Top Speed Diagnosis

[BeatDaSHO]

So please don't flame me for this but I wanted to test out the range of my SHO. I recently sold an 89 SHO. Last year, I took it on this one onramp and there is this big stretch of flat highway where there are no cops and no one travels at night. So I ran through the gears. I hit 135 on it easily by the time the exit ramp came. I sold that SHO and picked up my brothers 89 SHO. We raced last year up til 130 and they are both dead even. None the less, I picked this up and tonight I tested it on the same onramp. I eased into it and 1st pulled great, second pulled great, third pulled great........then the switch to 4th gear, it pulled sooooooo slow. I couldn't pull any faster than 110. It just stayed there. I held it there for over 5 seconds and it wouldn't pull anymore. I have no idea what's goin on. This car has had every bit of maintenance work to it, 60k done about 15,000 ago, i just replaced the air filter and tps (code came up for that)......I have no idea what is going on. Any ideas? Please help. Thanks.

Greg

 

[JoeHoe_SHO]

Check the timing belt.

 

[AutoSHO]

Fuel filter could be plugged.

Putting it on a dyno is really the solution.

 

[DHMag]

plugs and wires

before changing to Taylor wires and hotter plugs, i couldnt get a bit over 115

 

[revhardSHO]

plugs and wires

before changing to Taylor wires and hotter plugs, i couldnt get a bit over 115

What are you running for plugs? I was under the impression there was one and only one plug made for the SHO. As for the wires, just make sure you get OEM quality replacement.

 

[DHMag]

What are you running for plugs? I was under the impression there was one and only one plug made for the SHO. As for the wires, just make sure you get OEM quality replacement.

Bosch Supers. there are many plugs available for every engine out there, the SHO is no exception. it all depends on what the engine likes. in my case, i overheated the 32PPs, so i switched to the Bosch Super which is 2 steps hotter. been running them for about 6 months(6K miles) and love them. ill be taking them out this week to check them.

 

[BeatDaSHO]

The plugs and wires are only 15,000 miles old. A FULL 60k was completed 15,000 miles ago. The wires are motorcraft and the plugs are agsp32pp plugs. The fuel filter is the original though but would that allow GREAT performance from 0-110 mph and then totally stop? This car pulls reallll hard to 110 mph and then won't go any further. Now, if the timing belt skipped a tooth, would this allow great performance to 110 and then stop? I would think that it would be down on power in the whole powerband. What else do you guys think? Thanks a lot.

Greg

 

[Denny]

Rear brakes freezing up at all?

 

[stevemainian]

I got my atx sho to 135, i was still accelerating hard but i was getting scared so I let off. Im guessing about 145-150 it could do.

 

[SHO_Driver]

Did you say the fuel filter is original, meaning never been changed? The one they installed in 89? If so that can't be any good for the fuel pump.

 

[Slo-Sho]

Yeah, that's what I was thinking. It's a $9 part and takes about 5 minutes to change with a flathead screwdriver.

But wait, fuel filters don't get dirty. :headbang:

 

[platoribs]

But wait, fuel filters don't get dirty. :headbang:

Not on the outside anyway!

 

[AREA 91]

Had my plus up to 145-147 and she was still pullin!

 

[GEORGE 1992]

Yeah, that's what I was thinking. It's a $9 part and takes about 5 minutes to change with a flathead screwdriver.

But wait, fuel filters don't get dirty. :headbang:

Very funny! And also very true!!!

 

[stevemainian]

Where does the speed limiter kick in on a atx sho?

 

[DHMag]

The plugs and wires are only 15,000 miles old. A FULL 60k was completed 15,000 miles ago. The wires are motorcraft and the plugs are agsp32pp plugs. The fuel filter is the original though but would that allow GREAT performance from 0-110 mph and then totally stop? This car pulls reallll hard to 110 mph and then won't go any further. Now, if the timing belt skipped a tooth, would this allow great performance to 110 and then stop? I would think that it would be down on power in the whole powerband. What else do you guys think? Thanks a lot.

Greg

i overheated my 32PPs in less than 4K miles after my 60K.

 

[Joe'sSHO]

I don't think this is something that's been addressed yet. What about your speedometer? SHO guages are notoriously bad and I wouldn't be surprised if it's just reading incorrectly over 90mph. My red 90 used to read fine up untill 90mph then it would take almost all of 4th gear to get the speedo to read 100mph. I know the speedo was bad b/c i swapped the 90's engine and trans. into a 93 and had it up to 120+. If it feels like it's still pulling well (or at least feels like it's is still pulling at all) in 4th I would think you just have a bad gauge. Just my 2 cents. Hope you figure it out.

 

[anarchy04]

yeah, try watching the tach instead of the speedo

 

[DHMag]

yeah, try watching the tach instead of the speedo

the tach isnt accurate either.

as my dad always says, "Ford is not in the business of making critical data acquistion gauges, just cars."