some cars may have a different timing cover that splits, I might have to remove the 3 V belts to get the timing cover off.

before this problem I had a tow home that was due to a bad sensor in the distributor. I just swapped distributors.. the weak power and vibration issues may have crept up before that though.

I was just reading that is the O2 sensor fails that it can cause the engine to run lean, so I could try swapping that with a known good one and see if that changes anything.

I was trying to read the timing marks with a really old inductive type timing light and couldn't see them well.
I ( they work best in a dark room) I have since found my stroboscopic one so I can check that again..

by comparison : in my 1988 ford van the ignition timing is set with something unplugged so that the ECU is not playing a part in adjusting the timing and then the timing can be set by turning the distributor, and then you re enable the electronics. It has something called a "spud connector" this disables the ECU for the mechanical distributor timing adjustment on the ford..



in the volvo I didn't see a lot of difference in movement of the timing position and thought oh because the electronics were adjusting the timing, overriding it, so maybe it's not critical , but I did then realize that actually turning the distributor still affects the rotor position in respect to the cap and which plug wire the rotor points at at TDC so maybe distributor position does have an effect and Ive been wondering how to set this up properly so it's to spec. i dont think there is any procedure to disable electronic timing while making the mechanical adjustment ( turning hr distributor)

there isn't a great deal of adjustment in the distributor position so I think I just set it at about he middle of the range of adjustment.

I'm not usually one to make mistakes with the timing belt positioning. but who knows, I could recheck it. Ive done the timing belt replacement a few times over the years.

I wondered if a backfire could cause the belt to jump.

I'm going to have to redo the head gasket on my 240 so that will give me a refresher of checking the timing marks again. It's the same motor essentially..


If I remember right I need to find TDC right after the compression stroke on cyl 1
at that moment( yes I can use a straw too) I would be at TDC and then I should see the valves for cyl 1 both closed. I think. at this point it's about ready to fire cyl 1 I think..

maybe I can check that way, without removal of the timing cover? if he valves of cyl 1 are both closed and it's at TDC then the belt must be on correctly , I think?

a bit off topic,, but I just bought a 85 non working and non turbo Porsche 944 and I am learning that.. Evidently they sometimes alter the cam timing by 2-4 degrees, It gives them a bit more low end torque in exchange for a bit worse mileage. max power didn't change much. some put an offset key in the timing pulley or some use an adjustable pulley.

those cars are interference engines too so they will bend the valves if the timing belt fails, A Volvo just rolls to a stop.