Erratic idle

[dpuckett]

I recently went through (resealed and cleaned up internals) my 114 pump off my 90, changed DV holders and put it on my 92 to run while I decide what to do with my good (205) pump and where to get it rebuilt. Lately it has taken to idling just fine if I put the transmission in neutral and coast up to the light, but about 5seconds after a complete stop, the idle drops considerably- like "be careful starting in 1st, I may kill it" RPM drop. A/C does not afect it. I did notice some slack overall in the pump before and after the "rebuild", but thought nothing of it at the time. I did have it calibrated at the local shop and set to 90cc/ 1600 pump RPM.



So, even though I suspect it to be the pump, what else should I check besides the usual- fuel pressure, leaks, etc? Timing is at or near stock, but not behind, but this is a fairly recent development, too. Timing shouldnt be a factor. I know, swap pumps and see what happens, but I'd like to get my 205 ou & rebuilt, and get it back before the drive to IN next month.



Daniel

 

[Rebel Ram]

Daniel. I am with you on this problem. My 92 is loping real bad. If I turn up the idle to get rid of it, it comes back when i put it in gear and Rs drop. I took the top off the pump last weekend to try and clean up the gov mech. (not to be confused with my 93 sticky gov thread) But with this truck it did not solve the problem. I did notice though that when turning the gov mechanism by hand, it had a rubbery feel. I had not felt that with my other pumps. Maybe it was there and I just hadn't tried to rotate it as hard.

I suspect the rubber dampers on the governor drive gear getting soft and in turn causing the gov to hunt.

I am pulling this pump today and will disassemble to replace o-rings, seals and dampers. I'll post latter today with my discoveries.

 

[dpuckett]

Thanks, man. I took it apart as far as I could without the special tool to take off the triangle head bolts. It runs ok, just the idle seems to get lower and lower. One thing I have considered is fuel pressure, but that shouldnt affect idle too much should it?



-DP

 

[MMiller]

When my idle started dropping, soon after it would lope like a huge cam gasser, then rev up, then return to idle. There were two broken springs in the pump. They were pretty heavy springs, and I think they were in the head area of the pump. I had the pump pulled and rebuilt by a good diesel pump shop. He said if I would have kept running it, I would have bought a new head for my pump.



It started by having a low idle. Then after a few days of driving, it would idle low, then lope. Then after a few more days the engine would rev up. A few times it took off like crazy going down the interstate, blowing smoke out of the tailpipes... :--) This was before the pump was tweaked at all.



Scary stuff indeed. Don't really know if this is what you guys are experiancing, just telling you what happened to me.



Michael

 

[dpuckett]

I think I found part of it..... My jambnut for the low idle screw had backed off, allowing the idle screw to vibrate backward. I bumped the idle up to where it smoothed out, and have had no issues since.



Michael- when I had it apart, both plunger springs looked good and were the same height. The other two small springs in the top of the head tha tpush against the governor lever were not the same height, and were even different spring rates Think I'll just throw some springs and a seal kit in my other pump and run it some more, putting this 114 back on the 90.



Daniel

 

[Rebel Ram]

It took me a while to finally get to it, But I pulled my 92's pump today to find out what the problem was with my idle cold. When I took the top off and tried to rotate the shaft I could see that the throttle links were flexing. WTH? Then noticed that the slide collar was not free on the plunger as it should be. So off came the distributor head and plunger. It seems that I got a bunch of ***** on the plunger shaft, distributor bore and collar making for ALLOT of sticky bindup. So I cleaned up everything and installed new plunger springs and O-rings where necessary and all is good. Fired up on the first rotation and idles smooth as can be.