'91 Honda Accord rough acceleration, erratic speedometer

I have read a lot of info online, but still have questions. Hope
someone can help - please.
Background: One year ago lost the Timing belt while driving and messed
up 12 of the 18 valve. Car only had 58k miles (wife's grandma's car)
so decided to fork over $1900 for repair. After the repair it ran
great, better than new, I mean surprisingly smooth and fast. That was
a year ago.

Present - Yesterday driving to work it ran fine. However at lunch it
would run rough if the accelerator was depressed until the engine came
to speed then would run at constant RPM just fine. Acceleration was
very rough. I pulled a spark plug cable and after about 10 seconds
things got worse. It died and would not start, not even try to
start. No spark that I could see. I replaced the Ignitor (ignition
control module?), didn't help. Then I replaced the Coil; it then
would start (yeah!) however it ran exactly as before it died - rough
acceleration. I shorted the engine code diagnostic jumper on the side
footwell for passenger, turned on key and read the Check Engine light
flash: 1 long then 7 shorts. This would be 17, correct. This appears
to be a faulty Vehicle Speed Sensor, which would account for the
erratic Speedometer. But why is it running rough and why did the coil
fix the no start condition?

What I think: I think the no start condition was completely seperate
than the rough acceleration issue. Maybe when I pulled the spark plug
wire while the engine was running, I caused the coil (which is
probably original, 16 years old), to fail. What do you think?

But... what is the rough idle cause by. Bad fuel? If it was an
oxygen sensor, wouldn't that throw a code?

Sorry so long. Sincerely appreciate any help.

 

Letting the car run too long with a wire pulled to check for spark killed
your coil. You can do a very brief test that way, but the coil heats up
rapidly and dies. Look at you dead coil and you will probably see a burn
spot on the outer casing.

If you have a code 17, the speedo is screwed up, and your sports shift light
is blinking, you definitely have a bad VSS. Replace the VSS first and then
move on to the obvious like plugs, wires, cap and rotor.

 

==================================

When you pull a spark plug wire off, the high tension still has to go
somewhere to ground, so it goes through the module and destroys it. Have
you used injector cleaner regularly?

'Curly'

 

Well, I found the problem and temporarily fixed it with electrical
tape. While changing plugs, I realized the hard plastic case of the
plug wire that goes into the head had a crack and a couple of holes
that looked burned. Appears the wire was arc'ing into the head
instead of getting spark to the plug. Wrapped electrical tape around
it a few times and the car runs great. Obviously will have to replace
the plug wires. The Vehicle Speed Sensor is going to have to wait for
now. It doesn't throw a code often. Speedo works most of the time.
Thanks so much for the good advice.

 

For the future, if/when you encounter dead speedometer...

I had a similar experience on my 92 Prelude Si. My speedometer was
working intermittently and stayed at 0 for 99% of the time. I noticed
that when my speedometer is not working, my idle would be very rough.

My guess: Since there is no feedback from VSS (Vehicle Speed Sensor),
the engine fluctuates to compensate for the lack of data.

The fix: Had a mechanic replace the VSS, the symptoms went away.

Cost: You can buy a VSS for less than $200 (www.slhondaparts.com), but
replacing it yourself may not be feasible. The VSS can be located on
top of the transmission, but my VSS was obscured by the engine.

Note: VSS has nothing to do with your car not starting.

 

I lost my speedo at about 30k miles on my 93 del sol. The speedo was out
of calibration and the shop couldnt fix it without replacing the entire
speedo. Is there a way to roll the new speedo forward to read the
correct miles? My speedo now says 37K its actually about 67K ?