Can anyone help? My 1990 110 V8 runs fine when cold, but after 3 or 4 miles it starts backfiring & cuts out. It'll usually fire up straight away & maybe run for a few seconds or maybe cut out straight away. I've had it running while stationary for half an hour & nothing happens. I've replaced the coil & crawled all over the h.t. cables & dizzy. Is it possible to check the electronic ignition module/amplifier easily? Is this a fuel pump problem? Any suggestions would be gratefully appreciated while I've still got hair!
firstly make sure oil pressure/pump is ok , if the oil pressure drops very low the hydraulic valve lifters wont open the valves and you wont get the inlet valves open in order to draw fuel in and exhaust out .. i have had this problem once and it happens after the engine warms up, but will do it every time you drive it , to fix it either get the oil filter housing lapped again so its flat, or buy a pump booster plate kit which is a sandwich plate that goes in between the pump body and filter housing .
im not saying it is this but the oil pressure really needs checking just in case , it should be higher than 20psi at all times , if it drops lower you will start to see the engine popping and banging until eventually it will stop running, then 30mins later it may start again and run for a few mins . .
check fuel filter for water, change filter , check fuel tank doesnt have any water in the bottom , this problem can give you those symptoms you mention ..
check oil in dashpots if its a carb model , top up with ATF trans fluid or dexron 2 or 3 ..
you havent recently had an MOT and had the carb mixture adjusted at all ?? , too weak .
check the bolting point for the distributor and that the casting around the bolt hole hasnt cracked allowing ign distributor to rotate .
dizzy diaphragm , is it ok and working, rubber pipes to dizzy are they split at all .
rover cams do lose lobes off them, ie wear away , but this would cause a problem from startup and wont go away .
in the distributor cap you need a good contact with centre pin to rotor arm , ive had caps that have been bad , and also subsequent new ones have had same problem, but thats my fault for buying from same shop , ie same BATCH .
if youve changed for a new dizzy cap, clean the contacts inside old one with a knife and then put that back on and see if you have a problem still .
electronic ignition does go bad sometimes , you may get a spark, but a more yellow one , and the ign unit isnt working properly .
rover SD1 electronic ign units fit range rovers as a replacement .
have you manual choke , with fuel enrichment devices , ie stromberg carbs , perhaps mixture needle adjustment is too lean , does it run ok if choke is out slightly .
clean out flame traps on rocker covers , thinners inside , shake well and blow out with compressed airline .
I had the amplifier die on my 1989 Range Rover - I no longer have the car or the Haynes manual but there is a procedure in the Haynes manual which tells you how to check the amplifier (yes, really something in BoL that is actually useful).
However they either seem to work or they don't - and if they don't it does not start!
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