[Anzee]

Hello!
I have a '74 manta A with 2,0 L-jetronic injected engine; standard ignition over points..

The problem looks like this (and my friend with ascona has the SAME problem...):
if you drive the car without acceleration at high revs (for example at 4000rpm) it jerks - feels like it's loosing sparks or something. Besides that, in friend's ascona the rev meter starts jumping around. Then, if you connect direct +12V from the battery (bypassing the original resistor wire) it drives like new - but of course we'd fry the coil if we drove like that all the time!

We tried everything - new cap, condenser, rotor, points and their gap, ign. cables, 3 different coils, we measured the voltage at the coil and it is OK (even during the "jerking session"), changed distributors (altough we still suspect them...) - but nothing works... damn

any ideas? I can't go to sleep because of that...

 

[gtzero]

I had the same thing and it was a loose ground at the battery.

Good luck

 

[gtzero]

You might also have a bad fuse.

 

[nobody]

I would ohm the resister wire. I myself would do this after I cut it out to power a different coil that didn't need it. It sounds like you have isolated the problem now it's a matter of how do you fix it.

 

[Anzee]

I had the same thing and it was a loose ground at the battery.

Good luck

You might also have a bad fuse.

hello!
hm, I don't think it's the ground, because i've cleaned, greased and refitted the contacts... well, i'll re-check and also put a new ground to chassis wire...

which fuse do you mean? But then also other things wouldn't work, right?

 

[Anzee]

I would ohm the resister wire. I myself would do this after I cut it out to power a different coil that didn't need it. It sounds like you have isolated the problem now it's a matter of how do you fix it.

we tried to measure the wire... but the readings were a bit strange (or maybe I don't know how to measure it ) - is it correct that i connect the + battery terminal and + terminal (15) on the coil - then I should see the correct value of 1,8ohm, right? Well, the result was out of range (0ohm or infinity); but if I connected - terminal on the batt and 15 on the coil the value was ~40ohm...

at my friend's ascona the result was similar, only coil to batt negative resistance was lower (around 10ohm if i remember correctly...)

oh i forgot.. you said you switched to another coil which doesn't need the resistance wire or what? That would be the best option where can I get such coil?

 

[Sportwagon75]

Check the Tach Wire

If the car has a tachometer on the dash...check the entire length of the wire from the engine compartment all the way to the dash. Make sure it's not shorting out to ground anywhere. I had a similar problem years ago. The wire was rubbing against the sheet metal where it passes through the firewall. Road bumps and movement of the engine would generate an occasional ground fault and stall the engine. This happened once at speed...the engine stalled and loaded up with the exhaust with unburned fuel. When the engine fired again...it blew out my muffler with an explosion that was deafening!!!

 

[Anzee]

Sportwagon75:
no, I don't think that it's the wire to tacho - then it would do this when i drive over bumps, etc - but it doesnt...
and especially - why does the direct feed of 12V to the coil mysteriously cure the problem?!? if there would be a fault in the tacho then it would probabily be even worse...

 

[Gary]

Anzee, try putting a voltmeter or a test light on the coil terminal and move the resistor wire around. Look to see if the reading changes. It is possible the resistor wire terminal connection is loose or frayed, or there is a break in the wire causing the intermittent problem. if you put 12 volts to the coil and it works well, the problem must be in the resistor wire or it's connections.

If you are checking resistance, make sure you isolate the part being tested from the rest of the circuit so you don't get any confusing backfeed readings.

 

[baz]

well said sir knight
whilt the let me pass or dust thou require shrubbery

translation: i agree with gary if the fault is fixed with a bypass then the fault must be in the wire that you have bypassed

NEE

 

[greensmurf20]

i had same problem with my GT, so may or may not apply. it ended up being a loose connection on the back of the alternator.

 

[Anzee]

well, my friend solved his problem - he installed a vw golf II coil and bypassed the resistor wire... his ascona is working fine now;
and I got a electronic ignition yesterday, so I guess I'll manage to do it too

thanks for help guys!

regards
Anze