inj. pump leak
 

Hi everyone, the pump I put on started leaking, between the square body( in the back of the pump where the injector lines attach)and the main body of the pump. It only leaks when I shut the engine off. Is this an easy fix ? Can the O ring be changed with pump left in the truck? What causes this to leak?, my old pump leaked same place.Would a restricted return line cause this?Any help is highly appreciated. Does the pressure modulation valve wire have power all the time the engine is running? I don't have it hooked up at all now Thanks:argh:

give us some info on your truck. mainly, the year model.

the "pressure valve" you're referring to is the KSB which is a timing advance. mostly a cold starting aid and also advances the timing under high RPM situations. the '89-'91 non intercooled motors have a wax motor which actuates the internal advance piston. when power (12v) is applied to the "solenoid", it is inactive. when no power is present, the motor will actuate the advance piston. thus, advancing the timing. the '91.5-'93 intercooled motors are the exact opposite and use a standard solenoid to actuate the internal advance piston. when power (12v) is applied to the solenoid, it actuates the advance piston. thus, advancing the timing. when no power is present, the solenoid is inactive and timing reverts back to what it was. a word of advice if you place to run a jumper wire or a toggle switch to either style KSB, you do not want to run advanced timing at all times. however, it works fine for drag racing or dyno runs.

the leak you describe is usually caused by old/bad o-rings. most all the leaks will be caused by that. i believe you can swap the o-ring without removing the pump but don't quote me on that. i saw a thread recently on dieseltruckresource.com (DTR) and one of the gurus there made mention of just that task. i'll see if i can find it for you and relay the information.

i don't know if your right mine is hot all the time, doesn't matter if the engine is up to temp or not, if it's at idel or wot. i thought it was bad so i did some testing a wile back checked it cold checked with the engine hot at idel and wot it was hot all the time.
and if your talking about the gasget inbetween the top half and the bottem half it can be replaced with the pump on the truck, thats what you take off to swap in your 366 spring.

theres twp different styles of ksb,but i dont know if dodge used both.One has power till warm the other waits till coolant temps are up to shut off

Thanks for your help. The o-ring I am talking about is between what is called the hydraulic head(the block that the shut down solenoid screws into) and the main pump body. This is in a 99 F-350 with a 89 cummins. Where can I buy a seal kit for this pump? Thanks again, Al:argh:

early non-intercooled ('89 model) engines reference coolant temp to determine when to advance (no power). i don't know at what temp it would energize and retard timing to what it was prior. '90-'93 model engines reference intake air temp.

any fuel injection shop should have the rebuild kit you'll need. P/N: DGK-121. should only run you about $16. according to your sig, a factory non intercooled '90, it runs the KSB with the wax motor type solenoid. when it's cold, below 90deg. (i think) intake air temp, there should be no power to it. when it warms to 90 and above, it should then have 12v power to retard timing. however, if you're saying yours is hot all the time, it may be that you have a factory intercooled motor. cuz when the intercooled KSB's are cold, they would have power to them to advance and when proper intake air temp is reached, i think 90deg as well, it shouldn't have any power to it which would then retard the timing. the non-intercooled KSB's (wax motor type solenoid) actually take a few mins to change "modes" where as the intercooled KSB's are pretty much instant. what's the date of manufacturing on the engine ID tag?

that sounds correct, but i believe it is 64* F though not 90*

90* is only what i've heard from others. that's why i used keywords like "think" haha

10-89

you should have a non-intercooled KSB with a wax motor. so the reason you're seeing a 12v signal, WOT or running at normal operating temps, is because it's no longer cold enough to need the timing advanced.