1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

oil pressure gauge malfunction?

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Old 01-28-09 | 05:50 PM
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From: South dak
oil pressure gauge malfunction?

quick question: does the electronic oil meter on 13b's often malfunction.

i wonder because mine is reading low to zero on oil pressure so i cracked the line going to the turbo and it seemed fine and when revved it flowed alot more. i'm just worried because i swapped in a turbo 11 and neglected to replace the oil pump or the chain (bad idea).

so i'm wondering if the sensor usually goes bad (i swapped it with an old one and they seem to read the same) or maybe the chain is slipping on the cog? or the pump is going all together?
Old 01-28-09 | 05:55 PM
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From: Lynchburg, VA
I would recommend getting an aftermarket mechanical oil pressure gauge and see what your pressure really is.

Does it always read zero?
Old 01-28-09 | 09:41 PM
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From: South dak
not always zero sometimes it will move but nowhere near as high as the fsm says it should. like near 20 max probably. do u know if i could put a mechanical gauge in the same place as the electric one?
Old 01-28-09 | 09:53 PM
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You could, but would need an adaptor. The other option would be to drill/tap the banjo bolt on the rear iron and measure from there. It could be a problem with the gauge itself (let's hope). Since you are measuring something, it probably isn't a wiring problem.

Let me ask you this...did you put teflon tape or anything like that on the sender threads? If so, the teflon can increase the measured resistance and give you a false reading.

What year is the engine out of? Has there been oil related mods done (like bigger oil jets)?

Anyway, get a mechanical gauge on there ASAP. That way we will know if the oil pressure is low or if it is just a problem in the measurement.
Old 01-28-09 | 10:29 PM
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as far as i know (definitely true for 12a first gens) the stock oil gauge sucks big monkey nuts, i imagine its also true for the 13b's?....most people opt with an aftermarket one for accurate readings.
Old 01-28-09 | 11:29 PM
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From: South dak
the motor is a 90 i think or at least an s5. there r no oil mods its bone stock and no thread tape or anything like that. i thought about putting a guage on top the bolt that feeds it over to the turbo but not sure if i can find those kinds of parts here (in south dakota). at any rate i will try to clean the threads and the connection to the gauge
Old 01-29-09 | 10:48 AM
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I had this happen to my car years ago with the stock 12A. It turned out to be the senser going out. Sometimes it would show a small amount. I also re-soddered the conections on the back of the guages and now they all read right.
Old 01-29-09 | 05:07 PM
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From: South dak
put a mechanical guage on. one with a tiny hose to the guage and it reads about the same as the electric one. nothing at idle and about 20 psi at 3k rpm. is it possible for the pump just wear out slowly? wouldn't it just pump full pressure or none at all? with only the hose connected at idle it just drips out.
Old 01-29-09 | 05:16 PM
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No good. You need to get that fixed ASAP. Now we know it is not a problem reading the pressure. The pressure really is low. Here is why I asked about the year of the engine...

There is an o-ring that goes between the front iron and the front cover. Using the wrong o-ring or forgetting it all together, you will have low oil pressure. If you had oil mods (like the bigger oil jets), that would cause low pressure too. I doubt it is your pump. They typically last a very long time. Usually the pump and chain are in spec and can be reused.

Here is more about the o-ring problem:

http://www.mazdatrix.com/faq/oring.htm
Old 01-29-09 | 05:33 PM
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From: South dak
damn, thanks alot. so it looks like i used a gasket and the teflon ring with the o-ring (completely wrong). but since i have a first gen front cover and turbo 11 motor i'd just use the o-ring no teflon and silicone around the front cover right?

since i have it off should i replace the pump and chain anyways?

and also do u think there could be excessive wear from the low oil pressure? i've driven it only about 200 miles with the new seals, and its kind of noisy when running sounds like a valve tick if it were a piston motor
Old 01-29-09 | 05:40 PM
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From: South dak
redo: since its on the casting i'd use the teflon and o-ring and just silicone the f out of it
Old 01-29-09 | 05:56 PM
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From: Lynchburg, VA
yeah, I would think teflon ring + o-ring + silicone. Maybe someone with a TII swap can verify.

You can certainly check the pump and chain and replace if needed. However, if there is damage, it is already done and fixing the pressure issue will not undo the damage.

It is vital to make sure that you have good oil pressure (especially on a rebuild). Not saying you're screwed, but this is one of those things where it is important to catch right away. No reall good way for checking damage without tearing down. Drain the oil and check for metal. That is about the only easy way to check.

Sorry, man. Hope it will be okay.
Old 01-29-09 | 07:41 PM
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From: South dak
word, well thanks for the help, hopefully my next post wont be about another rebuild
Old 01-29-09 | 08:58 PM
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RacingBeat part number: 11802

Get an autometer temp/pressure gauge for the oil and read it off there. My old stock gauge was broken, I got all the above parts for under 100$ and works great.
Old 02-06-09 | 02:06 PM
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From: South dak
so here's the scoop. bought a new o-ring and teflon ring from mazda trix. did the complete front cover rebuild (by the way one of the needle bearings was getting crushed, just like the FAQ page on mazda trix said it would be). Fixed that siliconed the front cover with new ring and teflon and reassembled everything. started it up and the oil pressure was good, idle was perfect and it sounded awesome. Some two minutes later she lost oil pressure pretty much back to where it was when i first started. i'm thinking that the o-ring is getting squished into the oil passage of the front iron (plus i never even found an o-ring when we disassembled it in the first place and i know i put one on.) my question is: has anyone else ever had this problem with squeezing the ring into the oil passage? and if so how do i fix it because we were super careful about putting the ring and teflon and silicone. i dont know what else to do.
Old 02-06-09 | 07:32 PM
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nm i got the problem figured. called mazda trix. need only teflon and silicone not the o-ring. thanks self! jk next thread will be my dirty 1st gen pics!
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