AllDodge

iTrader: (1)

Being a MEFI 1 if the knock senor is being triggered you can pull the plug off the sensor and see if your rpms increase. If it does increase then stop, put the sensor back on and go slowly back to the dock and get the motor re-timed

debcod2

[QUOTE=Not Today;4498209]Thanks for the comments. Yes I did send out the injectors as part of the rebuild process for flow testing and cleaning. They all passed the flow testing after being cleaned up. It is possible something in the VST tank is restricting the fuel flow and not providing full pressure to the rail. I will check that, and better yet, I plan to run an in line fuel pump and trash the VST system and mechanical lift pump all together. I winterized the boat yesterday so this is all stuff I will need to look at in the spring. Could I have potentially detonated the engine and melted a hole in the piston? I'm nervous about this. The timing can't be retarded back to 8 degrees the way it is now. There is no more movement in the distributor. I will need to pull the distributor out and move it a tooth and then re

I Had a similar issue a while back but ours wouldn't get above 3500 rpms. Turned out to be a bunch of crap in the VST screen. cleaned everything out put it back together and she ran like a raped ape again.
Might be worth a shot to check out on yours as well.

Not Today

I'd be afraid to unplug it and try increasing rpms because it could be saving the engine from detonation.

SB

iTrader: (1)

I agree. That's why running with a scanner to see knock counts would be much wiser.

camptappakeg69

Did you put the ecm in base timing mode before trying to adjust timing?

Not Today

Yes - I had my mechanic that set the timing use a scan tool and put it in base timing mode.

getrdunn

iTrader: (7)

Makes ya wonder how we got by so many years and still going without knock sensors. You'll be fine. You just need to start the whole process of elimination deal with the simplest first. If it makes you sleep better pull your plugs and ck piston tops and cylinder walls with a bore scope. If you don't have one borrow one or buy one. They are a must in any tool box regardless.

DINOKOS

Hello, i have a 1999 sonic 260 with a 502 mpi and had the same exact problem. The fix was so simple but could be overlooked very easily. It turned out to be the vacuum line from the engine to the fuel pressure regulator. The vacuum line looked good but when i was doing my fuel pressre and vacuum tests i noticed the vacuum line collapsing trapping vacuum in the line to the fuel press regulator thus thinking its in a low power rpm.it was never opening up at w.o.t to let more fuel pressure to the the injectors. I had also had a merc scanner and there was no codes or faults. If you want to confirm, just pull the vacuum line off and go w.o.t to see if it fix's the problem.i did ck all the other obvious items first like fuel anti siphon ck vlv,plugs,cap, rotor, wires, i changed the vacuum line and the boat is running great again!!!!!!!!!!!!!!!!!!!! Hope this helps, dinokos