Intermitted Power Loss, Please Help!

I hear that !!








I guess your son should get the car then...

He's probably gonna crash a few cars as he learns how to drive anyway, might as well sacrifice the nearly dead one.
 
Found It !!

my first guess would be a worn out ignition switch. you can get one for about $40 on rockauto.com and install it (very carefully), and send it back if it doesn't fix the problem. I had a similar issue, but different in that it was a crank/no-start, rather than a no-crank/no-start. replaced battery, coil packs, plugs, wires, a VERY corroded grounding wire from the negative terminal to the frame. would often start on it's own, then kill itself in the first few seconds, then crank/no-start for a while. I was thinking maybe a fuel system issue, bc when i jumped the fuel pump relay port i could get the fuel pump to run, but not with the key. also, if the fuel pump was faulty, then it would show signs while running of lack of fuel delivery...but it was normally fine once i got it running. Moving on.

Then I was thinking maybe the ignition switch was sending inconsistent signals to the computer to run or not run the fuel pump pre-start. So I bought the ignition switch. Was going to replace, but after a mechanic mentioned that it could possibly be a coolant temp sensor sending false temp readings to the computer pre-start, I pulled and cleaned that off from black as F to shiny gold and new with a wire wheel on the end of a drill...started every time. has ever since. crazy, but hey, got my money back for the ignition switch.
(braindead
 
Okay, a new update.

The problem came back. I reset the ECU again, due to me fixing a small fuel tank leak that was created when I did the fuel pump and filter. The power loss issue came back, and also the stalls. I didn't totally lose power to a stop, it was only for a half of a second each time, but still a problem.

I am not sure what is going on, and I don't have a crap load of time of trying to figure it out, so I am going to just replace a lot of the sensors. I am about to order the parts now.

I am replacing the IAT sensor, ECT sensor, camshaft positioning sensor, and the crankshaft positioning sensor.

If the new sensors don't fix the issue, I will clean the EGR and IAC again, although, I don't think that this is the problem. I am also thinking of doing the timing belt, I am replacing the Alt belt and the AC belt, maybe I might just do the timing belt too.

Is there any sensors that could be causing this issue, that I am just not thinking of?

The camshaft positioning sensor was already swapped with a friends, and I ruled it out as not being the problem, but the old one looked really bad and really don't want to put it back in.

I also plan on cleaning some
 
Oh yea, I am looking at the engine coolant temperature sensor, is there a sender in addition to the sensor? I don't want to order the wrong one. Is the Sensor the one the green female connector?
 
I'm pretty sure there is only an engine coolant temperature sensor.
I don't know what color the connector is but I found this.

Part # 5





You're supposed to use an SST (specialty shop tool) but it looks like it's just a deep socket.
 
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Thanks for posting the remove and inspection guide, I can't look at it on my work computer for some reason, but I will check it out at home.

When I was looking for the ECT sensor, it looked like it was on the drivers side of the motor, on a pipe coming off of the upper radiator hose. I am pretty sure that is it. If it is, it doesn't look hard to get too, and it looks like an open ended wrench could be used if a socket doesn't fit.

As for the sensor itself, last night I ordered the top one you posted from Rock Auto, the Airtex/Wells one. The reason why I asked if there was a difference between the sensor and sender is because when I replaced the ECT sensor on my Turbo MR2, it had both a sender and sensor, Both were really close to each other, but one had a green cap (the ECT), and the other had a black/grey cap.

I wasn't sure if the P5 had just one or both, and Rock Auto was not clear about it.
 
I'm 98% sure that this the ECT sensor...
The one in the middle of the picture...
My connector is gray.

 
Little update.

I have been experiencing a lot of stalls, which I thought was fixed after I changed the fuel pump/filter. I have had a few power loss issues, so it is still not fixed.

Last week, I purchased the following:

Engine coolant temp sensor
Camshaft position sensor
Crankshaft position sensor
Intake Air temperature sensor
PCV valve and grommet - I don't think this is the cause of the problems, but it was really cheap, and figured I would replace my very old one
New AC and Alt belts
New spark plug wires - I replaced them a few thousand miles ago, but will try replacing them again

Everything was about $175 with shipping. Not bad imo. Most of the parts have already been delivered ahead of schedule. I love Rock Auto, and highly recommend them.

My heat is working in my garage now, and I installed a smart thermostat to turn up the heat before I head there. I plan on doing all the parts this weekend.

Ideally, I would like to do them 1 or 2 at a time, to figure out were the problem was, but considering that I have to drive a while after changing the parts to see if they fix the problem, I just don't have the time.

Wish me luck!
 
I'm putting my money on the Engine Coolant Temperature sensor.
If your old one is covered in crap, it can act as an insulator preventing the ECU from getting accurate data.

When it's cold out the metal it screws into can work as a heatsink preventing it from warming up properly.
When it's warm out there's not as much heat difference and the car can deal with the inaccuracy.

That's my guess anyway.

Let's hope you've got some cold days left to test your car so you don't have to wait till next year to fully test it.
 
