HELP - Protege5 Low Idle and Misfire

Victor1994

Member
:
2002 Mazda Protege5
Hello, I have a 2002 Mazda Protege5 (119k miles) with a low idle and a code for Cylinder Misfire #3 (P0303)

Now I'll start with this, 3 weeks ago I was driving home from work and my CEL came on. I took it to advance auto right away and discovered 3 issues.

P1250 - Fuel Pressure Regulator
P1250 - PRC/EGR Vacuum Solenoid (Device held by two bolts on top of intake manifold and on the other end of the vacuum hose connected to the Fuel Pressure Regulator)
& P0303 - Cylinder 3 Misfire.

I replaced the Fuel Pressure Regulator with one I found at the junkyard and it cleared one code, and a week later I replaced the PRC/EGR Vacuum Solenoid. However, right after I replaced the Vacuum Solenoid, connected the battery, and started the car, it stalled. Second time starting, it ran and then stalled once in drive. 3rd time, it ran for a while, drove around the neighborhood and then stalled again. After that, it didn't want to stall anymore but has a low idle at 500-400 RPM when in park/neutral, but drops down and shakes a little when in drive and reverse (Reverse is worse). Driving on the road and highway it seems like nothing is wrong and goes until it becomes idle. I disconnected the battery 3 times this past week, and I noticed the car stalls a lot and then doesn't want to again everytime I disconnect and reconnect the battery. The spark plugs, wires, and coil packs were put in at June this year, and I replaced all of them with a continued low idle and misfire. I cleaned the throttle body (Might have to again since I don't think I did a good job) and I'm having a hard time finding time (and how) to clean the IAC (Idle air control) and EGR Valve.

The only code left is the misfire in cyl #3. Some people have told me it could be a clogged/dirty fuel injector, but I'm trying to rule out everything else before going there (Injectors are expensive!) (headshake

Also, my car isn't violent at idle, there's a slight vibration that's noticable even with my exhaust on. And letting off the brake without pressing the gas pedal has a lot of hesitation until I press on the gas.

What do you guys think it is? I'm having a hard time and need the car for work.

P.S. - I cleaned the PCV Valve today (Also a couple months new), no change in low idle.
 

ucnr

Member
:
Mazda Protege5
Is the Protege EGR valve normally open or normally closed? I just rebuilt an FS-DE engine for the same car and it does not run for more than a few seconds below 1000rpm when warm. I heard that if an EGR valve is open it will appear as a large vacuum leak at low RPM. When i disconnect and reconnect the electric connector to the EGR, there is no change in symptoms.

I'm about to put wheels on it and limp it to the mechanic but the service fee will likely cost more than the $600 i payed for the entire car. I will send free parts for 01-03 Protege to anyone who can fix this problem (I have a wrecked parts car).

-No check engine light
-Oil is filled to proper level, no chips in the oil pan
-Has 135psi compression dry in each cylinder
-replacing fuel rail and injectors with a spare did nothing
-unplugging an injector causes the engine to run on 1 fewer cylinder so its not a misfire issue.
-good spark on all plugs
-I checked the timing belt, again, and all marks line up at TDC
-checked for vacuum leaks and could not find any
-cleaned the throttle body which did nothing
-radiator and engine passages are filled with proper level of coolant
-does not produce any horrible smoke
-no alarming noises
-battery is in good condition and it is recharging with electricity from the alternator
-all wiring harness connectors are plugged in
-engine knock sensor was replaced with a spare in an attempt to draw out a CEL, but that did nothing
-ECU has not been tampered with
-Upstream catalytic convert is in good condition
-intake hose and MAF are impeccable, and has new air filter
-The car ran fine but was burning a lot of oil before i rebuilt it

The crank position sensor wire shielding/ground is a little frayed but i think that is just another red herring.
 

Victor1994

Member
:
2002 Mazda Protege5
It's suppose to open and close, not stay on one side.

As for my problem, I found out that I'm losing compression in Cylinder 3 and my car is toast. Sitting outside until I can get the money to fix it. The piston ring is causing the compression lost along with oil burning.
 

ucnr

Member
:
Mazda Protege5
But is the EGR open when there is no electricity applied?

If you have a garage or live in a relatively warm and dry area with a flat concrete driveway you could rebuild your FS-DE motor. You will need an engine hoist, ~$150 at harbor freight, a build stand ~$30, a valve spring compressor ($50) the following parts, and sacrifice about 60 hours of your time. If you live near a U-Pull-n-Pay, they may have a motor available, but transporting it may be harder than rebuilding the one you have, and most of their stuff is in horrible condition anyway. It took about 1 month to do my first rebuild with no previous engine work experience. I did not de-glaze the cylinder walls though due to the oil injectors at the bottom of the engine block. The first one was well worth the effort though since it saved a car from total loss and got 36MPG at 65mph cruise with no more smoke on startup. That car was later wrecked and I paid $700 in interstate towing service to bring the car back so that I could save the engine, transmission, and tires to swap in $500 protege on craigslist that threw a rod.

