The boat is new to me and when we bought it, the original digital gauges didn't work so I replaced with the Faria tach and gps speedo.  When we lose the rpm's, both the tach and perfect pass lose the signal.  That leads me to believe it's not the tach but the signal.  

Maybe this will help

Click on the link and go to page 6-4 for the tach circuit wiring

If you're looking for the 10 way connector part 7 in the diagram, it's really an 8 plug connector on a PCM Gt40

As an added bonus, now you have a GT40 manual if you didn't have one already 

http://www.planetnautique.com/CorrectCraftManuals/GT-40%20Service%20Manual.pdf" rel="nofollow - link

What if you unwire the tach, does PP then work correctly?

I know nothing about PP, but the answers to the above would probably be helpful 

Check the voltage the PP is getting especially when it decides to malfunction. Use a VOM and NOT the gauge at the helm. 

Where the PP at the helm is getting it's power. 

Todd,

It's come up on site before that the PP's are sensitive to low voltage and the reason I suggested checking the volts. 

What year did they start using the gateway box?  ...............At least a couple years or so after 2002

Todd,

Digital or analog doesn't make a difference. Unless you get a very high end digital, they typically do not react very quick to short spikes in readings. There are times when I actually prefer an analog because you can see the needle twitch when there's a spike. 

8122pbrainard wrote:   There are times when I actually prefer an analog because you can see the needle twitch when there's a spike.

"TWITCH"

Yes you will be fine with ether a digital or analog.

David is just confusing the issue. 

David,

Sorry you've never had the oportunity to see an analog meter needle twitch. 

I think you have Pete twitching right now 

Easy enough to find out how long a "spike" lasts. Not very long.............one billionth of a second.

I think Pete has made up this "twitch" term.

By the way Todd, back to our regularly scheduled programming, I don't think you have a Faria gateway box to have to worry about in your 2002. Key word being "think" 

Not I but I feel sorry for Todd after Dave almost had him going out and purchasing a tektronix.oscilloscope.to measure a simple voltage check on a PP. 

Your 02 has Teleflex gauges right? Maybe your 02 has a box with a different name like "black box" 

It's called a PME box, it has breakers and relays to function with the keypads on the dash.

DV Skier has an 04 with a Chevy and I'd figure Faria gauges so he may have a Faria gateway box in a different spot.

Not that it really matters but was it just the tach and speedometer that got swapped or all the gauges?

I suppose if it's your black box that's the problem, you'll be spending lotsa bucks, probably enough to make you twitch 

What are you boating in? I didn't know you have a large yacht were the stern overhangs the transom! 

You want to look for low voltage. The PP's don't like low volts and the reason I suggested getting a reading. Don't worry about the twitch. I should have never brought it up. I only mentioned the twitch when I said there are times when I actually prefer an anolog gauge. Again, for you to get a voltage reading, you can use ether a digital or analog. Again, don't worry about the twitch. Put that out of your mind! 

4 hours!!!   That doesn't surprise me at all. 

 Where did you get the reading? If where the PP is getting the volts at the helm, that's a good reading.

Regarding PP's and low voltage, there are several threads on members having to upgrade their wiring up to the helm due to voltage drops affecting their PP's. 

Todd,

Check and clean all the connections in that wire. If there's any connector plugand sockets, open them up and take a close look. Use dielectric grease when reconnecting.

BTW, it's not a "short" but it would be an intermitant "open". Many misuse the term "short". 

Looking back, I don't see that you unplugged the PP and drove the boat to see if the tach malfunctions  with PP unpowered.

I'd do that, so you can say for sure that the problem is not in the PP or the tach, then you can look at the diagram (Fig 6-4) that's been referenced a couple of times by a couple of different people.

Only you and the PP guys know what you have for a PP setup, but I figure they could tell you how to pull the tach signal from upstream of the "black box" and power it from the battery too. 

They had PP for GT40's before they had the digital gauges so there must be a way to get that signal relatively easily.

The tach signal starts at the coil, goes thru the 22K resistor and your 8 plug connector along with the associated wiring to get to the black box.

You really don't know that it's a power loss at all and going by your voltage numbers from the other day, it doesn't appear to be. 

It looks a lot more like a signal loss, but I think you already know or suspect that 

Maybe you should unplug the PP and go for a ride............call it troubleshooting to try to find your problem 

The 8 pin connector is at the back of the engine and connects the engine harness to the boat harness that goes to the dash.

You can find the gray wire right there and it runs up to the dash area.

The 8 pin connector doesn't connect to the ECU.

Withoiut a diagram of the boat wiring, black box and it's connections, I don't think anybody is gonna come up with any suggestions.

If you can't get an answer from PP, try calling Jody at Florida Inboards in Panama City FL with your problem, he does plenty of work with  PP 

Here's a link below to some of his info

http://www.google.com/search?gs_ssp=eJzj4tZP1zcsq8w2tsgpMWC0UjWosLCwNLYwTjNJMrBMtDROtbQyqDAzSDVKMko2Mkw2SDVOMk7yEkjLyS_KTElUyMxLyk8sSikGALwbFQg&q=florida+inboards&oq=flo&aqs=chrome.1.69i59j46l2j69i57j69i65j69i60j69i61j69i60.3264j0j7&sourceid=chrome&ie=UTF-8" rel="nofollow - link

I left Jody a message so hopefully he calls back.

I haven't been able to run the boat with PP disconnected due to weather but I will try it.

In the meantime, I crawled behind the dash and push dielectric grease in the connector but struggled to find the other connections back in the engine.  Is this grey wire the tach wire?

Thanks again for helping instead of banning me from this site!

Have you looked for this 8 pin? 

KENO wrote: The 8 pin connector is at the back of the engine and connects the engine harness to the boat harness that goes to the dash.

Remember, you just don't want to add the dielectric grease to them. Make sure the male and females ends are cleaned up first. You what to look for corrosion that may be the source of the tach problem.

 

If you do find that any connector needs cleaning, I've found that pipe cleaners work great on the female sockets and a Scotchbrite pad works on the male pins. On terminals and studs, the Scotchbrite works great on them too.