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Discussion Starter #1
Hi, I've got a 1967 Mustang Coupe, 289 engine without PS, AC or power brakes. I'm installing a MP Products 5-gauge instrument cluster (which is an OK product - more on this later) and have hit a couple of snags. I have read through a lot of threads here and believe I understand where I should start looking for resolution, but I'd like some amplifying detail, please.

The gauges all work, but they all 'tick' when the turn indicator relay is operating. I'm guessing that this is a vehicle voltage regulator issue, though the ticking goes away once the revs are up - it only seems to do this at idle. As far as I can tell, there is no instrument voltage regulator fitted - do aftermarket gauges require an IVR? This didn't happen with the original cluster, though the only electrical gauge fitted was for the fuel gauge - all the rest were mechanical.

The needle on the water temperature gauge does not start at the left hand extreme, with the result that it sweeps almost to 250F on the gauge when warmed up. I know that the engine (and electric cooling fan) keep the temp down to 210F. Can I assume that a lack of efficient voltage regulation will affect the needle starting point? I had to fit a new temperature sender, so I still have in the back of my mind that this unit could be faulty.

On the oil pressure gauge, it started off well, but when warmed up at idle, dropped to about 5 psi. I know from the previous gauge fitted that the steady idle was around 17 psi. Again, can I attribute this to poor voltage regulation?

The fuel gauge appears to register the correct level (full, when I filled it up), though it still ticks. The tachometer also ticks.

My starting point for rectification will be to replace the vehicle voltage regulator (I was going to do this at the outset of the restoration, then the shop didn't have one for me to buy and it continued to skip my mind) and go from there. From reading other threads, it appears I need to go for an OEM regulator - unless someone can recommend an aftermarket unit. But I'd appreciate anyone's thoughts on the impact of poor voltage regulation on gauge accuracy.

Finally, a couple of notes on the MP Products instrument cluster. The harness is neat, though it would have been better to use a harness connector that matched the vehicle harness, so it would just plug in, as well as effectively blank the ammeter and brake wiring. The mounting sheet for the gauges has not been cut to size so I am having to cut it to get it to fit into the dash. There is no provision for an ALT idiot light, so I am wiring that circuit up myself, and fitting a light to the mounting sheet and modifying the bezel to suit. There is also no wiring for a brake light (though there is a mounting point in the correct position behind the bezel) and I will have to do that myself too. Overall, this product reflects the fact that it is a lot cheaper than the competition but with some work it can look good - perhaps value for money, but not necessarily a finished product. Finally, there are instructions only for setting the speedometer/computer and a wiring diagram for the harness connectors and the speedometer sender. I spent some time working out how to calculate pulses per mile for the speedo - a full set of fitting instructions would have proved to be very useful!

Thanks! Kev
 

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What do you mean by "tick"? Is it an audible ticking noise or the the needles move a bit in sequence with the turn signal relay?

slightly off topic- does the panel fit well to the dash? I was contemplating buying just the panel and installing another set of gauges that I bought. Other than the missing features of the panel- how is the fit and finish?
 

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The needles move in time with the turn signal relay - but I've done a bit more on the diagnostics. First, it's only the turn signal relay that affects it - not the emergency signal relay, for example. So, I'm checked out the wiring for the turn signal relay, and it appears that there is a broken wire (creating a short, I think) in the harness somewhere - I'll be checking this out tomorrow night. The temperature gauge goes to full deflection when grounded on the block, so I'm guessing that the temp sender is faulty. I'll be changing that tomorrow too. Once I've done that, it should (?) be all sorted.
The bezel is the standard bezel, so no shocks there and once the cluster is fitted you won't see what's behind it. The panel that the gauges fit to is a flat sheet of thick plastic, screwed flat to the bezel and with holes cut for the gauges and instrument panel lights, but it has not been shaped correctly so I am having to cut that to fit into the dash. Happy to answer more questions!
 

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New update - there appeared to be a short/ground/bad connection in the +12V supply to the relay cct somewhere - that appears to have gone away once I started messing with the harness. I did find a loose conenction at the back of the ignition switch, but I have found nothing else suspicious. So, now my gauges don't 'tick' - result!

So now I am working on the temperature gauge issue. And I'm flummoxed. I've tried another temperature sender, with the same result - the gauge registers approx 120F when I switch the ignition (engine is not running). I've grounded the signal to the block and I get full scale deflection. Without any signal, the gauge does not flicker. I've tried another gauge and that displayed the same effect (i.e. approx 120F when ignition switched), but the needle also moved without a signal (I can't work that one out....). My next step was to go for a known good +12V and ground and then apply the signal - that way I should be able to determine whether there is a harness issue or not.

My question is - can I use the + and - from the vehicle battery? It's an aftermarket gauge, so should be good with 12V. Thanks for any replies.
 
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