HELP!? - Intermittent Engine Stalling During Warm-Up

[tehbrookzorz]

Okay, my girlfriend has a 1992 Mazda MX3 GS w/1.8 V6 5 speed.

Last fall it crapped out in her mom's driveway. A family friend/GM Mechanic took a look and diagnosed it as distributor, replaced it, and several hundred dollars later her car ran well.

That is, until the crazy idle problems began. Surging idle and inconsistant stalling. This was fixed after the mech found a leak in the intake tubing from the airbox to the IAC/TB. This was removed, siliconed, and replaced. No holes, no idle problems.

Again, that is, until... About a month or two ago it started surging oddly and dying on her at random. Since I was not present I can't say exactly what it did for her. I was with her when it did it once. It died as she came to a stop at an intersection. She started panicking, so I switched seats with her, tried to get it to run, to no immediate luck. The car would turn over fine but refused to start. I sat in it a few minutes and finally got it going, turned into a nearby parking spot and drove home.
Thinking this was might be vacuum/intake hose related, I again removed the intake hose and made double sure there were no holes. She drove it to a nearby town the next day, apparently it died on the road up there, but she coasted into a Mazda dealership where they diagnosed her problem as being her distributor.

The GM Mechanic found the paperwork and replaced the distributor under warranty(thank god). The car was still warm when we picked it up, we drove it home and it was fine all the way, or so it seemed.

The next day, after it had cooled down, the car decided it didn't like the idea of running. It would start, idle high (normal for this cool weather), and then without apparent reason, cut out, or erratically start to surge and then die. Sometimes, with some aggressive pumping of the throttle it would catch and pickup, but I had to hold it at around 3000 rpm to keep it from dying on me. Every so often, under consistant pedal pressure, the revs would dip 100-200 rpm. Then, once it was warm, the problem seemed to go away.

Again, the mechanic looked at it, stumped and nearly as displeased as me, (but not nearly as displeased as my gf, who insisted I couldn't be as upset as her since it wasn't my car) and started wiggling things around, trying to find a bad electrical connection or leaky vacuum valve. He pushed on the airbox a few times and the engine seemed do come close to dying each time, which led us to check the electrical connections on the VAF.

Driving later that night, it died, while in gear. Tachometer went straight to 0 even though the car was still in motion in third gear. I heard a click, just as suddenly as they'd dropped, the revs caught up and the car ran for a few seconds before I heard another click. No power again, and the tach needle at 0. Click. Running. The car got me to the grocery store. I went in, did my thing, drove home. No further problems that night.

I pulled the entire airbox out, checked all electrical connections in the area, made sure there was nothing grounding, replaced the airbox, ensured there were no vacuum leaks, and drove 30 km with no problems.

I was late for work the next morning after my girlfriend offered me a ride to work. The car started, idled for about 30 seconds, and died. I jumped in, same thing happened. The car suffered a slammed door.

The dying now only occurred during warm up.

One of the teachers at the local college who also works part time at Canadian Tire (where I work) looked at it yesterday, and after an hour of scoping and diagnostics, didn't have much of an answer. Everything seemed good. Then again, the car was running and warm.

What he did find though, which may have explained some of the car's issues, and in fact some issues that other MX3 owners on this site have been having, was that there was a coolant leak just below the rad cap housing. The coolant was dripping down onto the electrical connector for the Cam Angle Sensor. Looking at the wiring schematics, we decided the coolant could be shorting the wires and modifying the signal to the ECU, resulting in it killing the engine.

I let the car cool, removed the rad cap, removed the rad cap housing, ignored the O-ring that was supposed to seal the housing to the pipe, cut a gasket, applied sealant to both sides and put the housing back on, topped up the coolant, and stuck a new shiny "bling" blue rad cap on there to prevent any other forms of leaks, and to make sure my coolant system had propper pressure. Then I tackled the wiring harness with contact cleaner, reconnected it, and stood back as the evening parts staff marvelled at the rad cap, insisting I should have an increase of at least 40 hp because of its 'bling' factor.

I started the engine, waited for it to warm up. Waited for it to die. Nothing. No dying. 'What the hell? This isn't very Prissy Die-er like. What's going on?' I wondered.

Truth be told, I took it out for a road test and it worked better than it has for months. Seemed to have more power, idled better. I was loving it. I brought it back to town, let my gf drive it, and she agreed that it was running better. I warned her not to get too excited, as this may not be the total problem.

So this morning I started it up, it started up perfectly. Idled smooth. No hunting like it used to have. Once the temperature guage got just over the bottom line it stalled out. No apparent reason, no dip in revs to warn me. Just. Dead.

I got back in, restarted it, with a bit of trouble, it tried to die, caught itself, then died again.

I'm a persistant bugger. I got back in, started it, didn't try to aid it, and it continued to run fine. The temp gauge got up to high-center where it usually sits and the car ran fine all around town since then.

