irregular tachometer rpm's

[whitey]

this has been going on now for a few months:
my tach will twitch/give me the wrong rpm reading/give me no rpm reading/or give me the right rpm reading. it all depends on how "Belinda" wants to be that day. im not even sure where to start, im hoping its a loose connection/wire shorting out, rather than a bad tach. does anybody here have an idea(ball park figure) on how how this will cost to fix at a shop? im mechanically inclined, but im not comfortable working on my own car unless its something simple...example:spark plugs(which i just replaced yesterday), oil change...i also want to mention that the car has 119,600 miles, and the transmission was rebuilt at 107,000 miles, im not sure if there is a sensor or something that reads rpm's that might have become loose during the rebuild or if it has nothing to do with it, but if i remember correctly, it started doing this after the rebuild. please excuse my ignorence on this subject guys, i was just never taught much about cars. thanks--whitey

[drewb457]

check the magnetism of the crank sensor see if its beginning to fail

[whitey]

drew....i have no idea what that even does/is......however, i'd love to learn!:) i dont know where it is or what it looks like, and how do i check the magnetism of it?

[jimbok1951]

Is that to the right of the Flux Capacitor ?

[whitey]

Is that to the right of the Flux Capacitor ?
hey now! i didn't say im a moron:lol:, i never had a chance to learn names of things, but im getting there...

is there a haynes manual for our cars? i searched but couldn't find one, not that i think they would have them anyway.

[jimbok1951]

Could not resist, just playing, but that magnetism thing sounds like Drewd457 is messing with you, but like you, I really don't know, he may be giving good info. Anyone else care to jump in ?

[jimbok1951]

Drewb457, I ment, fat typing fingers.

[fastblackmerc]

I'd disconnect and clean the contacts on the back of the instrument panel cluster.

Also check all the grounds under the hood..... could have a loose or broken one.

[whitey]

its all in fun jimbok

fastblack: how hard is it to get to the back of the instrument panel? im assuming i would have to pull off the entire dash?

[fastblackmerc]

its all in fun jimbok

fastblack: how hard is it to get to the back of the instrument panel? im assuming i would have to pull off the entire dash?

You have to take the trim piece off that includes the headlight switch and the radio. Remove all the "dot matrix" trim, remove the screws that secure the lower the portions of the dash trim. Then it's just a few screws that secure the cluster.

Drape a towel over the top of the steering column so you don't scratch it. Be careful that you don't scratch the plastic instrument cover.

[whitey]

fastblackmerc: i want to say thanks for giving me some pointers on removing the gauges, i just got finished taking it apart, cleaning everything i could with some quick dry electronic cleaner and a brush. it hasn't glitched so far but the real test will be tommorow's drive to work. one thing i noticed, with the flexible printed circuit board, there are 4 silver(color) boxes/squares behind the tach, on the circuit board, one says B, one says G, and it appears that 2 say S, the upper box on the S circuit has 2 points of contact with the copper circuit, well it looks like the contact on the lower side of that box is just barely touching the copper circuit, all the other silver boxes behind the cluster had definate 'visual' contact... it doesn't look like the 'pcb' was stretched, it looks like it came like that from the factory. just a bit strange looking to me....im a rookie electronics geek. well thanks again for the help--whitey

[SC Cheesehead]

hey now! i didn't say im a moron:lol:, i never had a chance to learn names of things, but im getting there...

is there a haynes manual for our cars? i searched but couldn't find one, not that i think they would have them anyway.

Check out this site for used 2003 - 2004 CV and GM factory shop manuals (they include the Marauder).

http://stores.ebay.com/Lorie-and-Jeff?_trksid=p4340.l2568

MUCH better than Haynes, and worth every penny of the price (normally less than $100)

[RF Overlord]

Haynes manuals are pretty lame. I've had a few for various family vehicles and all of them had lousy pix, and many times either missing or just plain wrong info. Don't waste your money.

[fastblackmerc]

Check out this site for used 2003 - 2004 CV and GM factory shop manuals (they include the Marauder).

http://stores.ebay.com/Lorie-and-Jeff?_trksid=p4340.l2568

MUCH better than Haynes, and worth every penny of the price (normally less than $100)
Haynes manuals are garbage compared to the factory manuals.

Lorie & Jeff have the best prices and selection.

[whitey]

thanks for the link, these manuals will show me how to diagnose/replace/repair things, right?

[fastblackmerc]

thanks for the link, these manuals will show me how to diagnose/replace/repair things, right?

Yep................

[whitey]

just for an update, the tach still acts jumpy....i'll figure out what it is one day....or i'll just get one of those big ricey 6inch tachs and velcro it to the dash with a shift light too!:lol:

[crouse]

Mine does the same thing.

[fastblackmerc]

just for an update, the tach still acts jumpy....i'll figure out what it is one day....or i'll just get one of those big ricey 6inch tachs and velcro it to the dash with a shift light too!:lol:


Mine does the same thing.

I bet it's a bad ground somewhere. I'll check the electrical manual.

[crouse]

It must just be the tach because at WOT, the tach is reading about 5500 rpm when it shifts from 1st to 2nd. I can tell the engine is at redline eventhough the tach reads 5500.