4.2 series 2 refuses to start

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supersonic62
Posts: 31
Joined: Tue Jun 28, 2011 1:47 pm
Location: cambs

4.2 series 2 refuses to start

Postby supersonic62 » Sat Jun 09, 2018 11:14 am

Hello
I wonder if anyone has had the same issue I am experiencing with my 1974 series 2 at the moment.I drove it last week for about 20 miles , , it was perfectly alright.I came home put it away and something I never do is leave the battery connected ( due to seldom use) but that day I did.It may not make any differance to the car but a week later, it wont start , fully charged battery ,plenty of fuel, you can smell fuel as your cranking engine (no leaks ) and can hear fuel pumps pulsating but engine refuses to start apart from about a couple of seconds and was able to rev it trying to clear anything then it stopped and it went back to spinning starter motor and slowly discharging battery. Any help would be appreciated as to cause , regards Paul

PPV
Posts: 519
Joined: Sat Jun 14, 2008 4:48 pm
Location: Nantwich

Re: 4.2 series 2 refuses to start

Postby PPV » Sat Jun 09, 2018 11:36 am

Does the starter turn the engine? If so then it should be fuel or ignition problems. Easy to check for a spark at the plugs. Does the fuel pump run on if the engine not being cranked? If so then it could be engine flooding so a carb float chamber stuck open etc.
Regards,
Paul V
Mk2 3.8
Mercedes A45 AMG
Mercedes AMG GLC43

supersonic62
Posts: 31
Joined: Tue Jun 28, 2011 1:47 pm
Location: cambs

Re: 4.2 series 2 refuses to start

Postby supersonic62 » Sat Jun 09, 2018 1:19 pm

Hello Paul V, the starter motor turns the engine but dosn`t fire, and both fuel pumps work as I changed over from one to the other when it wouldn`t start.The pumps do not continue to run on when engine is not being cranked.It is strange that on previous journey out although short, ( approx 20 miles ) 7 days ago the car didn`t run any different.It never matters how long the car has been left it always starts first time and I always make sure the battery is fully charged ( via trickle charge ) Regards Paul

PPV
Posts: 519
Joined: Sat Jun 14, 2008 4:48 pm
Location: Nantwich

Re: 4.2 series 2 refuses to start

Postby PPV » Sat Jun 09, 2018 1:29 pm

Hi, if you think fuel is getting through then it most probably is electrical. It needs a spark at the plugs at the right time so anything in that process could be at fault. I would check for a spark first though by taking the plugs out and seeing if they spark when cranking.
Regards,
Paul V
Mk2 3.8
Mercedes A45 AMG
Mercedes AMG GLC43

supersonic62
Posts: 31
Joined: Tue Jun 28, 2011 1:47 pm
Location: cambs

Re: 4.2 series 2 refuses to start

Postby supersonic62 » Sat Jun 09, 2018 1:41 pm

Hi again Paul v, Yes I feel that we may be looking at the plugs and if not going down the road of elimination as we go on, thanks for your help, Regards Paul

mike020150
Posts: 2294
Joined: Wed Feb 08, 2006 6:26 pm

Re: 4.2 series 2 refuses to start

Postby mike020150 » Sun Jun 10, 2018 2:10 pm

Two quick thoughts: more likely - a failed ballast resistor will allow the car to fire and then stop when the key is released - test its resistance with a multi meter; less likely - there is an oil pressure switch anti run on valve which is designed to stop the engine when oil pressure drops to a low figure. Both are worth checking for issues. Mike.
2014 XK Dynamic R convertible; 1977 Daimler Double Six Coupe; XE S

