Hi everyone, The first 1000 miles in the Mondial went flawlessly, so it's time for the weird stuff to set in! Recently, the car will start great (though occasionally it doesn't seem to run in all cylinders for a second before clearing out), but the unusual part is that it now appears to be losing spark when I shut the car off and attempt to restart it. My troubleshooting so far: - car cranks nice and strong either way - no other obvious electrical faults - car runs perfectly before shutting off - car starts fine when cold - new battery - battery was at 12.5V before my ~20min test drive yesterday and 12.89V after - I ran the fan on the test drive to increase load and check alternator capability; that appears to be fine - shut off the kill switch, waited an hour, and rechecked voltage - 12.75V after sitting, but car wouldn't start. Cranks but shows no audible signs of firing - water temp hangs at about 190 all day - oil temp lives just below 200 It seems like there's a heat soak issue in the ignition system, so I'm wondering if anyone has experienced something like this before and which measures you took to mitigate it? Next on my list today is pulling plugs for a look and replacement, then checking spark strength cold and possibly hot. Thanks!
Have you actually confirmed (with a measurement using a timing light or spark tester) that you have no spark during the "cranking but no start" event? Your symptom is far more representative of losing residual fuel pressure at warm shut-off.
Next on the list is checking spark cold and hot with the new plugs. Fuel pressure could be a possibility, but how long would it take to regain that if it is bleeding out? The car can crank for 10+ seconds with no signs of life.
It doesn't really "regain" it -- it's more that the fuel cools off enough to unvaporize if you wait long enough (so "car starts fine when cold"). At warm shut-off, the fuel pressure falls from ~5 bar down to ~3 bar and needs to stay there if you want to restart within ~20 minutes. If the fuel pressure falls from the ~5 bar quickly down to 0 at warm shut-off = some fuel in the system can vaporize = difficult to immediately restart.
Oooh, I understand what you're saying. That's a thought. I'll do some reading to see where people usually tee in a fuel pressure gauge to check that.
Fuel system has a fuel pressure accumulator which do fail, this makes hot starting a problem. Behind the rear wheel wheel liner along with the fuel pump.
Great info, thanks! I'll see what other people have experienced when they go bad and compare that to what I'm seeing.
When the fuel lines are cold it should fire up fine, but if you stop when its hot the fuel lines in the engine bay heatup from the engine soak and no fuel flow. If the accumulator is no good the pressure in the fuel lines is too low and the petrol turns to vapour- if the accumulator is working, it maintains the pressure and the fuel stays as a liquid, so it fires up. Common problem on these.
Well, that does sound pretty familiar. I'll report back with what I find! Does anybody ever insulate the fuel lines, or is that moot with a good accumulator? I'll admit this car started perfectly in all situations until recently so maybe that answers my question.
From what i recall it has a supply and return line, have a look on Eurospares uk web site for your model, then look at the fuel system diagram. On my uk car it was forward of the right rear wheel behind the wheel liner. It works well with no insulation
I had the same issue on my mondial 3.2, 1986. I am currently working through it. You may want to check out the thread that I started, which has a lot of good replies, some of the members that commented here also supplied helpful information on the thread. The thread is labeled Montreal, 3.2 that won’t start after short trips.
