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Followup To
Question -
Hi...Simply stated, while driving my car stalls in town, on the highway doesn't matter how fast I'm going. It has a 2.5L V-6. I've replaced the following: Fuel Pump & Sending Unit, Fuel Filter, O2 Sensor, Plugs, Wires, Distributor, Distributor Cap & Rotor, Crank position sensor. As I said, the car will lose RPMs all at once, the engine doesn't die completely, but after pulling to the side of the road, it will stumble at low RPMs almost like it's dieseling. I shut the ignition off and try to restart it. It will fire, stumble and die. After 15 to 20 tries, it will restart like nothing had ever happened and will go for a few more miles (10 to 30)and here we go again. Any ideas? I'm fresh out. Oh, by the way, it has about 118k on it. Thanks.
Answer -
Hi Erv,
You didn't say whether you had tried to have the fault code that may be stored in the engine controller read out. If not, then that is always appropriate. It is uncertain whether your car has the capability of giving you the codes via the ignition key, but it is worth a try. If nothing comes of it, you can have them read at a shop that has a code reader for the OBD-II system. Other than that, unless you can get it to fail in front of a shop that has a good tune up/trouble shooter mechanic it is not going to be resolved by throwing parts at it. It could be something that doesn't set a fault code (an off-value sensor that is still within the limits but nonetheless kills the engine). That is when you have to have the car at a shop where there is a diagnostic readout box that will display all the sensor and actuator settings that could reveal at the moment why the engine isn't running.
Try using the ignition key: turn it "on-off-on-off-on" and leave it "on" (doing this quickly, no longer than 5 seconds). By "on" I mean just the normal position when the engine is running, not the cranking position. The 'check engine'light will remain on when you leave the key in the "on" position with the engine still not running. But then watch the 'check engine' light to begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group them in pairs in the order that they came out, thus forming two digit numbers. You may notice that the pause is shorter between the digits of a given number, and longer between the numbers themselves. Then send me a 'follow-up' question telling me the results of your readout. By the way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of readout".
I have the troubleshooting manual for the 2.5L engine and we can look up the possibilities of what is wrong based upon what fault codes you show. There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers and also has some suggestions on other techniques for getting a code readout yourself. But then you need to get specific info for what exactly might be the diagnostic tests or parts to replace to complete the repair.
If these approaches don't produce fault codes at all, not even a 55, then you will have to go to a good tune-up shop where they have a more sophisticated code reader in order see if there are any codes. You should be able to get a readout for under $50.
Roland
Thanks Roland...We did put an Actron OBDII reader on it and it passed, did not produce any codes. There were no problems for 1 week after changing everything. I haven't thrown parts at it, all that was changed for a tune up. The fuel pump & sending unit come as 1 and my gas gauge was reading incorrectly. The distributor was changed because the coil tower inside broke when taking the distributor cap off to change it and the rotor. I did use a dial indicator to ensure that I had the right size rotor cam in the distributor as well. After the problem started, we checked into the possibility of bad or watered gas since we found out later that the station was going into rehabilitation for 6 weeks the next day. We even drained the tank, replaced it with clean higher octane fuel, and added ISO propanol alcohol (dry gas) no joy. Then, by reading through some of the issues that people were talking about on some of these boards, a similar problem was solved by the crankshaft position sensor. Changed that last night before writing to you, but still did not rectify the problem. Any other ideas?
Thanks alot.
AnswerHi Erv,
I would visually check the wiring harnesses to all the sensors and actuators, particularly the ones that run above the exhaust manifolds where the heat can damage insulation.
Unless you can get the failure to occur at a shop where there is a knowledgeable mechanic, it is going to be difficult to solve this one. It is something subtle, for example a MAP sensor that is intermittantly inaccurate, but not so greatly as to set a fault code, and that might very well cause an inappropriate mixture from time to time. This in fact was something I experienced. But it was found by a Chrysler mechanic using the DRB at the time it wouldn't run right; there was no code set. Other than watchful waiting for a code to show up, there isn't much you can do. If you have one of the old spark plug wires you could put a spark plug in it and then if you can substitue it for one of the installed plug wires when it dies next you could at least check whether the spark is o.k. when you are having the problem, and thus eliminate that side of the equation. Just hold the assembled and plugged-in plug/insulator/wire with the threads of the plug on the cylinder head, recruit someone to try the starter, and observe for the quality of the spark.
You might also take a look at the egr valve which if sticky in its motion in opening and closing can kill the idle very easily. Just observe the stem for motion (watching the slot in the stem) while the engine is revved. You could some WD-40 of the valve stem to make sure it is free to move.
Those are my best shots at such a situation. I know you will solve it, so let me know what it turns out to be.
Roland
