IHScoutman14
06-22-2006, 07:17 PM
The 345 i rebuilt in the scout is having some slight problems and the BB hasnt been successfully answering my questions so i will ask here.
I rebuilt this motor over the winter and over the past few months have been trying to get it in good running condition with my chevy FI system (tbi of of early 90's truck ecm. 7747). I started a new job at a garage and got help from all of the guys there as well as letting them work on it for 4 or so hours "on the clock".
At this point it is running well not under load. There is an occasional backfire/pop w/o load and it the idle will waver between 500-800rpm, but doesnt die. It seems like when you try to hold the throttle still it will rev up then slowly drop the rpms back down.
under load snortin up a hill it will pop and crack every few seconds and send the scout bouncin along but never dies. once the road levels out its ok but you cant put your foot into it too hard.
whats been done you ask? well: base timing has been set, timing should be good, we spent a lot of time on the timing portion and all the guys working at the shop are experienced. We checked the magnetic pickup in relation to the rotor and set it correctly. We hooked up all of the sensors to their respective testers and they all checked out in working condition. I had a bent intake pushrod which we replaced, the intake valve was stuck open but we oiled it and cranked the engine and moved smoothly, ran the engine and did a leak down test and the valve was then working. Leak downed all of the cylinders and they all checked out ok.
What makes this situation so tricky as that im dealing with a non-professionally rebuilt engine and a FI system thats not designed for that motor. The chip ",ecm with fedeal emissions chip for 350ci". Now i know thats for a chevy so do you think this is what is causing my problems? It seems possible just because its unlikely the two motors have the same timing curve or whatever.
Let me know where i should start, what i might consider doing, and if i should just set my scout on fire and see if it runss better afterward.
thanks
charlie
I rebuilt this motor over the winter and over the past few months have been trying to get it in good running condition with my chevy FI system (tbi of of early 90's truck ecm. 7747). I started a new job at a garage and got help from all of the guys there as well as letting them work on it for 4 or so hours "on the clock".
At this point it is running well not under load. There is an occasional backfire/pop w/o load and it the idle will waver between 500-800rpm, but doesnt die. It seems like when you try to hold the throttle still it will rev up then slowly drop the rpms back down.
under load snortin up a hill it will pop and crack every few seconds and send the scout bouncin along but never dies. once the road levels out its ok but you cant put your foot into it too hard.
whats been done you ask? well: base timing has been set, timing should be good, we spent a lot of time on the timing portion and all the guys working at the shop are experienced. We checked the magnetic pickup in relation to the rotor and set it correctly. We hooked up all of the sensors to their respective testers and they all checked out in working condition. I had a bent intake pushrod which we replaced, the intake valve was stuck open but we oiled it and cranked the engine and moved smoothly, ran the engine and did a leak down test and the valve was then working. Leak downed all of the cylinders and they all checked out ok.
What makes this situation so tricky as that im dealing with a non-professionally rebuilt engine and a FI system thats not designed for that motor. The chip ",ecm with fedeal emissions chip for 350ci". Now i know thats for a chevy so do you think this is what is causing my problems? It seems possible just because its unlikely the two motors have the same timing curve or whatever.
Let me know where i should start, what i might consider doing, and if i should just set my scout on fire and see if it runss better afterward.
thanks
charlie