PDA

View Full Version : 2006 5.7 Vortec PO300 troubleshooting.



nevinsb
April 23rd, 2024, 11:30 AM
I have a 2006 Chevy 3500 van with the Vortec 5700 that died. The place they towed it to replaced coils, plugs, MAF and O2 sensors. Now it starts immediately, has a P0300, and shakes/runs horrible from idle through upper RPM. Coolant and oil levels were normal. In/out of gear made no difference.

Is someone able to page through this log file to see if there is anything obvious that was missed? It will be quite a road trip for me to go look at.

In-Tech
April 23rd, 2024, 12:18 PM
Hiya,
I can't remember if the vans still had a distributor or if they were coil near plug.
If distributor/wires they have the firing order wrong(probably old sbc), the new stuff is LS1 firing order.

Ignition Firing Order For Misfire Detection

Sequence Cylinder #
7th 4
8th 3
1st 1
2nd 8
3rd 7
4th 2
5th 6
6th 5

Well shoot, I just looked up a 2003 Express van 5.7L and it still uses the standard firing order(18436572) vs the LS1 firing order(18726543). Either way, if it is using the "crab cap" cam sensor distributor, it's very easy to have wires mixed up, you have to pay close attention to the terminal vs wire and not just location like the old days.

nevinsb
April 23rd, 2024, 12:54 PM
Coil near plug (No distributor). It's basically an LS motor with a cast iron block.

In-Tech
April 23rd, 2024, 01:13 PM
If you get a chance, post a pic of those valve covers with the coils. I'm curious how they look.

ScarabEpic22
April 24th, 2024, 04:23 AM
Ok so it's either a 5.3 or 6.0 if it's LS based in a van, the only 5.7s in vans were a SBC and stopped after 2002/2003ish (in the US/Canada, other markets like Mexico had the SBC for a few more years).

I looked at the log, it ends right as the van gets near normal operating temp. The idle spark is jumping around a decent amount and STFTs are negative, but both STFTs and O2 mV swings look semi normal.

How did it die originally? Has a compression and/or leakdown test been done? Wondering if there's physical damage.