Assuming that you did the compression test correctly then it sounds like you indeed have an internal engine problem.

The problems that contribute to low compression readings are either engine wear, poor valve sealing or stuck rings.
Stuck rings can, on occasion, be resolved with a decent internal engine cleaner but more often than not, will require a full teardown and replacement of internal bits.
About the only way I know of to isolate rings from valves would be with a leak down test (this involves applying a measured amount of air and listening for the escaping air either through the crankcase (rings) or through the intake and/or exhaust (valve leakage))

When you say that "it doesn't heat up much" are we talking engine temperature?
If the engine is not getting up to proper temperature, the FI system WILL cause a rich condition in order to try to get the engine up to temperature, this too can make the plugs black and wet and can confuse the issue, over-fuelling will also cause low compression numbers as the excess fuel tends to wash down the cylinders, reducing the ability of the rings to create a seal and build compression. (More often than not, this condition will be caused by a defective thermostat)
If this is the case, usually the oil on the dipstick will have a distinct smell of raw gas.
This condition can also cause excessive oil usage.

If the compression test was done correctly (and you are not over-fuelling) you really only have 3 options at this point:

1) try another engine flush with a quality product
2) rebuild or replace the engine
3) RESTORE - this product is available at most automotive stores but understand that it is at best a stop-gap, bandaid, temporary measure until you can perform option #2

I am not a fan of RESTORE, nor would I recommend it, but have seen it put off the inevitable, on a few occasions.
If you go this route, it will have to be added at every oil change.

An exhaust leak will not help, especially if it is leaking at the manifold, while it can affect power, it isn't likely to affect oil usage.
BB

[Burntboot]

As far as "reading" plugs goes: they should be a light brown colour and be dry, grey indicates oil burning (often with deposits/build-up), black is usually from over-fuelling.
Both oil and fuel can cause the plugs to appear wet.

While it could just be the picture, yours do appear to be showing the signs of oil burning.

If there was oil in the tubes (that thing still on #4 plug) then replacing the tube o-rings can solve that issue, but I am seeing what appears to be oil down around the electrode area, not up above the compression washer. The only way that oil in the tubes could get down around the electrode area is if the spark plugs weren't actually tight.
Usually if the O-rings are bad, the tubes will fill with oil until it starts to degrade the rubber boots of the spark plug wires.