[04mazdaspeed]

Hey everyone, I have a 91 plymouth sundance 2.5 with around 110k on it. For the past 2 months now, I have been getting this very random and very intermittent stalling problem with the car. If it happens, its usually while Im waiting at a light. The second my foot touches the gas pedal the car dies like i turned the key. It has started up not not for usually about 45 seconds of cranking with 5 sec breaks to cool the starter. Now this doesnt happen all the time. It seems to just do it when it wants to. Now while Im driving there are no problems at all. Once while I was driving it kind of jerked on me like the motor stalled while driving but it happened in a split second and everything was fine since. Also, every one in a blue moon, if I drove to the store and the car sat for a few hours and come back out, it wont start. That has happened to me twice now. It took about 2 mins of cranking to get it to catch and when it does it runs fine for a while. Im at a loss as to what it could be. From what I have been reading online it could possible be the speed sensor and/or the distributor(hep?). Any and all help would be greatly appreciated. Also if anyone knows where the speed sensor is located at on the car since my haynes manual doesnt say where its located. Thanks so much. Mike

 

[ImperialCrown]

Welcome to Allpar. A Haynes manual might not help much for these kinds of problems. Any fault codes?
The speed sensor is located at the right side transaxle housing where the axle enters, but I don't think that is your stalling or no-start problem.
The distributor HEP? Maybe, but I would also expect it would quit while driving. An intermittent TPS (throttle position sensor) may also cause this.
Do some diagnosis first if you can. http://www.allpar.com/fix/fixee.html

 

[04mazdaspeed]

No fault codes. I wish it was that easy..never is. Not sure it has anything to do with my problem but my tach doesnt work unless I tap on the cluster. It will stay working unitl I come to a stop and the rpms drop down. Then it just goes to 0. I will check to see if it could be the tps. Thanks

I will also say that It hasnt stalled on me so far but I also have been holding the rpms up to around 1000 when im at a stop.

 

[ImperialCrown]

The tach problem sounds like a bad terminal/solder connection to the cluster circuit board and probably not related to the engine stall/no-start issue.

 

[Bob Lincoln]

The TPS has nothing to do with the tach. The tach gets its signal from the HEP.

And the speed sensor won't prevent starting or restart. Check the condition of the HEP wiring.

Back to basics: When was the last time you did a full tuneup? (Plugs, wires, ignition rotor, cap, air and gas filters, PCV valve, throttle body cleaning) How many miles and how long ago?

These cars eat ignition rotors, and I replace them every 15K miles in a mini-tuneup. Once I let it go to 20K miles, and had a no-start situation for 3 days, after it having run perfectly. Took me that long to diagnose it. The rotor tips will char and can cause this.

The tach has a daughter card that plugs into the instrument cluster board, it's probably loose or has a bad solder joint.

 

[04mazdaspeed]

I changed plug wires, plugs, pcv valve, cap, air filter, and rotor roughly 5k miles ago. The only thing I didnt change was the fuel filter. Is the hep wiring below the rotor in the distributor? My haynes manual only provides a description on what the hep is not where its located. Thanks for your help so far. Mike

 

[Bob Lincoln]

Yes. The HEP is accessed by removing the distributor cap and rotor, then the plastic plate just lifts up. There is a 3-wire round plug connecting it to the harness. Quite often people blame the HEP itself as the failure, when actually, it's often the 3-wire ribbon cable that fails. It gets crushed under the edge of the distributor cap by careless people and becomes intermittent as the strands break under the insulation. Look for a crush mark in the cable. Also check the round plug on both sides for corrosion or other damage.

It still has to be replaced if that's the fault, but its not often the magnetics or the sensor electronics.

Fuel filter should be changed every 5 years or 50K miles.

 

[ImperialCrown]

At 110K, also check your distributor shaft for side-to-side wear or the HEP reluctor metal vanes for looseness or slop on the shaft down in the body of the distributor. If they wear enough, the vanes will hit the HEP element as they go past.

