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Engine cranks but will not start.


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Have 1989 TC, SOHC, 4-cyl.  First start of the day is OK, After running to normal temp and I shut it off, engine will not re-start (turns over but not start). Wait a couple of hours, engine will start and run normally.  Bottom line, engine will only start if cold.  Any ideas as to the problem?

 

After extensive troubleshooting, discovered no power to fuel pump (12 volts dc), replaced auto-shutdown relay with no success, I suspect SMEC is defective, any suggestions as to cause of problem?

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Ok... its been a really long time since I have worked on one of these. IIRC there is no straightforward method to troubleshoot Chrysler's "automatic shutdown" circuit. I remember it having 2 relays. You mentioned you replaced the auto shutdown relay. Did you replace the fuel pump relay?

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Looked extensively last few days in blue service manual wiring diagrams and fuel/fuel injection sections, could not find any mention of fuel pump relay, also checked all illustrations relating to fuel/electrical components, no success.

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26 minutes ago, no1parfive said:

Looked extensively last few days in blue service manual wiring diagrams and fuel/fuel injection sections, could not find any mention of fuel pump relay, also checked all illustrations relating to fuel/electrical components, no success.

 

I could be wrong. Many Chryslers of that era did have two. ECM (smec) failures were relatively rare. I hope you find the trouble.

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The asd relay powers the fuel pump,  I know this from working on my Daytona and le baron. (It's how i power up the fuel pump to get the stale gas out of the line) If it's not coming on the pcm is not powering it up so it may be bad. Check that the pcm is getting power from the ignition switch before you replace it. The asd relay doesn't stay on with the ignition switch. It with stay on long enough to prime the pump then shut off unless you crank it.

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15 hours ago, no1parfive said:

Fuel injection system wiring diagram identifies a component called Power Module, is this component the one you identify as "pcm"?

In what manual are you seeing Power Module? That name went away when both the Logic Module and Power Module were combined, forming the Single Module Engine Controller or as we know it, the SMEC. Logic Module and Power Module were 1984 through 1987.  "pcm" is not a word used on Chrysler products, though many use it in place of SMEC on these model cars. It came along later in time. 

Regarding your starting difficulty, if all your testing was correct and under the proper operating conditions, may I suggest considering the MAP sensor. That is the Manifold Absolute Pressure sensor. If it does not see (sense) the proper vacuum signal, there will be no fuel supplied to the engine.

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1 hour ago, Hemi Dude said:

In what manual are you seeing Power Module? That name went away when both the Logic Module and Power Module were combined, forming the Single Module Engine Controller or as we know it, the SMEC. Logic Module and Power Module were 1984 through 1987.  "pcm" is not a word used on Chrysler products, though many use it in place of SMEC on these model cars. It came along later in time. 

 

Techs of the time said "ECM" instead of "PCM"...... It is just a generic term for what some would call the "computer". PCM implied transmission control in the same box as the engine.

 

Chrysler kept changing the name of it every couple of years or when the technology inside the box changed, driving everyone crazy. Correct terms were used mainly for ordering parts.

 

At some point in the 90s the federal government stepped in and standardized terms. As an example, that is when "alternator" went away. You might notice alternators are called "generator"s in newer service manuals.

 

Excluding the original late 70s Chrysler Lean Burn system that had the magic box hanging on the air cleaner, and burned fuel pump circuits in Bendix/Cadillac EFI, I can count the number of truly bad ECMs (including SMEC) I have seen on one hand.

 

I have seen hundreds that were replaced by someone else trying to solve a problem. Just throwing that out there. The SMEC could be bad, but the odds are against it.

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11 minutes ago, Bloo said:

 

Techs of the time said "ECM" instead of "PCM"...... It is just a generic term for what some would call the "computer". PCM implied transmission control in the same box as the engine.

 

Chrysler kept changing the name of it every couple of years or when the technology inside the box changed, driving everyone crazy. Correct terms were used mainly for ordering parts.