I'm putting my money on the Engine Coolant Temperature sensor.
If your old one is covered in crap, it can act as an insulator preventing the ECU from getting accurate data.

When it's cold out the metal it screws into can work as a heatsink preventing it from warming up properly.
When it's warm out there's not as much heat difference and the car can deal with the inaccuracy.

That's my guess anyway.

I hope you are right! I am still worried it might be a short somewhere, the timing belt/tensioner, or something else that will be a lot more complicated to fix.


I tried using my expensive obdII scan tool to read the current engine temperature to see if it is way off, but I guess my tool is not compatible with the P5. It will read CEL codes, but not current stuff.

I thought about causing a code just to get the info, but at this point, I might just wait until I can install the new sensor.


Let's hope you've got some cold days left to test your car so you don't have to wait till next year to fully test it.
I looked at the upcoming weather in my area. There are some cold nights, but after the next few days, it will be mild weather during the day.

I might not find out if the problem is fixed by the new parts until next fall/winter.
 
Man, that sounds like an expensive way to fix a car. Just keep throwing parts at it until it works? I understand your frustration but I would have to test the components so i'm not guessing at what is wrong. When you keep throwing money and parts at the car it is only going to increase your frustration.
 
I don't think he's doing too bad.
He could easily spend $175 taking it in somewhere and only having one part replaced.

I'm thinking that even the temperature test for the the ECT may be unreliable due to the fact that it isn't screwed into metal for the test.

However, if it was me, I'd just remove the ECT, clean it, reinstall it and see what happens.
 
I tried using my expensive obdII scan tool to read the current engine temperature to see if it is way off, but I guess my tool is not compatible with the P5. It will read CEL codes, but not current stuff...

You can get an EML 327 code reader that broadcasts to your phone using the torque app.
They're only about $10 online.

 
Man, that sounds like an expensive way to fix a car. Just keep throwing parts at it until it works? I understand your frustration but I would have to test the components so i'm not guessing at what is wrong. When you keep throwing money and parts at the car it is only going to increase your frustration.

You are not wrong.

But, I just have a very limited amount of time that I am able to mess with my cars.

I have 4 cars, and 3 of them are old and require a lot of attention. A 91, 02, 03, and a 2015. With regular maintenance and things going bad, I spend a lot of time fixing various issues with them. Actually, the Mazda has been a very reliable.

So, when it comes to the current problem with my P5, I only have very intermitted symptoms to diagnose these issues, not CEL codes. The car runs perfectly sometimes, and other times I see the symptoms. I just think the time it will take to diagnose every potential issue is not worth it for me.

None of the parts that I just purchased have are too expensive, and some I purchased, like the belts, need to be replaced. Even if the sensors I purchased are not bad, the readings of those sensors could be a little off due to the age of them, so replacing them will probably help the P5 run a little better and more efficiently.
 
Believe me i know where you're coming from!

By chance have you checked for a clogged cat or partially clogged cat? Maybe worth looking into; I don't know how your car is as far as oil consumption/burning/blowby but if it's dumping raw fuel or oil into the exhaust that's not being burned off, the cold weather could cause it to congeal and become more restrictive.

Same for injectors. inspect your spark plugs closely for any signs that something is off. A spark plug never lies and tells a lot of the story about how an engine is running. If one of them (or more) have different burn patterns then that may help to narrow down the cylinder/coil/injector/etc that's causing problems. IF you've got one or two spark plugs that indicate it's lean compared to the others then you may have clogged injector(s). Or if an injector is sticky/sticking you'd see it's running rich. it would be best to keep some tools with you and pull the plugs as soon as it stalls for best readings, if it's rich the plug will still be wet.

I'd personally ignore everything you've done up to this point and start from a clean slate. Start with the basics; you need fuel, fire, and squish to make the engine run. if it's dogging out like but runs great other times the compression is probably fine (though it wouldn't hurt to test it just so you know where you're at). Looking at your spark plugs as soon as it dies will tell you what your fuel to fire ratio is.

Only other thing I could possibly think of off hand is maybe ECM. If it's got a cold solder joint somewhere or cracked solder joint on something, metal contracts when it is cold so it could open that crack so there's intermittent or no continuity. but when it's warm it works. Something like that could also kill the car and not throw a code.


Just throwing out a few ideas, but like anybody working on a problem car for a long time, you tend to get tunnel vision and miss the obvious stuff right in front of you. It happens to us all. Hell, it could just be a loose or corroded ground wire somewhere that's killing injectors or ECM or something and causing it to stall even.
 
You can get an EML 327 code reader that broadcasts to your phone using the torque app.
They're only about $10 online.


I looked into these. Yesterday, I asked a friend of mine if I could borrow his to see if they worked on my P5. He uses an old phone, and just has it mounted in his car.

I will probably try his soon, if it works, I will get it.
 
They apparently work for our car...
The only thing was that the guy had to get Torque Pro to get a voltage reading.
I've got one but haven't used it yet.

I've got a plugin handheld kind that I use but it only reads and rubs codes.

I used to own an Ultra Gauge but it didn't show everything so I sold it and got the ELM 327 and a phone.
 
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