ol_granns

Hey y'all,

My swap '04 6.0 LS in a 1990 Nissan Hardbody died on the way home today. Can you help me figure out what I should try and replace?

I recently drove across country in it and it handled itself fine. On the last couple days, the engine would "hiccup" and not fire for a cycle or so. It might do that a couple times, before running fine for a while longer.

After my trip, every time I would start it for the day, the truck would stall out. I would pop-start it with my momentum and it might stall once more, but it would run fine for the rest of the day.

On my way home today, it would get into stalling fits, I would pull over, let it sit for 5 minutes, then keep going. About 10 miles later, it died for the last time. If I tried to start it, I get a ~300 rpm sputter that is definitely not firing on all cylinders and has big black clouds of exhaust. Some times it doesn't fire at all and the starter is just spinning the engine.

Could it be coils or injectors? I will try and scan for codes tomorrow.

Edit: It seems like it was the old coils crapping out after the engine got to temp. If you don't hear further, replacing the coils was the solution!

G Atsma

I would check each and every connection for bad pins or shorts. Also check all grounds.....
If you can move a connection, it is too loose, Lautrec....

pcguy

Sounds like there may be more than one contributing factor. Like in addition to a bad/loose connection you could also have a clogged fuel filter, or???

G Atsma

I agree with this, though the intervals between "stallings" seemed long. But I would check into that too.

ol_granns

I'll order a new fuel filter and check grounds and connectors. Could a failing CPS and/or CPS also cause this? The Cam PS is new, but I never replaced the crank sensor.

pcguy

Just re-read this and it may just be the fuel filter. Where is the fuel pump? And is the filter external to the fuel tank? If so, remove the fuel filter and blow through it (wipe it clean and dry or put a piece of clean hose on it). It it has any resistance to air flow, that is likely the whole thing...

ol_granns

I swapped the stock LS fuel pump into the tank. I have a 100 micron filter in line filter followed by the 10 micron filter/regulator on the firewall. I'll rent a fuel pressure checker when I go back today to make sure the fuel pump didn't kick the bucket.

B52bombardier1

Will it run at least a little while on starting fluid? I don't like to recommend starting fluid because it is tough on the cylinder wall oil film but it is a useful diagnostic test point in situations like this.

What do the spark plugs look like?

Rick

01CamaroSSTx

iTrader: (3)

Check for any bad connections and make sure the fuel pump is working and you have correct fuel pressure.

True story,

After an engine swap in the Tahoe I went to start it and all it did was turn over so I then hooked up my code reader and got a code for no crank signal. The donor engine's was bad so I swapped it with my original and it started right up and was running great without issue. We ended up driving into Houston and on our way back home we hit one of their infamous potholes and the damn thing started acting up and then stalled out leaving us stranded on the side of the freeway where my wife started freaking out and now thanks to me we're stranded.. Being that this is a drive by wire setup I wiggled the bulk connector at the throttle body hoping that was it but it was just turning over and no start so then I traced the harness down to the ground wire that's bolted to the top of the block just behind the intake manifold and found that it was only hand tight and that I forgot to tighten it.. It was a happy ending though because I was able to tighten it enough by hand to get us home and instead of being by the Mrs. I get the

ol_granns

Went back to the truck today and did a couple tests. There are no new codes other than P0107 (low MAP signal) and I've had this code for months. The fuel pressure was slow to reach 58 psi from 0, so I tried starting it to see if fuel pressure held.

It started right up and idled fine. I revved it through the range and it stayed at 58 PSI and it would only dip 2 psi if I stabbed the throttle.

I hit the road and it started stalling again. I got it down the road two miles later before it wouldn't restart anymore. Fuel pressure was still at 58 PSI when I tried to start it again.

I pulled 2 plugs from each bank. Do they normally have hot spots on one side of the porcelain?


Hotspots showing under electrode


Three flipped over. Bottom right still showing hotspot

Here's a video of the spark from a few weeks ago. Sorry for the blog post lol. Does it look weak? I forgot to try starter fluid after our nice evening drive together, but I can try tomorrow.

Do you think it could be heat degradation killing the old coils after reaching temperature?

B52bombardier1

No need for the starting fluid now - it runs with good fuel pressure. And your spark plugs look OK to me. As suggested above, I think you have a connection / ground / PCM power problem. Or maybe, though low probability, a bad PCM. With as inexpensively as a replacement PCM can be acquired and programmed these days - think "LS Droid / PCM Hammer / Tuner Pro RT" - its good to keep a known good functional spare on the shelf.

Rick

Old Buzzard

Start it, & take a screw driver, and lightly rap on the MAF sensor, with the handle end.
Stumble? Quit?

dw456post

Since you have a MAP code showing---Do you have any splices in the map wires? I had an intermittent problem like that and it was a crimp fitting in the map wiring. I cut the crimps out and soldered the connections, never had the problem again. I guess that could be the case for any crimps that you have.

ol_granns

Thanks for the comments everyone. I replaced the coil packs this morning and it had no issue driving the rest of the way home.

I'm not 100% convinced that isn't a false positive lol. I will check the MAF and MAP next time as I've had problems with both.

G Atsma

I would hook up the old coils again to see if the returns. If NOT, it was a bad connection....