Tach to 0, rando

adawil2002

adawil2002

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Tach to 0, random

Driving on the Kancamagus in NH. Car running great, smooth, powerful, confident. Then no warning, tach goes to 0, very disconcerting att speed. Try to restart while moving and get the car running starter screetch.

When stopped, car starts with a little cranking and gas. Runs fine until...nothing. I'm running Pertronix 1868.

I've been chasing a random small 'hick', new cap & rotor arrive tomorrow. Oldest part if the ignition is the coil...which will be ordered tomorrow.

Any help is greatly appreciated.
 
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First

check for power at the coil and resistor. Resistors have been known to go bad, produce enough heat to crack the back side of the ceramic and cause an intermittant connection.

You can measure the resistance of the coil to see if something's abnormal from spec. A coil can be had from any auto parts store. (I paint mine black because I bought an Accell and didn't trust the Bosch from Argentina- heresy I know.)

With the black wire from the pertronix hooked to a volt meter you should be able to see the action on the meter ( what was the points closing and opening.) by activating the ignition switch.

But since you lost the tach-check the battery connections. Usually a resistance also means heat somewhere but be careful feel don't touch.
 
adawil2002 said:
Driving on the Kancamagus in NH. Car running great, smooth, powerful, confident. Then no warning, tach goes to 0, very disconcerting att speed. Try to restart while moving and get the car running starter screetch.

When stopped, car starts with a little cranking and gas. Runs fine until...nothing. I'm running Pertronix 1868.

I've been chasing a random small 'hick', new cap & rotor arrive tomorrow. Oldest part if the ignition is the coil...which will be ordered tomorrow.

Any help is greatly appreciated.
Click to expand...

The intermittent "cut-out" is unlikely but not uncommon. I have experienced something similar that seemed to occur during light acceleration in second gear. Wanting to make sure the problem was not merely rough road, I pulled over and could reproduce the hick-up a couple of times while still in the drivers seat, but that was it. The engine did not stall, but a pronounced hick-up caused the tach to jump. I was not able to locate the gremlin and never able to repeat the problem at home base - rough, smooth, hot, cold, wet or dry. Since it has not happened in well over a year, I try to attribute it to bad gas and forget it. But.

First impression is that it is electrical and ignition-related and I wonder about any number of possible loose connections including under the dash (ignition switch) and the starter connections. If the switch is wonky, imagine turning off the key and turning it on again (more on that below). Naturally, anything that could interrupt the flow of electrons to the coil is suspect, and that includes any loose wires or poor grounds. Not clear how starter screech is related to what seems to be ignition cut-out. Likewise unclear how the Pert-X point-replacement is involved, especially if it functions after the incident - unless there is a microscopic-heat-related short.

OF secondary concern is fuel injection, since it too is reliant on electricity to function. When pointing the finger in the DJet direction, I would be concerned with wiring, including the wiring connection at the forward portion of the right frame rail - if you have a major coupling there (not all do). Also, the on-off symptom similar to turning the key on and off, has often been mentioned when a throttle position sensor starts to go bad. This often can be debris on the printed circuit board or old-fashioned wear. To be clear the Throttle Position Sensor might cause a miss on acceleration, but I wouldn't expect it to cause a complete shut down.

More food for thought: http://www.e9coupe.com/forum/showthread.php?t=2879

HTH
 
I had this issue on my 2002, thought the tach wire was grounding out or the tach had a short. Car would die with no warning while driving, it would happen every 40 or 80 miles. The fix was to put a 1.8 ohm resistor in it, it had the original 1.0 ohm resistor which was fine for the black coil but the red/silver coil needs 1.8. I think it may have caused an over heating issue with the coil or perhaps a weak wire connection.
 
Thanks for the replies. Apologize for the misspellings and weird title...of the original post...phones are not the best forum machines.

