I have posted on this truck before and am about to my wits end. It just does not have the power it should. I drove home from work tonight and was driving into a headwind and was emabarrassing to have the pedal practically floored. (1998 W150 4X4 318 TBI 108,000 miles automatic No OD) The best way I could describe it is like it has apples stuck in the exhaust pipes. (It has new duals with cherry bombs and no cat). I have done several tune up procedures on it and cleaned the throttle body as well as ran mopar combustion chamber cleaner thru it. Has new computer, map sensor, O2 sensor, EGR valve, plugs, cap, rotor, wires, K&N air filter, coil, hall effect pick up coil, EGR valve. I have spent a great deal of time checking and looking for intake and vacuum leaks with a small handheld propane canister. I ran a compression check and all cylinders read between 140 and 150 lbs. I have checked out all of the leads for lack of power suggested in the haynes manual. My old 85 Dodge van with a 318 will run circles around this thing. Here is what has me stumped!!! When I attempt to set the timing on it, it runs horrible when it is anywhere near what the catalyst sticker calls for which is 10 degrees BTDC. The only way I can get it to run halfway decent is to set the timing by ear insted of using a light. I am unplugging the coolant sensor before attempting to adjust the timing. I usually see 9 and have not seen over 10 MPG even on the highway. It idles as smooth as silk, but does hesitate when engine is not fully warmed up. I drive this to work daily! I am wondering if the timing chain is real loose or if their is a problem with the distributor itself somewhere? I am open to ideas! Thanks.

 

when you set the timing by ear what does it actually read?

 

It goes out of sight where other engine components are blocking its view.

 

It is a 1988 model. Also I went out a little bit ago and pulled the distributor cap and stuck a big socket and wratchet on the crank pulley nut and slowly turned the engine over by hand and the pulley would turn about 1-1/4 to 1-1/2 inches before I could see the rotor start to turn. I then cranked the engine several times and repeated this with the same results. I did this whole procedure 4 times and each time the crank pulley traveled over an inch before the rotor began to turn. Is it time for a new chain??

 

pull off a valve cover and see if the camshaft has the same amount of play.

If it's the original chain, it might be time to replace it anyway, but it might not be the cause of your problems at all.

 

My distributor does not have a gear, its just looks sorta like a keyway that might go straight into the oil pump. I looked at a picture of a new one at a online parts store that had some detailed pics of it. When I grab the rotor and try to turn it, it will turn about 1/8 inch and does not move from side to side at all. I pulled a valve cover and turned the crank with cover off and it appeared to start moving a rocker arm right away but it was real hard to tell since it would start out moving only the one that was ready to raise up or down. I needed a helper to watch while I was turning. I also ran the #1 piston to TDC and pulled the cap off and it was right smack at #1. It could be a combination of the distributor and the chain both being worn. I just hate to spend the $130.00 on a distributor or put in a new chain and gears without knowing what the problem is 100%. I am new to Dodges and I appreciate all of your help.

 

If the chain or gears were that worn would the rotor still point right at #1 when I had it at TDC?

 

Yeah dodge leaves the gear in the engine instead of at the end of the distributor shaft. That key slides into the gear. Not sure why it's done this way.
Are you the original owner of the truck? Do you know if the chain has ever been replaced before? I'm not sure when the maintenence schedule has you replace the chain, but it very well could be due.

Have you checked your timing marks, out of curiosity? If you run #1 to TDC is the line right at 0?

 

I am not original owner and I doubt the chain has ever been replaced. I believe the 108,000 miles are original but it is a 88 model so miles and age both enter in to it. Yes the line goes right on zero when the #1 piston is TDC

 

Odd. Is the vacuum advance hooked up right? I'm running out of ideas here. If you pull your distributor out how does the end of the shaft look 0 fine or beat up?