So... I'm thinking the next step is EGR cleaning or TPS adjustment. Any comments?

Also: While I understand that when you put the car in gear at idle, the revs go up a couple hundred rpms, which it is doing fine when it's warm right now. The only other thing is, when I apply the brakes IN THIS SITUATION ONLY, the car idle hunts. The revs play up and down consistantly with a difference of about 800 rpm. If I remove my foot from the brake, this condition stops. If I put the car in neutral and hit the brakes, there is the slightest dip in revs, but no surging. I also noticed that, when the car is in gear with the clutch depressed, if I pull the e-brake, I hear a relay click as the brake warning indicator lights on the dash, and click again when the light turns off as I put the ebrake handle back down. This is followed immediately by a dip of 100 or so in the revs. Again, this is only while the clutch is engaged and the car is in gear. Somebody who knows more about the circuitry in this car may be able to help here? I know that the relay or switch that I'm hearing clicking is in the same location as the A/C Relay should be. The car doesn't have A/C, though I'm not sure if that matters.

Please, any help would be greatly appreciated. I've sorted through the archives and searched everywhere, but I'm running out of ideas. Thank you!

[PATDIESEL]

That is the goofiest problem I've heard of yet.

I'd say that it is the ignitor in the disty, but since you've replaced it so many times maybe not.
I'd also say it could be a vaccum issue, but the main intake tube is usually the culprit and since you say you have exhaustivly checked it then maybe not.

I'd then say to check some things you havne't looked at yet. First check the fuel pump relay. It should click on as you turn the key to the on postition. If you cannot hear it place your finger on it and you can feel it. (it is located in the black box on the drivers side just infront of the battery)
However, the fuel pump relay should not be affected by the temp of the car that I know of. Since you say that you hear a click though I'd give it ia shot. It is one of the few audible clicks in the car.

Secondly, I'd check the disty one more time. (exchange it that is) If you were getting it wet constantly then it may have kept shorting out the cam sensor or ignitor. Since you just fixed the leaking hopefully it will not happen again. (if that is the problem)

Also, you need to check the oil for any water/radiator fluid. Since you came close to overheating it the heads could have warped and are causing the vaccum problem when warm. Lets hope you don't find any though since that is a costly repair and possibly not worth fixing on a car as old as the MX-3.

[Mnemonic]

the EGR system wouldnt effect the motor at all, so cleaning it would be a waste of money, and it doesnt sound like a tps problem

[tehbrookzorz]

The car hasn't ever been overheated, the cooling system does its job well, and was just flushed about 2 months ago anyway.

I took it out tonight without warming it up. I got out of the driveway and down the street a bit and it died just before the stop sign. Didn't want to start right away so I sat there with the four ways blinking for a few before it got going again. I decided to take some backroads, got across the street and around a corner when I heard that wonderful 'click,' and shazaam; no power, tach at 0. I left it in 3rd without applying the clutch petal. 5-10 seconds later, the 'click' sound again, and the car started driving like normal again. That is, I didn't stop, I didn't actuate the starter, the car just continued on its merry way.

This happened about 3 more times, the car dying with the click, and starting again with the click, then the car got to the temperature at which it runs fine, and no more problems tonight. We drove all over town with it, then went for a drive in the lightning 30 km or so. No problems after warm up, except for that 'clutch+in gear+brake pedal rev surge,' which acts oppositely, only occurring when the car is warm.

I think the 'click' I hear is actually inside the car. It sounds like it may be from behind the center of the dash or where the A/C Relays are in front of the passenger door. This makes me wonder if it could be the circuit opening relay I'm hearing, or something else? Even so, I may only be hearing the relays because the ECU is telling them to shut down the fuel pump due to a sensor signal. Any more thoughts?

[XxantwawnxX]

Have you pulled codes from the car? could give ya another place to check. If the egr is stuck open it wil make ur car run poopy at idle, thats about the only prob that can cause. It REALLY sounds like a bad ignition module in your disty, but damn youve changed it.

[Bucking Bronco]

I met you on tuesday @ Canadian tire small world guess your not going to call and sell it to me cheap Glad to see your trying to work out your problems with it.

[lakersfan1]

I'd suspect the distributor again, but only if the block's not grounded properly. Use a multimter to check the resistance between metal at the mounting point of the distributor and the battery negative. Should be less than a tenth of an ohm resistance. Last distributor I replaced on someone's car I ran an extra ground from disty to the chassis ground point just in case.

[tehbrookzorz]

Oh sweet! Codes 3 and 4! I'm going to go reset the codes, and see if they come up again. Hopefully they're old codes from before the last new dist.

[tehbrookzorz]

Went out this morning. It's chilly out. Wet and chilly. The car started after the second try, once I let the system prime. Ran shortly, then died. Got it to start once after that, then it died, and wouldn't start.

