Injection Pump dying? / H20 in fuel?

[65-f100]

OK guys - need some help. 96 K2500 Suburban. Bought a few years ago with approx. 175K - now has about 205K. Recently replaced injectors, lift pump, OPS, glow plugs, Heath upgraded ECU. (All about 3 months ago). Previously also relocated PMD. It has been running better than ever until now. About 2 weeks ago it started stumbling, spitting, sputtering etc. intermittently. Shut off completely a couple of times. Would restart easily and continue. I thought I may have H20 in the fuel since I had refilled at a small station that I do not usually use (Real low on fuel - no choice). The symptoms started after about 1/2 tank was used. Suspecting H20 - I drained the filter with the engine running and it seemed to clear up for a while. When it acted up again the next day - I topped off with good fuel and it immediately started running better. Drove it at least a week with no problems. Then it started again - now becoming harder to restart after it shuts off. This was after about 1/4 tank of fuel. Used a double dose of Diesel Kleen since it supposed to help with H20. Then topped off again with good fuel. Drove again another 20 miles with no issues. Then it goes down hill. Time period between shut offs is now much shorter and restarting has gotten harder. After speaking with Heath - drained a fuel sample from the filter housing to look for H20 - none visible - looks very clear. Last night I replaced fuel filter and cleaned filter housing - a little gunk in the bottom but not bad. After bleeding the air - restarted- ran ok. Drove around the neighborhhod - hesitated once but did not die. After approx. 5 minutes idling the shop - it dies again. I have no Water in Fuel light - I have no trouble codes. I do not know the age of the IP. What is the best way to test for a weak or dying Pump? Any other ideas?

[JohnC]

Look for the stalling thread at the top of this forum.

[65-f100]

John - I have read most of that thread before but it relates much more to the PMD. As mentioned in my post - I relocated mine using the Heath kit and installed a new PMD at the same time. The symptoms I'm experiencing now are not the same as the PMD. With the PMD - my truck would just cutoff suddenly, but would immediately restart. Most of the time - I just threw it in neutral on the fly - restarted and kept going. The symptoms now are more stumbling, sputtering and much harder restarts.

[Hubert]

From reading a dying DS pump should output some codes. And have some other symptoms more smoke, weak on power, or run away with no throttle input.

Intermittent problems are tough.

1. Clean battery connections really good. Note between passenger side positive cables. Clean grounds really good too. Really take them apart and clean and tighten things up even if they look good. Maybe add another ground to rear node by tranny dipstick.

2. Could still be FSD or electronics. Even new parts can be suspect quickly on an older truck. Now that its 10 yrs old wiring may have degraded. Clean fuse block with contact cleaner and look for any corrosion.

3. Heavy dose some FPPF 8+ and some Stanadyne performance formula. Power service is OK but the other two work better for me. I am usually not brand loyal for chemicals/oil but for me power service increased smoke and did not perform as well. It is however good maintenance to add a little every so often of most any fuel additive. If it was bad fuel it might take a few tanks to get out.

[65-f100]

Hubert - thanks for the input. I can certainly try the things you listed just to make sure. I have not added an extra ground at this point, but certainly can.
(1) Do you run one from the block to the firewall? What other ground connections should I be looking for other than the (-) batt cables?

(2) Could be the FSD, but it is acting different than when it failed before

(3) Where are you getting your chemicals from? Did not realize it would take that long to get the bad fuel out.

(4) What part of SC are you in?

[Hubert]

1) I bought two of those dual connection side post bolts. I added a second ground battery cable directly to the ground node by the tranny dipstick. Also clean the wire where it bolts to the hood. On drivers side I ran a second to the fender.

2) Good luck on diagnosis of FSD they fail all kinds of ways. Not saying yours is dying buy it might die differently now that its remote mount. Unfortunately still no way to test it easy.

3) I get chemicals from mail order or from a diesel injection shop in Greenville. I think there is a Stanadyne shop in Columbia too. If it means anything I figure if a diesel shop carries it its probably better stuff. Sometimes the truck stops have the FPPF but not all the varieties.

4) I use to live in Blythewood, north of Columbia - and still pass through every so often. I now live in Anderson.

[tommac95]

65F100-

Since the FSD and fuel issues can cause similar symptoms ... and since both new FSDs and LPs have been known to fail within months , proceed orderly, with good record-keeping.

LP and FSD both depend on Ig switch for power. Dirt in fuel can lodge in LP valves , causing fuel output to fall off. OPS points can fry, esp in hot operation idling ; LP not designed for sucking air . Consider pressure and delivery test for fuel LP output, maybe volts at LP if any doubts.

>>After approx. 5 minutes idling the shop - it dies again.
I've had this when trying to run bad fuel . A new filter + bleeding rectifies.

If you can run engine while draining filter , LP seems good. If you don't bleed filter of air (top port) after draining water (bottom port) , you may be running with only a little fuel in the bottom of the filter housing, thus limiting filtering capacity.
t m.