howudodat

95 gt, stock
moved from Colorado to Las Vegas (coincidental? not sure)
started to hear some slight pre-detonation so went to reset the timing (oops, forgot to check what it was when I started)

So...I removed the spout connector and painted a line with whiteout at 0, 10 and 20 degs. Fired her up and set the timing to 12deg. She purred quite nicely. I put the spout connector back in, drove around the block, sounded ok. Next day I drove to work and heard pinging even worse, got home and timing was at 30deg. off to set the timing again.

I pulled the spout connector and set the timing, and it jumped back to 30 deg. pull the connector and timing drops back to 12 deg.

If I set the timing with the spout connector in at 12 deg, it holds, (it will jump to 30deg at about 4000 rpm).

What gives?
Peter

projectresto83

Well you are supposed to pull the spout out to set the timing. Since you are in colorado set it to 8-10 and see how it runs. Higher elevation, thinner air. What octane gas are you running?

FivePointOhh

when you plug the spout in its supposed to jump up. eec adds 20* when you plug the spout back in(give or take 3 degrees)

TrimDrip

I have been having problems with detonation too. I had the mechanic check the spark while I turned the car over and he said the spartk was weak. Against everones advice, I went ahead and ordered the msd distributor instead of the module.

howudodat

Actually I'm in nevada I thought 12* was factory?
Have tried all 3 grades same result on the pre-detonation (I'm assuming it's that based on the sound) with no change. That's why I went to timing
OK, will reset it back to 12* without spout - although it seems to be running nicely right now
so the detonation could be weak spark...hmmm hadn't thought of that. How do you test for weak spark?

Peter

TrimDrip

He stuck a screwdriver in one of the plug wires while I turned the car over. He said he could tell by the color.

The module is all it could be on my car, we replaced everything else. This is at low rpms too, like driving in stop and go traffic.

He claimed that the spark is not hot enough to burn off the fuel.

Now I am not saying that is the problem with your car but, it is a possibility.

I will let you know if it fixes my car after I put in this afternoon when I get off work.

howudodat

ok, it's been a while since I poted on this topic because I have been trying everything I can think of.

I have reset my timing back to 10* and have replaced the spark plugs, wires, coil, cap and rotor.

Symptoms: car knocks under load. Worse when it's hot outside - right now it's 105*. Early morning at 80* it's not as bad. In fact hardly noticeable.

I also noticed that my car seems to have a very rough idle. It will vacilate between 1100 rpm and 400 rpm - again only when hot.

Finally my daughter said my exhaust sounds like it's blowing bubbles Not sure exactly what that means but I thought I'd throw it out there.

Thanks everyone for your help...I am out of ideas on what to try.

Peter

mjr46

okay no 1 when you put the spout back in you are allowing the ecm back in the loop to control timing and it will jump it up past 20 degrees, that's what it is suppose to do, you are drawing a incorrect conclusion/ correlation to the prob.........if the detonation is worse when the temp outside is greater....first thing to check is cooling system....is your cooling system up to par/ temp in the normal range/ no overheat or running hot condition??? if it is fine move to no. 2......have you run a koer test/ checked for codes?? specifically looking for any egr codes??? egr is there to reduces NOX/ lower cumbustion chamber temps/quench cylinder temp so as NOX and or detonation doesn't occur... If no codes are present something now to look at is carbon build up, excessive carbon build up in the cumbustion chambers and on tops of pistons will raise compression and in turn elevate cumbustion temps and flacilitate detonation, A GOOD INDUCTION CLEANING OR SEAFOAM treatment will cure the issue or for that matter 2 seafoam treatments to be safe, one in the booster and one in the tank for an entire fuel system cleaning.

howudodat

I forgot to mention...sorry...took the stang to the mechanic. He said no codes. I paid $190 for an induction / injection cleaning. (Dont remember the name of the chemical, but like BG44 - said it got sucked through the intake and through vacuum).

Then he sid I had bad gas and to run Chevron with Techron premium. Am on my 3rd tank of that with no change. (Ran with premium normally)

Cooling is running normal - unless I really push the engine hard while it's nocking. Then it goes a bit warm, but well within the normal range. Not sure the temp, but I normally run about 45-50% of guage travel, and when it gets real hot it might be 60% of guage.

Peter

mjr46

go to autozone or even wal mart and for 8 bucks you can purchase a can of seafoam, read the instructions and try it