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Old 04-19-2012, 05:45 PM   #1
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Default Rpm Gauge cutting out when WOT and bumps

So I'm assuming its a ground or power issue that I need to locate but I have no idea where to start looking. Does the instrument cluster use one ground? And if so, then why would only the rpm gauge cut out while the speedo was fine? At a loss here...
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Old 04-19-2012, 06:09 PM   #2
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Try cleaning all your grounds in the engine bay. The one under the throttle body and the one near the brake booster. There is also one under the car somewhere I think. I had a similar issue with my old car.


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Old 04-20-2012, 07:52 PM   #3
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Mine is kinda similar to yours. Except is a lot worse. I cant go over 4k or else it just drops to 0 or if I hit any bumps it drops down. I cleaned the ground under the throttle body and checked all the other grounds I could find yet its still persistent. I don't have any idea about the ground under the car though
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Old 04-20-2012, 07:59 PM   #4
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Speedo is cable drive, not electronic. Tach gets it's signal from the ignitor, I can't remember where it grounds.

Edit: I see you have a '99...maybe your speedo gets a signal from a speed sensor. Dunno.
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Old 04-20-2012, 08:14 PM   #5
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Yea its just the tachometer? I tried to look at some wiring diagrams and maybe trace the grounds but I got lost real quick
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Old 04-20-2012, 08:17 PM   #6
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take the plug out, then put it back. This fixed the problem on my 1991 car. That connector is funky.

Edit for smartphone fail.

Last edited by hustler; 04-21-2012 at 01:05 AM.
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Old 04-20-2012, 09:14 PM   #7
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Off the back of the instrument cluster?
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Old 04-21-2012, 08:40 PM   #8
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So I disconnected the plugs from the back of the instrument cluster and plugged them back in but I'm still having the same problems! Starting to wonder if I buy an external tach if it'll have the same problems...
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Old 04-21-2012, 11:55 PM   #9
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Quote:
Originally Posted by WonTon View Post
Try cleaning all your grounds in the engine bay. The one under the throttle body and the one near the brake booster. There is also one under the car somewhere I think. I had a similar issue with my old car.
At around 42 seconds, it looked like a sprayed car without a progressive controller.

Quote:
Originally Posted by cowboys647 View Post
So I disconnected the plugs from the back of the instrument cluster and plugged them back in but I'm still having the same problems! Starting to wonder if I buy an external tach if it'll have the same problems...
Buy an FSM if you plan to keep the car. Worth its weight in gold.
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Old 04-22-2012, 08:32 PM   #10
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Yea I probably should... Bump for anyone with any ideas! Settings in ms maybe?
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Old 04-22-2012, 10:15 PM   #11
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The ground that you're looking for runs between the car frame beneath the brake booster and the "trans plate" which mounts between the engine and transmission - the bolt that holds the ground to the trans plate also supports the dipstick tube. The bolt beneath the master cylinder is a popular mounting point for your heat shield, make sure it's tight.
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Old 04-22-2012, 10:45 PM   #12
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Check cam and crank sensors.
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Old 04-23-2012, 08:37 PM   #13
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Quote:
Originally Posted by fooger03 View Post
The ground that you're looking for runs between the car frame beneath the brake booster and the "trans plate" which mounts between the engine and transmission - the bolt that holds the ground to the trans plate also supports the dipstick tube. The bolt beneath the master cylinder is a popular mounting point for your heat shield, make sure it's tight.
Yup their nice and tight.. Will check cam and crank sensors in a min
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