1989 Dodge Ramcharger Starts, runs 1-30 minutes, then immed

Tiny
LINDSEYRIDGE
  • MEMBER
  • 1989 DODGE RAMCHARGER
  • V8
  • 4WD
  • AUTOMATIC
  • 142,000 MILES
Vehicle did this two years ago, replaced pickup coil and that corrected the prob. So I replaced the p/u coil again, started it, ran it for 30 minutes. Turned off to button everything up, restarted and it ran for 30 seconds then cut off. Replaced Coil, start/run relay and ECC as this is has TBI was told it doesn't have an Ign module, or if it did it was in the ECC. After I replaced the ECC the truck started, I let it run for an hour, drove it down the road about 4 blocks, it shut off again and would restart, but only run for about 10 seconds. Thanks for any suggestions
Wednesday, January 13th, 2010 AT 6:33 AM

14 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Are you loosing spark? If you are, I need you to remove the 14 pin connector to the single module engine controler (SMEC) (with key off) and check all pins but specifically pin 12 and 14 to make sure they are not corroded and or bent. Chances are the smec is bad and causing this.


https://www.2carpros.com/forum/automotive_pictures/249084_aaaa_1.jpg



If it looks good, remove the coil positive terminal and connect a jumper from the battery to the positive on the coil. Momentarily ground pin 12 to produce spark.

If spark is produced, replace the SMEC. If there is no spark, use a jumper to ground the coil neg. If no spark is produced, either you have a broken wire in the harness or the coil is bad. I have a feeling the SMEC is the cause of the problem.

Let me know what you find.
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Wednesday, January 13th, 2010 AT 8:08 PM
Tiny
LINDSEYRIDGE
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Thanks! Will perform suggestions this am: The smec is built in to the ECC unit. Two lines plug into it, the one you want me to test and a much larger one. When you say you suspect a bad SMEC are you talking about the plug itself or the internal part of the new ECC I just replaced. Thanks again, I'll respond later.
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Thursday, January 14th, 2010 AT 6:24 AM
Tiny
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  • MECHANIC
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I'm hoping it is just a bad connection or wire.
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Thursday, January 14th, 2010 AT 7:52 AM
Tiny
LINDSEYRIDGE
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O.K, Cleaned all connections. Have fire all the way to plugs. Now vehicle won't start at all. Checked fuel, and is getting to the TBI but not dumping from injector. One step forward two steps back.
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Friday, January 15th, 2010 AT 5:44 AM
Tiny
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Wow, I agree. You have the same luck I have. Are you getting power to the injector?
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Friday, January 15th, 2010 AT 11:36 AM
Tiny
LINDSEYRIDGE
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  • 7 POSTS
I checked the plug going to the injector wires, not sure if I know what I'm doing. There are two green wires on the outsides and a tan and a white. I turned the ignition to on and tried all of the combinations looking for 12v, but got no reading. I did check the auto shut down relay and got 84 ohms which I think spec calls for 75. I pluggged the injectors back in and the truck started and ran for about 20 sec, and then kept restarting for 5 sec burts. Starting to suspect fuel pump now, but the vehicle shuts off so suddenly with no run-on what-soever. Took the line off at fuel filter. Turned ignition on and no fuel, but spurted fuel while cranking. I know it's and electric pump, but acting like a mechanical. Pulling hair out now. Thanks David
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Friday, January 15th, 2010 AT 5:42 PM
Tiny
JACOBANDNICKOLAS
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Dave,
Din't pull out your hair. I did and lost most of it by 26 years old! Now at 45, I've learned to take my time and think thing through.

First, we need to check fuel pump pressure. Yes it is electric, but you should have 13.5 to 14.5 PSI when cranking the engine. I hate to say it but the SMEC runs the injector too. However, it sounds like a bad fuel pump based on what you described. Check the pressure and let me know what you find.

Joe
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Friday, January 15th, 2010 AT 6:10 PM
Tiny
LINDSEYRIDGE
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Thanks Joe! Same age, but losing hair fast! Any preferences on junction to check fuel pressure? Youre killing me with this SMEC theory, but ultimately may be correct. I hate these fuel/electric conspiracy issues. Thanks for your feedback. Much appreciated
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Friday, January 15th, 2010 AT 6:39 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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Check it both before and after the fuel filter. Also, thanks for the positive feedback. It's appreciated. Maybe the hair loss is from Dodge. I've owned them since I was 16.

Let me know.

Joe
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Saturday, January 16th, 2010 AT 3:12 PM
Tiny
LINDSEYRIDGE
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Joe,
Update! Dropped fuel tank, found a deterioated sock and a bad connection at neg post on fuel pump, so thought I had hit pay dirt. New pump, sock, filter and I replaced the SMEC again. Still starts, then shuts off. If I put fuel in the TB it starts right up. I went looking for an auto shutdown relay, but parts store say they don't show one listed. My repair manual shows its the middle relay of the three mounted on the drivers fender well. I don't think I have anything left to replace, Maybe the injectors, but why would they run for a second, then quit without a command from something else. Meanwhile I have requested another SMEC swapout under the warranty. That will be #3.
Thanks,
David ( exhausted in Tennessee )
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Saturday, January 23rd, 2010 AT 5:54 AM
Tiny
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  • MECHANIC
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Here is food for thought. With the key in the run position, if there is no ignition signal present, the ASD shuts down the fuel pump, injector, and coil. But that doesn't explaine why it starts with fuel in the throttle body. Basically what I am saying is, the ASD will shut down the ignition too. Have you checked the MAP sensor? I can't remember.
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Sunday, January 24th, 2010 AT 1:44 AM
Tiny
LINDSEYRIDGE
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  • 7 POSTS
I replaced map sensor Friday, was thinking along your lines, as well I replaced the ASD, I had them look up for a 90 model instead of 89. Still same issue
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Monday, January 25th, 2010 AT 5:33 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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There isn't much left. Is it consistant in how long it runs before it shuts down? Every time?
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Monday, January 25th, 2010 AT 7:27 AM
Tiny
JACOBANDNICKOLAS
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Hi:
I was thinking about this problem most of the day. For the most part, I'm at a loss. The more I think, it takes me back to the pick up coil. I know you replaced it, but something has to be going on in the distributor. Was it doing the same thing with the old one? Is your pick up one that you can get from the top or do you have to disassemble the distributor? Something tells me it is heating up, loosing spark, and then working again.

This may sound crazy, but I have to figure this out! It's been eating at me.
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Monday, January 25th, 2010 AT 7:57 PM

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