92 Lumina problem

[JakeMetz63]

My roomate's girlfriend's 92 Lumina (3.1) has a problem where the speedo shows the speed at about 10mph slower than she is actually driving. Any suggestions? No mods or anything done to it that i know of. Origional tranny.

[19Cutlass94]

How are the speedo cables? also (long shot yes I know) but are there different size tires on the car?

[Crazy K]

We need more info.

how was this error determined?

Does the car have the factory tires? A base model lumina should have 195/75r14, which are smaller than the typical euro's 215/60r16. You should be able to find a tag indicated factory tire size, probably on the doorjamb or trunk lid.

 

edit:

fixed typo.

and the speedo is electronic, no cable involved.

[3pt1lumina]

Euro's came with 215/60/16's

[88Regal Limited]

base model lumina should have 195/75r14, which are smaller than the typical euro's 215/60r16.

That's odd because my base model regal came with 195/70[.b]R14's, and I know they're origional size.

[Crazy K]

nope. 195/75R14.

 

but the next size tire could be used on the same rim for a slightly wider track with minimal effect on the speedometer.

that is 205/70R15 10 mm wider, and the slighlyt lower profile keeps the diameter about the same.

 

back to topic.

[joberlee]

is it always the same amount off, or does it get more off as you go faster?

 

I ran into that speedo problem in the 89 regal i had, at the same time i had lots of running issues and the SES light was on a lot. The problem ended up being a bad computer, swaped it out and the problems all went away.

[slick]

VSS?

[JakeMetz63]

She says that the amount its off by increases depending on how fast shes going, stock tires, and everything else is normal.

[joberlee]

i don't think a bad vss will do that, if you have access to an extra computer i'd try that and see if the problem goes away.

 

it's posible for it to be in the speedo itself, but they are usually more eratic when they fail.

[Supreme Cutlass]

VSS?

[NeonKnight]

i have a 1991 lumina Euro 3.1 it came with the stock 15 inch rims (look exactly like the Z34 rims but they are 15) the tires are 205/70/R15 and that is what has always been on my car

[19902drlumina]

my 90 lumina euro has 16s like above. i also have a speedo problem but its to fast not slow im with joberlee, on the computer

[JakeMetz63]

Any info on VSS would be appreciated.

[Crimson Fury Z]

have you checked for codes or the ses light come on? do the paper clip trick and see. the vss related codes would be

-24(except 93 3.1 CA)circuit fault indicated when car is in motion. check tps setting also. disregard if drive wheels aren't turning(park or at idle).

-72(3100 though)voltage signal lost when traveling @ road speeds

-79(93 3.1 CA)misadjusted P/N switch will cause a false code

of course it says check wiring from vss to ecm, replace vss if needed and so on.

 

where is it? here it is;

at the rear of the transaxle housing near the right drive axle(plug in adapter). looks like 4 7-8mm hex bolts to remove it.

[JakeMetz63]

SES isnt on, grrr.. not worth the trouble for a girl im banging

[Crimson Fury Z]

LOL!!! go ahead and check for codes and see if you get anything.

[joberlee]

I'm telling you... check the computer