'01 Dmax getting harder to start

[chessy56]

'01 K2500HD w/6.6 Dmax. 115,000 miles. original injectors.

It seems my Dmax is getting harder to start. Started noticing this in late Dec last year ('07). Engine used to start in 3 seconds or so even if fairly cold outside; if warm (or if engine was plugged in over night), 2-3 seconds cranking before it would start.

Now it appears to take up to 6 seconds of cranking for the engine to start if the engine has sat for several hours (even with the engine plugged in over night or, after the glow plugs have cycled). If the engine has been run for a while and shut off for less than an hour, 3-4 seconds of cranking is needed. I did have a problem late December where the engine appeared to start normally after about 2-3 seconds of cranking (after sitting for ~8 hours @ mid 20s temperature), but quit after running ~15 seconds. Had to crank the engine nearly 30 seconds before the engine was able to be restarted.

No SES indicator appears and the local dealer tech saw no codes set in the ECM. I changed the fuel filter 1st week of Jan '08 with no improvement in starting. Not seeing any signs of leakage from the top side (filter, fuel rail, injector lines, etc). I'm getting my fuel from a local truck stop; it's the new ultra low sulfur fuel.

Any hints? Fuel pump slow to develop pressure? Injectors failing? Would appreciate any help. It's taking at least twice as long to crank/start my engine than it used to. Thanks a bunch.

Chessy56
S. Milw, WI

[Duramaster]

Regardless of the current temperature that you are experiencing right now, it sounds like the injuectors are failing. The way to verify this is to watch the fuel pressure while cranking the engine over. The engine needs at least 1500 PSI to start. If the engine does not build enough fuel pressure rapidly enough, it will have an extended crank. :(

[DickWells]

:)You didn't say how much mileage on the injecters. My 04 had 78K on it when I had to have new ones. My only issue was a lot of smoke at idle when the engine was warm. Cost was 0000.00 $!
If it is your injecters, I hope you don't have more than 7 years on your truck. The (special) warrantee is 200K or 7 years. You won't even have to pay the $100 deductable. If a dealer gives you a hard time and you're within those limits, go to someone else. I bought my truck, used, in Texas, Vermont is my State of residence, and had the injecters changed in Washington. Not one question of non-elligability, even when I told them that I had the Edge Juice W/monitor.
Best of luck,
Dick Wells:)

[chessy56]

I forgot to include an additional symptom which may or may not be related to my hard starting. Lately, I've begun to notice my engine surging at idle. Sometimes the surging is very faint (can hear it, but it's not seen on the tach). Other times, it's more noticable and actually shows on the tach. The engine idles at ~600-650. The engine doesn't always surge; it comes and goes. Can this play into a drop in fuel pressure?

[Mark Rinker]

Surge at idle is the fuel pressure regulator. This could also be related to your hard start issue.

[chessy56]

Don't know if this helps, but I've got further information. I have access to a Tech 2 monitor (I work for Delco in Oak Creek, WI; we made my '01 Isuzu engine controller here). I started my truck at lunch and had to crank for ~5 seconds after the glow plugs cycled. I logged ~100 frames of engine data and noted the following:
* fuel rail pressure varied at idle between 5200 and 6800 psi.
* engine rpms ranged from 676 to 703 (could heard some surging, but very mild).
* FRP Regulator fuel flow ranged from 1730 to 0 cubic mm (if stepping through all of the logged data frames, I saw an occasional frame with 0 or some reading in the lower 400 range, while most other frames logged something close to 1700. Indicative of a bad flow sensor or just lost data in the ECM???).
* Fuel regulator current draw appeared steady at around 1.4 - 1.5amp.

Does this help any? Is there other data that would be of importance? I watched the fuel rail pressure while I was cranking and it appeared to pop up towards 5000+ psi. Is my extended crank requirement beginning to sound more like injectors? Just changed my oil 2 days ago- no fuel in the oil and no signs of smoke from the tail pipe.

Please advise if there is other engine data you would like for me to capture. Thanks again for your help!

[Mark Rinker]

Its over my head, but hopefully one of our GM techs will chime in. I'm just a farm kid that knows the idle surge is indicative of an FPR.

As for capturing frames - isn't that a bowling term? ;)

[Duramaster]

Addredd the injectord first. Then the regulator. Actually, there is software that addresses the surge condition for the 2001 trucks and possibly the 2002. Anyway, there was a ton of software updates for the 2001 DMAX's. Software won't fix the hard start condition in any case.

As far as the snapshot data goes. If you have access to TIS2WEB, you can upload the data and map it out on a spread sheet. It makes a pretty cool graphic representation of how the engine is actually running compared to what the ECM is actually commanding.:D