A brief informational for v6 owners looking to install a sport cluster.

[iceman]

For those of you who are interested in this swap and have the same truck here is a little informational so you can avoid one of the pitfalls I ran into. I recently installed a sport cluster in my 1991 v6 4x4 mighty max, got everything installed including the oil pressure sending unit and everything worked great, except the tach and that really sucked since it was the main reason for doing the swap so I hit the books, well the internet actually. From everything I found it looked as if the truck did not come pre-wired for the tach however after 4 trips to the wrecking yard and a day of confusion I found out what the problem was. It turns out the trucks, at least the 4x4 v6's and I'm pretty sure all v6's come pre wired for the tach (I cannot speak for the 4 cylinders). The only thing is some of them (like mine) are missing a key component that makes the tach work. Pictures of this device and the mounting location are attached. Now if you need this device the V6 montero has the exact same device in the same location as our truck and it is a direct fit and of course the max's with a sport cluster do as well. If you really get stuck in a bind and cannot find one I have a couple extra and I will mail one to you free of charge If you PM your address to me (keep in mind they came off of a used vehicle and are not new). I hope this helps someone out because I could've used the info when I went to install my cluster. IMAG0520.jpgIMAG0521.jpgIMAG0522.jpgIMAG0523.jpgIMAG0524.jpg

[joey_crandall]

my v6 had this already. it seems like the more the rpms go up the more inaccurate the tach gets with mine, or my truck revs real quick and can handle 8k rpms

[iceman]

For some reason some of the trucks have them and some don't. My truck was one of the ones without the little part, and maybe something webt bad on your system?

[meandmit]

what do these clusters go for?

[iceman]

On ebay there is one listed for 70 bucks which I think is outrageous since it doesn't even come with the oil pressure sending unit but if you can find one in a scrap yard they are usually anywhere from 15 to 40 dollars depending on how the person you pay feels that day. I got mine for $35 and that included an electrical warranty.

[manorchurch]

It looks like a capacitor (condenser). A tach (most basic design) takes voltage pulses as input, and averages them out to a voltage level that triggers a current amplifier that drives the meter movement (or, with analog-to-digital conversion, to some digital value equivalent). You can pick up pulses from the input side of the coil, assuming you don't load-down the trigger circuit. Electronic circuits are very sensitive to the addition of components that draw current. In a meter movement, full-scale deflection of the needle is rated in milliamps, typically, something like 10 ma or so. Deflection of the meter has to be calibrated to produce accuracy. A capacitor shunts pulse duration, making the pulse more of a spike. At some value of capacitance, input to the meter circuit averages out correctly for full-scale deflection at max rpm. $35 is an outrageous amount of money for a capacitor, but if it works, it works.

[iceman]

It looks like a capacitor (condenser). A tach (most basic design) takes voltage pulses as input, and averages them out to a voltage level that triggers a current amplifier that drives the meter movement (or, with analog-to-digital conversion, to some digital value equivalent). You can pick up pulses from the input side of the coil, assuming you don't load-down the trigger circuit. Electronic circuits are very sensitive to the addition of components that draw current. In a meter movement, full-scale deflection of the needle is rated in milliamps, typically, something like 10 ma or so. Deflection of the meter has to be calibrated to produce accuracy. A capacitor shunts pulse duration, making the pulse more of a spike. At some value of capacitance, input to the meter circuit averages out correctly for full-scale deflection at max rpm. $35 is an outrageous amount of money for a capacitor, but if it works, it works.

Alright, that's good to know but slightly over my head haha and I payed $35 for the cluster Ecology gave me the capacitor for a dollar.

[obsidian]

These are called Noise filters. They were notorious on the 90 DSMs and one of the main reasons a lot of people don't get a 90. You can simply bypass this little guy by making a jumper wire into the harness that it plugs into. At least you could on a 90 DSM (I have a 90 Eagle Talon).

[lush90]

Does your sport cluster have a 4x4 indicator? The only clusters with tachs that I have seen are 2 wd or at least that is what I thought.

[obsidian]

The truck I just got my cluster from was 2wd. It was a sport model max. 94.

[ultrakill]

Hey Iceman, thanks for the post. You helped me solve my tach problems on my 1990 Montero RS. Do you still have any of those LC filters? I would be interested in buying one off of you. The white wire on mine is completely lopped of and there is really no room to solder a new wire on.

Thanks!

[iceman]

Yes I'm pretty sure I have one or two of them laying around somewhere although it might take some digging lol. I will look around today and if I find one ill send you a message.

[Traven1188]

Hi, I can't attest to the V6 because I had a G54B in my 88 but I can say a few things that were true in my case. I also realize this thread is way old lol

1). My 88 had the simple 3 gauge cluster. I found a sport cluster at the local junkyard and popped it in and it worked no problem. Again not sure about the V6 models but I believe that most models of vehicles are manufactured with some sort of standardized wiring harnesses installed. The cost of making multiple versions is greater than the extra material used installing in a vehicle which may have wires that are never used. Plus those wires would need to be run should the missing components ever be installed. For example: some one wants a sport model which includes let's just say for simplicity special wheels, gauge cluster and bucket seats. The dealer has 0 in stock but 5 base models (forget 2.0 vs v6 etc). The ability to convert the base to a sport by popping in a new cluster without running wires is much more convenient and eliminates wiring mistakes from service techs.

FYI the wires for the dash clock are also there as well as cavities for speakers under the door panels.

2). My 88 uses the same part although the # is 284L01701. It is not the noise filter (again on my 88).

Its an inductive filter and its purpose is to ensure that the tachometer receives its signal smoothly and consistently instead of being subjected to massive changes.

The noise filter for me at least is a little black square with 2 metal prongs that bolts to the body, with both a blue wire to the coil(-) and a ground wire which clips into a network of black wires with brown dots that ground out before clipping into a white wire that eventually becomes a shielded gray wire terminating at the FBC ECM.

The 87 montero electrical service manual has this illustration. Screenshot_20210217-085131_Adobe Acrobat.jpg

[Chargerx3]

Thanks for the bump.

Its also important to note that not all Sport Clusters are equal. There are several part numbers out there for 4 cyl and v6 models. I don't know all of the differences, but there are hardware differences at least on the back of the clusters. They go as deep as to even the circuitry routing on the rear.

You will also notice the tach on a 4cyl has a 100rpm lower redline than the v6. And probably most important, the tachs will read incorrect if you swap a 4cyl into a v6 and vise versa. Be sure to get the right sport cluster from the start.