Search feature sucks, crapweasel temp gauge

[MahtyMaht]

this thing is killin' me. It gets one more shot tomorrow, then, I'm gonna hack it, and run my own wires. This infuriates me, because it's dirtbaggin'. DIRTBAGGIN'! Boat's goin' to the water tomorrow, and I'd rather go irritated and tasting the dirt of failure than without temp info. The wires have already been run, (Mercruiser covered this), I just can't make'em work. The search feature here seems to suck, as It can't find a week old post about this. There are only 3 wires that matter - ground, hot, and sender. I hooked the gauge hot terminal to 12V, the ground to threads on the sender, and the gauge sender line to the stud terminal of a sender. It stayed @ 0. I put a lighter to the gauge, and it promptly started creeping up; Take it to the boat, and it pegs with a cold engine. I checked and got continuity at the dash ground wire and engine block, then turned the key to run, no voltage. Did the same test on the hot wire, got open, (no continuity to ground), with key off, 12v w/key on. 3rd wire is hooked to sender, and I got continuity between the dash sender wire, and the engine sender wire, so I hooked it ti the sender's stud terminal. Of course, it pegged immediately. Yeah, so apparently, 1+1 = 12 again today. Oooooookaaaaaayyyyyy. WTF????? Where is this thing scarfing an un-modulated 12v? How is it getting a full 12 past the sender? Oh my JesusGod I'm skippin' pi$$ed!!!

 

[JustJason]

Re: Search feature sucks, crapweasel temp gauge

Okay... If you want some real help try this.
1. Use some punctuation, it will go a long way.
2. Cut out the crap words and any other colorful adjectives you may have. It doesn't help us help you solve your problem.
3. Be clear, concise, and to the point.
4. We are not mindreaders, tell us exactly what you are working on. A good way of doing this is going into the "user cp (control panel)" and edit your signature to reflect the boat that you have. Make and model of the engine are a must, if you have an approximate year that will help also. And, if you have a gauge problem, tell us to the best of your ability the manufactorer of the gauge.

 

[NHGuy]

Re: Search feature sucks, crapweasel temp gauge

I feel your pain, stinks to have a problem.
I'm thinking ground loops. When gauges tell lies that's where to look, start cleaning...at the main harness links.
But also, what are you workin on, maybe someone else on here just fixed the same problem.

 

[Joshua Nichols]

Re: Search feature sucks, crapweasel temp gauge

The search feature here seems to suck, as It can't find a week old post about this.

Noticed that too did ya.. It's really picky that's for sure.. It hates OMC like everyone else here

 

[Haffiman]

Re: Search feature sucks, crapweasel temp gauge

Is this the one you are looking for?
37 sec search!
http://forums.iboats.com/showthread.php?t=439993

 

[NHGuy]

Re: Search feature sucks, crapweasel temp gauge

Haffiman, you are the geek.

 

[MahtyMaht]

Re: Search feature sucks, crapweasel temp gauge

You got it NHguy - That's me - still. I didn't mention the boat because I don't see that it matters. It's a 1988 Merc 454, B1. Originally had Medallion gauges, I'm using a VDO temp gauge. http://www.egauges.com/pdf/vdo/0-515-012-123.pdf I put the meter to the ground and hot wires with the key at run and at off, and got 12 on the hot with key at run, 0 at key off, the ground stayed at 0. Then I did a continuity check between the engine and dash ends of the sender wire, to be sure I had the sender wire. Bench tested gauge and sender, worked great. It's a boat wire problem, isn't it? Ground loops, huh? Wonder where the dash end of that harness gets it's ground. JustJason, I guess from your response, that my initial post was unintelligible, and for that, I apologize. When I realized that this thing had me beat again, I got all huffy and came in to post, lookin for new ideas. I've got some now, so here I go again - as always, thank you for the responses, gentlemen.

 

[MahtyMaht]

Re: Search feature sucks, crapweasel temp gauge

Still don't get it, but I found that if I ground the gauge and connect the sender wire and nothing else, the gauge pegs. This suggests to me that the tan wire ain't the sender, or it's shorted into 12V somewhere else. Ran a test wire from the sender to the gauge, hooked up +12 and -GND, no gauge movement. Now if I can just isolate the tan wire's 12v source....

