1991 300te24v won't start

[berkinamerc]

Hi there everyone, I'm pulling my hair out trying to get my W124 auto started. The story starts as follows... bought the car in Nov with a suspect head gasket as reason for sale. It's taxed and mot'd with a twin tank LPG conversion, so I thought I'd gamble a few £ and see how i get on. Back then the car would start instantly on the button, switch over to gas smoothly, go forwards backwards and brake perfectly, but after say 5 miles of driving would behave erratically and finally come to a halt. If left for about an hour, then topped up with a few litres of water, the car would act as if nothing had happened, start instantly, drive fine for the next 5 miles then repeat its doc jeckle/ mr hyde impersonation. I wasn't convinced it had a head gasket prob, and diagnosed an internal rupturing of the autobox fluid cooling side of the main radiator. That explained the oilyness of the coolant, inexplicable loss of coolant, and eventual temporary loss of drive. So I sourced a replacement rad, drained off the 4litres of water and the rest of the dextron from the bottom of the autobox, refilled with transmission fluid, went to start the car, and the battery was dead. I charged the battery in situ, then tried starting her again. Hazards started flashing, so I found the original immobiliser fob, which stopped that going on in background. Starter span eagerly, but no joy. Took battery out for a deep overnight charge, pulled back plastic cover behind battery bay and checked connections of brains/asd relay. replaced battery, disarmed immobsr, had friend check for spark from one of the plugs which was fat and yellow. Gave it a sniff of WD40 to see what it made of it. Then tried turning with a sniff of carb cleaner at the inlet, still no joy. OK the car has sat for the xmas period outside and got pretty damp, the battery has died and been brought back to life, but other than that,the car's essential the same as when it used to start on the button. The gearbox has admittedly had an ingress of coolant that couldn't do things much good at that end, but a faulty autobox shouldn't hinder the starting of the engine, or could it? The petrol in the tank may have lost some of its freshness, but it's only a matter of 3 months it's sat. Does the brain need resetting after the battery has run dead? Would fresh spark plugs help. Where's the best place to check fuel delivery, and is it under much pressure? I'm reluctant to try easy start, but the closest to firing I've had so far is a backfire of unburnt carb cleaner. Any ideas anyone?
I'm going to check for lose/furry connections, buy a couple of gallons of fresh fuel and recharge the battery in the meantime. Cheers PFK

 

[Bolide]

Halfords sell a little plastic neon that plugs in between an HT lead and a spark plug. Great little diagnostic device

I'd charge the battery, pull the plugs and clean them up. I'd also remove the distributor cap & clean the cap & rotor arm. Then I'd remove the king lead from the coil and turn the engine over a few times. Then I'd put the plugs & the king lead back in, plug in my Halfords HT diagnosticator and turn the old girl over

If you smelt petrol when turning it over with no plugs that would suggest there's fuel. If you get a flash from the HT doo-dah that says you have spark. With the two of those it should fire up

My suspicion is that either the LPG system or the immobiliser are to blame and that fuel or spark is missing

Nick Froome
www.w124.co.uk

 

[type49]

I'd 2nd the dizzy cap. 5mm allen key to remove & 3mm to remove the arm. It will probably be green & white with corrosion inside.