Problems starting

[34 M]

I have a 03 duramax and when temperature gets down to around 0 to plus 1-2 I have to plug the block heater in. I have check glow plugs intake heater all good. Even when it is plug in all night the next day still strugles a little bit to start.

[More Power]

Is that 0 degrees C?

Always change your fuel filter as a first step whenever you experience an engine starting or running problem.

Assuming your glow & intake heater systems are operating normally, it might be worth a check of the actual & commanded fuel rail pressure while cranking (using a Tech II scan tool or Predator programmer).

Lastly, engine cranking speed affects startability. Is the engine cranking normally?

Jim

[34 M]

Yes it is Celcius. And filter had be replaced by GM on a recall. How senitive is the duramax to cranking rpm. I believe it may have slowed down a couple of rpm.

[More Power]

If you have noticed a reduction in cranking rpm, it's probably more than you think. To eliminate batteries as a possible cause of a lower cranking rpm, try jumping the batts from another vehicle during one of those times when you can tell whether a jump assist might help or not.

Faster cranking rpm helps the Bosch hi-pressure pump generate the required fuel rail pressure. Faster cranking speed also increases compression pressure - resulting in hotter compression temps, which aid cold starts.

Jim

[Kennedy]

The ECM will not begin delivering fuel until the system reaches 5,000psi or so. Cranking speed, filter condition/supply restriction, and injector return volume are key factors here. I'd first get the cranking speed figured out, but seeing it is a 2003, there's a good possibility that the injector return rates are getting high. It seems the 2003's were more prone to this.

[chrisinkanata]

How many miles are on it? Experienced the same symptoms last winter after two winters of flawless, but very loud cold starts. Changed both filters, tried an additional battery all that. In the end, 8 new injectors. After that, like new.

Chris

[34 M]

Chris my 03 has 61,012 miles. Just had my batterys load tested to day and they where done. So I pick up 2 new ones with 975 cold cranking amp in stead of the 770 waiting till mornning to see if it helps. What did 8 injectors cost you if you dont my me asking.

Derek

[VA_Dmax]

8 new injectors shouldn't cost you anything. I have a 2003 and had all 8 replaced under warranty because of the program GM had to replace defective injectors.

[ahg2005]

FYI my brother has a 2003 D/A with 34000 kms it was hard starting so he took it to the dealer and the replaced 8 injectors, that cured the hard starting.

[FrankA]

You should be able to take it in to your dealer and tell them you are having hard starting problems as this is one of the symptoms (as far as I know) of injecter problems. Good luck

[chrisinkanata]

Derek,

Sorry for the delay....out of town 'til last night. No charge for the injectors. Warranty. Huge bucks though if I had to pay. Don't know the flat rate for 8 of them, but the parts alone would be several grand.

Chris

[34 M]

Chris

They wold cost $4000 canadian plus labor. Thanks for your comments.

Derek

[Timstoy]

My 2003 with 59K has been an awesome truck. A few weeks ago it started to take longer and longer to start. No smoke or difference in performance, just more cranking time on the key every morning. It's in right now getting new injectors on warranty and I get it back tomorrow.The dealer had them in stock and almost got the truck back to me the same day. I'll post again during the week to let you know how it's running.
TH

[Timstoy]

I got my truck back yesterday and it starts and runs like new. The service writer reminded me that since the injectors have now been replaced, they have a lifetime warranty....
TH