Slow to start P6 V8

Alfaguy

New Member
My ever so reliable 72 Rover P6 V8 has been slow to start of late. I put it down to it needing new plugs and a general service but this has failed to cure the slow starting problem. It always starts eventually and once warmed up starts on first turn. Its only when the car is left alone in the garage for a few days that I get this problem.

Just wondered is there some knack for starting I might not know about. My car was fitted with electronic ignition when it was being restored by the previous owner.
 
It could be that the fuel is running back to the tank while the car is standing, and it takes a while for it to pump back up.
 
Yes and with a mechanical pump the fuel pressure is only restored as you crank. When I put the electric pump in whereby it primes the fuel system on the ignition, starting became a lot easier.

Saying that, you should really have enough in the float chambers....
 
Quite likely that the valves in the mechanical petrol pump are not sealing as well as they once did allowing the fuel line to drain back to the tank, its a common problem.

Graeme
 
Ironically shortly after posting this thread I went to the Rover and it started first turn after not being driven for the last three or four days. We have had a bit of a heat wave here (in Ireland) for the past few days. Might be temperature related?
 
Ironically shortly after posting this thread I went to the Rover and it started first turn after not being driven for the last three or four days. We have had a bit of a heat wave here (in Ireland) for the past few days. Might be temperature related?

I'd go with what the chaps above had said on the pump probably being a bit lazy/ letting fuel back when shutdown.

Its also likely that on a very hot day the engine bay temps are enough to evaporate some of the fuel from your carbs after shutdown. This would do two things that would probably cause a slow start:
  • Fill the inlet tract with rich petrol vapour - possibly too rich to light off properly.
  • Lower the fuel in the carb bowls so these need to refill slightly before you can get going.
In my series 2 Landrover on hot days in heavy traffic I have had the situation where the carb became so hot that after shutdown it would not restart as the fuel being pumped in was apparently flashing into vapour as soon as it hit the carb body. The only way around this is to slowly pour water over the carb until it has cooled sufficiently, then it will start right away!
 
I had the same problem in my series one , took a few turn overs but always started on the first go, no problem when hot.
Fitted an electric fuel pump with no difference apart from lessening the battery charge.
New points, plugs, leads,coil etc.
Maybe it was too rich. Never solved the "issue"
Anyway I have a series two now and it doesn't have that "issue".
 
The car does drain the battery if I leave it connected so I always have to disconnect the negative lead whenever it is being stored. Its a common feature with old cars and tracing the cause of the leak is like looking for a needle in a haystack so I don't even bother.
 
my 74 3500 has always been like this ,if used would start ok but if left for any time i have always had to spray "start ya bastard " up the intake , also electronic lumenition fitted,i am also looking for a reason for this,looked at the timing the other day and at tickover was around 6 deg btdc , good sparks on all plugs ,will run a compression test next ,my old amazon was difficult to start due to low compression before rebore
 
my 74 3500 has always been like this ,if used would start ok but if left for any time i have always had to spray "start ya bastard " up the intake , also electronic lumenition fitted,i am also looking for a reason for this,looked at the timing the other day and at tickover was around 6 deg btdc , good sparks on all plugs ,will run a compression test next ,my old amazon was difficult to start due to low compression before rebore
Try setting your timing at 32 - 34 deg at around 3500 rpm. I set mine like this and disregard setting at idle. I use super unleaded, no pinking, electric fuel pump, and it starts instantly
If you have a mechanical pump it will take time.
 
My battery used to drain and I had to disconnect the lead, but I found the problem, the boot switch for the light needed adjustment as it wouldn't go off.
I found that by removing the bung in the boot floor seeing light.
 
The standard distributor makes 11 degrees of mechanical advance = 22 degrees at the crankshaft. The maximum advance is 28 degrees at 4500 rpm minus 22 degrees = 6 degr BTDC at idle. The mechanical advance starts at about 1000 rpm. I do not know, what advance still is possible between 3500 and 4500. When it´s 2 degrees, you will reach a total of 36 degrees advance, which means you are setting your idle at 12-14 degr BTDC.
It´s exactly what Des Hammill recommends, but carefully testing for automatic cars and all components should be in a good condition. Worth to try.
For starting I took another way. I have installed now my new relay which operates with the ignition line and 2,5 secs delay. If the engine does not fire up (and relay gets signal from terminal 1 at coil), the fuel pump stopps. So I have no chance for a lazy starting :D
 
mine is always hard to start when cold .needing lots of cranking . when hot starts first time on key unless..... stopped for along than few minutes. i have prefaced everything form leads. plugs. fill electronic dizzy . carb kit .balance checks. timing with strobe to 8 degrees btdc. using octane boost in tank. it suffers i think vapour issues after a minute or so sitting there due to ethanal in fuel and heat from engine etc.
it also cuts out when pulling up at lights ( well not always but when you select drive.. 9 out of ten it stalls grrr ) not tried setting to 36 at 35 rpms. might be worn a go. compressions are Ok but not best in world. balance within 15% overall.
 
Try setting your timing at 32 - 34 deg at around 3500 rpm. I set mine like this and disregard setting at idle. I use super unleaded, no pinking, electric fuel pump, and it starts instantly
If you have a mechanical pump it will take time.

Are you talking about dwell angle (32-34 deg) ????
 
Mmmm - just thunked again .And mine was slow to kick into life way back . I had an 'lectronic module off a landrover fitted . Nec minut - vaaroom.Burble burble burble. Hardly use the choke now and she fires into life everytime.
 
Back
Top