Need Advice - '89 V6 Pickup Low On Power (1 Viewer)

[NMC_EXP]

I recently bought a 1989 4WD with the V6 and auto trans. It has 31" x 10.50 x 15" tires. The previous owner was good about changing the oil but not much on tune ups. The plugs were last changed at 50K miles.

It was idling rough so I took the truck to a Toyota dealer for a tune up. At my request they installed: new plugs, new plug wires, new distributor cap, new air filter, and new PC valve.

I also asked them to install a new EGR valve. They said the old one was OK and did not change it.

I asked them to change the fuel filter. They did not change the fuel filter and told me (1) the fuel lines get brittle and might break when changing the filter, and (2) they never knew of a fuel filter to get plugged (???). That sounds like a load of Bravo Sierra to me. I think they forgot to do it and were just blowing smoke.

Anyway, the truck ran well here in the flatlands of Illinois. Last week I took it to Colorado...wow.

At 5000 foot elevation along I25 on long easy hills it was hard to maintain 60 mph even when out of overdrive.

Up at 8500 feet on backroads where RPMs were down it would barely pull itself up mild slopes.

At the higher elevation it starts fine and runs smooth. Just does not have any power.

I left the truck out in Colorado and will play with it when I go back. I plan to first change the fuel filter and if that doesn't help either get rid of the original catalytic convertor or replace it.

Any other ideas and/or suggestions on what is ailing this truck?

Thanks

Jim

 

[goschbrandon]

It's probably just the 3.slow

What hills are you talking about specifically? The altitude has a very noticeable effect on the 3.0- I drive from Colorado Springs to Tempe, AZ every year for school, and the difference is almost night and day. I ask what hills because I can maintain 75 for most of the drive from Colorado Springs north to Wyoming, but on the drive southward towards Pueblo and up over Raton Pass, there are some hills that I end up going slooooooooooow. This is with the 5 speed as well. I-70 west of Denver is even worse, some of it's 3rd gear at 50 mph. But this is the joy of a slow car on big hills at altitude. It pretty much takes 4000 RPM in 4th gear to really hold speed on the hills for me, and sometimes that's not enough, for what it's worth.

If you've got a specific hill in mind, I could probably tell you how fast my 4runner can go if it's near Colorado Springs or on I-70...

cheers ,

Brandon

 

[NMC_EXP]

Brandon

The only hill I can specifically identify is on I25 near Walsenberg CO. A valley really - down one side and up the other. I could run 50 or 55 on the upside after getting a 75 mph run at it from the down side.

This is 50 to 55, tranny out of OD and with my foot in it. Still losing rpm and speed at the top.

Jim

 

[Bear80]

Just an FYI with is contradictory to what many do and say here but toyota fuel filters are not designed to ever need to be changed. Some will testify that it has made a difference after changing it but I think it's a carry over from older domestic cars that required it. Oh and as far as brittle fuel lines, the dealer should have atleast looked and checked, it could corrod with the snow/salt mix.

 

[Bear80]

Look into the sensor pack on the back of the engine. It's a bitch to get to but if the temp sensor is not reading right, the computer will not set the right fuel mix and you will lose power. Also look into the knock sensor, it may go bad and not throw and light but retard the timming way back.

Also I've heard (never got to try) that if you set the timming BACK from what the specs call for you get better power.

Keep in mind that in CO if you run regular it's only 86. I know my 94 runner sucked it up in CO but would burn the 32x12.50's off here in TX.

 

[goschbrandon]

I know this hill...

Brandon

The only hill I can specifically identify is on I25 near Walsenberg CO. A valley really - down one side and up the other. I could run 50 or 55 on the upside after getting a 75 mph run at it from the down side.

This is 50 to 55, tranny out of OD and with my foot in it. Still losing rpm and speed at the top.

Jim

I do know what hill you're talking about- I usually hit it going near 90 at the bottom, downshift to 4th once I drop to 80, and still top out in the 50 range, it's one steep and long mofo, and with the altitude, well, not much you can do. Not saying there's nothing wrong, but doesn't sound like anything out of the ordinary to me.

