Logo
FULL SITE MENU

Water Temp gauge trouble

M

mashed_finger

Member
Greetings all:

Just got a new VDO water temp gauge and matching sender, installed the thing and it worked intermittently then quit; if I hit a deep wake hard it would work until the next bump and then nothing. Checked all the connections, every is well connected. So I grounded the sending wire at the sender and turned on the key and the needle did not move. So I grounded the sender at the back of the gauge and turned on the key and the needle moved from zero to max temp. So, I either have a bad connection some where or a broken wire, which would be my luck.
What I want to know is, can I just run a new wire from the engine temp sender to the sender connection on the back of the gauge, and just bypass having to chase down the bad connection/break, and fix it at another time (when I have the time)? Or is this wire connected in parallel with another sender, and there fore must be fixed in-line. The thing is, all the other gauges work as normal. When I looked at the wiring schematic in my Seloc manual, it doesn't really clearly show what if anything else it might be connected to, except possibly the pressure sender. I assume this could be an oil pressure sender but am not really sure. Since I have the Ford 5.0 V8 there is another sender just to the right of the water temp sender on top of the intake manifold that has the same color wire, and I am not sure what it is. Especially since the oil pressure sender is down next to the oil filter.
A new wire would be much easier for the time being, but if I really need to chase the thing down I can do that also, but would rather leave that for next season. Any thoughts would be helpful. Thanks in advance.

Rick
 
Ummm, why would I do that...., of course if your talking about the brand new VDO water temp senser, it was just installed 10 days ago, in a perfectly dry compartment, so it has no rust, and it is a single pin engine ground unit, with one wire. The wire is tan from the engine sender to the back of the new VDO gauge. According to Seloc to test the gauge to see if it is faulty, you ground the senser, turn on the ign., and viola', if the needle swings from zero temp to max temp, that gauge is good. The test did not work from the engine senser side, but it did work perfectly from the gauge side, so it is eithor the wire, or an up line connection that has gone T.U. some where. I was just wondering if running a new wire directly from the sender on the engine to the sender pickup on the back of the gauge would work. All the gauge does is convert factors of OHm from low to high into needle readings on the gauge. I just want to know from somone on the forum who knows a bit more about how these OMCs are wired if that will work or not.

I swear, these boats are wired as if Lucas electric bid the job, no wonder the Brits like warm beer. Any help would be most appreciated.

Rick
 
Your not getting what the Chief said. All the wires from the engine up to the dash go through a big 10 pin Cannon barrel connector, it's quite common for corrosion to get in there, have a look at this link for reference, see the water temp sender down near the bottom with the tan wire, it goes into the big connector and from there up to the dash. You are describing classic symptoms of a corroded or loose connection in that connector. It's usually mounted up high at the rear of the engine.

http://www.selocmarine.com/content/manuals/3404/pdf/340410w154.pdf
 
Ok, I'm obtuse; I took that apart as I was trying to trace down wires, and all the pins looked good, could something have worked loose? My seloc manual shows a 2 color wire coming form the barrel pin receptacle that the tan wire pin plugs into, but something happens to it from there, because by the time it gets to the back of the dash again, it's tan. I see by the schematic you sent that it appears that the water sender wire and the oil pressure wire are one and the same? This just gets better and better, those wires were wrapped by some one who must have had stock in 3M, because there is about a mile of black tape to undo. But I'm gonna check where you both said again and see if I missed something; so my running a new independent wire, is that not a good idea, even if I left it for a short time? Crikey, this is irritating, there is nothing I hate worse than chasing down bad wiring. There is another senser on the right side of the thermostat housing and I can not find anywhere what it is, any ideas, the seloc manual does not tell, the oil pressure sender is down on the right side of the engine next to the filter, and is unmistakeable, but this one sender I can not find a description for, and it has a tan wire. It does not give any instructions for dealing with the ESA, I learned how to do that from this site. Is there a better manual out there one can get.
Thanks Bob and chief for your advise, I shall do as you both say. Rick
 
ok...you are mixing things up a bit. The water temp and oil pressure that are wired together are warning switches not the senders for the gauges. (I know this can be confusing) they are wired together because if you overheat or lose all oil pressure they feed an alarm up at the dash (the alarm is optional, you may not have it). As I said earlier the actual temp gauge sender is located near the bottom of the diagram by itself with a tan wire, the oil pressure sender is up in the top left corner with a light blue wire. Also the diagram in my link is more generic, you may not even have the addition oil/temp switches. Running a separate wire is a good trouble shooting technique but if that fixes it you should be able to pin point where the real problem is and do a permanent fix.

Also I'm curious why you had to replace the gauge and sender? could this problem be related to the original?
 
i swear that was my next question. Go ahead run a new wire i was just trying to save you work aint gonna hurt nothing. Just use the same gauge.
 
