1994 W124c Starting problem

[PatJC]

Had my car in storage for 8 months and started it regularly to run the engine with no problems.
On taking it out of storage i experienced the following problem.
The car ran fine for about 15 minutes and then stopped.
Over the last few weeks it either will not start i.e. turns over but will not fire,
or if it starts it runs sweetly for about 10-15 minutes then cuts out and will not restart.
Can anyone help

 

[blobbyknobby]

Start with alternator, battery, rotor cap and arm, leads all the usual suspects

 

[grober]

What engine have you got?

 

[PatJC]

E220 4 cyl Petrol Auto 2199cc
Nr WDB 124042 2C 100105 3
Family owned car from new genuine 120,000 miles.
Had the car on the road for 4 months in summer 2012 after little use
for several years and it never missed a beat, appreciate any suggestions you can make.
Regards
PatJC

 

[grober]

My suspicions would immediately turn to any dealer fitted alarm/immobiliser system [ they were all dealer fitted at that time- at least in the UK market. ] We are increasingly seeing failures with these units as they age leading to problems. They normally interrupt the functioning of the fuel pump relay or OVP relay or both. Immediate cure is to identify the wiring concerned and re-instate the original factory connections. If this cures the problem I would suggest removal of the old alarm unit and replacement with a modern unit. These old cars are not immune from theft being highly prized in the old communist block and Africa.