replaced batteries now engine cranks but doesn't fire

[tomking]

I replace my batteries because they would not start the engine and would not take a charge. Now the engine cranks over like new but won't start. I know there are several threads on this but I can't seem to find them. I would appreciate if anyone could supply links to the existing threads. My truck is an 02 2500HD with the 6.6 duramax. Thanks in advance for any assistance.

[DmaxMaverick]

Just for the heck of it, pump up the filter primer and give it a try. If that does nothing......

The previous no-start cranking episodes may have confused the computer. Try cycling the key slowly a dozen or so times (no crank). If that doesn't work, disconnect BOTH Batt+ terminals and ground one of them for 20-30 minutes. This will reset the computer to default (and clear any codes). That should work, but if it doesn't, it probably has an issue with the security system, and may need a Tech II for a reset.

The next time you replace both batteries, replace only one at a time (weakest first, if you know which), or use a jump battery to keep the system powered. Even one of those cigar lighter battery thingies (Harbor Freight?) is enough juice to keep the computer happy during the replacement (this works on earlier models, but some later models have key switched power outlets).

[Kennedy]

Sometimes the VATS gets tripped up and sometimes it seems the ECM's can get confused/corrupted somehow. The Delphi units in the LB7 and LLY can be pretty fragile.

Like Mav said start with the hand pump to be sure it isn't just a loss of prime.

[tomking]

Thanks Guys,
I did the fuel pump thing so I don't think its fuel. Tried the key on and off with no luck. I am in the process of resetting by grounding one of the POS battery cables. Will let you know how it works out

[Kennedy]

Be sure that both negatives are removed from the batteries.

You could try a manual theft deterrent learn.

Attempt to start-no start leave key in run position a full 10 minutes.

Turn key off 30 seconds

Repeat 3 times.

If that does not work you could send me the ECM and I can see what I can figure out, but in some cases they are toast.

[DmaxMaverick]

Be sure that both negatives are removed from the batteries......

If both positive cables are removed from the batteries, the ground cables don't have to be removed (2 cables removed, and no additional equipment/tools required). The objective it to ground the Batt+ cable without shorting the batteries. I suggest removing both + cables because it's just more simple. If the ground cables are removed, you'll either have to remove a Batt+ cable to ground it (3 cables removed), or use a jumper from ground to a Batt+ cable (requires an additional grounding device or cable).

[Kennedy]

I'm old school in that both negatives get removed first. I've just seen a lot of ECM's smoked due to improper handling of cables and arcing out.

I'll hot swap an ECM no problem, but both negatives come off to do anything major.

[EdHale]

I always remove the passenger side battery to replace the fuel filter (easier for me than working around the tire), but I always have a strip of electrical tape already torn off to tape up the terminal end while working.

[tomking]

Ok so I removed the pos+ battery cables from the battery and left the Neg- ends attached. Grounded 1 pos cable to ground using a jumper cable. Waited 30 min and then reconnected everything. Still won't start. Had it towed to the dealer. Turns out the system would not recognize the key so anti-theft prevented starting. They reset and relearned and now all is running like normal. The only issue left is my remote start fob won't lock the doors. It does everything else, start, unlock but no lock. Dealer says I need to go back to the company that installed the remote. Guess I will be headed there next.

Anyway thanks for all the ideas and quick responses.
Tom

[Kennedy]

Had it towed to the dealer. Turns out the system would not recognize the key so anti-theft prevented starting. They reset and relearned and now all is running like normal. The only issue left is my remote start fob won't lock the doors. It does everything else, start, unlock but no lock. Dealer says I need to go back to the company that installed the remote. Guess I will be headed there next.

Anyway thanks for all the ideas and quick responses.
Tom

That is what the free procedure that I outlined does:




You could try a manual theft deterrent learn.

Attempt to start-no start leave key in run position a full 10 minutes.

Turn key off 30 seconds

Repeat 3 times.

If that does not work you could send me the ECM and I can see what I can figure out, but in some cases they are toast.