I am certain that I have mixed things up some, this seloc manual is a bit confusing, and you are right about the color of the wire to the actual oil pressure sender, it is light blue. It's this mystery senser on the right of the thermostat housing almost parallel across from the H20 sender, it has a tan wire. This OMC Ford 5.0 does not have warning lights, or buzzers that I can see anywhere. Usually I am a fairly decent Automotive (shade tree) mechanic, and known to be pretty good in the wireing department, but this boat wireing has me a bit confused. From my manual, it looks like some of the senders are tied together, now where ground and hot are concerned as well as the light, that makes perfect sence, but the senders; I have scratched a bald spot, on my bald spot!
The boat started overheating last year, the guy who owned it before me rebuilt the engine and bumped the HP/Torque a bit, but he never replaced all the bolt on's. Then I got it and guess what, I got to replace all of them, along with both water pumps and thermostats. The boat then ran much cooler to the touch, but the original gauge said I was running about 210 to 220 plus, even though it did not feel that hot to the touch, and I could not hear any boiling in the engine after I shut it down.
So I have this fancy little multimeter that does ever thing one could ask, and it came with a very long thin wired temp probe of the type that one can put inside a hose, and then clamp it shut. So I did that, and s***** the probe within about 2 inches of the bottom of the thermostat, clamped it up and ran the engine, and it said that I was running cool and normal, about 155 to 165 degrees, but my boat gauge still said I was really hot.
I decided that the thermostat sender was bad, so I went to NAPA, because they sell Siera boat parts here in Spokane Wa. for a good price, and bought one of their senders. I put it in and fired her up, and there was no difference, the gauge still read 210 to over 220, but my multimeter read normal. So I went back to NAPA and bought a real nice VDO gauge and it's matching sender, put the thing in, started the boat (with muffs) and she heated up to exactly what my multimeter said. So I was satisfied that it was fixed, but when I got her out on the lake, the gauge would not work at all, then as I hit a few good wakes, the new gauge started to work as it did at home. So I cleaned off some contacts when I got back home, and went back out last weekend and it worked for 5 mins. and then quit and did not work again.
I performed the ground test that the seloc manual said to do, and got no reading from the engine side, but got the proper reading from the gauge side. So I knew it had to be down stream from there. So now it is just a matter of running continuity checks in quadrants, but now that both of you mentioned the barrel plug, I am suspicious that I may have a problem there. The thing has a tendency to come unplugged in rough water, so I will have to find a way of tightening up those connections. I am going to run the new wire, but just for testing purposes.

Thanks very much for your help and advise, this gives me a different direction to look at, and hopefully I will find the problem. I was hoping for a major brain fart to help me solve this, but you guys helped with just the right kick in the a__, and knocked it loose.

Rick
 
the main barrel plug should have a wire clip on it. one wire could be bad in the plug itself one side or the other.

Just last week i replaced the radiator in my elantra with 142 thousand miles i now drive, about a year ago the water temp gauge stopped working.

So in went the radiator and for 7 bucks i hooked up a water temp gauge and the sender were all one piece wire and all. Hardest part was drilling a hole in the firewall, so many black elec, boxes and chit under the dash there was only one spot.
 
For the Cannon plug (barrel connector) I've always had a big SS hose clamp around it to keep them together. Those senders that you see tied together are really the alarm switches I was mentioning, they look like senders but they are either on or off, there is no variable resistance that changes like the senders do. OMC could have put them on your engine but the boat manuf may not have wired them up to an alarm. If you find both of them wired together (tan wire) and it just stops with a plug on the end you can buy aftermarket alarms and hook them up. This is just one example and it even includes the O/T and low oil switches.

http://www.jamestowndistributors.com/userportal/show_product.do?pid=11377
 
So I can clear that mystery up about what I thought were senders of some sort, and since I have no buzzers or idiot lights to speak of, and I do have a separate sender next to the actual oil pressure sender as well that is wired in tandem with the oil pressure sender. You would have thunk that Seloc would have included those in a picture of some kind.., at least it would have helped me some. Since I have no retaining clip on my barrel plug, I am going to do the SS hose clamp, that sounds like a winning idea.

I noticed in the wireing schematic that there are inline fuses in places around the engine, there wouldn't happen to be one of those attached somewhere for this sender wire, would there? Just wondering, now that I have you guys helping me out, it doesn't hurt to pick the brains of experts who might know if there is something else lurking I should check? If not, I am going to give the barrel connector a good looking over and I shall let you guys know what I find. Some time back, when I was going through this with the old gauge, someone wrote in that there could be current surges coming from a bad alternator regulator, that can effect these things, and even burn out a gauge, should I check on that as well. My alternator seems steady at about 14 1/2 volts, it may twitch a bit from time to time, but it all seems ok, I checked the diodes a month ago, and they were still only going one way. So anything you might think of off hand would be a help. I am printing all of this and adding it to my repair manual. Thanks for all the help.
Rick
 
Should not be any fuses on the ignition setup at all. Thats ok with the alt. i twitch every once and a while myself.

So with your gauge setup you have a common ground for all the gauges? The power for the gauges go thru one fuse ? And the fuse was takin out and the fuse holder is shiny and clean inside ?

And the connections clean the ground also? The main ground on the block is good ?

What do you have on the ends of the wires ? Maybe one is just being held on by a single strand of wire or green under the rubber insulator.

Want me to go away now ?
 
chiefalen said:
i twitch every once and a while myself.
Click to expand...

