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My 2001 dodge ram

  1. Please fill out the following to ask a question.

    DESCRIBE ISSUE...engine fails to start after warm up, but starts again after cooling off.
  2. I assume it does still crank when warmed up, correct?
  3. Have you scanned for codes?
  4. Yes, it cranks normally but doesn't start when warm.
  5. I will scan for codes today. Now that you mention it, the check engine light has been on and off lately.
  6. Well,I have 2 stored codes ; PO340, and PO123 Also a current code ;PO138 Darn thing is falling to pieces on me!
    If the camshaft position sensor needs changing, where is it?
  7. The most probable cause of your starting and stalling would be the TPS code you got. Address that first, Your other code p0138 is a O2 sensor short to voltage which also is not a good thing, and the Cam position sensor code is saying PCM is getting no cam signal. So all of these three codes in junction could cause any of this.

    If you want, post back if you want the flow charts for these three codes. I would not suggest throwing parts at this car yet, cuz when multiple code arrive at same time like this, it could be a harness issue, and no amount of new cam or TPS and O2 sensor will fix this. I suggest some pin testing first. You may just find a gad ground wire or a chewed harness, some irish green shyte in the PDC box etc.

    Start checking connectors at the PCM to see if any wiring or connectors are in obvious disrepair.
  8. All three of these sensor get signal, 5v reference and ground via the PCM. I hope you are getting my drift.
  9. Thanks for advice. I can check continuity and reference voltages after looking for obvious problems at PCM. Never worked from a flow chart though. I'll bet they make troubleshooting easier. Could you post them?
  10. Here they are. They are white on black, for some reason my virtual printer has never let convert these types of files in normal format, but they are readable. But cost alot to print. If you get my drift. But with a laptop or tablet/phone, easier to bring to the truck and use as a reference than a bunch of pages. Simply download them and send to a tablet/phone or such and your good to go.

    Included here are also snap shots of the affected sensors to help you trace the wires from sensor to pcm. Back probing here will be essential for the TPS. Just click on the snap shot to enlarge to a readable format. Screenshot (8).png Screenshot (9).png Screenshot (11).png Screenshot (12).png
  11. ACE 0 pdf is 123, ACE 1 is 138, ACE 2 is 340. If you can find a way to revert them back to black on white, go for it and print them. I just can't find a way for Bullzip virtual printer to that for me.

    Seem it a common occurrence for bullzip users and the software is free. So sue me for being cheap. ;):bat:
  12. Most of the test in the flow charts can be done with a multimeter when asked to do so with the DRB oem scan tool. Most ppl don't have a OEM capable bi directional scanner, but they can be done with some agility and a good DVM. Sweeping the tps in back probe is quite alright, but I prefer to sweep them disconnected in OHM mode, allows for a better catch of the glitch of the tps when you sweep it. Look for a dead spot, but I may be getting ahead of myself. Just follow the flowcharts step by step.

    You never know, you may find you have a hidden talent for diagnostics if you follow directions.

    Most ppl get frustrated and throw parts at car just cuz they refuse to follow step by step instructions and then get flustered at the person giving instructions when dumping hundreds of dollars in parts a whine and rant etc instead of looking at themselves.
  13. Hope this helps, and if you need more advice, I pop in here quite often, but not so much as before as I am now back to work and swamped as usual.

    Also, other wrenches here are quite generous of their time. Trust them also. Don't gripe, we won't respond well to that.

    So in that regards, happy hunting, hoping you save time and more important, hard earned money.
  14. BTW, you will notice all the affected sensors can be pin tested at the C1 connector of the PCM to each individual sensor you need to test. SO I thought a picture of the pin locations of that connector would be helpful, so here it is.

    Hint, if you study all the wiring's I provided, all three affected sensors use sensor ground pin 4 of connector C1 at pcm.

    SO by disconnecting the C1 connector and each sensor, leave your neg lead of your DVM on pin 4 and then use your pos lead to check each senor ground of those sensor connectors. If you do that first, you just may have found why all three are coding at once, you are basically looking at a bad sensor ground wire or bad, corroded pin 4 or possibly a bad PCM which will no longer ground itself. I am not saying all three sensor failed at once, but highly unlikely, so this is a logical first step to take, and it is free and easy to do. However, I doubt the PCM would be the issue, as many more sensors share this same sensor ground, but they do splice off at some point to share within the harness, so wiggle testing the harness and observing the DVM on each sensor would be helpful in spotting a bad wire, split, intermittent in the main harness.

