Gas gauge, temp gauge: both dont work

**Leev** · 10-22-11, 1:25

3 years total, on my 2nd cluster, 2nd fuel pump assy.

When i first purchased the car, the gauge was iffy, but worked 95% of the time..

Fast forward a few years to current, gas gauge and temp gauge both are dead 99% of the time.

Depending on ambient temperature (really hot outside, or really cold) they might work for about 3 mins or less after start up, then die.

Like i mentioned, im on my second cluster, and fuel pump assembly is from an 89 PGT, as is the walbro pump. But before the change, it still was off and on, so that can be ruled out in the case of suspicion.

Grounds that ive unbolted, cleaned, sanded, and re-torqued:
-2 trans grounds, airbox side
-fuel rail ground, t.b. side
-timing cover ground, and egr valve area ground
-fuse box ground
-a mics. ground to the left of the cluster

I did search of course, found a couple related threads, but no definitive solution or conclusion.

If you'd like pictures of anything, more info, or more specific info, please just ask.

3 years without knowing your fuel level..can you imagine?

**ugly mx6 guy** · 10-22-11, 9:24

It looks like you've tried used parts so far, if I'm wrong tell me. If not though have you tried a new fuel sending unit? I understand you're stuck with the used cluster thing. The temp gauges are famous for not working or barley working. When I first bought my car it had the exact problems. The ultimate fix was a new fuel sending unit and then an used gauge cluster next. Good luck, I kind of know your pain.

**Leev** · 10-22-11, 12:36

Quote:

Originally Posted by ugly mx6 guy

a new fuel sending unit?

To be exact, not NEW, but ive switched between the mx6 assembly, and the PGT assembly, and on top of that, ive taken both sending units apart and cleaned the internals.

still nada.

and its BOTH gauges, the coolant and gas, they die together, and flick on together (if and when it does)

**ugly mx6 guy** · 10-22-11, 17:42

It sounds like more of a wiring problem. Does the low fuel light come on when you're low? At least that would give you a warning before you run out. There's a ton of differences between sending units on these cars. Stuff like trim level,trans type, turbo or n/a and even digi dash or analog. Good luck with your problem.

**Leev** · 10-23-11, 3:43

Quote:

Originally Posted by ugly mx6 guy

Does the low fuel light come on when you're low? At least that would give you a warning before you run out. T

Wouldn't that be nice..

but no, the low fuel light is perma-on, since the swapped PGT pump assy, there's a one prong connector that doesn't have a home.. i would assume it has something to do with the light, but not the gauge as it still works that 1% of the time.

**Leev** · 10-25-11, 19:23

I didn't expect anyone to care lol, so i thank ugly mx6 for his advice..

but seriously, no one else wants to piss in the wind and offer anything helpful?

**Leev** · 10-30-11, 5:38

187 views

lol...

Its like a group of people staring at you from behind the glass, "hey i can see you" i say, to which the crowd responds "...."

Unless your a long time member and tight with the already shrinking original community, no one gives a [shizzle] about your problems, you only make enemys, and you prove your reasons to say F-it and go anywhere else with every post.

Prove me wrong mx6.com, cause so far, Ive only been proved right.

Dammit i just want a working gas and temp gauge..

last time i saw them working, it was on a different mx6, in an ONLINE VIDEO.

**blackmx6** · 10-31-11, 11:19

i have a spare cluster mtx analog, but when's the last time you changed your fuel filter

also, just cause you change the actual pump from the pump assembly might not be your problem, it might be the assembly itself has a faulty sensor that doesn't detect the fuel level correctly.

the temp, mine creeps up and down all the time, but i blame it on the thermo sensor, prob on it's last leg.

thought it was the harness itself as it was dried out/rotted, but replaced that and still have the same problem. might want to look at those things first then blame the fuel reg, rail, pump or filter.

**Leev** · 10-31-11, 15:01

Quote:

Originally Posted by blackmx6

but when's the last time you changed your fuel filter

hmm...about 3-4 weeks ago.

Quote:

Originally Posted by blackmx6

the assembly itself

which is why I've played musical chairs with 2 separate assys, and 2 pumps.

cleaned both, tried both.

Quote:

Originally Posted by blackmx6

then blame the fuel reg, rail, pump or filter.

see the main point of this is, its the coolant gauge AND gas gauge, they both die together, and both randomly work together.

its not a one or the other. its connected by a flaw somewhere...like a ground that somehow I've missed....

thanks for the reply btw

**concealer404** · 11-1-11, 8:27

Quote:

Originally Posted by Leev

187 views

lol...

Its like a group of people staring at you from behind the glass, "hey i can see you" i say, to which the crowd responds "...."

Unless your a long time member and tight with the already shrinking original community, no one gives a [shizzle] about your problems, you only make enemys, and you prove your reasons to say F-it and go anywhere else with every post.

Prove me wrong mx6.com, cause so far, Ive only been proved right.

Dammit i just want a working gas and temp gauge..

last time i saw them working, it was on a different mx6, in an ONLINE VIDEO.

Or maybe... it's just because we don't know? I've been watching this thread in the hopes that i can learn something for future reference, but i've never had this problem, never really heard of this problem. So there's probably 20 views with no replies accounted for.

But hey! Here's a reply! Good luck!

PS: i'm going with wiring. As to where and what the problem is? I can't diagnose that over the internet. Time to break out a multimeter and the FSM.

**ugly mx6 guy** · 11-1-11, 10:37

I really think this comes down to the cluster somewhere. If it was one thing (fuel) I would say sending unit more than likely. But both fuel and temp working that way together would indicate to me some sort of cluster wiring or a solder issue in the board. I hate to suggest it, but try a different cluster if you can find one. Remember one thing too, the temp gauges aren't very reliable on these cars from personal experience. I've read plenty of stories about other having problems with them too. I do know your problem dealing with a non working fuel gauge. It took me several months before I got my problem sorted out when I first bought my car.

**Mazda 626** · 11-1-11, 11:10

Have you even look at the wiring diagram?

PS: Ppl still showing you love...

**Leev** · 11-2-11, 12:35

Quote:

Originally Posted by Mazda 626

Have you even look at the wiring diagram?

PS: Ppl still showing you love...

(After bumps and begging for it...but whatever)

Anyway, diagram?

Studied it.

Traced all the wiring I could, down to every relay and fuse and ground, all good at a visible level.

Havnt gone so far as to break out the multi-meter, so that can be next.

Now to those saying its the cluster, when I took the original out, and replaced it with the current one, both gauges instantly flicked on and moved, but within a few mins, went back to dead...

This really makes me think its not the cluster, but some weird problem elsewhere....

But where?

I guess ill take concealer advice and break out the multi meter..make sure the sending unit is in fact spitting out a value.

Ps: 'mazda 626' I love your sig..makes me want to share a laugh face to face with you.

.....

**concealer404** · 11-2-11, 13:31

Visual check won't do anything but showing you if there's an actual break in the wiring, which what you described... already tells you that's not what's going on.

Unless you literally see a cut apart wire, it's ALWAYS multimeter time.

Or at least a test light, but that's not likely to help you much in this case.

Do you know how to do a voltage drop test?

**Leev** · 11-2-11, 13:53

I do, besides the main starting point, (battery, fuse box) where would you recomend I start testing?