tach needle jumps alot

[ercp98]

hi,
i have been noticing this more and more lately.
the tach needle jumps up to 4 or 5K when i start
my car.
i know it is suppose to move when starting the car.
but it did not do this before.

could my cas be a problem?

the car still start normally.

thanks for any input.


click

 

[prove_it]

I would suspect the gauge might be bad. Is it only when you start the car? Does it then works normally after that?

 

[ercp98]

the tach functions ok after the start up.

the tach needle just jumps during start up.

i will try to load video of it.


i cant up load the video.

 

[turbowop]

Last time I had similar symptoms to that, the CAS went bad shortly thereafter.

 

[DynastyLCD]

^^ x2. had the same exact issues with my GVR4 except they were jumping all over the place. it was the CAS.

a few years ago, i had a 2g TSi. before i bought it, the P.O. brought it to me with similar issues, plus a bad misfire, turned out to be the ignition transistor.

 

[ercp98]

added video . click ---> click

 

[ercp98]

to update:

i have replaced the cas with a known working black top cas.
the tach needle still jumps a lot when starting. also it start but with hesitation.
almost the same symptom as starting with a dying battery.
ecu clicks and mpi clicks loudly.

battery was just tested(autozone) and it read 12.9v
i can get the car to start with jumper from a reving montero.
i have the battery relocated to the trunk.

theories?

1. battery is weak to start car by itself because of the
relocation?
- battery checked out ok.
- relocated battery has been like that for many years.
2. cas still dying?
- using black top with same results
3. alternator dying and not charging battery
- will check this next.
4. bad starter? i.e. solenoid is sticking causing all these electrical
gremlin to show itself?
5. ecu... caps was checked last night and very clean
no obvious bubbling of the cap body or leaks

any other posibilities?

 

[ktmrider]

The latest descriptions sound like poor ground(s).

Degredation of contact points over time ( corrosion, loose, borderline small diameter ) could logically explain the current symptoms.

 

[ercp98]

ok . good idea.
i will re check my grounds.

any more ideas guys?

i did my battery relocation as per vfaq by the way.
i did not follow the one in the how to section.

 

[James]

I have one ground that comes loose often. I have to tighten it atleast once a month. One of these days ill actually fix it.

 

[ercp98]

just to update and close this.

it turned out to be the starter solenoid.


thanks for all replies.

 

[socalgvr4]

seems to be a common issue. How did you actually fix yours?

 

[ercp98]

the starter solenoid in my old starter just took a crap.
i ended getting a used working starter and just replaced
the old one.

beware about the threads for the starter bolt. they strip easy.