Hope this helps,

Brandon

 

[NMC_EXP]

Just an FYI with is contradictory to what many do and say here but toyota fuel filters are not designed to ever need to be changed.

Not being argumentative, but the only way I can see that a fuel filter would never need to be changed is if the fuel and gas tank were perfectly clean.

Thanks for the other info on the sensors. I'll check it out.

Jim

 

[2ndGenToyotaFan]

Why do they have threaded ends, and aren't just part of a long fuel line?.... Sorry, I had to.

 

[NMC_EXP]

downshift to 4th once I drop to 80, and still top out in the 50 range, it's one steep and long mofo, and with the altitude, well, not much you can do. Not saying there's nothing wrong, but doesn't sound like anything out of the ordinary to me.

I appreciate the info.

It does help...but I would rather have heard about some cheap and easy fix which would let the little truck walk up that hill like it wasn't there.

Jim

 

[Bear80]

Why do they have threaded ends, and aren't just part of a long fuel line?.... Sorry, I had to.

I don't doubt the need for the filter to bolt on but Toyota lists the fuel filter as a "life of the vehicle part." Of course with anything in engineering there is a projected life and I'm sure a filter will eventually need to be changed, just like the head gasket on my 80 series. Just as an example, my pickup before the engine spun a bearing had over 250k and ran stronger than my new engine with a new fuel fitler. Just a side note I'm inclinded that it's a senore issue, water temp or knock. I just guess to each his own and if you really want to spend the day changing the fuel filter by all means, but I have better things to do with my time, like 'wheel.

 

[nanuk]

If you don't find anything else out, I would do a compression check.
My 90 with auto was running on 4 cylinders when we traded it in. It ran, but was SLOOOOW on the hills from Penrose to Ft Carson. Ran great on flat roads.

 

[Grim Reaper]

What is the FACTORY tire size for the vehicle? If it was truck that came with 235's it will be geared differently then a truck that came with 31's.
http://www.pirate4x4.com/forum/showthread.php?t=459180 about a 1/4 way down posted by 4Runner rick is gearing for tires size and how to read the plaque on the fire wall to see what gear the truck came with.


Change the fuel filter......While some may say under normal conditions its not needed If you wheel the truck it changes the Game. Its normal for sediment to form in the tank. A normal road going vehicle will have very little problems with it. You start bouncing a truck around off road it will break that sediment up and get it sucked up. I change them on every car I buy that has over 100K. CHEAP piece of mind.


Airfilter. Change it if its 5k or you run in dusty conditions often you may need to change every oil change.

Do you have a K&N? if so loose it. It will screw up the Ambient air temp sensor in the AFM. If you have one then pull the AFM and hold it like it mounts and spray off the nub that hangs down to get the oils off it. Contact cleaner would be best to use on this part. DO NOT TURN THE AFM UPSIDE DOWN. There is the potential of the contact cleaner getting up into the the metering area and causing issues. Also try to keep the cleaner out of the hinge on the door as it will wash the lubrication out.

Replace the Thermostat with the factory spec part from the dealer. If its running a low temp thermostat the engine my not achieve enough coolant temp to allow the ECU to go into closed loop mode. If it doesn't go into closed loop with will not correct fuel mixture.

O2 Sensor. They usually go fat when they start going bad. Not as noticeable near sea level but you get at altitude and its going to be real noticeable. 60K recommended change interval.

Do you have to Smog there? If so How did it do last check?

 

[NMC_EXP]

What is the FACTORY tire size for the vehicle? If it was truck that came with 235's it will be geared differently then a truck that came with 31's.
http://www.pirate4x4.com/forum/showthread.php?t=459180 about a 1/4 way down posted by 4Runner rick is gearing for tires size and how to read the plaque on the fire wall to see what gear the truck came with.

Change the fuel filter......

Replace the Thermostat with the factory spec part from the dealer.

O2 Sensor.

Great info -- thanks.

The tire size / gearing issue had occured to me. Right now the truck is in the Rockies and I'm in the flatlands. I'll check out the code on the data plate next time I'm out there.