5.0 spark knock under hard acceleration

[johnmcgt]

Hey everyone,

HELP, my 94 Automatic GT Convert, is knocking under hard acceleration. I have NEW plugs,wires,cap,rotor and fuel filter, timming is at 8 deg with spout disc.
Are there settings for electronic sensors that can help, any ideas would be appreciated.

Thanks,

John

[PKRWUD]

Make sure that the spark plug wires that are going to cylinders #5 & #6 are not touching each other at all, from the distributor cap to the plugs. Buy extra separators if necessary.

Take care,
-Chris

[95mustanggt]

Originally posted by PKRWUD
Make sure that the spark plug wires that are going to cylinders #5 & #6 are not touching each other at all, from the distributor cap to the plugs. Buy extra separators if necessary.

Take care,
-Chris

Will that cause detonation even with FMS 9mm wires?

My car still detonates the odd time. It used to happen when it was warm out, but then I cahnged my MAF and I was OK. Car didn't detonate at all in 90+ degree weather and then all of a sudden the lasl couple weeks it's been doing it again (temps are around 60-70 degrees).

I guess I could move them and see if it helps...

[gtsr515]

Absolutely, crossed wires will arc with ANY spark plug wire.

You can try several more things too, I would get rid of that Superchip, time it at 10 degrees, you said you timed it at 8 degrees with SPOUT out, did you reconnect it, or leave it laying on the radiator, as I have done many times? Also put a 192 degree Motorsport thermostat in it.

Pro-M once told me to try simply removing the Hot Wire sensor from the MAF sensor and simply put it back on, said this can change your calibration by 2%, seems petty, but it works.

Also, you sure you ain't got a vacuum leak?

How are the 02's?

[Reipen]

i have a 95 gt vert aode and im having the same problem with my chip.

At 10 degrees timing (i was at 14 then dropped it to 10 when i got my chip) i am still pinging at around 4k rpm through 6 in 3rd and at like 5500 rpm or so in 2nd. My friend dropped my timing down to and i dont ping anymore, but my car runs like a dog. With the 10 degree timing i was running 14.4/5 with a 2.2 60ft but i was also pinging. Now with the timing at 8, i couldnt break below a 14.6 and my mph was at 94 instead of 96.


I was wondering if it was the chip's program being to agressive with my timing but maybe it is my wires. THe number 5 and 6 wires are which ones? The last 2 on the passenger side or?

Thanks

[PKRWUD]

Originally posted by Reipen
THe number 5 and 6 wires are which ones? The last 2 on the passenger side or?

Thanks

The forward most two on the drivers side.

Take care,
-Chris

[johnmcgt]

Thanks for all the great replies.

Are 5 & 6 the only two that need to be seperated????
I do not have a chip, yes the spout is back in. My GT has 108,000 mi on it, when I got it wires,cap,rotor, fuel fltr were all original, I would guess O2's are also.
I have a scan tool and no codes are being sent.
I have heard of putting a 180 thermostat in, what is the factory one??? I live in Florida, it has already been 95+ deg with 90% humidity. Not the best for performance.
I would feel better if I could get rid of this problem, sounds like I am not the only one. Has anyone had experience with the fuel system. A person at work has a GN, he put a new fuel pump & regulator and said this solved a lot of his problems.(I told him the only problem not solved is it' still a buick, HAHA)
About gears, what will an AODE rpm be at say 60 mph??

Thanks for all the great help,

I hope all this talk solves everyones problem.

[PKRWUD]

None of the wires should be touching, but it's particularly important with 5 & 6. They fire sequentially( 1-3-7-2-6-5-4-8), and are next to each other on the same side of the engine. Perfect conditions for a misfire. As the rpms increase, so does the coil output, which makes even the best wires little good if they're touching.

If a 180 degree t-stat drops your engine temp, then the radiator is partially clogged. Your cooling system is designed so that the hot fluid stays in the radiator long enough to lose the heat. A lower temp t-stat allows the fluid to circulate back into the engine too soon, and will eventually cause the system to overheat, UNLESS there is something restricting the flow, like a clogged radiator, so that the fluid loses it's heat while in the rad. Like I said, the bottom line is that if cooler than stock (192) cools the system more, than you have a problem, likely a clogged rad.

Mustang fuel pumps are no better than anybody elses, and yours will need to be replaced in the not too distant future. Listen for it to start getting unusually noisy, especially in the morning, as a sign that it's end is near.

Take care,
-Chris

[MustangGT]

Like Chris suggested make sure you check your wires. I had the same basic problem once with my 95. Messed with me for the longest time. Turned out I cleaned my air flow sensor and it helped a LOT. Finally I replaced it a walla problem solved.

MustangGT

[95mustanggt]

I guess it is time to organize all my wires. If that works...whoa man, I'll buy you guys the beer if we ever meet.

[7000rpmisheaven]

Under hard acceleration if you go lean it can also cause detonation. May not be likely but its another idea.

[Skywalkr57]

how and what do you use to clean the maf sensor?

[Reipen]

and pick up some dialectric spray or i heard carberator cleaner works too. just becareful as those 3 lil toothpick sized prongs are very sensitive.