injector pump leak

[formula]

My injector pump decided to leak tonight. It was about 5 deg out when I started the engine. It had sat at the commuter parking lot all day so the engine was good and cold. Started up just fine, only two cranks to fire. After starting the engine I idled it up to about 1200 rpm for a minute then I popped the hood to check the washer fluid. As I was closing the hood, I smelled diesel. Got my flashlight and looked under the truck. There was a puddle of fresh diesel under the truck about a foot in diameter. I looked at the injector pump and fuel appeared to have come from the lower backside of the pump (facing engine block) I shined the light down the back of the pump and revved the engine a bit. I could see a very light little spray of fuel, but I could not tell where it was coming from. I figured I'd just warm the engine a little bit and see if it continued to leak. I checked after another 5 minutes and there was no more fuel leaking. Decided to drive it home, highway driving, about 30 miles. I checked for leaks when I got home and there still was no more dripping fuel. Revved the engine to 2500rpm for about a minute, still no leak again. The pump has never leaked like this before. I searched around and found some posts that suggest the o-ring on the cover plate for the KSB mechanism or a shaft seal could be the culprit. But the thing that's got me worried is this sudden occurence. I will be taking the truck in to have things looked at and possibly the pump pulled this saturday. Any advice would be much appreciated.



Sean

 

[R.E. Miller]

Formula,

There is a cup type plug on the back of you pump that can leak like this. We had a truck com into work like this, all we did was pull off the pump, take it to the pump shop, had the plug re-done, and had the pump checked out, reinstalled it and no more leaking. Hope this helps out, and it could be something else, but that plug in the back is the common one.



Russell

 

[BushWakr - RIP]

There is a cover plate on the back side of the pump, facing the engine. It is oval shaped and has an o-ring seal under it.

It can fail and cause a leak. It is also possible that the failure MAY be due to weak seal and higher internal pump pressure forcing it to fail due to cold weather. The cold will cause the KSB solenoid to engage... this will basically double the internal pump pressure while the engine warms up enough to de-activate the KSB.

Once the engine gets warm enough the KSB shuts off, pump pressure returns to normal and the leak stops.



Now, this is just a guess based on my limited knowledge and, your symptoms, but it may be the problem.

I have also seen a post by a pretty knowledgable guy that excess internal pressure can actually cause the oval plate itself to warp, causing a leak.

The only solution to either of these is to remove the pump and have it repaired.



Bob

 

[jbolt]

I was thinking the same thing about the KSB and the higher internal pressure (was reading my manual last night )



Jumper the KSB straight to the fuel solenoid and see if it leaks. Then go find it... GRRRRRRRR!



Good luck



Jay

 

[wraney]

my pump started leaking this morning also. real steady stream from back of pump on engine side 180,000 miles ksb? cause this maybe.











thanks,wade

 

[nascar mark]

Originally posted by BushWakr



The only solution to either of these is to remove the pump and have it repaired.



Bob

Bob is 100% correct.

 

[formula]

Thanks all for the replies

I'm aware that the pump will have to be pulled to effect any repairs to this leak. A good time to get a proper timing adjustment also.

An update on the leak: It appears that the leak is linked to temperature. It did not leak this morning when it was about 0 deg and the truck was plugged in. This afternoon was about 15 deg, truck not plugged in (at the commuter lot). Started up and got a drip-drip-drip for about 1 minute then it stopped. I "flogged it forthrightly" on the way home, no leaks, no power loss. Must be an old seal that doesn't like the cold. Anyhow, it'll be taken care of soon.



Sean

 

[JLEONARD]

Sean,

It could be that the extreme cold is causing a seal to shrink... .

cold has this effect on many parts..... of. . uh... the truck



Hope it's an easy fix.

Jay

 

[formula]

Originally posted by JLEONARD

cold has this effect on many parts..... of. . uh... the truck

:-laf



Until I get things checked out, I disconnected the KSB wire to keep the internal pump pressure down.



Sean

 

[BushWakr - RIP]

Hmmmm... . you know, I think we should start a new thread for the technological terms..... and the top of the list will be... ... ... .



. . " Flogged it Forthrightly"... . :-laf :-laf :-laf



Bob.

 

[RGT]

I was wondering about disconnecting the KSB, it seems to only effect low rpm timing(which should not be a problem for Formula) when cold, looking in the manual the only side effect might be smokier cold operation, which I guess might be a problem long term with oil contamination/cylinder wear especially if the truck was not run long enough at operating temp after(read "flogged forthrightly")..... my old VW rabbit diesel had a pull out for changing the timing( I'm not sure if it was supposed to advance or retard) during cold start/operation and I could never discern any differrence in cranking feel/sound or running feel/sound/smoke. I lived in Maine a couple of winters, no garage or plug in and could always get it started but spent a lot of time cranking and analyzing the situation. I will be interested to hear how you make out with it disconnected...

 

[formula]

FIF



The truck started fine today without the KSB, not plugged in and about 10 deg outside temp. Still got some fuel dripping from the pump for about a minute again. The KSB has the effect of raising the internal pump pressure (2 to 3 times normal operating pressure) to advance injection timing. As rpms go up, the effect of the KSB becomes minimised.



Something I have been thinking about... ... since I (and many others) have already advanced the timing, why bother using the KSB anyway? Is it known how much advance the KSB provides? (in terms of degrees)



Sean

 

[BushWakr - RIP]

The normal internal pressure with a warm engine is about 4 bar, or roughly 58psi. When the engine is cold and the KSB engages, it basically doubles the internal pressure to 8 bar or 116 psi.

The KSB can be pulled out of the circuit if you want, but personally I'd continue to use it. Since we are tweaking pumps, and putting in bigger injectors, the KSB is even more appropriate in my opinion. With out it, on a stock truck you'll have rough idle, white/blue smoke until the engine warms up. With tweaked pump and bigger nozzles the picture can get ugly if you have some really cold weather. You may also start to experience cyclinder wash down too, and that is not good since it contaminates oil, and soots up the injectors and vavles.



Bob.

 

[JLEONARD]

Sounds like it's worth an experiment to me.

Sean, I think you should give it a go especially during the next few days when it's still supposed to be bitterly cold here in the northeast.





Jay