    Also another hint, if you read the possible causes of each flow chart, all three mention open sensor ground circuit.

    Screenshot (13).png
  15. I took alot of time and effort to research this for you, so you owe me an imaginary beer. :beer::beer::beer: or three. So if ever you get it fixed with my advice, plz donate to the site a dollar or two, it keeps us rolling to help you in the future. If you don't, we don't care, it is a non profit site. We are here only to help others. My main profit is hearing my advice helped someone else out in this hard economy where easy made cash is only on wall street. Unless your a 1%er in a different sort of club.;)

    Anyone see the new tv movie "the wizard of lies" with Robert De nNiro?

  16. It's obvious that you spent a good amount of time on my problem. I'd be happy to buy you a beer or three. As messed up as the world is at times it's good to know there are still a few decent guys out there, willing to help out for little or no monetary gain. I'm a retired machinist, living on social security, so can't pay a lot to have my truck repaired by a pro. I believe your advice and charts and diagrams are going to help me find the problem. Some of your "diagnostic technician" jargon is a little beyond me, but I have a good understanding of electricity and have always repaired my own vehicles. I'm looking forward to taking that info out to my shop and getting to work on the old girl. And perhaps finding that irish green shyte you spoke of . :) I'll post again when I find the problem. Thanks
  17. Is this a "hard failure" to start when it is warmed up, pretty repeatable? I'll let nickb2 guide you through the diag charts, but be sure to try some simple tests, too.

    The next time it won't fire, pull off one plug wire and see if there is any spark.

    Try a quick blast of starting-fluid (nickb2 hates that, would want you to use carb-cleaner) and see if it fires briefly with that.

    It would be great if you could remove a plug and see if it is dry or wet immediately after a "no start" episode.

    Also, check fuel pressure with a gauge, both now and when it won't start.

    Use live-data to quickly check what various sensors (ECT , TPS, and CKP being prime suspects) are doing. Again, nickb2 can guide you on ways to do this inexpensively using ELM327-type connections to a laptop, pad, or phone.

    Does anybody know if this engine has a trigger wheel that can run without the CMP sensor, like a 36-1 or 60-2?
  18. If it fails when hot, you may have a sensor that shorts internally when hot, causing your no-start. So, locate and disconnect O2 sensor and cam sensor. ( I believe the cam sensor is inside to distributor, and the connector is a few inches outside the distributor, thankfully) Now recconnect those sensors, because that was just a practice run for later, when the engine is hot and not starting.
    When it fails, disconnect O2 sensor and see if it will start. If it starts, reconnect O2 and see if it is no-start again. If reconnecting a hot O2 causes n0-start you have a shorted O2.
    No luck with O2? Try disconnecting cam sensor. Try to restart. Gets a little tricky here because some cars will not start without a cam signal. Dodge/Chrysler often will start, but only after cranking about 10 seconds.
    So, when your are doing your "practice run", try to start your cold engine with the cam sensor disconnected and see what happens. Remember that you may have to crank it a LONG time to get it to start when cam sensor is unplugged.
  19. I'm rather amazed at all the good advice I've received on this. I was in the process of doing an ignition tune up (plugs,plug wires,distributor cap, and rotor) when I first posted here. The plugs were worn, but dry; the cap and rotor showed obvious signs of wear, but I can't tell if there's any hairline cracks or arcing; the old wires were ok. Since then it hasn't failed to start or logged any more codes. I've driven it 75 miles and restarted it when warm about 15 times without fail. I did some of the checks suggested by Nick2b and found nothing so far. Also, I had previously tried pouring a little gas into throttle body, but to no avail. I feel like I'm driving on borrowed time, but my dad always said "Max, if the summich ain't broke, don't fix it." Anyone think I might have inadvertently fixed it? Or is it impossible for an ignition "open condition" to cause all these codes and failure to start when warmed up? One other thought: I laid on top of the engine for some time changing distributor cap and rotor. Maybe I moved some wires around and fixed it without trying? Anyway I want to thank everyone, especially Nick2b for the time spent on advice.
  20. <y french grand dad said the same thing, if it don't work , hit it or leave it alone.