308gt4 will not start

I hope someone can suggest what we do next. I have a 1979 308GT4 with single electronic type distributer. The problem started when the main oil cooler flexible hose fretted thro. and I had to be towed home. A new hose fitted and then although we managed to start the engine it ran very roughly, spitting and backfiring.

We have installed new vr sensors which both read 680-700 ohms. (the old ones had badly corroded wires). We also fitted new advance and retard weights and springs as someone had been in there before and the wrong springs were fitted. Also new Bosch coils and Beru ignition modules along with new wire type ignition leads and red type plug extenders. The engine tries to fire but will not start. I checked with a bulb across the coil red and black wires and this flashes regularly when cranking over, I think suggesting that the ignition modules are functioning ok. Compression pressures checked and all between 120-130psi, not really sure what to expect. I did install a timing light on No.1 cylinder lead and whilst it would not start the light did not flash on every firing stroke maybe suggesting the distributer was at fault. I replaced the distibuter cap but this made no difference. We then checked the engine earth wire to Magneti coil pack and ignition module and ok. I did check the flywheel timing marks and set the distributer rotor arm to face the No.1 cylinder plug lead on the cap, thinking that would be close enough to get it going. As the car had been sitting we drained the fuel and refilled with shell V-power. The only part not renewed are the spark plugs which look new, but will now renew.
On the face of it, the electronic system looks simple, but I wonder if we are missing something obvious. I should say that when we installed the VR sensors, we set the gap at 0.25mm and could feel the slight resistance as the toothed wheel comes past. I also had to file off a small piece off both sensors mounting plate as the sensors plates fouled each other. Any help much appreciated.
Steven

 

DO you have any fuel . Did you pull the plugs to see if they were wet. Fuel , spark and air is all you need so one of them must be missing. If you pulled the dissys did you put them back in correctly. If it ran before why did you change the dizzy springs after.

 

If the distributor you have is the same as the one on my 1980 308GTB (i.e. electronic) then I can tell you that:

1. New bob weights and springs will be way off the correct advance/retard.
2. The positioning of the 2 sensors is critical - not just the gap but also that they are fully square.

 

Yes there is fuel. Plugs have been out but don't look too bad and it was running a few weeks ago, I will be replacing the plugs later today though. We put new bob weights and springs in because on one side the springs weren't doing anything at all which didn't look at all right.

 

Thanks for your reply Andy. We have spent hours following you're previous posts . The Dizzy is the SM805A one which I believe is the same as yours.

Although the Bob weights maybe off would that actually stop it from starting ? I would have though that would affect it more at higher revs?

When you say fully square I don't see how you can actually put them in incorrectly, I have attached a photo of what it looks like. There is one alarming thing though, why did we have to file down the edge of the new vr sensors in order to fit them (they would have overlapped), that certainly didn't feel right, could they be the wrong ones? Got them from Eurospares
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Hi,
I haven't got an immediate answer to your woes but the metal plates on my VR sensors were a very tight fit - which possibly lead to mine being aligned poorly.

IIRC the holes in the metal plates allow some adjustment. I do know that mine needed to be corrected. Let me go back through my notes this and see what else I can find - I'll try and do it tonight.

My car used to start and then gradually peter out until the revs dropped so low that it died. This was down to using coils that were too weak. Foolishly I had thrown out the original (AEI?) coils and bought the ones that Superformance sold at the time (BK2A's). These were too weak and I had to replace them with something more powerful - again I'll try to give you details tonight.

Also, you appear to have done exactly what I did when I disassembled my dizzy and saw the odd assortment of springs (I actually posted that 'some idiot had put the wrong springs in...').
The original springs and bob weights (i.e. 35+ years old) were re-installed and the advance/retard curve was perfect. The springs supplied with the new kits are way too strong.

Be back

 

Thanks Andy much appreciated.

Interested to know how you aligned the VR sensors.

I bought the following stuff and running out of ideas .... and money

new Bosch coils - 0221122334
new Beru amplifiers - ZM005
new Red extenders - Superformance
new HT leads - Superformance
new Dizzy cap - Eurospares
new NGK BPR8EIX Plugs (coming today)
new Bob Weight Kit - Eurospares
new VR Sensors - Eurospares

I wonder if maybe I should send the dizzy off to professionals to get it setup correctly, do you know of any?

Thanks
Steve

 

Hi Steve,
This thread is very good:
http://www.ferrarichat.com/forum/308-328-sponsored-yellow-compass-group/435679-rebuilding-308-electronic-ignition-sm805a-distributor-marelli-aei200-ignition.html

It does confirm that you have bought decent coils.

 

Jockster, where are you located? That might help us identify a (reputable) local shop in your area that can help with the dizzy work.

Fellow 79 GT4 owner here - #14768 - if your car's not yet in the registry, please sign up!

 

The mechanic that worked on my GT4 for the previous owner told me about a problem he had with my car not starting after it was converted to a Pertronix set up. The problem was traced to voltage loss in the old wiring loom resulting in too low a voltage for the Pertronix to function. Running 12v from the battery to the Petronix apparently fixed the problem although it seems like it would be easier to just run 12 volts from the alternator. Might be worth checking voltage to the coils and ignition modules?

 

Send me the link for the Registry and I will add my car.
Steve