Brian Batres

i just set the timing but how can I adjust the idle besides the idle screw? and I have to take apart the hubs to change the brakes and rotors, is it possible to put them on incorrectly?

Brian Batres

and i made sure they were free in the right position

Brian Batres

*DID take off the hubs to change the brakes* sorry for that mistake

Brian Batres

Am I gonna have to mess with my TPS? Maybe it was adjusted incorrectly?

Co_94_PU

iTrader: (-1)

Idle speed is set by the large screw on the top side if the throttle body, its cast into it and easy to find. Poke around and you will find a picture.

This won't effect your throttle sensor adjustment.

It (tps) could be off adjustment but if you don't get codes set doing timing adjustment the important (IDL) part is OK.

..
Hubs are easy to get wrong. Iirc, they can also bind up in that case they indicate unlocked but are stuck on the axel. Could be as simple as making sure they have the indexing ball and spring, or just putting them back on the "free" mark.

Co_94_PU

iTrader: (-1)

If the idle screw is already bottomed out, and the engine still runs, this points to leaks in the system. You'll have to hunt those down and fix them.

It's possible the throttle plate is out of place due to someone adjusting it when they shouldn't have, or a worn out shaft and seat for the throttle blade. Symptoms include irratic idle, idle that changes when you let off the pedal and the plate doesn't always return to the same spot. This will also effect the idle signal to the computer depending on severity.

Brian Batres

The idle screw is turned all the way in , and if there is a leak where are the common places for a leak? And I will check that the hubs are installed correctly . They have the springs. The idle does not change when I left off the pedal.

Brian Batres

The truck also kind of shakes when turning off due to the idle being high. So a lot of these problems are kind of connected to an idle issue?

Co_94_PU

iTrader: (-1)

Hubs: it was the photo that brought this up, in your picture the selector is not pointing to free. Like it maybe shifted because the indexing spring or ball wasn't holding it in place. There are the two springs. One assists the lock mechanism, the other is in the side of the selector and has a little steel ball that clicks into the detent of the hub body.

Idle: leaks have to be on the back side of the throttle plate. You have the "gas filter", this is the multi port vacuum connection at the rear inner side of the plenum, it has three vacuum lines attached any of those that are brittle or the hose spins with out force needs new hose. Forward of that is the PCV, this is susceptible to lots of heat but not a standard part store hose. Next the CSI, there is a non reusable gasket here that can leak. Forward of there is the power steering and air conditioning idle up, again any hoses that are free floating or spin easily are dry (oversized) and possible leaks. Less easy to spot or diagnose are leaks in either the head to lower intake and lower to upper intake gaskets.

A very commonly over looked issue is the idle air control valve (iacv). The hoses to this are almost certainly dryed up and hard. The input hose will give a bit of a lean idle, since its unmetered air (not read by the vafm). A leak on the output will do the same as well as negate the valve closing (a symptom being the cold idle never drops when warmed up).

There is also the throttle body gasket that mates to the plenum (upper intake). And the egr valve at the rear of the plenum. As well the brake booster and its vacuum line.

Do you mean "dieseling" (engine runs and sputters out after the ignition is switched off), or is it just shaking. Its hard to describe the difference in short, someone might need to help me out here. It's possible its just a bad engine mount and you notice it most at shutdown because it is low frequency type of vibration.


...
Due to the oversized tires you need to get an adjustment factor figure for the odometer. Or you won't be able to properly calculate the actual gas mileage. For example, my tires are (iirc) 29.5", my speedo indicates 50 while GPS says 55. That is a ten percent error so I need to multiply my odometer reading by 1.10.. 172(miles) * 1.10 ÷ 12 (gallons) ~= 15.76 MPG.
​​​​​​

jefro

I have an 86 Turbo also when I first bought it I was getting around 11-13 MPG. My fix was to ditch the automatic and stuff a 5 speed in it now I average around 17-18 MPG. I have no idea if the automatic was working rite or not. But judging by the performance increase with the 5 speed I think the auto may not have been in top shape although it only had 218000 miles on it.

Brian Batres

i would to swap in a manual if i could find the transmission. Lately its been okay on the gas. If you really baby it and dont hit boost that hard it will last but thats no fun. When my dad drives it, he just says" You can fly with that truck!"