 

At some point in the 90s the federal government stepped in and standardized terms. As an example, that is when "alternator" went away. You might notice alternators are called "generator"s in newer service manuals.

 

Excluding the original late 70s Chrysler Lean Burn system that had the magic box hanging on the air cleaner, and burned fuel pump circuits in Bendix/Cadillac EFI, I can count the number of truly bad ECMs (including SMEC) I have seen on one hand.

 

I have seen hundreds that were replaced by someone else trying to solve a problem. Just throwing that out there. The SMEC could be bad, but the odds are against it.

 

Terminology is a matter of for whom you worked. In the Chrysler dealerships at the time, we referred to the Power module ( mounted beside the battery) and the Logic module (in the passenger side 'kick panel'. Then later we had the SMEC and SBEC.  

If it drove you crazy, you must not have been much of a tech. The lingo was used because Chrysler referred to the components in those terms.

As far as changing the name of the alternator, which Chrysler introduced in 1960, to generator which was the name of the energy producing component on vehicles from the earliest days, is ridiculous.  That must be so we don't confuse the MARSHMALLOWS of today who are so easily offended and seem constantly confused! No wonder, nothing remains the same as far as component names are concerned.

A generator produced a continual flow of electrical current and an alternator produces an alternating current which is rectified by the + and - Diodes to direct current.

Once again dumbing down the shallow minded.

 

But, we are here to try to help someone with a specific problem, so let's stick to that, OK?

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1 minute ago, Hemi Dude said:

 

Terminology is a matter of for whom you worked. In the Chrysler dealerships at the time, we referred to the Power module ( mounted beside the battery) and the Logic module (in the passenger side 'kick panel'. Then later we had the SMEC and SBEC.  

If it drove you crazy, you must not have been much of a tech. The lingo was used because Chrysler referred to the components in those terms.

As far as changing the name of the alternator, which Chrysler introduced in 1960, to generator which was the name of the energy producing component on vehicles from the earliest days, is ridiculous.  That must be so we don't confuse the MARSHMALLOWS of today who are so easily offended and seem constantly confused! No wonder, nothing remains the same as far as component names are concerned.

A generator produced a continual flow of electrical current and an alternator produces an alternating current which is rectified by the + and - Diodes to direct current.

Once again dumbing down the shallow minded.

 

But, we are here to try to help someone with a specific problem, so let's stick to that, OK?

 

Hey, I dont mean to ruffle any feathers, nor argue with you, I am just reporting what I observed at the time. Of course we used the correct names when ordering parts, making notes on work orders, etc. I was a driveability tech for many years, 3 of them at a Chrysler dealership. I very much appreciate your help here.

 

I thought the loss of "alternator" was one of the stupidest things I had ever heard, and still do, but many of the terms we hear today (and observe in manuals) are a direct result of that government issued list, including "PCM" if I remember correctly. I thought at the time that the people who came up with that list probably killed "alternator" because it was a Chrysler term, and they were annoyed at Chrysler for changing the names of things constantly. Maybe not. In any event, I can't prove it. It is off-topic and I wont say any more about it.

 

 

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56 minutes ago, Bloo said:

 

Hey, I dont mean to ruffle any feathers, nor argue with you, I am just reporting what I observed at the time. Of course we used the correct names when ordering parts, making notes on work orders, etc. I was a driveability tech for many years, 3 of them at a Chrysler dealership. I very much appreciate your help here.

 

I thought the loss of "alternator" was one of the stupidest things I had ever heard, and still do, but many of the terms we hear today (and observe in manuals) are a direct result of that government issued list, including "PCM" if I remember correctly. I thought at the time that the people who came up with that list probably killed "alternator" because it was a Chrysler term, and they were annoyed at Chrysler for changing the names of things constantly. Maybe not. In any event, I can't prove it. It is off-topic and I wont say any more about it.

