QuestionCar/engine described in subject. Daughter melted timing-belt (didn't see, hear or smell a thing...) and bent many valves. I went to salvage engine but ended up rebuilding the junkyard engine anyway.
I totally rebuilt engine - new rings, bearings, valve seals, lapped valves... Torqued every bolt to Chrysler S-M spec, etc...
Engine started right up and ran BEAUTIFULLY for ~1.5 days then started missing. Daughter drove ~45 mins away, fine when parked at mall but on return trip started missing.
I dug in...
It was fine when cold - PERFECT - but became almost undriveable when warm. One code: "misfire on cylinder 3" per reader, "multiple misfire" per key/flash.
I did compression test - ~185 on all 6 cylinders. Spark was weak, inconsistent, so I re-=checked plug gaps after comp-test and re-connected all wires to distro.
I tested all fuel-injectors - didn't like reading on #3 and one other, so I swapped the whole set and the fuel-rail from my old engine. Those injectors all tested 14.8 Ohms exactly, and "clicked"/dripped on 12v command, and worked fine in old engine before daughter killed it.
ZERO help. Changed *NOTHING*.
Next I swapped distributor for the one from our old engine. It too had been working fine until death. Car would not start at all - distro apparently dead - so I swapped 'em back.
Starts/runs fine cold, misses horribly hot -- NO CHANGE!
Fuel pressure adequate - I mistakenly popped fuel line and sprayed gas EVERYWHERE. Still may replace fuel-filter later, but seems no problem now...
Much discussion with various fairly knowledgeable people came up with (3) new possible culprits:
(1) Bad distributor/cam-sensor
(2) Bad crank sensor
(3) Bad grounds
Installed known-good distro, came from "yard car" used by salvage guys until the car blew a head-gasket. NO CHANGE good or bad.
Installed Crank Sensor, NO CHANGE good or bad
Built a ground-bus, using 8GA wire and solder to attach pigtails and rings. Hooked to battery-ground on driver fender, to distro-body, to water-jacket on back end (thus grounding both heads and block), direct to both heads, direct to block, direct to water-pump, then other end to a bolt on the passenger fender.
Additionally, there's a ground-wire coming from the harness to the rear end of the 2-4-6 head -- I ran an 8GA wire with soldered rings from there to battery-ground.
This seemed to make things MUCH WORSE. Took a short ride, missing horribly, then car would cut out -- I'd start, cut right out again. Had great trouble getting it up my 2x2-inch-stepped "ramps" I made of 2x12 so I can get the jack under the car.
Finally made it up, then it cut out and would not start again.
Now it will not start at all!
A mechanic-friend came by - we went over everything and dug in together. Decided we MUST check cam-timing -- found that 1-3-5 cam (drives distributor) was off by one tooth - looks like a piece of zip-tie got pulled in and let 'er slip one tooth - I found the zip-tie in the crank-timing-cover base where ripples prove it'd obviously been through a cam-pulley...
For the record, to accomplish this without having to remove the PS pump and bracket, we set crank/2-4-6-cam to TDC and used a long screw in the distro-cap hole to compare the position of the distro rotor to the old engine (sitting on stand).
We carefully compared the old engine, using a short straight-edge down the side of the rotor and measuring distance from screw, comparing "right on" the cam-timing mark with "off by a tooth" on the old engine -- much careful measuring back-and-forth proved it was off by one tooth.
I fixed that -- checking several times to verify timing was correct on both cams and crank, rolled engine on starter several times then re-checked, and then re-assembled everything.
Damn car still won't start.
There are no codes according to my cheap-ish code-reader and a much better one borrowed from Auto-Zone. No freeze-frame data either. Key-3-flick/count flashes trick shows only 12 (battery disconnect within 50 key cycles) and 55 (end of codes) -- no help there either.
I'm losing my frigging MIND!!!
One new thing happening since cam-timing fix: after cranking stops I get a couple of muffled "pops" - I think muffled back-fires - from inside the intake. This tells me I need to go back and double-check the plug-wires. When I reconnected them, though I was extremely careful, I am human -- I may have crossed a couple. I certainly couldn't have screwed up enough to make it not even TRY to start, however!
I'm basically crippled - mangled leg - and all this has made me in so much pain I can barely move. I'm almost to the point of giving up and having it towed to the junkyard who sold me the engine -- they have the scanners to diagnose and a very good mechanic (one of the aforementioned resources I used to come up with my 3 possibilities).
Any and all other input you may have would be appreciated!
DD
AnswerHi "Dad"
I am impressed with your saga and the detail you have given me!
I have a couple of suggestions. Because this began as in issue only when warmed up it would be good to check the resistance of both the engine coolant temp sensor and the intake air temp sensor. Those should read in the range of 7-13k ohms when cold and 700-1k ohms when hot. The other possibility is that the egr valve is stuck ajar which is leaning out the mixture too much for a start and an idle. So check to see that its valve stem is moving freely and that is is closed positively by internal spring-action. You can put the tip of a screwdriver in the slot of the stem to move it, and if you find it gummed up spray the stem with WD-40 where it enters the valve body.
I suspect you are aware of the fact that the wires on the distributor cap don't externally agree with the firing order but rather there is a re-arrangement between the internal rotor contacts and the external wire plug sockets that is built-in to the cap. But I thought I should mention that. Those are the possibilities that I see based upon the history and lack of fault codes. If the spark seems weak you might want to change the wires/plug caps if not already done, and verify the rotor and cap as usual.
It could be the crank or cam sensor is failing but not so severely as to set a code. So you could measure the voltage pulsing on the sensor wire of each to observe whether it pulses reliably between 5 and 0.3V as you turn the engine over by hand.
Please let me know how this resolves itself, and best of luck.
Roland
PS Sorry for the delay but I just found your question in the 'pool' to which it had been referred by Kevin, the other 'expert.
Please 'rate' my answer, and where you see the question about 'volunteer of the month' consider giving me a 'yes' if this response has proven helpful. Thanks