 

[Don S]

Re: Search feature sucks, crapweasel temp gauge

You didn't use teflon tape on the sender did you? It MUST have good contact with the threads to complete the circuit.
Is your sender in the manifold or on the thermostat housing?

One thing you can try, with a big clip on a test wire, hook the big clip on the body of the temp sender. Then clip the other end to a good ground and see if you get a reading when warm.

 

[Alpheus]

Re: Search feature sucks, crapweasel temp gauge

The search function works great if you wouldnt use such a stupid title for your post.

"Aww, Come ON - It's a friggin' temp Gauge"

Honestly would this come up if someone was trying to do a search for a similar problem they are having???

And to make it worse, any info in this post would probably not come up again because of the title. Good job...

 

[rodbolt]

Re: Search feature sucks, crapweasel temp gauge

like I said before, some VDO guages require a VDO specific sender.
the tan wire does NOT get 12 V. never ever, if it does something is wrong.
with it unplugged you may see a 12V potential but thats not how it operates.
its dirt easy to test with a simple 0-400 ohm potentiometer from radio shack.
Most senders are of a negative temp coefficeint, some VDO temp gauges use a positive, as do some of their oil pressure senders.
means with the wrong sender its backwards.
so on the gauge, make sure the good 12V power source goes to the I terminal, the ground to the ground terminal. then check the tan wire from the gauge to the thermistor device ( temp sender) and see what ya got.
all that temp sender is,its a variable resistor that controls current for the needle magnets.
the magnetic field on one side of the needle is greater than the other.
so on the other we allow more current though the inductor and increase the magnetic field and it starts pulling the needle.
so it comes down to is the senders variable resistance going the same direction as to the gauge manufacturers requirements.
we can do it either way, one way isnt better or worse than the other.
but the SENDER must have the correct temp resistance coefficeint as the guage.
have you actually place a multimeter set on ohms between the sender terminal and the sender body? read the resistance cold then heat it and watch which way the resistance goes, it will climb up or down but if it doesnt your sender is bad.

 

[MahtyMaht]

Re: Search feature sucks, crapweasel temp gauge

Hey rodbolt - The VDO 240F gauge, they bill as 'marine', and they claim it to be able to use commonly stock senders. I did check the resistance of the sender at ambient temp, got about 450 Ohms. Merc thinks it ought to be 447, I'm thinkin' the gauge won't know the difference. I ended up dirtbaggin, and running my own wire. Temp gauge works fine now. I really appreciate your feedback, though, because it confirmed that I was not nuts as to how I thought this thing worked. I guess Alpeus is just one of those people who hates the way I talk. I write exactly like I talk, so I've seen this response before. Makes for log posts, but it's how I try to paint a picture of what I'm thinkin'. I'm sorry it's hard to interpret for some folks, but the search feature still kind of sucks. As always, I thank everyone for the responses, and again, I do mean EVERYONE. (Lookin' @ u, Alpheus).

PS - That's NOT sarcasm

 

[LAC_STS]

Re: Search feature sucks, crapweasel temp gauge

The search feature works fine. It's pretty much the same search feature as on many many other boards.

I never have a problem using it. Even to search for OMC. Granted your not going to find a thread if you title it in absolutely unsearchable words.

If your looking for a thread you started or one you posted in all you have to do is click the link "my replies" that's right under your screen name at the top of the page.

It's all pretty simple.

 

[MahtyMaht]

Re: Search feature sucks, crapweasel temp gauge

LOL - Never saw that 'My Replies' link before. Feelin' a little simple myself.

 

[LAC_STS]

Re: Search feature sucks, crapweasel temp gauge

If you subscribe to a thread you can also click "User CP" and then "list subscriptions"

If you choose to get email updates of your subscribed threads you can also just click one of the emails you get from a thread and then click the link in it and it will take you straight to the thread.

For the search feature, you just have to try different terms to search for until you find what your looking for. If your searching for a threads title then select "search titles" or if you want a ton of stuff to come up select"search posts".

If your having trouble searching for a certain word try putting it in " ". That makes the results come up only when they have that word in it. (that also works for Google and other search engines)