speedometer "jiggles"

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Nov 17, 2005 | 06:15 AM

lattices2

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speedometer "jiggles"

'90 351W EFI (just passed 160,000 miles)

Just read a speed sensor post so thought id post new rather than continue.

As i accelerate or decellerate, my speedometer "jiggles" back and forth a little as it goes up or down.

I dont know if its always done this or if id just started paying attention. I think i would have noticed it before. Ive had the truck 4 years

Is this a possible speed sensor problem or just ignore it?.
Thanks

Nov 17, 2005 | 08:18 AM

jmalecek

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From: Jasper, GA

If it's a '90 your speedo is cable driven. Sounds like the cable needs to be replaced.

Nov 17, 2005 | 08:42 AM

lattices2

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'90 351W EFI

If thats the case Ill ignore it for now. I assume it has no inputs to the computer and is just a mechanical thing.

Nov 17, 2005 | 03:48 PM

greystreak92

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From: Gateway to the West

Yep, Ford didn't switch to the PSOM setup until 1992. From 92 on the speedo and the odometer were fed information via the VSS which also sent the same info to the computer for shift functions and cruise control monitoring.

Last edited by greystreak92; Nov 17, 2005 at 03:50 PM.

Nov 18, 2005 | 05:36 PM

thenewjohndeere

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From: Raleigh, NC

My '91 does the same thing ... i took it out and regressed it once and it smoothed out, but a yr later its back to were it was ... i think that mabey the chain/wire that runs from the speedometer to the sensor is just starting to catch on the plastic sleev its in (almost like the wires in the chain have developed some breaks in it). I'm no mechanic and i'd take this as just an idea, but i figured i'd give my 2 cents.

Does yours do it more when its cold? I know its winter when i drive to the end of the street (800ft) and it says that im going 75mph.

I think its the chain but im too cheap to drop money on it. Actually i looked at the advanced page and there like 20 bucks, i could have sworn that it was 50 last time i looked ... might go get one this weekend.

(i guess you know your done with your post when you talk to yourself on it)

Nov 18, 2005 | 09:11 PM

Tim Halliday

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From: Wyoming, Ontario

Quote:

Originally Posted by thenewjohndeere

Does yours do it more when its cold? I know its winter when i drive to the end of the street (800ft) and it says that im going 75mph.

I had a similar problem with my '91 a while ago. I lubed the cable, but it didn't help. It turned out that there was a piece of dirt in the pivot point of the spedometer needle. The needle would go up just fine, but got stuck coming down.

A little spray silicone lube and never had a problem since.

Nov 19, 2005 | 12:40 PM

lattices2

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thanks for the info. Where is this cable where i can access it? Since its now snowing and cold i need to spend as little time as possible under my truck.