[Help]'97 Mazda B2300 fluctuating oil pressure

MisterMycelium · Feb 6, 2016

I have a 1997 Mazda B2300 that has made a slight ticking noise on occasion for a while now. Previously this noise was very rare and I usually took it as an indication that I needed to change oil (usually only happening around the 4k mile mark.) Recently my gauge has started becoming "wobbly" bouncing around a bit and even hanging low for the last 300 miles or so. I originally assumed I had an issue with the oil pressure switch and have inspected and replaced to no avail. I have now purchased an oil pump as matter of course and will soon be replacing, but I am not certain on procedure, nor am I certain that this is the cause of my issue.

To clarify some details for the helpful people here:

The ticking noise is now much more constant. Generally quiet on cold starts but after touching the throttle the noise seems to appear even when cold.

The motor was rebuilt around 50-60k miles ago without replacing the oil pump (a stupid decision) which has led me to believe that this may be my problem.

I have ordered a DNJ OP448 oil pump for replacement.

My questions to the fine folks here are:

One: Do the described symptoms portray a malfunctioning oil pump?
Two: Since the oil pump is directly driven by the timing belt, and I have not found this information elsewhere, does anyone have a good tutorial on the replacement procedure?
Finally: Is there any chance (with the oil being caramel colored at each oil change over the last 20k miles to my knowledge and without any trace of metallic content) that I have a more serious issue?

I have a great many other questions as well but I'm sure that many of them will be answered without asking

tomw · Feb 6, 2016

One: no, not necessarily.
Two:The oil pump is not 'clocked' to be in a specific position, so it does not care, and I don't think you have to disturb the belt to replace the pump.
Three: Define carmel colored. Most oil I have seen is golden more or less when installed, and will slowly turn darker in color with use, and finally will be black if kept in the sump for the 'recommended' interval. If you look on the dipstick, it should be mostly transparent, with slight brownish color. When drained, there will be more apparent color in the oil. So, 'carmel colored' may be perfectly normal.
Replacement of the oil pump in most cases will do nothing but lighten the wallet and provide some mental assurance. The pump is lubed at all times... First thing in line to have oil... It can be worn, and produce less pressure, if there are particles in the oil that wear the gears.
A flickering gauge may just be the voltage regulator dying. If you want to actually know what is going on, install a mechanical gauge into the port on the side of the cylinder head in place of the pressure switch. Ford installed a switch that signals pressure is above ~5psi, and the signal goes through a resistor to put the oil pressure gauge in the middle of its travel, no matter if the pressure is high or just above 5 psi. An actual gauge will tell you if there is an actual problem. You can do a temporary install, and then replace the switch if you are satisfied there is nothing wrong.
tom

enjr44 · Feb 6, 2016

If the pump was not replaced during the overhaul, I would assume the lifters/cam(s) were not either. So some valve lash tic could just be normal old age. What weight oil are you using? Maybe time to bump up the second number a little.

Oil pumps rarely wear out (not never).

Ford/Mazda did not use an oil pressure gauge. They use a on/off needle (instead of a light). So if oil pressure is anything above 6 (I think) psi, it will read normal. Less it will read zero (where it sits with the engine off and key on). So reading "low" does not occur unless it is the "gauge" or a wire problem.

MisterMycelium · Mar 14, 2016

Thanks for the replies and sorry for the late response. Computer died and phone is impossible to navigate. So here's where I am. Faulty connection was the likely culprit for the pressure gauge, as I have ~57 psi cold start and ~22psi after idling for 20 minutes or more. Confirmed with mechanical gauge mind you, as well as ~50 psi at 2k warm. Definitely keeping this gauge installed. It seems a bit more likely that my noise is coming from the injectors. I have used my stethoscope and hear a teeny bit of noise from the valve cover, but rather loud ticking from the injectors. I don't think they're the same pitch though. Mind you my stethoscope is likely older than myself, what is normal pressure in these?

PS the oil pressure gauge is leaking a very slight amount and does need to be re installed. There may be some slight off reading caused by the leak, though I wouldn't think more than 1~2 psi

Mark_88 · Mar 14, 2016

Fuel pressure on a 97 is approx 40 psi...between 35 and 40 is OK...

A 2.3 that doesn't tick or make other noises to me is probably not running and never been started...

Mine made a rather intimidating rattling noise about once every few months and then quickly went away...for no apparent reason.

It could be your injectors ticking...and an exhaust leak in the right place can sound very much like a ticking engine...only difference is you can smell the exhaust leak.

I have found that in most cases turning up the radio is enough to hide the noises from under the hood enough to calm my nerves...and most of my engines last five or six years and run the normal course of good and solid to needing a rebuild or replacement...which is somewhere around the 200,000 mile mark...and they would have gone further if they were fuel injected as opposed to a leaky in need of rebuild carburetor.

MisterMycelium · Mar 15, 2016

I was running 10w30 but am now running 5w20 again. The sound has had very little change over the course of the last oil change. I did use seafoam though with a degree of success in quieting my tick. It stayed quiet for about 40 miles or so max, but has since been a little louder. This truck has 225k on it and I've rebuilt once before. I did replace the vast majority of everything in the head. (Basically everything minus the obvious parts). I do have an exhaust leak, made obvious by palming the tail pipe. Right around the flange connection for the cat. As well as the cat itself. A light noise used to come from it, but it's a bit more wallowed out now.

Mark_88 · Mar 15, 2016

I wouldn't say to totally ignore any or all noises...just to clarify.

Definitely pays to find the source and keep an eye on things and it sounds like you are being very careful with things...that is always good. And as you probably appreciate as much as anyone, these things are not inexpensive.

I wanted to clarify on my post also that the engines in my truck were already high mileage when I got them or had them installed. The first 2.0 had 250,000 km on it when I bought the truck and I added another 100,000 or so in two years of really hard driving (commuting) with ticks and oil leaks.

When I finally replaced the 2.0 I put in a 2.3 that had 140,000 km and drove that one another 100,000 km over four or five years...and I beat the snot out of it by hauling on average 600 lb loads hundreds of times for about a year or so before it finally blew out something and caused more smoke than go.

If it isn't smoking badly and still gives you good power I'd suggest maybe rounding up parts for another rebuild or just get a second block and have that ready/rebuilt for you to drop in whenever you see the telltale signs of excessive wear.

I tried to do it that way on my last go round but was sort of forced into an outright replacement...

MisterMycelium · Mar 16, 2016

So my noise has developed into a misfire. Haven't pulled codes yet, but I have two thoughts. One: low fuel pressure causing fuel delivery problems, or two: valve train issues. I have inspected the spark in the last 100 miles, all plugs are good, had one with a crack so went about with replacement. All seemed good. I also have seen a slight oil pressure fluctuation. Needle bobbing a slight bit, around +-1 psi for a 2 or 3 psi swing. This oil pressure fluctuation did resolve itself after driving for about a minute. This was well before the misfire.

[Help]'97 Mazda B2300 fluctuating oil pressure

MisterMycelium

New Member

tomw

Well-Known Member

enjr44

Active Member

MisterMycelium

New Member

Mark_88

Well-Known Member

MisterMycelium

New Member

Mark_88

Well-Known Member

MisterMycelium

New Member

Sponsored Ad

Sponsored Ad

Staff online

Members online

Member & Vendor Upgrades

Latest posts

Truck of The Month

Recently Featured

Follow TRS On Instagram

Latest Album Photos

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals