|
Post by markymark on Apr 11, 2020 12:10:37 GMT
Hi All, Resurrecting this thread as celebrating eight years of ownership with taking on the fix to the stalling issues as a lockdown project. So to recap, she stalls with headlights on at idle. Higher revs she runs fine. Patch cable from ignition control fuse to +ve on coil fixes the problem but then I have no tacho.
I’m looking at the wiring diagram and it seems to show a white cable from ignition switch to coil and a white/yellow to coil via tachometer. When checking continuity between ignition switch and coil I only have continuity when the white/yellow cable from the tach is connected.
I’m thinking that I need to run a new cable from tach to coil directly replacing the white/yellow but confused by the wiring diagram and wondered whether I need to run two cables - or whether the white cable shown on diagram is for when a tach isn’t fitted....
Also, I seem to have another cable at coil that has continuity back to the tach that isn’t connected. Could it be a case of simply connecting that? There was mention earlier in the thread of such a wire... Any thoughts welcomed...
Thanks, Mark
|
|
|
Post by djm16 on Apr 12, 2020 1:00:41 GMT
Hi Mark, You need to do this methodically!
You are going to test voltages at various points in your system. Check the following with the engine off. Each checking point you will write down the voltage under 3 conditions: a) nothing turned on b) ignition on c) ignition and lights on. This will establish if you have a significant voltage drop causing your problem, and if so, where it is occurring.
1) put your voltmeter across the battery terminals - not the clamps - the terminals! Measure your 3 conditions. While you are there, move each voltmeter lead to the terminals instead. All three voltages should be identical to the measurements you made before. You should get something like 12.6, 12.0, 11.5V under the three conditions depending on how big / new / charged your battery is.
2) move to the engine bay, and connect the black voltmeter lead to a chassis earthing point and leave it there. The red lead goes to the +ve feed to starter solenoid. This is also where the rest of the car gets its power supply (lights, ignition, wipers etc). Your numbers will now be more like 12.6, 11.5, and 10.5V. If so, then so far you have an acceptable battery and main battery lead.
3) next move to the + supply to the distributor. Your values will be 0V, 11.0 and 10.0V (all approximate). If the numbers are significantly lower, then you have a bad contact in the ignition switch, or less likely, a bad contact somewhere else in the path from common +ve supply (top of starter solenoid) through ignitions switch, to distributor.
Write the numbers down, and post back.
|
|
|
Post by markymark on Apr 12, 2020 7:47:40 GMT
Hi there. Yes, need to be methodical...
The battery was on a charger overnight, so initially the voltage was 13.2v but soon settled down to a steady state. No difference seen between battery terminal and leads..
At battery:- 12.75v, 12.50v, 12.06v At solenoid:- 12.72v, 12.46v, 12.00v Coil +ve:- 0v, 12.30v, 11.80v At fuse 3-4 ign control:- 0v, 12.35v, 11.88v
I added the last reading as car runs with lamps on when patched from that fuse.
These look good readings to me, but interested to hear your thoughts....
Mark
|
|
|
Post by markymark on Apr 12, 2020 8:23:17 GMT
|
|
|
Post by markymark on Apr 12, 2020 9:02:16 GMT
Just carried out a further test.
Engine running, no lights Voltage at +ve on coil = 11.20v Voltage at fuse 3-4 ign control = 13.5v I turn on headlights and engine dies
Engine running, no lights with patch cable between fused side of ign control fuse 3-4 to +ve on coil. Lead from tach disconnected:- Voltage at+ve on coil = 13.45v Headlights no problem
Thanks all for any suggestions you may have. It seems to me that with engine running there is insufficient voltage at coil. So, am I to run a new cable to the tachometer? Despite results would engine running showing little voltage drop? Or could it be tachometer not compatible with electronic ign?
Cheers, Mark
|
|
|
Post by markymark on Apr 12, 2020 12:10:27 GMT
Ok so further update. I bypassed the tacho by connecting white to white/yellow and still had barely over 11v at coil with engine running. I then checked voltage at tacho on white wire -13.4v with running engine. I then ran a patch cable replacing white/yellow from tacho to coil. Running engine with 13.2v at coil. Clearly the problem is in the white/yellow cable which I will now replace properly..... I think I’m there now....
|
|
|
Post by markymark on Apr 12, 2020 15:10:01 GMT
I have successfully replaced the white/yellow between tachometer and coil. Running beautifully now. Thanks all...
|
|