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Hello Everyone,

     I own a 1997 Mazda 626 4Cylinder, and although I have tried my best to keep up with it, lacking proper funds to make repairs over the few years as i should have, I've recently run into a debilitating issue. While driving a couple weeks ago, I lost charge voltage, as well as loss of acceleration and power steering. I managed to get home, and after attempting to salvage the alternator I had, I ended up replacing it. The alternator was in bad shape, damaged brush, one of the coil wires came undone, and I'm thinking there was regulator damage, but i can't be sure. In any case, I replaced the alternator and was getting good voltages again. I'm driving to work and encounter the issue again, so I stop and do some checking of the wires and voltage at the battery. Then I notice one of the belts quite literally stopping while the engine was running. The AC compressor was seizing. i turned off the AC and removed the relay (so i wouldn't turn it on out of habit as I live in Florida...). I was still having issues however. I bought a smaller belt and took the compressor out of the loop. After all this, I got good voltage at the battery, and didn't lose power steering. Although I was getting closer, I was still having issues with acceleration.

I've had a couple codes for a while for the Catalyst warm up efficiency and the downstream o2 circuit, and stupidly never took care of it. However after checking the computer, I had two new codes I'd never seen.

P0400 Exhaust Gas Re-circulation Flow

P0340 Camshaft Position Sensor A Circuit

Prior to the aforementioned issues, these two codes had NEVER shown up.

I pulled the EGR valve (damn it was clogged...) and cleaned it out. I reinstalled the valve and disconnected the downstream o2 sensor and checked the connections, which looked good. Reconnected it, and cleared the computer.

After driving it, I still can not accelerate, and so far, only the P0340 code has returned. Given what i've been reading, I'm sure this is what's causing my inability to accelerate. Another thing I noticed though, is that while coasting or sitting idle , is that the engine has vacuum, but if i push the peddle to accelerate, it moves towards 0 but then mid acceleration it climbs back to high vacuum. Is this normal?

I have almost no money, I can't really afford to buy a new car, and I can't afford a mechanic. Any help would be GREATLY appreciated. As it stands right now, I still have to drive it because I have to get to work. I'm babying the accelerator for the time being, and avoiding situations where i would have to accelerate quickly.

Thank you for your time and patience with me! I have severely limited knowledge and limited tools, but... I'm trying lol


also, the voltage in one of the images, is voltage at the OBDII interface, with the radiator fan and lights on. The voltage at the battery is of course higher.




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I won't have a chance to do anything until this weekend, but I took this video, not sure if it will help any. As for the o2 code, I've admittedly ignored that one for a while... I'm pretty sure that sensor is dead or dying, so I'm going to replace it. I also plan to clean out the throttle body and egr valve better and replace the intake, exhaust, and throttle body gaskets. I've had the code for catalyst warm up efficiency below threshold for a while in the past, so I think I need to replace the front catalytic converter.
My starter is bad too, so that's on the list to fix.. I feel like it's not worth fixing, but... I can't afford another car either

Yes I have lacked maintenance... Having an only income taking care of a family didn't leave much spending money :/ I originally planned to get another car by now, but here I am.


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  • 2 weeks later...

Okay, been a bit longer than I intended, however, I have managed to correct the timing. Both cam gears were definitely off.  She starts, runs, and accelerates so much better.


So far I have replaced...



Exhaust gasket (as well as a missing bolt)

Cracked air intake past maf sensor

Downstream o2 sensor

Battery terminals


I have another gasket for the exhaust manifold to front catalytic converter on the way to seal a leak. I also have a new throttle body gasket and intake manifold gasket to do when I have time. I'm getting 14.3V at start and after driving for a bit with the radiator fan on I get 13.9V at the terminals(at idle).I haven't had any codes return yet, but I'll be keeping an eye on it!

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  • 2 weeks later...

I decided against changing the compressor and had the balancer replaced for 73 dollars since i couldn't get the bolt to break lose on my own..

Idle is smoother, there's a bit less vibration from the engine, and the voltage I get at idle is steadier.

Still getting two codes though.

catalyst warm up efficiency below threshold

EGR flow low or no flow.


I haven't taken the throttle body off to clean it properly yet, I have a new gasket and some cleaner for it. So hopefully that code will go away. As for the catalytic converter, I hope i don't have to replace it. Lol

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