can someone tell me symptoms of a stretched chain? its a 1989 w150 5.9 tbi 4x4 automatics trans

 

Well, skipping timing is the most drastic symptom. Other than that, possibly no real symptoms until you actually start looking at it. The only other thing I can think of off hand is a retarded ignition system.

What's the truck doing?

 

well it cranks for a few before starts then when it starts it revs and idles fine ,but under any kind of load it boggs down and backfires threw throttle body and/or dies ,ive replaced a lot of stuff on the truck like....injectors, pick up coil,coil,wires,plugs,tps,coolant temp sensor,air charge sensor,tied another computer(it was used tho) ..............the trucks egr and air pump have been removed,and no cat converter


the truck was passed n to me from my grandfather who bought it new ,so its gonna be in family

Thanks a lot for any help

 

The cranking likely isn't related to the ignition me thinks, but if the truck has more than 100k mi on it, change the timing set out.

 

also if it has over 100k miles on it you probably need a new o2 sensor if it has not been replaced. you want to get a ntk brand one. if they are too expensive at your local parts store you may want to check rock auto. they have them for $30 plus shipping.

 

well I actually replaced it twice I replaced it but I had a exhaust leak then it started running bad so I fixed the leaked new man. gasket and had muffler put on and pipe ran all the way back ,,,thought maybe the leak burnt it up so I got another new one less than a month ago ,and the fuel pump and filter are new........its showing 15 psi even when I rev it ,the truck has always took a few seconds of cranking to start even when the truck ran good so im assuming that's another issue beside whats goin on now ,I just tried watching the rotor will I moved the crank the balancer moves about a inch before rotor when I turn it back and forth

 

do you still have one of the old o2 sensors still? could try re-installing it and see if it runs better. what brand o2 sensor did you install. some o2 sensors do not work as good as the OE NTK brand one.

 

Do a deflection test on the timing chain to see how much stretch you have. That way you will know for certain if you need a new chain\gears.

A bad O2 sensor will not cause any problems starting since the computer will not even look at it until it is in closed loop.

 

whats the deflection test? how do I do it?.............I put bosch o2 sensor in it both times its the direct fit not the universal kind

 

You may need a helper to watch while you do this:

Remove the distributor cap (but leave the rotor in place) and rotate the engine until you reach TDC or BDC and your timing pointer is pointing at zero degrees. Now turn the crank in the opposite direction SLOWLY while watching the distributor rotor. As soon as the rotor begins to move STOP. Note the timing mark the pointer is now at. Anything more than 5-6 degrees of crankshaft movement and I would replace the chain and gears.