Mechanical pump change

[HH]

I have been having problem with a hot start issue with my 1993 - mechanical IP, over 120,000 on pump, about 100,000 on marine injectors. I found a used pump to install, and installed it last weekend. Pump had about 40,000 miles. Trusted source. He blew up engine he bought from that outfit in NY, #1 cylinder rod came loose. Pump looks very clean.

I got the truck started, but it appeared to produce alot of white smoke. Drove it for about 10 miles and it did not clear up. I checked and tighten all hose clamps. Still would not clear and run smooth. I let the truck sit a few hours, 3 - 4. After sitting, it will not start. Used some WD40 and fired right up and kept running, but smokey, whitish in color, and a little rough. It also would produce a large cloud of black smoke when stomping the pedal. All lines hooked up right. Next step I moved the pump timing about 1 -2 line widths to the passenger side, still did not run or clear up.

Put old pump back on and truck runs fine, except I still have hot start issue. White smoke cleared in a matter of minutes.

I talked to the person who I got the pump from and he indicated that the pump was "turned up" slightly and they had to advance the pump to get his truck to run right and start quickly. Hesitant to advance timing more.

What can I do to bring this pump back to stock? Bring in for a rebuild? I am hesitant to put it back on the K3500 and waste another day. Could something have happened to this pump when he blew the engine?

As always, thanks for the help.

Hans H.

[DmaxMaverick]

Retarding the timing will only make the condition worse. Remember, the pump rotates opposite the crank. Try moving the pump the other way, about 1/16" at a time from the timing mark. Also, if the timing set has a lot of miles on it, it may require more timing advance to get the injection timing right.

A lot of black smoke revving at WOT may indicate the fuel volume screw has been adjusted by the PO. It will not effect starting or normal running, only WOT fuel volume. I suggest installing an EGT gage and watch for the black smoke under load to get a better picture of where it really is. Once "adjusted", it will take a trip to a Stanadyne shop to have it calibrated if you don't know, exactly, what the adjustment was from the original calibration (to provide the "correct" starting point for future adjustment). Most "adjustments" made by DIY'ers are done by the uninformed. It's easy to take the advice of someone (usually the dealership tech's, given just enough info about it to be dangerous) to just "turn up the pump". 1/8 turn is a lot, 1/4 turn is a whole lot. Most I know about (the DIY'ers) start at 1/4 turn...... which, of course, is wrong. Some have even removed the screw completely (intentional or by accident), which often leads to a WOT throttle lock at max pump volume (ouch).

[HH]

So I took the used pump in for what I thought would be a minor rebuild. They tell me it needs a new head. Current one is 20% below on cranking pressure. :( At least now I'll know what I have.

[Robyn]

Sounds like the used pump had a lot of issues.

Get it rebuilt and you should do fine.


Missy