I left it for a moment, thought about the comment regarding the base of the distributor being grounded, found a wire, grounded the base of the distributor (I don't have a multimeter to check it, so I just made sure it was grounded), and started the car. It started up, ran for a few seconds, the revs cut about 1-200 rpm as if it was trying to die, but it didn't. Then the CEL came on and stayed on. This hasn't happened before.

I checked the codes. Now I have code 2 as well.

What to do?

[corbanbrook]

Well I had a similar problem before, which turned out to be a combination of faulty o2 sensor, faulty water thermo sensor and a generally underpowered alternator.

The low power alternator is going to cause the problems where your idle hunts when breaks or window wipers, or fans are on but generally it shouldnt stall out because of this, idle might drop to 100-200 RPMs but should correct it self over time.

If the car runs well while cool, dies at the halfway point and then runs well while warm, I would bet on the water thermo sensor. .. but some of your symptoms seem out of place with that. For instance you mentioned that the car died while moving, was the car in gear at the time? if so then thats pretty messed up and is probably electrical related.

I guess the reason i am replying is because I just had a new clutch put in my car a couple days ago and I have been noticing similar problems.. car running well while cool.. but as soon as it is warm the engine dies as soon as i disengage the clutch.. yet i can get the engine started again if im moving, and rengage... so pretty much every time i stop the car it dies.. sometimes im luckier.. and it would stall but the idle will drop to almost zero then violently shake and shoot up again to 500ish then back to zero and continue on for the duration of the stop or stall after doing this for a while.

It almost feels like the time I didnt properly tighten an o2 sensor i installed ... things worked fine for the first couple days of driving, but as it gradually loosened more and more, and preassure was escaping from the exaust manifold the idles dropped to the point where the car wouldnt keep idle unless i was giving it constant gas.

Oh well.. good luck with your problem. I hope you find out what it is.

[jschrauwen]

Good call Corban. Just the same things i was going to suggest. Car is old, mucho km's, ya, water thermosensors might be on the way out. Something like 50cdn a pop i think at Mazda. Poor power output from alt..... sure agian tied into the age thing. Not sure how long this car has been owned but it may appear that the "time expired" issues of the MX are starting to surface, especially if it didn't get regular TLC or better than average TLC. Poor alt output and I would also tkae agood look at all of the major grounding wires and points when you referred to the surging idle when brake applied. Have you done a couple of plug changes/pulls to check the quality of the burn??? Is it excessively richer than it should be? O2 sensors is also a good call. When the O2 finally hits it's optimum heat temp range it may be sensing an excessively rich misture whether it be true or not. Replacement O2 's can be had for as cheap as 30cdn each for the 4 wire ones. It was never mentioned that during the removal (several times) of the intake boot, that you didn't clean inside the intake boot itself or that you tried to clean out the TB. if all of these other potential items are slowly beginning to fail it may be a safe assumption that there needs to be a good cleaning of the TB and perhaps the IM. Steps to do that have been covered in other threads. After a thorough cleaning of the TB, a TPS setting will need to be done. Again there are simple "how to's" to tackle that issue also.
So if we look at the alt for correct output.
Check and reconfirm grounding wire integrity - (actually remove and clean all of the contact surfaces) or better still, make your own set or get an ebay one that will give you even better electrical performance - which will be recognized/realized.
Check/replace water thermosensors.
Check/replace O2 sensors.
Check/replace spark plugs.
clean and inspect TB. Odds are the air bypass passage that the air idle screw controls is probably seriously plugged up / carboned up and will affect idle.

Clean and inspect intake tubing/tract. The coming to a stop and the engine dying could have been caused by the slight shift of the engine on it's mounts enough to create intermittent vaccum leaks in the intake tract. PLUS couple that with touching the brake with a pooralt/grounding system and voila => engine stalls at the stop lights.
I haven't even touched on EGR or Cat but then again CEL codes will point to that anyway.

Hope this helps.


John

[mitmaks]

did you find the problem?

[tehbrookzorz]

I may have found a source of a problem... Oil in 4 of 6 spark plug wells. Could this have led to failure? Also, HEI seems not to work.

[tehbrookzorz]

I reset the codes on Sunday. Absolutely reset and confirmed. After it died during warmup on Monday, I decided to see if any new codes were in the ECU. Tuesday's code readings were codes 3 and 4. Crank angle sensor codes, if I'm correct. From what I've read that usually points to the distributor, but my mechanic seems to think this is unlikely since he just went through the trouble of replacing one in November, and another last month after Mazda diagnosed the car and suggested a new disty.

According to one of the MX-3 members, oil in the plug wells could lead to some sort of ignition failure. What would fail, and if so, can the full HEI conversion fix it? Has anybody had luck with this conversion?

I'm going to pull of the valve covers and replace the gaskets, and I'm going to change the intake manifold gaskets at the same time. This will at least prevent further oil leaking into the plug wells. I may replace the plugs but the wires list for 200+ for some reason. Any advice would be appreciated.

[RacerX]

Dude just get some off the internet for like 60 - 100 for MSD, Talyor whatever type.