Slight surging at idle???

["Mad Max"]

So I am noticing recently that the engine is surging at idle, very very slightly, like around +/- 50 rpm, just barely visual on the tach, but I heard it before I saw it. Usually the idle is rock steady, no fluxuations at all, and it isn't constant - maybe mostly right after start up and before a cruise. Anyone know what may cause this? Power is fine, temps, pressures, boost are all fine - but maybe some water in filter? Going to drain later and recheck, but just wanted to air this one out to the panel.



T-minus 3 days and counting.....



Thx,

- Sam

 

[dpuckett]

Bad/ old fuel (old fuel is bad isnt it? A bit redundant, I'd say) Lift pump pressure? Was it a sudden happening? Or was it over a few hundred miles? Fuel filter may be pluggin up. I've seen them plug up in farm tractors in a few hours after a fill up with bad fuel.

Anyone else?

 

[MMiller]

Hmmm, First I would check the wires that connect to the cold start high idle element on the injection pump. If the wires have poor connection then it might fluctuate the idle some.



Don't want to condem the injection pump yet but... Several years ago the return springs in the rotor end of the injection pump failed and the truck would run fine then all of the sudden rev up then almost die, rev again and then be fine for quite a while. The other problem was I would be going down the interstate and all the sudden the truck would take off smoke like mad and then return to normal speed. I don't think this is the problem you have... ... ... Yours doesn;t sound like this problem tho. Mine took a rebuild of the injection pump.



I would check the wires first. long before condeming the pump.



Michael

 

[rowland]

I second the bad fuel theory. My truck caught the same bug once, it would run fine off of idle but surged so bad at intersections that it almost sounded it was going to die. This was 2 days before I was scheduled to drive 4600 mi back to Alaska. Needless to say I was a little worried. New fuel filter didn't cure it, but a tank from a different station and alot a fuel lube did. I hope yours is that simple.



Good luck



Isaac

 

[BushWakr - RIP]

Is this a "cold only" condition, or "hot only" or all the time without relation to engine temps???



Is there anything you do that seems to make it stop or decrease??



On the fuel issue, I see exactly the same thing after I have run the snot outta the ole girl and also at the change over to winter fuel.

I can duplicate this by adding a good dose of fuel additive, however this usually results in an idle increase of about 50-75 RPM, which is a stable increase and, not a fluctuating situation... .



Can you provide any more symptoms, sounds, behaviour etc. . ??



OH, I may have overlooked this and if so I apologize in advance but how many miles on the truck???



bob.

 

[RGT]

You might check the breakover spring adjustment on the throttle plate, maybe it is not adjusted and thus allowing the throttle to float a little...

 

["Mad Max"]

... sounds like I may have some bad gas (after all I DID eat at Taco Bell recently... ), but in hopes that it isn't something mechanical going bad I'm going to fill up at a reputable #2 store next time - What types of additives can we add to #2 to remove water, etc???



Father Bob - the rig has 222k miles (soon to be 225k after this weekend ), and I'm looking at some hardware upgrades



Hope it's just some bad fuel. Doesn't seem to make any difference whether hot, cold, run hard or easy. I am also wondering if the injectors are dying. Well, I'm sure it'll either get better or worse over the next two days and 1200 miles of driving. I'd normally say that I'd post the results, but looks like I can tell most of y'all in person! See you at PDR... .



North bound and down... 4 wheels a'rollin... we gonna jam to VC and have fun... . (take-off from best song ever written - Smokey and the Bandit)

- S

 

[J DeMaio]

My old truck did this same thing about a year ago, I put the recommended amount of Power Services conditioner in the tank, drove it on an hour trip, and the fluctuation in RPM's was gone.



John

 

[JBournes]

Mine is surging too!

My truck is surging too, has no pattern hot or cold, i just changed my f/f, and it still did it so i think i will go get some conditioner and try that, and change my filter again in about, 500 miles. If that doesnt fix the problem i guess its time for a new injection pump. I just put a new lift pump on thinkin that was the problem, but it wasnt. anymore ideas?



JEB

 

[southpaw]

It may need a new pump

my truck was checked out this week by a diesel repair shop the results were the injection pump is going kaput any time so don,t go far. The good news is the engine appears to be in excellant condition otherwise. The truck will occasionally stall from reverse to fwd or at stop lights. it, my 89, 250 reg cab auto with 140k. all stock except for k&n and vented air box. my question to the members is, a rebuilt pump reliable?and i realize it depends on who does the rebuild. or is a new pump in order? I have a quote from which i,m still gasping for air. so any good advise will be welcome. I may contact Piers after i recieve some replies from fellow members. Oo.

 

[cerberusiam]

If you buy a new pump you know what you have. A lot will depend on how bad your existing pump is and the cost of the pieces to make it reliable. I had mine rebuilt 20k ago and no problems even though the body was showing some definite wear in places. Just replaced the internals with the updated pieces and newer seals. Cost and reliability will depend on the rebuilder.



How much was the quote for rebuilding? You should be able to freshen a pump and update it for around $600. A reman with all good pieces is running around $900 and a new pump is about $1300.

 

[RGT]

Are there still new pumps available for our engines?

 

[Midnite]

Originally posted by RGT

Are there still new pumps available for our engines?

PDR appears to have them available, as well as rebuilt ones.



Mike

 

[cerberusiam]

The last time I checked, 2 months ago, the VE pump was still available as a new item from Bosch. What has happened in the interim is anybody's guess. Piers list the pump as new and not rebuilt as do several other suppliers. The VE44 was used in a lot of applications from trucks to farm equipment to backhoes. Bosch is pretty good about making new parts for these motors because they last so long. How long that will last is a good question but considering how long they run the cars and trucks in Germany and how many diesels there are its a good bet they will continue to make new parts until some regulatory agency tells them they can't.

 

[southpaw]

ve pump

well i checked early today on the price of a pump from a local dodge dealer, rebuillt $1350. exc. I didn,t even bother to ask how much the install would be. The parts guy didn,t know who did the rebuild and said there aren,t any more new ones. He must live in the parts box all goes out nothing comes in. I have found rebuilts for $675 exc. out of Texas but don,t know who rebuilds them or if they are warranted. I definitely will contact pastor Bob at the alter of acceleration to see what might be in store there. Thanks for all the suggestions. K. E.