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97 Concorde 3.5 code P0340 & various misfire codes

Model: 97 Concorde Fault Code: P0340 Posted: 2007-07-16 20:43

Out of the blue my Concorde will not start. It never hesitated, no Check Engine light...it always ran beautifully. Now it just turns over and will not fire. My first thought was that the timing belt may have broken or slipped, since it's over 20k overdue for changing, but for it to happen at the moment the car shut off or right when I went to start it next seems highly unlikely. I know the belt is not broken, though, because I removed the cam sensor and observed the cam sprocket spin as my wife cranked the motor. Also the water pump, which is driven by the timing belt, has been dripping coolant periodically for the past few years and I haven't gotten around to tearing the car apart to replace that. So then...maybe the water pump bearing siezed and torqued the timing belt, causing it to slip? Since the motor died I have noticed a considerable amount of oily coolant pooling on the garage floor underneath the timing cover, getting larger each time I try to start the car. I also tested the supply and signal voltages of the cam sensor: supply 8v, signal .03 - 5 volts as the motor is turned by hand. My Haynes manual says the lower voltage reading should be .3 but my reading was .03...whether this is a negligible difference or a fatal typo, I don't know. Perhaps this is evidence that the cam sensor is bad? I pulled the following trouble codes: P0340, P0300, P0302, P0304, P0306. The misfire codes make sense, after all the car won't start. I've also checked the supply voltage to the CRANK sensor, but due to tight space in the engine compartment I wasn't able to actually check for an output signal. So here are my questions: 1) Does it sound feasible that the timing belt could have slipped under the conditions I've described? If so, could the timing issue cause the PCM to set a P0340 code due to the cam and crank signals being misaligned? 2) Is there a way I can check whether the timing is off without tearing into the timing cover (just for troubleshooting sake)? 3) Is there a separate code for a faulty crank sensor/circuit? 4) If it is the cam or crank sensor, what would explain the recent pool of oily coolant? 5) Can I do anything more than look up codes with my Actron code scanner? Thanks for any help you can give....sorry this is so long. -Mike

Related fault codes
P0340
Comments (12)
Anonymous 2007-07-17 07:10

First of all, timing belts are the most likely to break at startup, or under a hard accel. I don't think Im going to even address any "is it the cam or crank sensor" issues when you have pooling coolant on your garage floor and your timing belt is already 20K overdue. Your lack of awareness to complete these tasks is defeatist. First, replace the timing belt and water pump, that will solve the pooling coolant and will allow you to visually see if the timing was off or not. If not replace the belt and we'll go fromthere. I hope Comp doesn't see this. He'll go ballistic.

Anonymous 2007-07-17 07:14

Why would you think the leaking water pump and probably the front engine cover behind it wouldn't shorten the lifespan of the timing belt! Yeah it's 20 000 overdue for it's recommended changing when the belt isn't being soaked with oil and coolant! Put away the DVOM and start removing the front of the engine to check it or tow it to a shop! Shut down and starting tends to be when old belts break form my experience! On start up you've got the already strainned belt pulling against stopped timing gears and on shutdown the pistons stop moving but the cams spring pressure and inertia will contine to want to pull on the belt. Seems to be the most logical times to break if you ask me! Codes are useless at this point. Of course there's no cam signal because it's out of time or not turning at all! Even if you did have a crank sensor problem hypothetically why stress it when coolant and oil is spilling out from where the timing belt is!

Anonymous 2007-07-17 07:40

exactly my point

Anonymous 2007-07-17 08:23

Too late it's seen! replace the pump and put the old belt back on??? put a new belt on an old pump? RU serious? If you could get the pump to stop spewing long enough to hold pressure I'll almost gurantee the front cover behind it is leaking as well so Start from there and work your way out replacing everything. Why do things 2 and 3 times. If the gasket has never been replaced then it's either already leaking or going to soon. Same with likey the cam seals, valve cover and tube seals, intake gaskets etc, etc!. You guys and your code readers some days I swear!

Anonymous 2007-07-17 08:26

Thanks for your replies. I've already stated that: "I know the belt is not broken, though, because I removed the cam sensor and observed the cam sprocket spin as my wife cranked the motor." I did not realize that shut down and start up put the greatest strain on the belt...that bit of info is very insightful. Certainly I considered the timing belt as a good possibility in the first place. Given all the experience represented on this forum, before I go opening up the motor I would like to know if a slipped timing belt can cause a P0340 code. Do you guys know? Discover more Dodge Ram 1500 truck Ram Yes, I've been negligent in maintaining the water pump and timing belt, but go figure, it's not like my Lumina which has an external pump that I can change with my eyes closed. Then wouldn't you know, the starter on that car just gave out so now both my vehicles are down. Any attention to my other questions would be much appreciated, although I'm now certain it is time to change the pump and belt anyway. Thanks again... Mike

Anonymous 2007-07-17 08:27

Try drilling another hole in the bottom of the boat to let more water out! all in good fun mike, all in good fun.

Anonymous 2007-07-17 08:31

I do all the maintenance that I can myself; I'm no professional mechanic to know exactly what all ought to be replaced. Comp, are you suggesting I replace the main seal and cam seals? What other specific seals/parts are in need of replacing at 123k mi?

Anonymous 2007-07-17 08:37

*to self*: should I use my invisibility for good or evil?

Anonymous 2007-07-17 08:59

I'm suggestting towing it to a dealer or a good repair centre that's familiar with that engine. Yes a slipped belt can generate that dtc! On some instances you could remove the cam sensor plug and the engine would start after cranking over twice as long provided only the cam signal was bad and the cams were still turning. I'm not sure on yours cause I'm not there! Im suggesting replacing most seals etc that require timing belt removal. Might as well do them while you're in there instead of paying the labour again to do it down the road. Most 3.5's aren't interference engines although cranking too much with a cam out of time is never a good idea, interference or not! this repair is beyond the scope of most do it yourselfers in my opinion but then again I have been wrong once or twice before!

Anonymous 2007-07-17 09:51

I've done a few big jobs, for instance the timing chain and gears on my Beretta 2.8...not an easy job, but as with them all I know it was done right. I have gotten screwed over at shops before over smaller things, but it's mainly because I could never afford to pay someone to do this job that it HAS to be within my reach. Of course I would replace any seal or gasket that would be disturbed whatsoever in removal...who would re-use old seals they had to break/take out? I'm very meticulous in my repairs (another reason I didn't hurry in to do this job) so I'm confident that with the help you've given me I'll be on the road in a week or so. Your insights are greatly appreciated. Thanks again! Mike

Anonymous 2007-07-17 09:59

Im not referring to seals that have to be removed that goes without saying! Im referring to that gasket that's behind the waterpump on that engine that leaks often and is misdiagnosed as a waterpump leak! Again we're not here to discuss people getting screwed over at shops, We weren't there and we don't know the circumstances from when you say you were screwed. It may very well be in your grasp to tackle this repair but I feel better warning people then just telling them it's easy and having them make it worse!

Anonymous 2007-07-17 10:02

You're welcome! Hope it works out okay!