Archived Message
Engine would not start-update
Following the thread I posted on the 8th August I promised to post an update after the problem had been investigated by an MG specialist. This was carried out last week but no problems were identified. However after driving home some 30 miles on a hot day similar as before except no traffic jam I parked the car outside went to start it an hour later and it would not start. The fuel pump did not prime. As before I tried it a couple of hours later the fuel pump primed and the engine fired immediately. It would appear that the fuel pump fails when there is excess heat under the bonnet so is there a part under the bonnet that shuts off the power supply to the fuel pump when it is too hot?
Malcolm Roots
11/09/2012 @  07:28
Under topic: RV8
Archived Reply(ies) received for this Message
Engine would not start-update

Most cars of the last 20 years have a safety cut out switch intended to cut off the fuel pump if the vehicle is in an accident. Usually it has a reset plunger and is located in the engine compartment on the bulkhead. Others who know the RV8 can elaborate on this. This cut out may have developed a heat sensitive fault (but not actually be tripping). It may be worth temporarily bypassing this switch and seeing if the fault remains.
Bob Owen
11/09/2012 @  08:15
Engine would not start-update
If you can't hear the fuel pump priming when the engine is hot, Malcolm the first step I would take, is to see wehther there is any power actaully getting to the pump itself. There is a relyy for the pump (no.3) located on the engine bulkhead behind the centre dash board area. Maybe that is failing under heat conditions and so your fuel pump is not functioning. In my case I would simply drive along to my Bosch guy after a run to see if that is the cause. The next logical step is to see whether you actually have a thumping spark when the engine is hot and you try to start. Again your electrical specialist can easily carry out tests.
Peter Garton
11/09/2012 @  08:51
Engine would not start-update
The RV8 does have a fuel cut out switch which Bob mentions and is located close to the rear rh bonnet hinge at the rear of the engine. Normally one would reset it by pressing on the rubber top which will reactivate the fuel pump. It would normally cut off the fuel flow if one is in an accident such as a collision. If, for some reason, in hot conditions, it cuts off the fuel the car won't start obviously. Thus, Malcolm, you can try this the next time you can't start the engine when its hot. If it then fires up, I would assume that you would require a new fuel cut-off switch.
As you can see, there are several areas to check up on.
Peter Garton
11/09/2012 @  14:11
Engine would not start-update
I agree with Peter and would suspect the Fuel Pump Relay. A new relay is not expensive and could well cure the problem. Certainly, if the pump doesn't run for five seconds when you switch on the ignition, the engine is never going to start.
Mike Howlett
11/09/2012 @  22:18
Engine would not start-update
Thank you for your repiles. The relay does seem the most likely. Will probably have to wait until we have another hot day similar to the "two" we have had this summer.
Malcolm Roots
12/09/2012 @  07:41
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