Pinto Running on ……..

[LeicJim3a]

So after many months and a fair few quid my car is done ! Well nearly went for a drive today was absolutely awesome ! Pulled up at home turned ignition off it chugged a bit then like a 12 bore shot gun out the exhaust, 

 

it has always done this since I bought it, I have replaced carb and set up on gas analyser timing is spot on thanks to RichyB all fuel lines and filters changed new k&N air filter new plugs leads cap and arms in fact it would be easier to list what hasn’t been changed 

 

but still this running on issue !!! Any clues or advice greatly received

 

thanks in advance

Jim  

[dandan62]

Considering all the things you have tried and the timing definitely isn't too advanced then the only thing I can think of is there is a hotspot in the cylinders somewhere possibly caused by carbon build up. I had this problem once which turned out to be timing, but I remember someone suggesting this and also a possible damaged valve which was causing a hotspot too. All I can offer I'm afraid.

[Sparepart]

You have not indicated the carb type or ignition system, if you have the carb that goes with the ESC II ignition module as fitted to some Sierras then you will have a "Power Hold" relay, which keeps the ECU powered up after the ignition is switched off. In the manual it indicates that this lets the ECU return to an idle state and reset the stepper motor on the choke and reduce likelyhood of "overrun" by venting the inlet manifold. So if you have this sort of system then a malfunction of the power hold feature could cause your symptoms. On another tack, if there is a "hotspot" its not likely to affect more than one cylinder, so you might try running the engine on three cylinders and changing the non firing cylinder to see if the there is s difference when you turn off the engine. This is just a suggestion, Ive never tried, perhaps running on three is too rough to notice a difference.

Edited February 20, 2023 by Sparepart
correct spelling

[LeicJim3a]

After some thought carbon build up and hot spot was most likely easily caused from previous running everything was out when I bought it and it has not had a decent long run for quite a while, decided to borrow a carbon clean machine from work ran  it on this for 30 minutes today once round the block ignition off and …….. no run on at all ! It seems to have solved it fingers crossed, going to fill up with decent fuel and take it for a proper drive in a couple of weeks. 

[dandan62]

That's good news. I didn't know a machine like that existed. You can enjoy the car now.

[IanS]

About 20 years ago I did an inadvertent carbon clean of my wifes 1.2 vauxhall nova but only on cylinder 1.

Driving along and suddenly large amounts of white smoke from the exhaust. Coolant level dropped so I topped up and crawled home.

Right I thought head gasket gone so purchased a new gasket and took the head off, piston and valves to cylinder 1 looked like they had been polished the other 3 looked like you would expect after 60,000 miles so I cleaned them. The old gasket looked good but I replaced it and fitted the head back on and topped up the coolant. Started the engine and lots of white smoke, BLEEP, BLEEP. I took the head off again and then removed the inlet manifold (a lot easier with the head off) the inlet manifold gasket had gone between inlet one and the heater coolant takeoff, problem solved.

The thing is just how clean cylinder one was, obviously coolish coolant hitting red hot carbon cracked it off, I do not say that this is a good way to decarbonise an engine but even at tickover it takes a fairly massive waterflow to cause hydraulic lock with most of the water exiting down the exhaust every cycle.