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2.9L Rebuild - performance improvement advice


rusty ol ranger

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Has anyone had trouble with their instrument panel voltage regulator?? Mine seems to have shit the bed as my gas gauge reads full no matter (has new sending unit). With alternator wired up separately, isolating it from the wiring going to cluster, it runs great . However, after test drive, under load it stumbles for a second like it dies outright for a split second (had similar issue before but it was more severe before and more often).

This voltage regulator is hooked in to my ignition and they are know to go bad. It’s also hooked to my gas gauge. And the alternator. So if it’s intermittently shorting, it could be what’s the matter with it all.
Update: put junk yard volt reg in cluster and it was mildly better but when we bench tested that one, it too was bouncing from zero to 7 volts. On our way to buy a steady volt step down 12v to 6v from electronics place and hoping that’ll sort it and bring gas gauge back and allow for alternator to be hooked up business as usual.

Anyone had issues with these f***ing things before let me know
Mine will randomly max the gauges out sometimes. You can tell cause they all go up in unison.

Never had any other ill effects though
 


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RonD

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The fuel gauge uses Pulsed 5volts from a voltage regular behind the cluster, and its only used by the fuel gauge

There is an anti-slosh module on the back side of the cluster, this often fails and causes FULL or EMPTY gauge all the time

Google: Ford anti-slosh module bypass

As far as the alternator, set volt meter to AC Volts, and test battery with engine running, if you see more than .4vAC then you have bad diodes in alternator.

If all gauges go high then its more likely a bad Ground not a 12v issue
 
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Paulos

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I had an after-market fuel sending unit that did not read right from the start. I noticed that Rock Auto had some inexpensive original Ford pump/sending units so I bought one. It worked like it should, so I figured that the after-market part had the wrong resistance (it did). I still have that part, but never figured out what I could do to make it work right (I thought maybe an in-line resistor).

I also considered that the issue was the instrument voltage regulator, and bought a few of them from the local pick-a-part, but they made no difference. After that I bought the Ford fuel pump/sending unit.
 

RonD

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Ford changed fuel gauges and sending units in 1989

1988 and earlier, 73 OHMs Empty and 10 OHMs Full
1989 and up, 16 OHMs Empty and 160 OHMs Full

So there is no way to converter a sender or a gauge, no resitor or other in between device would work that would be cheaper than changing the sender or gauge
 

MarkusMcBride

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Sorry maybe I didn't say it in the post, I bought and installed a new alternator to eliminate that as potential problem. Pretty sure I didnt need one now but hindsight is 20/20 and now I have spare.
PROBLEM SOLVED... so far so good.

All that was done in the end was changing the voltage regulator in dash
to a new part from electronics store that converts any voltage under 24v (fluctuation in voltage allowed) to whatever you set it to.. Set it to a steady 5.95v. SEE IN PICTURE, set volt output with tiny screw in blue box on chip board. Solder it to old pulse regulator terminals and a ground.

Other thing we did was direct link to battery from alternator for the yellow wire (from voltage reg on alt) and for the 2 black and orange wires that come out of alt main plug (and join together 6" from plug). Those wires now go direct to battery +

Also dropped fuel tank, removed sending unit, tested gauge with sending unit plugged in (but out of tank) and manually operating float. Went over wiring along frame rail, seemed ok. Seems to work now. I will say that it is a spectra unit, not ford. I was cheap and went against my gut ordering it.. I've had bad luck with spectra before. Hoping she stays operational but I'll have a jerry for a bit to be sure.

Anyways, truck is running great now. Can tell she is breathing better. Sounds throatier/raspy. Had it out for a good drive when this got settled. Shifting well on rebuilt transmission. Wanted to make sure it wasn't going to do the split second cutting out crap when under load. Had it about the 5k mark, no problems. Fresh motor, fresh transmission rebuild.

IMG_1103.JPG
IMG_1102.JPG
 

franklin2

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Has anyone had trouble with their instrument panel voltage regulator?? Mine seems to have shit the bed as my gas gauge reads full no matter (has new sending unit). With alternator wired up separately, isolating it from the wiring going to cluster, it runs great . However, after test drive, under load it stumbles for a second like it dies outright for a split second (had similar issue before but it was more severe before and more often).

This voltage regulator is hooked in to my ignition and they are know to go bad. It’s also hooked to my gas gauge. And the alternator. So if it’s intermittently shorting, it could be what’s the matter with it all.
Update: put junk yard volt reg in cluster and it was mildly better but when we bench tested that one, it too was bouncing from zero to 7 volts. On our way to buy a steady volt step down 12v to 6v from electronics place and hoping that’ll sort it and bring gas gauge back and allow for alternator to be hooked up business as usual.

Anyone had issues with these f***ing things before let me know
The bouncing voltage is how they work. They work like a turnsignal flasher does, they work on heat. There is a bi-metal piece in there like a toaster has, when it gets hot it curls up and breaks the circuit. It then cools off and restores the circuit. It keeps doing this over and over. As the voltage in the vehicle goes up, it heats up quicker chops the voltage up more. When the voltage lowers, less chopping occurs. The guages work on heat also. The needles are hooked to a bi-metallic piece and when it gets hot and curls, it moves the needle. This operation in the gauge is so slow, that the choppy voltage from the instrument cluster regulator doesn't affect it, it averages it all out.

This is the way Ford gauges have worked since the early 60's.
 

MarkusMcBride

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I think mine was faulty, putting out up to 12v at times. I don’t think they are supposed to go much over 6 volts with the pulse. I have since learned that the pulse is their function but with the new part in there I think I can expect more reliability.
 

rusty ol ranger

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I think mine was faulty, putting out up to 12v at times. I don’t think they are supposed to go much over 6 volts with the pulse. I have since learned that the pulse is their function but with the new part in there I think I can expect more reliability.
I think its 5 volts actually. I didnt realize they only controlled the fuel gauge though.

So why the hell do all my gauges (temp, oil, fuel) all go up in unison at random times? I thought that regulator controlled everything
 

RonD

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Either the Ground or the 12v wires to the cluster are causing it
 

franklin2

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I think its 5 volts actually. I didnt realize they only controlled the fuel gauge though.

So why the hell do all my gauges (temp, oil, fuel) all go up in unison at random times? I thought that regulator controlled everything
It does control the voltage to all the gauges. The diagram below is for a 1985 f150, but the gauges are wired the same as the Rangers and Broncos

 

rusty ol ranger

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Is it possible to replace those?
 

franklin2

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Nez'sRanger

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Here's a link to a new gauge regulator.


P.S. I am assuming this fits the early rangers and Bronco II also, but you had better do some more research to make sure.

Looks like a 9v battery plugs into it... Where would that go?
 

jimbott388592

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30 x 9.5-15 achilles desert hawk
any tips on finding a shifter for an fm145
 


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