Mechanics

RPM NEEDLE GOING CRAZY!!!

1994 Nissan Pathfinder • 180,000 miles

On my 94 Pathfinder SE V6 Automatic yesterday I noticed while driving the RPM Needle jumped up to Redline then back down then it did it again and again it did it a bunch of times then it would jump halfway then go back down and do it a bunch of times then it would go dead for a while and then start going crazy again then it would work normal for a while then start jumping and going crazy again. It's been doing this the past few days. The only thing I did before it was happening was gave a VW a jump and had an Oil Change. So if you could please Help and give me some suggestions I'd REALLY appreciate it! Thanks in Advance.
Avatar
Tlowdon
February 18, 2012.



You may have fried something in the ECU. Check the wiring to the distributor.

Rivermikerat
Feb 19, 2012.
Ok thank you very much!

Tiny
Tlowdon
Feb 19, 2012.
So if I did fry something what needs to be replaced? The ECU or the Distributor or Both and how will I be able to tell? I'm wondering if it has something to do when I jumped that car?

Tiny
Tlowdon
Feb 19, 2012.
Most likely the ECU, unfortunately. Pay special attention to loose grounds and connections. There's also a control module under the right front seat. The grey wire there feeds the tach.

Rivermikerat
Feb 19, 2012.
Ok thanks again!

Tiny
Tlowdon
Feb 19, 2012.
My pleasure. Let us know what you find out and tell your friends about us!

Rivermikerat
Feb 19, 2012.
Ok sounds good I hope I can figure it out and I always tell my friends how Professional you guys are!

Tiny
Tlowdon
Feb 19, 2012.
The tach signal comes from a couple of sources. There's a crank position sensor in the distributor, and the negative, or tach side of the coil. Those feed into the control module I mentioned above, which generates the signal to the tach.

Rivermikerat
Feb 19, 2012.
Ok I'm not to Mechanically inclined so I'll have to wait for a Buddy of mine to check it out thanks again!

Tiny
Tlowdon
Feb 20, 2012.
My pleasure. Let us know what you find out.

Rivermikerat
Feb 20, 2012.
Page 1 of 2