 

 

 

A little good-natured discussion is sometimes necessary just to be able to emphasize an opinion.

I worked at Chrysler dealers from 1959 until April of 1988. Then had my own 'Chrysler only' shop until 2012.

So, I strive to be specific since we are communicating about a Chrysler.  No offense taken here, I find it 'good sport' at times to vent.

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Interesting discussion, but back to my situation.  Finally got car running after changing fuel pump but it runs rough, lack of power to the pump was not the problem.  However, I now have a bad fuel leak when running accompanied by very white exhaust smoke.  The leak creates a big spill on the garage floor underneath the engine a little behind the engine. I've looked all around the fuel injectors, lines, and other fuel related components under the hood and can't find anything leaking, suspect something underneath the engine like broken fuel lines.  I'm also wondering if the fuel leak has anything to do with the white exhaust smoke and rough running, any help on these problems would be appreciated.

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I don't know, but you are going to have to find and fix that fuel leak before anything else.

 

Follow the fuel lines from the tank all the way to the fuel rail. Also, if your fuel regulator has a vacuum hose, pull it off and make sure that fuel isn't coming out of the vacuum port.

 

Did it run ok on the occasions it would actually start before you replaced the fuel pump?

 

White smoke usually comes from burning antifreeze. Don't worry about that yet. Fix the fuel leak.

 

 

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Fuel leak appears to be around a fuel line clamp located under and behind the engine, will look closer and repair.  As stated earlier, I did get the engine started but It ran rough with white exhaust smoke.  Now, it will crank but not start, I discovered no spark from the coil, which was recently replaced along with the fuel pump, fuel pressure regulator,  auto-shutdown relay,  and map sensor.  I will continue to troubleshoot and hopefully find the problem.  I'm very concerned about the white exhaust smoke, which is and indication of a blown head gasket.  I had this problem about three years ago and replaced the gasket.  I really don't want to give up on my car but my patience is running very thin.  I'm thinking I may have a defective smec unit but don't know how to determine if it's bad.  Any and all help would be appreciated.

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6 minutes ago, no1parfive said:

Fuel leak appears to be around a fuel line clamp located under and behind the engine, will look closer and repair.  As stated earlier, I did get the engine started but It ran rough with white exhaust smoke.  Now, it will crank but not start, I discovered no spark from the coil, which was recently replaced along with the fuel pump, fuel pressure regulator,  auto-shutdown relay,  and map sensor.  I will continue to troubleshoot and hopefully find the problem.  I'm very concerned about the white exhaust smoke, which is and indication of a blown head gasket.  I had this problem about three years ago and replaced the gasket.  I really don't want to give up on my car but my patience is running very thin.  I'm thinking I may have a defective smec unit but don't know how to determine if it's bad.  Any and all help would be appreciated.

 

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And you have replaced the pickup inside the distributor, right? With a new one? I think I saw that in an earlier post.

 

Does anyone in this thread have the correct manuals and wiring diagrams for this car?

 

My recollection of the auto shutdown circuit is it is very difficult to troubleshoot. Every manufacturer had some way to shut the fuel (and maybe the ignition) down in the event of a crash. This was Chrysler's. It is extremely effective. As I recall there are several things it looks at, like the MAP, the pulse from the distributor, etc, etc. to determine if the car is running. If it loses an input it wants to see, EVERYTHING (fuel pump, ignition, injector power) shuts down. You may find yourself wondering as I often did what failed first and shut everything down. One of my coworkers used to keep some old used parts around to substitute. Usually it was the pickup in the distributor that turned out to be bad. Those can cause all sorts of symptoms, but the most common is... won't start hot.

 

If you are really down to the SMEC, it is time pull the codes (if you havent) and see if any relavent circuit like the MAP or the distributor pickup have set codes. If not, then get a wiring diagram out, pull the SMEC connector off, and make SURE that all the 12v hot pins, key-on hot pins, and grounds are present. Keep in mind that some of the grounds might run all the way back to the engine block. If so, they could be broken from vibration, eaten by squirrels, etc.