Chief...you should get that looked at....could be a sign of having too much fun??? :D:D:D


mashed_finger (must be a story behind that name eh????) here is a another link to an OMC dash wiring diagram for future reference http://www.selocmarine.com/content/manuals/3404/pdf/340410w202.pdf

The fuses at the engine (depending on what year) you will have 2 50 amp fuses in black rubber holders or 2 50 amp breakers and like the Chief says your regulator in the alt sounds fine.
 
You assume that the gauge and sender are good because they are new. Hah, I say. I am guessing that your fancy multi meter has confirmed that the gauges and senders have continuity.

If you had purchased a Faria gauge and sender you would not be scratching away at your bald spot. Just my experience that Teleflex pretty much sucks, and VDO I have never even considered.

Sierra stuff is my Plan B. They tend to buy "whatever" and put it in a Sierra bag hoping that it will be OK. I much prefer the OE stuff when I can get it.
 
Yes chief I have a common ground for all the gauges, and what looks like a common hot as well, I have ohm tested the grounds across the gauges and they all read about the same, and all the rest of the original gauges work well, it was just the H2o temp gauge that went T.U. on me. I never bothered to check the power fuse for the gauges since they are all wired together and all register the proper voltage when the engine is off, and when it is running..., should I still check this anyway? I have always followed the addage that if it ain't broke, don't fix it, line of thinking, unless I have a wild weed up my a__ that says replace it all..., which has happened. But no, I have not checked the fuses..., my boat has a line of reset buttons under each switch, and I don't know if the gauges are linked to those, since the Seloc manual doesn't even list them.

However, there is a main ground on the back of the engine, right where it would be hard for God to reach, that is not in good shape, lots of rust with about 4 wires and cables attached, I have tried to get it loose, and just about pop a hemorrhoid every time I try..., so come friday, I will put on a real tight belt and see if I can get that bugger loose. That hasn't bothered any of the rest of the systems on the boat..., but I know what your gonna say, so I am going to take care of that along with the barrel connector.

All the ends have good connectors on them, but some one put that water proof goo on each end. Some of that stuff seeped in between some of the connections to where there was very little left to make continunity with, that gave me fits when I first got the boat 3 years ago and I still have to deal with some other connectors that still have it on.

You could be right about a broken wire, it is what is suspect is my possible problem, the entire harness looks like it has been man handled one too many times, but I am gonna check all that we have discussed. No need to go away, I enjoy the discussion, besides, you guys have given me other ideas to check on, which I did not have before so thanks much.

Bob, thanks for the site, I have put that on my computer desk top, my boat has several breakers, as well as those fuse holders...those things are hard to get apart, can I squirt them with silicone to loosen them up? As for the Mashed finger, that is exactly what it means, only I didn't just mash it, I crushed it bone and all with a sledge hammer on top of a 2X4, I wasn't smart enough to get it out of the way. I blame that one on my stubborn Italian/German blood....gets me in more trouble. It would have hurt less if I had just cut it off....not a good day..., but thanks for asking, and all your good help.

2batsea, I hope that the gauge and sender are good..., because the new Faria gauge and sender I bought before the VDO gauge and sender were not. I was going to get a Stewart Warner..., but they really think a lot of their gauges! The VDO gauge is really easy to read, and has a stronger light than the Faria did, but after Friday, we shall see just what the problem is. I also have not had good luck with Teleflex gauges, but my throttle/gearshift is a Teleflex, and it will need to be replaced in the near future, and it looks like Teleflex is what I willl have to end up with. I have had good luck with VDO gauges in the past, I am hoping there is nothing wrong with the new one.
I haven't had any trouble with Sierra stuff "yet" but there is always the first time. OE or NOS stuff is great, unless the price is out of this world, as some of it has been..., but you are right that OE offers a better chance of no problems. My multi meter did confirm continuity at the gauges, the wire from the sender does not have continuity, and I did not check the sender yet..., but I will, thanks for the heads up.

Thanks to all for your help...I enjoy B.S.ing with you all!
Rick
 
Ok, here's the skinny; Bob and Chief were dead on correct about where to look first. It was the barrel connector, that was the problem; I had excellent continuity to the engine side, and to the dash side of both the male and female barrel connectors, but put them both together, and the gauge would not register a thing. The female side apparently was the corroded end, and I never inspected it 'cause it never dawned upon my feeble mind, that there could be a problem there, but I got out my ign. & carb. files and cleaned up those contacts. And I noticed that the pins, where the space that is cut in the center, had been completely closed together, and that all the spacers that should have been placed in between were gone, except one. So I spread the gaps so they were further apart, and filed around the edges, then repluged the 2 barrel connectors together, and not only my water gauge worked as it should, but my volt and fuel gauge quit twiching.

I got a large hose clamp and put around the male barrel connector end, and started the boat and everything works as it should, and I did not have to spend a whole day as I expected I would. So..., my hat's off to Bob and Chief..., and a hearty well done and thank you very much for the good advice!

Rick
 
Good for you Rick....glad you got that little annoying problem fixed but you know there's always another just waiting around the corner for you :):):)
 
Back
Top