timing chain - 91 Sub

91 Sub has about 190k miles on it. Runs fine except for a new problem that just started. Engine started missing badly over the weekend after replacing the EGR valve, EGR modulator and TPS. Miss is most noticeable when engine is cold / warming up and during acceleration. Seems to run okay after reaching speeds over 50 MPH. Fuel mileage seems to be okay but probably in the 12 to 13 mpg area. Checked timing today, mark is whipping back and forth about 4 to 5 degrees at idle. Am thinking it is time to replace the timing chain, possibly gears as well. What else could it be? Thanks!
Reply to
fireant
Loading thread data ...

Did you unplug the ESC wire before checking timing? If the answer is yes, and the idle was steady then yes it's a good guess the timing chain is stretched. Given the mileage it's due anyways, and always do gears and chain as a set, and dont get cheap with the replacement parts.

Whitelightning

Reply to
Whitelightning

Water pump?

Reply to
Meat Plow

How can a bad water pump cause the strobe timing marks to be jumping around? Can't see it.

Reply to
Augustus

No I meant if you do the chain and gears do a water pump too. Unless GM has relocated it.

Reply to
Meat Plow

You're there anyway.

Reply to
nonsense

Whoooooooooooooooooooooosssssssssssssssssssshhhhhhhhhhhhhhhhh!

Reply to
nonsense

OK..I get the stupid prize for today....

Reply to
Augustus

LOL no problem.

Reply to
Meat Plow

Yes, picking up a new water pump is a great idea. I would grab a harmonic balancer repair sleeve as well. It is always nice to have everything ready when you start tearing into it. You can always take the sleeve back if you dont need it, after you are done with the job. When I changed my timing chain on my 94 ck1500 with 220,000 miles, it needed a repair sleeve. since you are going to loose alot of antifreeze, it might be a good idea to completely drain and refill with fresh antifreeze and distilled water. Antifreeze becomes corrosive over time. Be absolute certain to unplug the little wire before checking timing like WhiteLightning said previously. The wire was located at the passenger side fire wall just behind the black plastic cover on my 89 ck1500, it was under the glove box on my 94 ck1500, if i remeber correctly it is a single brown wire with a black trace.

Reply to
Guppy

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.