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violent stall and weird timing mark behavior
https://slantsix.org/forum/viewtopic.php?t=49055		 Page 1 of 1
Author:  Ed Mullen [ Thu Jun 14, 2012 7:10 pm ]
Post subject:  violent stall and weird timing mark behavior
I recently replaced my 87 van's original carb with a 1980 E.I. 1945 that the local carb shop salvaged from thier pile of cores and rebuilt for me.

I changed the timing set (which was in fantastically bad shape. I don't understand how/why it still ran).

I set the timing (16 degrees btdc w/vac line to lean burn capped).

I changed the choke t'stat (recently bought 4. 1 really well made one from carburetor-parts.com and 3 Chinese KEM ones on clearance from rockauto.com).

I corrected some improper wiring that I had ignorantly done trying to reconstruct my burnt engine harnass a few years ago. (In so doing I found the wires I previously couldn't find to power the idle solenoid on the lean burn carb. They were attached to my choke modulator, and the choke was powered directly from the oil pressure switch, that is supposed to connect to the choke modulator, first.)

I set the curb and fast idles.

When I put a timing light on it now, the mark appears in 2 different places 3 degrees apart. It does not jump. There are two steady "marks."

Also, (and this may be wholly unrelated, and probably is) every now and then it stalls violently. I don't know how else to explain it.

I first thought that the trans or rear was failing in some catastrophic way (only because of the vehicle-shaking way it happens.)

I realized later that if any part of the drive train behind the torque converter were to seize, it would not stall the motor, and would be no different than slamming on the brakes (which causes no such stall.)

Paying more attention the last few stalls, it sort of seems as though pistons are randomly firing at the wrong time when this happens.

Is that something an ESA does on it's last legs?...kick out random spark, causing it to kick backwards and stall? Is that even possible? (I'm having a hard time conceiving how that could happen. The workings of the cap and rotor would not allow spark to go to a cylinder at a 'wrong enough' time. The rotor only has continuity to any one spark plug wire maybe 10-15 degress. Double that for the gear ratio of the timing set and the crank can only be off by double--20-30 degrees. Thats not enough to kick it backwards, right?)

Could the same thing, then, (if at all possible) be caused by the neg coil wire grounding out randomly, triggering a random spark?

I'm trying to get it to run perfectly before switching to HEI to keep things scientific. I guess that might not be an option. (I may briefly run the lean burn distributor with the hei module to see if the phantom timing mark disappears--just set the idle and timing and observe idling behavior with a tach and timing light, then install the E.I. distributor and readjust all.)

Any input is greatly appreciated as always.
Author:  sandy in BC [ Thu Jun 14, 2012 7:55 pm ]
Post subject: 
Sounds like spark plug wires cross firing to me.....
Author:  SlantSixDan [ Thu Jun 14, 2012 11:33 pm ]
Post subject: 
Yup. Spark plug wires -- which are not on your list of replaced parts -- are prime suspect here. I like Magnecor wires, but there are other good ones, too, and even a plain ol' parts store replacement set will have to be better than the ones now on the vehicle.

What's an "E.I. 1945"?
Author:  Ed Mullen [ Fri Jun 15, 2012 6:28 am ]
Post subject: 
Quote:
What's an "E.I. 1945"?
Sorry.

I mean it's a 1945 that came off a electronic ignition motor v.s. one that had lean burn. (baby step towards HEI conversion).

Spark plug wires are 4 years/800 miles old Bosch set. I'll inspect for damage.

Plugs were done right before carb swap. (NGK)

The Magnacors look great (I got a set for my wife's Valiant. I didn't get around to installing them yet.) I rarely drive the van so I can't justify the expense for it.

I have a bunch of low mileage wire sets around (from arbitrarily changing the wires every tune-up back when it was my daily driver.)

Thanks.
Author:  SlantSixDan [ Fri Jun 15, 2012 10:18 am ]
Post subject: 
I don't think much of Bosch plug wires (the ones they sell through auto parts stores tend not to be of very good quality), but those aren't very old and shouldn't have broken down yet. How old and what brand are the cap and rotor? When they're working as designed, you're right about there being continuity only to one cylinder's terminal at a time. But if a crack or carbon track develops the spark can jump to the wrong cylinder.
Author:  Ed Mullen [ Fri Jun 15, 2012 10:57 am ]
Post subject: 
The cap and rotor are from the same tune up 4 years ago.

I think they were the tan/brown Standard garbage. (Maybe Auto-zone brand or something, even).

I grabbed a couple of MO-3000 rotors from Napa a few months ago, in case they stop making them, and ordered a CH-410 cap from rockauto.com.