Made it home with only 3 stalls, 1 in parking lot immediately after starting, car sat for 2 hours. Had checked connections, alternator, battery, coil, & distributor before starting, all looked as it should. Noticed aux air slide filter(?) the little air filter near the starter had fallen out during the trip...it was in there yesterday. Made it to my home exit off the highway and dead after 2 1/2 hours of being fine, restart, 1/2 mile and dead.


The throttle position switch is new, 2 months old, less than 400 miles of use.
Frame rail plug cleaned and secure.

When Pertronix was installed, bypassed the resistor, voltmeter read 3ohms resistance out of the coil. Will revisit this.

All battery connections feel tight and all grounds have been cleaned.

I plan to go through all connections and really check closely for loose/broken connections.

MMercury:
I turned the key to position 1, and tried to restart and the starter screetched like the car was already running.

This was the first 'real' drive since purchasing the car and spending all winter sorting, fixing, cleaning everything and upgrading the suspension from tired & sloppy to, HDs, CN front springs and sway bars. So something getting shaken loose on a rough frost heaved road is likely.

When it's working correctly, the car is simply amazing. An absolute pleasure to drive, fast and graceful.
 
Ugh! Intermittant electrical faults like this are tough to debug. All we can do from afar is tell you what the root cause was for similar issues that we experienced, and you can try replacing or inspecting those components.

For me, it was the "load shedding relay" - the high-capacity relay that lives above your hood release. When it died, my tach went to "0", and most electrical systems quit. The root cause of that failure was a voltage regulator that allowed the alternator output to get too high, frying the coil in the load shedding relay, as well as the electronics in the Pertronix.

If your car restarted, you don't have the same problem that I did. Obviously a fried Pertronix wouldn't heal itself. But, your load shedding relay may have become intermittant, perhaps due to oxidized points. Removing its cover, and filing the points could be one step in your debugging process.
 
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Pertronix says keep the ballast resistor if your car has one. May not be the issue but if the coil gets too hot it may cut out.
 
adawil2002 said:
Thanks for the replies. Apologize for the misspellings and weird title...of the original post...phones are not the best forum machines.

Made it home with only 3 stalls, 1 in parking lot immediately after starting, car sat for 2 hours. Had checked connections, alternator, battery, coil, & distributor before starting, all looked as it should. Noticed aux air slide filter(?) the little air filter near the starter had fallen out during the trip...it was in there yesterday. Made it to my home exit off the highway and dead after 2 1/2 hours of being fine, restart, 1/2 mile and dead.


The throttle position switch is new, 2 months old, less than 400 miles of use.
Frame rail plug cleaned and secure.

When Pertronix was installed, bypassed the resistor, voltmeter read 3ohms resistance out of the coil. Will revisit this.

All battery connections feel tight and all grounds have been cleaned.

I plan to go through all connections and really check closely for loose/broken connections.

MMercury:
I turned the key to position 1, and tried to restart and the starter screetched like the car was already running.

This was the first 'real' drive since purchasing the car and spending all winter sorting, fixing, cleaning everything and upgrading the suspension from tired & sloppy to, HDs, CN front springs and sway bars. So something getting shaken loose on a rough frost heaved road is likely.

When it's working correctly, the car is simply amazing. An absolute pleasure to drive, fast and graceful.
Click to expand...


My suggestions were based without knowing the overall condition of the vehicle and what had been replaced. Some cars may be all original and neglected, others may have been jury-rigged to the point where almost everything is fair game.:confused: In any event, it seems safe bet to start looking for something that may be heat-sensitive, since your problem seems to arise only after you have developed a full head of steam. Ballast resistor comes to mind, and I did see where you bypassed yours, so maybe this is a non-issue. A perfectly good looking wire can still be problematic if its insulation is worn - where you can't see it. But any Packard man knows that.

