2003 EFI PCM in 2003 SAN 210 running rough/restricted at 2000rpm after an hour

[damoandjed]

Hi guys,

Took the 2003 SAN 210 out couple days ago and it ran well for the first 50mins or so, then as I tried to pull on the next run the engine got to 1800-2000 rpm and it was running very roughly and wouldnt go any higher/harder. Oil, temp, voltage etc were all normal. Put the 'clutch' in and it got to 3500rpm fine, and ran smoothly. Engage the prop and once again ran rough. Seems to run ok in reverse (though didnt push it too much)... Any thoughts? Have replaced fuel filter, plugs, plug leads and its still happening. engine temp sits around 175. is this about right? if the engine has gone into 'limp mode', can the engine still rev higher in neutral? or is it restriced no matter ifs its in gear or not.

no warning lights or buzzers come on. engine has 420 hours on it.

any help would be appreciated as im fairly new to the pcm engine. (im in australia and nearest pcm dealer is 1800km away!). thanks

[crobi2]

Sounds slightly more like fuel than spark. If you have a fuel pressure tester, test the pressure at the fuel rail - since you already replaced the fuel filter it could possibly be a clogged antisiphon valve at the tank or even a bad fuel pump (high or low pressure one).

Probably has not gone into limp mode if big red light is not on.

Check your tranny fluid and v-drive oil. Check the driveline by spinning the prop by hand (when the cutless is wet).

Check that nothing is blocking the air intake. You might even check your compression. Check the spark while you've got the plugs out. Check under the distributor cap and clean it up some if needed.

I think a good first step though is to check your fuel pressure.

[ski4evr]

Had the same problem, turned out to be a bad distributor cap, was cross firing.

[damoandjed]

how did u diagnose bad distributor cap? ust replaced it and fixed the problem?

fuel pressure is good. all fluids are full. drive-line spins freely. flame arrestor is clean.

[ski4evr]

The cap was new, so I was pulling out my hair on the problem. Tried plugs, fuel filter, fuel pickup tube, fuel tank vent, prop, fuel additive, plug wires, and lots of beers, and all while on vacation sitting at the dock. Got home, and stuck a timing light on the plug wires looking to see a steady flash on each cylinder. Three of the cylinders were dancing around with very fast and intermittent flash. The other 5 were steady and flashing properly. Went to zone, got a cap and rotor for a 98 vortec 350 truck for 12 bucks and everything is fine. The cap that failed was a new pcm part. Hope it is something as simple for you.

[damoandjed]

thanks mate. have ordered a new cap/rotor kit and will see how this goes. not the easiest parts to get here in oz, though thankfully enough vortec engines made it across for some supplies to be found