They sent me some black Chinese trash instead (including a rotor that looks like it is for a life-size 'Visable V-8' toy), which they had me keep for free as they knew it wasn't worth the postage to get back.

I'll get a CH-410 before the HEI swap, but in the meantime I have caps and rotors left over from past frequent tune ups.

Thanks again.
Author:  matv91 [ Sat Jun 16, 2012 7:40 pm ]
Post subject: 
Lean burn distributor has start and run pickup coils. After its running disconnect the start pickup. See if one the marks goes away.
Author:  matv91 [ Sat Jun 16, 2012 8:24 pm ]
Post subject: 
Burned engine harness,Stalls violently. Does this have computer controled lock-up torque converter?
Author:  Ed Mullen [ Sun Jun 17, 2012 7:12 pm ]
Post subject: 
Quote:
Lean burn distributor has start and run pickup coils. After its running disconnect the start pickup. See if one the marks goes away.
Didn't know 2nd p'up was for starting. Bad wiring there may explain delay getting spark turning over cold.
Quote:
Burned engine harness,Stalls violently. Does this have computer controled lock-up torque converter?

Only "computer" is ESA. Only 4 wires to trans (2 for reverse lights, and 2 for neutral safety switch.)

I am noticing it happens coming out of reverse, or shortly thereafter.

Spark plug wires seem fine. Didn't pop off cap yet.

Maybe torque converter is suspect (noticing violence of stall proportionate to rolling speed).

My experience with failing TCs is that engine moves and car doesn't.

That is not happening.

I guess I'll drain some fluid from the TC and check for suspicious particles.

thanks
Author:  matv91 [ Mon Jun 18, 2012 3:26 am ]
Post subject: 
http://www.slantsix.org/forum/viewtopic ... 3118bbe076 One wire too many.
Author:  Ed Mullen [ Mon Jun 18, 2012 7:19 am ]
Post subject: 
Wow.

I would have never guessed that.

If I use a toggle switch instead, when should I have it on? (freeway driving in high, or just whenever I'm not coming to a full stop?)

Thanks so much.
Author:  Reed [ Mon Jun 18, 2012 8:04 am ]
Post subject: 
Interesting. I would enjoy seeing pictures of where this wire goes on the transmission, and pictures of the internals of the transmission (especially the valve body) if you have the time.

1987 was an odd year for the slant. Last year of production, electronically controlled lockup torque converter in some models, and we even had a board member a while back claiming that his 87 Dodge truck was equipped with an OBD-I plug. If you happen to find an OBD-I connector, please take picture and share.
Author:  Ed Mullen [ Mon Jun 18, 2012 9:09 am ]
Post subject: 
I've seen the posting you reference, as well as the same connector on my van (mine is/was inside the firewall under the dash).

It's not an OBD-I, it's just a diagnostic connector (who knows what you are supposed to plug into it, or what it could possibly tell you?).

If I remember, I'll take photos next time I change the filter. Somewhere between 2k-5k on the last transmission rebuild--I really never drive the thing. (Rebuilder never mentioned the electronic lockup, but it did take him forever to get the new TC into his shop. If he offered that, or anything else as an explanation, I don't recall).

That said; I don't see me doing that anytime soon.
Author:  Reed [ Mon Jun 18, 2012 9:43 am ]
Post subject: 
Quote:
It's not an OBD-I, it's just a diagnostic connector (who knows what you are supposed to plug into it, or what it could possibly tell you?).
That is what I figured. I know that starting in the late 70s/early 80s, some Mopar cars and trucks got the Diagnostic Connector. I have owned a few vehicles with them. I once found a wiring diagram that broke out what feeds went to the diagnostic connector. It is things like battery voltage, (-) coil wire (for a tach feed), and a few other items like that. It would be a handy thing to have functioning if you could find a plug that would fit the connector. It would be very easy to fabricate a rolling diagnostic machine that you could plug into your car and get an at a glance picture of how the engine was operating during a tune-up.
Author:  Ed Mullen [ Mon Jun 18, 2012 6:13 pm ]
Post subject: 
Quote:
...where this wire goes on the transmission
There is a sending unit looking thing screwed into it above the rear driver side corner of the drain pan.

The wire plugs into that.

I disconnected it for now, coiled it up under the doghouse, and wrapped the connector w/electrical tape.

This weekend I'll trace the wire back to the relay, find the apparent short, repair or bypass the wiring, and start making provisions for a switch to control it. (I only drive it to the train station during the week and don't break 45 mph.)
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