I haven't had to replace an auxiliary air valve filter in a long time. Suffice it to say, if you are not a slave to originality, a filter can be found by adapting one of those valve cover breathers typically used by the hot rod crowd. Some of them may even have the advantage of being washable.
knn-62-1560_w.jpg
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Regarding the screeching starter, your description suggests the possibility that the starter bendix drive is turning but not engaging the ring gear/flywheel teeth. This can happen for any number of reasons including: misalignment, a loose starter, worn bendix gear, worn starter nose bushing, or even worn flywheel teeth. Even worn flywheel teeth would not be the end of the world. Often a new bendix gear can "help" make up for some of the ring gear wear. :wink: Again, these are wild guesses on my part and there is hardly any guarantee that I am right.

Gremlins are a fact of life on even new cars, otherwise the repair bays would be empty. Good Hunting!

warner_hall_1981_528ia_09.jpg

wornstarterandflywheel.jpg


Auto-Parts-Bendix-Drive-Starter-Gears.jpg


41602006_z.jpg

images
 
Thanks again for all the suggestions, advice and experience. This forum has been a huge help to me sorting, diagnosing and improving Athena.

As one who is a bit obsessive about preventative maintenance and reliability. Any part in doubt or question will be replaced, repaired and/or corrected. I'll systematically check wires for loose connections and broken strands at the back side of the crimp connections. I had a problem with Vern and a single strand left at an alternator wire, different symptoms of course.

With the missing air filter, I had event cut a double sided tape 'donut' to the top of the filter and squeezed the housing slightly to make it more secure knowing it was a problem, I could not remove it out with just my fingers anymore. Think I'll replace it with the 'cone' style after market. The originality police, me included, will have to make an exception...or I'll modify it to look correct/original.
 
OT reply

Andrew,
We should coordinate sometime, I was out there this past weekend, too. I put on almost 400 miles between the hill runs on Sat. and going down to the Cars-n-Coffee-like event in Manchester, NH on Sunday. PM me if you want to meet up.
 
Part of the problem...

Looking closely at all the wires, the throttle position switch and the injector regulating pump(?) wires exiting the plugs look marginal/fractured. (see photos)

I'd like to remove the individual connectors inside the plugs and solder the wire ends and re-crimp. I see the spades in the plugs have a lock tab on one side and a molded catch on the other.

Does anyone have a 'trick' to push in the lock tab, and lift the connector off the molded plastic for removal?

Thanks in advance.
 

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Update: Still Stalling

New cap, rotor, reconnected ballast resistor...car ran better than ever until it didn't, stalled 4 times in 30 miles. Replaced coil, died in the driveway...restarted...drove 1.5 miles turned off ignition. Restarted shortly, moved 100 yards and...nothing again...restart. This am, start to move car to put on the lift, starts and...almost immediately...silence.

Today starts operation 'find your shorts'. Believe operation 'suspension of disbelief' stiffness hastened the issue. PO receipts show repeated diagnostic repairs for 'stutter/hesitation'
 
What is the condition of the ballast resistor-did you inspect it and put a meter on it? Does it spec out? Seems worse since reconnecting it?
 
In the Hack Mechanic spirit, I'd put a voltmeter in series with the 12V side of the coil and drive it and see if the voltage goes zero, low, or high when it dies.
 
back to basics

Voltage- what is the running voltage? If you're exceeding 14 or so volts that would not be a good thing, causing heat, which causes all sorts of issues.

The reason behind the suggestion is due to your comment on the coil resistance which you stated as 3 ohms. That's a resistor coil or a replacement. Then you hooked up the ceramic resistor adding an additional 1.3 and the car ran better than ever. So you reduced the voltage to the distributer again and the car liked it. Measure the resistance of the coil- + to center tower; compare to specs.

Check the alternator output or more importantly the plug./ connection. Another known bad issue.

Second, go to the temperature sender and check the connection as well as the resistance of the sender and compare to specs.

On early fuel injection, this was a known cause of no starts so much so that Bosch changed it on later versions of Motronic.


In the spirit of and further to the hackmechanic's words of wisdom- by pass the ignition switch temporarily by hot wiring the coil to the battery, taping off the + wire to the ceramic resistor. If it runs and doesn't stop, then it's in the wiring or switch and before the coil.