supersonic62
Posts: 31
Joined: Tue Jun 28, 2011 1:47 pm
Location: cambs

Re: 4.2 series 2 refuses to start

Postby supersonic62 » Sun Jun 10, 2018 5:29 pm

Hi Mike
would I be looking for the ballast resistor somewhere near the coil ? It`s not something I have come across before not knowingly anyway.I have ordered new sparkplugs, rotor arm and I have a new coil that I had already just in case.If it were to be the ballast resistor I see on SNG Barratt site that they only stock ones for XJ12 S 1/2 with opus ignition, XJ6 3.4 and XJ6 S3 4.2. How difficult would it be to obtain one I wonder,Regards Paul

supersonic62
Posts: 31
Joined: Tue Jun 28, 2011 1:47 pm
Location: cambs

Re: 4.2 series 2 refuses to start

Postby supersonic62 » Sun Jun 10, 2018 5:41 pm

Just thought I would add it is a 1974 Series 2, whether that would be any difference between it and the late series 2 models as they had some changes along the way, like fuel injection etc, Regards Paul

PPV
Posts: 519
Joined: Sat Jun 14, 2008 4:48 pm
Location: Nantwich

Re: 4.2 series 2 refuses to start

Postby PPV » Sun Jun 10, 2018 6:32 pm

Hi Paul, thought I would mention if is has a ballast resistor then it uses a different coil to standard. SNG should advise.
Regards,
Paul V
Mk2 3.8
Mercedes A45 AMG
Mercedes AMG GLC43

mike020150
Posts: 2294
Joined: Wed Feb 08, 2006 6:26 pm

Re: 4.2 series 2 refuses to start

Postby mike020150 » Mon Jun 11, 2018 11:56 am

If it's a standard 1974 UK car, it should have a ballast resistor attached to one leg of the coil bracket. Mike.
2014 XK Dynamic R convertible; 1977 Daimler Double Six Coupe; XE S

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NATONEIL
Posts: 366
Joined: Mon Jul 26, 2010 11:17 am
Location: Bourne Lincolnshire

Re: 4.2 series 2 refuses to start

Postby NATONEIL » Tue Jun 12, 2018 9:59 am

I had a similar problem with my Suffolk which has a 4.2 engine and I had a broken earth wire between the points base plate and the distributor body. The insulation was in place but the conductor inside the insulation was broken so would work one day and not the next.
Neil

Suffolk SS100 Jaguar
Honour the past, drive it today

supersonic62
Posts: 31
Joined: Tue Jun 28, 2011 1:47 pm
Location: cambs

Re: 4.2 series 2 refuses to start

Postby supersonic62 » Wed Jun 13, 2018 12:25 pm

Hi,
I have just managed to see where the ballast resistor is and crikey that looks a tight fit ! I have ordered one so hopefully covering most things.I have checked along the wiring and haven`t found anything loose but will do again and be looking again at distributor cap etc . Did try to start again this morning and met with the same starter motor spinning and swopped from one tank to other and they both clunk so power is to them and of course you can smell the neat petrol.The boot always has had a faint smell of petrol since my late father bought it new and obviously because pumps proximity.It certainly dosen`t help having big hands, you look the other side of the engine bay and there`s plenty of space.Thanks for everyones input , Regards Paul

supersonic62
Posts: 31
Joined: Tue Jun 28, 2011 1:47 pm
Location: cambs

Re: 4.2 series 2 refuses to start

Postby supersonic62 » Fri Jul 06, 2018 2:26 pm

Hi folks, just an update on the problem I was having trying to start my 1974 4.2, it turned out to be the live feed cable to the electronic ignition it had become brittle and was the cause of the problem.Cable replaced and running smooth once again,relieved thats for sure.Have a few parts I purchased to use for future maintenance ,Regards Paul

mike020150
Posts: 2294
Joined: Wed Feb 08, 2006 6:26 pm

Re: 4.2 series 2 refuses to start

Postby mike020150 » Sat Jul 07, 2018 9:59 am

As ever in engineering, 'simple is beautiful' and it's usually cheaper. Mike.
2014 XK Dynamic R convertible; 1977 Daimler Double Six Coupe; XE S


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