 

[04mazdaspeed]

Ok, so I checked a few things yesterday morning. I found that my distributor cap was cracked and loose so I went and replaced that with a new cap. I was hoping that was just my problem. Everything was fine on my way to work but as I was accelerating the car acted wierd for a split second. It almost seemed like I hit the brakes then let off. It didnt do it again all the way to work. Also after work I go to start the car after it sitting and no start again. I drove the car about 2 hours before I left work so the car was still kind of warm not cold. I was cranking it for almost 2 minutes before it caught itself. It drove perfectly fine all the way home which is about 20 miles. The no start hasnt happened to me in about a week so its a very intermittent issue. Once the car is driving it drives normal. No hesitation, no stumbles, except for that little brake check it gave me for some reason. It hasnt died on me at a light yet but I also have been holding the brake and gas at a light to hold the revs up. That seems to curb that stalling at a light issue. I did look under the rotors black plastic piece and it looked fine to me. Not really sure what I was looking for though. I did try wiggling the shaft and it didnt move. The small wire looked fine but where it goes to the plug looks a little oily. Could it still be the tps sensor? Should I try unplugging the tps to see if the motor does anything different? On a side note, after the no start today I checked for codes again right after is gave me code 12, which is battery disconnected/reset. I never touched the battery so not sure why its giving me that code now. Didnt have any codes before. Hopefully you can guide me to a solution. Thanks again, Mike

 

[Rickorino]

I had a failing battery which caused periodic code 12's. Carry an old spark plug with you and when this happens, unplug one of the plug wires,lay the plug against the block have someone crank and check for spark. I doubt that a sensor would prevent the engine from starting.Don't throw money at it, diagnose the problem.I had a sped sensor go out and the speedometer stopped working but the engine ran fine. If you have spark, look at the fuel system. Fuel pumps can go intermittently. Sometimes banging the bottom of the fuel tank can bring a fuel pump back to life.

 

[ImperialCrown]

12 is always the preamble code to a 'ck eng' light code check. 55 is always the last, which is the end of the code read. I wouldn't worry about 12 and not everything will set a fault code. Cranking for 2 minutes will shorten starter life considerably.

 

[04mazdaspeed]

I wasnt cranking the starter for 2 minutes straight. It just took roughly two minutes for it to finally turn over.

 

[Bob Lincoln]

I would disconnect the battery, thoroughly clean the posts, cable clamps, and inspect the cables for corrosion creeping up under the insulation. Also check where all grounds connect - battery, left fenderwell, driver's side rear corner of the block, and braided strap from intake manifold to passenger side firewall. Also clean that plug from the distributor and make sure the connection is tight.

If the dist cap was damaged, inspect the rotor and see if it needs replacing. Look for cracks and char marks. The 'brake check' was undoubtedly the engine stalling for just an instant.

 

[B10alia]

IC, I think you're mistaken on that-- code 12 is a "thrown" code, unlike code 55, which displays every time. My Spirit will only show a code 55 if she's running normally.
The battery issue could be mitigated by your revving the car at lights-- 1000rpm is more than the designed idle RPM, so your alternator current output is higher. That could be the difference between losing power and staying running, although a flat battery would probably give you other symptoms. Make sure that those terminals are really clean and tight-- I had some issues with the aftermarket ones (original cracked in half) where the steel plate that clamps the wires was ever so slightly loose. The car would run fine for literally months, and then refuse to start. The solenoid would click and everything would go dead. If you looked at it a certain way (literally seemed like that was all it took), she would start right up and run fine.
When you get the "hitting the brakes" sensation, how does the car run? Is it smooth or does there seem to be excess vibration?