Or grab another spark plug, pull a wire, ground it somewhere and see ifn you got spark - blue is good. Yellow is bad.(weak)

Since you have an original spark plug wire set ( the extra wire) measure all the resistance of every wire, Especially the coil to cap. Find both ends of that wire. If that wire end is on the coil but flopping around under the diagnostic plug- that's a direct ground.
 
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Possible Eureka!

Mike Stumbo (MikeS) came over and we checked circuit continuity from the coil to everything the coil connects to.

The short version: Real time 5 hours.
Checked continuity of entire ignition system. All checked out fine. Did find a nicked red wire 1 inch below the headlight relay, fixed it.

Removed the 'white 62 62' wire from the resistor/+coil, no fuel pump when when key turned to 'start'. Went to the fuel pump relay and found an incredibly loose relay and stripped partially out ground screw. Traced and tested continuity from + side of coil and the green power wire to #30 on the relay connector and EUREKA it goes to the resistor/+coil, good circuit!
We put in a larger dia. SS screw and star washer, it tightened up nice and solid.

Theory: Screw was marginal to begin with, new suspension upgrades stiffened car enough to loosen ground screw enough losing circuit to fuel pump & ECU shutting off connected systems instantly. As time went buy screw kept getting looser increasing stall frequency and starting difficulty.
Good tight ground will keep circuit continuous at all times and eliminate random 'miss' that has plagued this car since the previous owner and driven me nuts.

When/if it stops raining later this week and dries out, real world testing will be done extensively. Need some bumps and lateral Gs to try and induce stall condition.
 
NOT it Fixed

UPDATE: The Test Run for The Vintage.

Home to Boston/Larz Anderson Cars 'n' Coffee, 2.5 hours, car performed flawlessly earning my 'perfect' status. All highway. Clear cool, sunny. Good to meet fellow forum members.

Larz to VSR, Bow NH. 1.5 hours All highway, car was great for 1.25 hours then stalled 6 miles from the shop. Clear weather warming up considerably. Tach started to surge and bounce yet engine performance was unaffected, then progressed to sudden stall.:twisted:

Following suggestion of removing cleaning fuse panel checking securing connections. Found that the ignition circuit runs through fuse #7 on the coupe.

VSR to home 2.5 hours. Cross lots, 202 to Saco/Biddeford. Clear hot, sunny. Turned the vent window in to cool things off..black jeans and rugby shirt, not good 'summer wear'.
In NH just after a stall, I pulled the back seat, fuel pump relay ground is solid, relay hot like holding a cup of hot coffee, ECU cool.

Engine back fires sometimes on stall, feels like fuel stops and engine runs on fumes and momentum. Takes a few seconds for the red 'L' to come on, then engine is off. Hard starting, like lack of fuel or bad ground.

Stall condition worsens as trip progresses to the point it was happening every 2-3 miles on 295, dangerous and very frustrating. Earning my 'POS' status

So this is time and temperature dependent, no good for a long trip south Time to get the car reliable for the 980 mile trip to 'The Vintage' is this coming Saturday, plenty of time.

Old thought it was fixed post:
Test drove Athena...dried out enough today.

Despite a stall before I left the driveway, restarted and went for broke.

Once warm, she was smooth, powerful, confident and sure footed. Ran flawlessly in all conditions as I tried to cause the 'sudden death'. Fast on and off ramps, hard accel/decel, traffic - for me that's a few traffic lights, washboard back roads, horrible wash board section at a light, spirited sprint on a windy section at 55-60+, sit at idle for 10+ min.

Tested electrical load through out with high & low beams, turn signals, wipers and fan at all speeds, radio with iPod-it's powered with an accessory plug I mounted in the glove box, GPS in lighter, all windows.

Excellent!

Turn on fog lights, a few minutes later car dies, same 'sudden death'!:idea: These lights were not on when the original issue manifested.
Easy enough to re-wire.

Excellent!
 
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