OK, I turned the fuel screw in the other night ... but the idle was too high (@1100rpms, the auto wanted to over run the brakes)

No biggy, I dug out the metricated wrenches and took a couple of twists off the lo-idle screw... *slight* (100-150rpm drop). Took another turn off... nothing! Took another off... nothing! Then I realized the lo-idle screw wasn't even touching the tab!

What does this mean?
- Turn the fuel screw back out until it WILL idle down?
- IP is pooched?
- Some other (possibly simple) adjustment elsewhere?

Honest, I searched, but with eleventy billion returns for "idle", "high idle", etc... short of spending the next 3 weeks searching, it was going nowhere!

 

Lengthen your adjustable rod, also back out the high idle screw. Solved it for me [smile]

 

Thanks Mike, I'd found BC847's reply to Maxx asking the same question:

Unfortunately, I just lengthened it almost 1/2" and it did nothing... With the linkage REMOVED from the IP bellcrank, I can't make it rotate any further and the tab is still NOT touching the idle screw. Am I missing something?

 

You may need to re-index the throttle lever. You can move it one notch and get more travel in the low direction. I had the same problem on mine. It's a bit confusing to know which direction to move it but you want the lever to move CCW one notch in relation to the shaft.

Edwin

 

I follow what your saying... but I don't understand exactly how it would help

The lever/bellcrank doesn't appear to be impeding the throttle shafts motion, unless there's something underneath it (other than the "idle stop" tab) that's stopping the rotation? IOW, the throttle shaft appears to be rotated fully CW...

Or is that it will allow the linkage to move further CW?

I just hate the thought of backing off the fuel screw now that's it finally making *a bit better power* (very, very light smoke under initial WOT)!

 

Yes I understand your question but I cannot remember if there is a hard stop before the screw is fully back. There may be but without pulling the lever off I couldn't tell you for sure. You could check it yourself. Just use a big metric Allen wrench to unscrew the top nut (I call it a nut only because it has internal threads but in fact it looks nothing like a nut) and pull it all apart. You'll have to do that to reset the notch anyway. Just be careful to not disturb the current position in case I'm wrong.

It could however be that the stop is internal on the shaft itself in which case you don't want to disturb the current index of the lever and shaft. In this case the reason it won't idle down is that you've just turned the fuel screw in to far and in fact you're getting near runaway condition.

Edwin

 

Check that your supply line to the VE isnt getting in the way. After that, the lever should come right around to the end of the screw. If it doesnt, something inside is binding.

Daniel

 

The supply (hard line to front of pump?) is plenty far away. I did manage to squeak the throttle arm back to the idle screw for -50rpms and pulled 1/4 turn off the fuel screw for another 100rpms....

Also changed the fuel filter. Still runs about the same w/ VERY slight smoke initially @ WOT and clear the rest of the way. EGTs are @1000-1050* and boost up slightly.

Hopefully, I'll have more time in the next few weeks to see if I can get another turn or 2 on the fuel screw *AND* keep the idle speed in check. Planning to spin the fuel pin another 45* to deepest and tweak the smoke screw & starwheel.

If anyone has any suggestions...

 

After I did mine the TPS made it hang up. I had to take the TPS off and give the screw on the bottom of it a little turn. Same truck same year.

 

Thanks freeride! NOW we're getting somewhere! I could tell "something" was causing the whole throttle arm to hang short of hitting the idle screw!... maybe this is it? I'll check it later this week and hopefully add another turn to the fuel screw!

 

I'm having a similar problem with the idle speed in my 92. I recently turned up the fuel screw 1 full turn, and then the idle speed was way too high. I then backed out the idle speed screw, and it brought the idle speed down to what feels normal. However, when I rev the engine up and let off the throttle, the rpm's drop down really low(below normal) for a split second and then come back up to regular idle speed. Has anyone else experienced this problem after turning up their pump? If so, do you have any suggestions, or were you able to fix it. I've heard about a high idle screw, but I only know of the one idle screw.

Thanks,

Dawson

 

I had this problem after several turns on the screw. Ended up being a clogged fuel filter and fuel pressure was dropping to low.

 

I tried changing the fuel filter to see if it was just a dirty filter, but even with the new filter it did not fix the problem. I've heard that the sending capacity of the lift pumps on these engines is barely enought to meet the stock settings of the injection pump. My truck has over 430,000 miles on it(truck used to be my dad's), and I'm pretty sure it still has the original lift pump because I don't remember him ever changing it. I'm thinking the lift pump might be on it's last leg, but I want to check all the simple things first.

 

I ran into the same problem and wound up raching the point where i either had idle where I wanted or full power. I couldn't get both. Wannadiesel took and traded places with the return spring and the linkage. That shortened the throw of the linkage a substantial bit. I went one further and drilled the throttle lever and moved the link up about a half inch or so. Now I have the idle I want and full power too. IF you are going to do the same thing you will need a carbide drill. The link is HARD!.