Hi all,
Sorry for the lengthy post but it covers a lot. I have a 5.7GI-300-J (2008 with EGC computer, 300 hrs) that has been running horribly since putting in the water this spring. Last year it was running perfect after new fuel pump/filter/pressure reg. and distributor cap/rotor. Winterized it and then put back into water in April. This spring did some other routine maintenance including taking exhaust risers/manifolds off to check for clogs or riser thinning, as well as changing raw water pump and some pulleys that were corroded. Getting a mechanic to look at it is taking weeks so I tried to resolve myself.
Symptoms: running rich (strong smell of gas in exhaust), rough/unstable/low idle, plugs fouled with soot (especially on left side cylinders 1-3-5-7), low power when driving, left side exhaust riser doesn't get hot unless really revved (unlike right side), and even then only warm
During troubleshooting, I recognized that I could pull injector connectors or plug wires off any of the left side cylinders and it wouldn't affect the poor idle. In contrast, doing so on the right side cylinders would cause worse idle and lower speed. Clearly the left side is not really firing.
What I have done after searching online based on symptoms:
Root cause seems to be left side not getting correct spark/fuel timing. At this point, I suspect could be a computer problem (injector pulse width or spark firing at wrong times?) As it is EGC, I can't get a reman'd one easily so swapping/replacing it is last resort.
Or maybe issue with distributor. I have read many threads that these flat top distributors have critical alignment issues but not sure if that would cause these symptoms.
Diacom software says cam retard is 11.5* to 12.5*. Does anyone know what is correct number? I only have engine manual for engines through 5.7GI-E, and it states Ignition timing is 10* BTDC. Is this same as cam retard reported by Diacom? It also says spark advance goes from 10* to 30* as I rev from 1200rpm to 3000rpm.
I am at my wit's end. Any thoughts or suggestions? Thanks!
Sorry for the lengthy post but it covers a lot. I have a 5.7GI-300-J (2008 with EGC computer, 300 hrs) that has been running horribly since putting in the water this spring. Last year it was running perfect after new fuel pump/filter/pressure reg. and distributor cap/rotor. Winterized it and then put back into water in April. This spring did some other routine maintenance including taking exhaust risers/manifolds off to check for clogs or riser thinning, as well as changing raw water pump and some pulleys that were corroded. Getting a mechanic to look at it is taking weeks so I tried to resolve myself.
Symptoms: running rich (strong smell of gas in exhaust), rough/unstable/low idle, plugs fouled with soot (especially on left side cylinders 1-3-5-7), low power when driving, left side exhaust riser doesn't get hot unless really revved (unlike right side), and even then only warm
During troubleshooting, I recognized that I could pull injector connectors or plug wires off any of the left side cylinders and it wouldn't affect the poor idle. In contrast, doing so on the right side cylinders would cause worse idle and lower speed. Clearly the left side is not really firing.
What I have done after searching online based on symptoms:
- checked wiring and connections incl. sensors for any breakage or disconnects
- fed a container of new gas into the fuel pump to make sure it's not gas quality/water. Also dumped out fuel filter and no water seen.
- measured or verified for correct fuel pressure and no leakdown, correct plug wire order, signal present at each injector using noid light, spark at each cylinder, ok cylinder compression (all similar about 160)
- verified no fuel leaking from fuel pump vent chamber to manifold (heard this could cause rich running
- verified left side plugs are heavily sooted but not wet
- changed ignition coil/module, IAC, MAP/T, plug wires, and changed dist cap again
- had fuel injectors tested and ultrasonically cleaned (all were at spec before and after cleaning)
Root cause seems to be left side not getting correct spark/fuel timing. At this point, I suspect could be a computer problem (injector pulse width or spark firing at wrong times?) As it is EGC, I can't get a reman'd one easily so swapping/replacing it is last resort.
Or maybe issue with distributor. I have read many threads that these flat top distributors have critical alignment issues but not sure if that would cause these symptoms.
Diacom software says cam retard is 11.5* to 12.5*. Does anyone know what is correct number? I only have engine manual for engines through 5.7GI-E, and it states Ignition timing is 10* BTDC. Is this same as cam retard reported by Diacom? It also says spark advance goes from 10* to 30* as I rev from 1200rpm to 3000rpm.
I am at my wit's end. Any thoughts or suggestions? Thanks!