72.99 bearings and rings https://www.ebay.com (commissions earned)

75.41 water pump, belt, and tensioners https://www.ebay.com (commissions earned)

54.95 complete gasket set https://www.ebay.com (commissions earned)
 

ucnr

Member
:
Mazda Protege5
I cleaned the EGR and it does move freely. It seemed to have moved freely before the cleaning too though. I started the car, and it idles slightly better now, although the outside temperature was 15F warmer as well. Is it possible that the stepper motor is not working properly? There is no CEL though.

I did the compression test again, this time with a warm engine and oil in each cylinder. I got 120-120-125-120psi after nine cranks per cylinder.

I bought a harbor freight leak down tester, zeroed the gauge, and tested each cylinder. All were within the green 10% leakage mark.

The spark plug of cylinder4 has less soot on it than the other three cylinders.

The suggestion was worth a try, please let me know if you have any other ideas. Thanks for the help.
 
:
13 CX5
Does not sound like a motor thing. After the cleaning the egr not to sure what it could be. I personally would try and pin the obd connector under the hood and raise the idle a bit and see if thats a good band-aid to fix it.

Whats the trans fluid look like?
 

ucnr

Member
:
Mazda Protege5
The original transmission fluid was brown, so I changed the filter and filled it with Dexron VI. There was not an unusually large amount of chips on the collector magnet.

I made a mistake. This is actually not an idle issue but rather the poor idle is a consequence of an engine that runs rough. Its as if it were down one cylinder and vibrating more than it should. The tailpipe does not exhibit a constant flow of exhaust but pulsates. All the motor mounts are new though and the engine runs worse as each injector is unplugged (to try and isolate a potential faulty cylinder).

Is it possible that this is related to oil pressure or circulation? I initially overfilled the motor by a quart, which resulted in the filter not receiving any oil during the first 5minutes of operation. The filter was completely dry. So I drained the oil, and refilled it with the precise 3.7 quarts. Now the filter receives oil. The oil pump is original and has 184,000 miles on it. I don't understand how this could cause the engine to vibrate though.

Should I install an oil pressure gauge? Thanks
 
:
13 CX5
No, I have had some ass hats at a local dealer over fill my 03' by a quart and it ran fine. Move the coils from each other and see if the miss follows. Has to be something easy.
 

ucnr

Member
:
Mazda Protege5
Swapped coil packs, but no change in symptoms. I drove the car around the neighborhood and now have a battery/alternator light. No belts are squealing, and lights are bright. The battery light goes away if i raise the rpm to about 2500. This is the first time i have seen the battery light during this campaign. Will the battery light come on if there is a fault in the spark ignition?

I disconnected cylinder 1 and 4 coil pack and connected another one outside of the head so that I could insert plugs and check the spark in the open during night. Cylinder 1 and 4 spark looked identical to another protege. I was not able to disconnect the coil pack for cylinder 2 and 3 without stalling the engine. Therefore, cylinder 1 and 4 are unable to keep the engine moving on their own. The other protege however did not stall when i tried the same diagnosis on it. Pretty sure i tried this already but I'm going to swap the plugs with the old ones, even though the ones installed right now are new NGK copper.
 

ucnr

Member
:
Mazda Protege5
Replaced spark plugs with the old ones but no change in symptoms.

Going to drop it off at the Mechanic on Monday but not sure if he will know how to fix it either. Only other pieces i can think of swapping would be the crank and cam position sensors.
 

ucnr

Member
:
Mazda Protege5
Just got word from the mechanic that the alternator is causing the misfire!

The assumption that bright headlights means a good alternator was flawed because the computer will send more current to the headlights as a safety measure if the alternator is going bad. Another clue that I did not mention, was that when I tried to jump start another car using this P5, it took a few minutes of waiting for the battery to charge the other car. I assumed this was due to using rotten dollar store cables that did not have a good clamping mechanism, but it may have been due to the alternator instead. I will swap the alternator tonight to see if it works.
 

ucnr

Member
:
Mazda Protege5
It was indeed the alternator! POS car runs to perfection now. So much for all that diagnosis.
 

ucnr

Member
:
Mazda Protege5
Yes it was only producing at 11.6V. My dad thinks that the computer was working, since its digital, therefor it either works or it doesnt. Rather the analog to digital conversion for the sensors was flawed since there was not enough voltage to run those properly. Garbage in garbage out, causes the car to run crazy.
 

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