Well I have about 15000 miles on the truck since I changed the plugs, wires, cap and rotor. I have been noticing that the engine has been detonating a bit lately in the past month with no trailer on the back under hard acceleration and thought it was just crappy fuel. I put half a tank of 89 octane in it when it was on empty this last time before I went and picked up the boat this past weekend thinking that would solve it but it didn't. I had no detonation after I changed all that stuff after the last tune up even when towing on 87 or 89. I'm sure it was there to some extent but not to the point where I could here the pinging. I don't want to beat the bearings out of this 170k mile motor so what Am I supposed to be towing with as far as octane? I am also going to check the plugs. I think it needs O2's. They have not been changed since I have owned it. Wires all looked fine but I'm also gonna pull the cap and check it as well just to double check it. Cooling system seams to work just fine. It 's full of coolant and temp never moves once it gets up to temp. moves a slight hair sitting in traffic with A/C on but that's to be expected. It's a 98 Tahoe with stock vortec stock exhaust all the way back and stock tune.
What octane fuel do you guys use to tow with?
- Thread starter Jaycenk
- Start date
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Ceejkay
Full Access Member
if you arnt throwing a cel i wouldn't touch o2 sensors.. i tow and drive with the low grade stuff and dont have a problem..
SunlitComet
OBS Jedi-Do Good
I don't tow anything yet but I use the highest octane available at the gas station.
domin8
Just Plinking
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- May 9, 2011
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I use what the owners manual says. I don't tow much, but I've never had problems doing it this way.
AtomicHoe094
Atomichoe094
Did you gap the plugs?
ch4d
Full Access Member
i use 87 thats it to tow and it tows nice with the flat bed and 4-5 quads on the back.
SunlitComet
OBS Jedi-Do Good
Do you have a scanner or scan gauge unit to determine if when your are detonating it is because the timing is advancing? if so you knock sensor may have goofed on you.
I did gap the plugs but it was 2 years ago so I can't remember what I gaped them at. It was what ever the book called for.
I have a scanner but it does not show knock counts. It does show timing so I guess I could try and see if the timing is jumping around when it is pinging. I'm gonna pull a couple plugs and have a look tomorrow and see what they look like as well. I check for codes and there was an old one that never threw a CEL something to do with the O2 heating circuit on one of the up stream sensors. It passed the emissions readiness check and I had to dig for old codes to find that one.
I have a scanner but it does not show knock counts. It does show timing so I guess I could try and see if the timing is jumping around when it is pinging. I'm gonna pull a couple plugs and have a look tomorrow and see what they look like as well. I check for codes and there was an old one that never threw a CEL something to do with the O2 heating circuit on one of the up stream sensors. It passed the emissions readiness check and I had to dig for old codes to find that one.