 

I hope Hemi Dude has some ideas.

 

 

 

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1 hour ago, Bloo said:

And you have replaced the pickup inside the distributor, right? With a new one? I think I saw that in an earlier post.

 

Does anyone in this thread have the correct manuals and wiring diagrams for this car?

 

My recollection of the auto shutdown circuit is it is very difficult to troubleshoot. Every manufacturer had some way to shut the fuel (and maybe the ignition) down in the event of a crash. This was Chrysler's. It is extremely effective. As I recall there are several things it looks at, like the MAP, the pulse from the distributor, etc, etc. to determine if the car is running. If it loses an input it wants to see, EVERYTHING (fuel pump, ignition, injector power) shuts down. You may find yourself wondering as I often did what failed first and shut everything down. One of my coworkers used to keep some old used parts around to substitute. Usually it was the pickup in the distributor that turned out to be bad. Those can cause all sorts of symptoms, but the most common is... won't start hot.

 

If you are really down to the SMEC, it is time pull the codes (if you havent) and see if any relavent circuit like the MAP or the distributor pickup have set codes. If not, then get a wiring diagram out, pull the SMEC connector off, and make SURE that all the 12v hot pins, key-on hot pins, and grounds are present. Keep in mind that some of the grounds might run all the way back to the engine block. If so, they could be broken from vibration, eaten by squirrels, etc.

 

I hope Hemi Dude has some ideas.

 

 

 

Back to you in the morning...

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I also replaced the distributor pick-up (hall effect unit)  I have the large blue service manual for my car which contains all the diagrams and have traced out all the circuits connected to the smec unit and are in the process of making dc power checks at the various components associated with starting, which I have replaced except the smec itself.  I pulled the codes and the only one I got was 55,  which says that no codes were stored.  Will continue the troubleshooting process, wish me luck and thanks again for the help.

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Just an added bit of info, I get 12 volt dc to both terminals (pos & neg) on the ignition coil when starting, but no spark from wire going to distributor when making a spark test.  As stated previously, coil and wire was recently replaced, just can't figure this one out, any suggestions?  Also, would the capacitor connected to the positive terminal of the coil have an effect on this?

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The start sequence is:

 

Key on

SMEC gets key-on signal

SMEC turns on ASD circuit to prime fuel system (also gives power to injectors, sensors, O2, and coil)

SMEC looks for signal from HEP

If no signal from HEP within a certain time, it turns off the ASD until it senses the "start" position which will "reboot" the sequence

If signal from the HEP is received, then it determines when TDC #1 is (looks for the "window" on the reluctor wheel as the starter turns the engine over) and fires the injectors and coil at the appropriate times

 

You need 3 things to run an engine: compression, spark, fuel

 

We believe you have good compression. You've replaced a good bit of stuff for spark. Have you used a spark tester or looked for the spark on the secondary side outside of the cylinder? Being as you've replaced stuff on the spark side of things, that's why I jumped to fuel. The injectors are fired by the same sensors, so if they are getting signal to fire, then  something else is going on. If they aren't and you don't have spark, we're back at whether the SMEC is actually getting the signal.

 

As a note, over the many years I've messed with turbo Dodges it's been the community consensus that if you can run a known good OEM MOPAR HEP, that's your best bet as aftermarket ones have proven to be of suspect quality...to the point of even having the sensor pick-up locations WAY off, meaning that the timing signal the computer was getting was way off unless timing of the distributor was also changed.

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On 5/21/2018 at 12:50 PM, no1parfive said:

Which component(s) signals the injectors to fire? Are you referring to the control module (SMEC)?

Yes, the SMEC provides the grounding circuit to fire the injectors, the hot (+) is a constant.

The SMEC also provided the grounding circuit to the ignition coil  (-) terminal, in order for it to discharge the secondary circuit. (make the spark)

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