 

[04mazdaspeed]

The battery posts believe it or not are spotless. No corrosion or acid so im assuming the battery is somewhat newer. All the grounds look good and intact. I will clean the plug from the distributor tomorrow. Can i use terminal cleaner that they sell at the store? The rotor looked fine but im thinking Im going to pick up a new one and compare/replace to rule it out. Ive been checking for codes for the past few weeks almost everyday just to see if something would get thrown after the no start and I never got any codes except 55 which is nothing until yesterday when i got 12. Since I never unplugged the battery I thought it was a little odd that it would throw that code now. The only reason i keep holding the gas and brake at lights is because thats usually when it wants to randomly stall. Always at the worst time too so Ive been doing that and it hasnt stalled that way. See when I get the no start, it is cranking perfectly no clicking of the starter. It just doesnt seem to catch itself. Then voila its turns over like a brand new car...When I get the hesitation its just like that. It stalls for a split second, then its fine. That has only happened to me a few times compared to the no start im getting like twice a week now. Definetely no vibrations and its smooth other than that little brake check it gives me. Also one of the other guys up top suggested its possibly the tps. From what ive been reading and seeing videos on, it seems that usually a bad tps gives a searching idle which I dont believe mine is. It doesnt sound like its searching at least. I cant see what my idle rpm is since the rpm gauge only works when im driving and I tap on it. Sometimes it randomly comes on as well.

 

[B10alia]

The TPS is pretty simple, it's just a potentiometer like a volume control on a radio. Over time, since there's a moving wiper and a coil of wire inside, you will start to get "flat" spots in it where resistance isn't what it shouldn't be. The resistance should change smoothly over the range of the sensor's rotation. This is best checked with an analog voltmeter. As far as I know, that's really the only way they can fail. With vehicles this old, you get crud in the electrical connections themselves. Often, you can plug and unplug the connector a couple times to wipe the contacts off, or better yet, hit it with a pencil eraser and some tuner cleaner. Any time I unplug a connector, I repack it with dielectric grease, just to be safe.
Tuner cleaner is safe for any contacts you run into. The rotors are about 6 or 7 bucks apiece. I would buy two so you have a spare when the one you put in fails, as it will rather quickly...

 

[Bob Lincoln]

I would not be looking at the TPS at all.

Just because the battery connections look clean doesn't mean they are. My truck refused to start once after running an errand, and the connections looked great. But in fact, cleaning the posts and terminals got it started again.

If not the battery, then probably this is the HEP. What is the voltage at idle and with engine off after being parked overnight?

Code 12 is normally NOT present, and shows up under two circumstances: When power has been interrupted (or fallen below a threshold), or when a fault code is stored. 55 is not a fault code, it's "End Of Message". So a healthy car only displays code 55. If it shows 12 and 55, the battery voltage has at some point gone low or been interrupted. If it shows other codes, 12 shows up first, then the fault(s), then 55.

 

[04mazdaspeed]

Ok I will do the old baking soda trick on the terminals in the morning just to be sure. I will check the voltage in the morning also. So if everything comes back fine with the battery the it very possible its the hep. Now how do I go about replacing that? Im assuming I have to replace the whole distributor. Is there a walk through for r/r this online? Thanks and will report my findings in the morning. Mike

 

[Bob Lincoln]

Baking soda is not necessary unless you have buildup of sulfur crystals on the terminals or battery case. You should be using a battery cleaning brush/tool on the clamps and posts.

The HEP is replaceable by itself - you do not need to buy a distributor. Lift the dist cap, the rotor, and the HEP just lifts out and unplugs. It has ears that line up with the screw holes for the cap. They are usually about $30 to $40.

 

[valiant67]

IC, I think you're mistaken on that-- code 12 is a "thrown" code, unlike code 55, which displays every time. My Spirit will only show a code 55 if she's running normally.

The logic for code 12 is not that simple and not well documented. Code 12 is often set any time a new code is set. So if there are no codes stored you may only get code 55. But if there is a trouble code set, you are very likely to get code 12 set as well for no real additional problem. Therefore in most cases code 12 could simply mean start of codes rather than any actual fault.