Help!!!
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Help!!!
This is strange. I completely overhauled the engine in my truck (1988 Ranger 4X4 w/2.9). It runs great, smooth no problems at all, except---.
Here's the catch the tachometer runs backwards (not exactly backwards but more of a reverse, with the engine off the tach rests at full deflection of the gauge "7000 RPM" when started the tach reads about "6000 RPM" as the engine is revved the needle move to the lower numbers "5000 - 4500 RPM" and will not go lower than 4500 RPM). Now, all who have worked on this type of equipment before know that the wiring harness is such that it CANNOT be wired backwards. Now here is another interesting bit of info. I thought that the needle might have flipped due to an electrical spike while reconnecting everything. So, I took the cover off the tach to manually flip the needle back to the correct position. Get this, the truck would not start after that. I put the needle back to the "WRONG" position and the truck started. I repeated the procedure with same results. What I'm thinking now is that I missed or have a bad ground. What do you all think? Thanks.
Here's the catch the tachometer runs backwards (not exactly backwards but more of a reverse, with the engine off the tach rests at full deflection of the gauge "7000 RPM" when started the tach reads about "6000 RPM" as the engine is revved the needle move to the lower numbers "5000 - 4500 RPM" and will not go lower than 4500 RPM). Now, all who have worked on this type of equipment before know that the wiring harness is such that it CANNOT be wired backwards. Now here is another interesting bit of info. I thought that the needle might have flipped due to an electrical spike while reconnecting everything. So, I took the cover off the tach to manually flip the needle back to the correct position. Get this, the truck would not start after that. I put the needle back to the "WRONG" position and the truck started. I repeated the procedure with same results. What I'm thinking now is that I missed or have a bad ground. What do you all think? Thanks.
Last edited by ItsD; Mar 31, 2004 at 08:31 PM. Reason: double post
Postmaster
Joined: Aug 2003
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From: St. Peter
It sounds like you've got reverse polarity going to your tach somehow. i'd follow the wires back (if possible) and make sure everything is in the right order. Also make sure that all the wiring is fully covered, there are no bare wires showing. now why it doesnt start when you flip the needle around is WAY beyond me.
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Joined: Nov 2003
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From: California Desert
Is the tach hooked up to the proper wire? Maybe...just maybe...you have an important engine wire running through the tach instead of the tach signal. If you moved the needle down it would have changed the resistance (maybe) and would have killed the engine. Not saying you don't know what you are doing or anything...that's just the only thing that comes to mind though.
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Well I've looked everywhere for broken wires or unconnected terminals but am not able to find any. Like I said in my first post, all the wiring harness connections are "keyed" so-to-speak and cannot be connected wrong. One thing that I still need to do though is check and see if any of the terminal pins may have pushed themselves back when I reconnected all the terminal plugs and thus are not making a connection. Thanks for the help I really appreciate it.
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