Engine won't start - At a loss what to do next

[Simeon]

Ok guys i'm stumped

Rv8 3.5

Set engine to no 1 cylinder TDC on compression stroke both valves closed. Aligned dizzy so No1 post was pointing at rotor arm. working clockwise fitted the leads in the correct firing order 18436572.

Getting a spark. Getting fuel. Still wont start, will only make popping noise when the pedal is floored.

Please tell me what to check next?

[steveshaw]

Have you set the static timing.
Set bottom pulley marks at about 6 btdc
Take off dist cap and look for marks on the pick-up and the rotary splitter, line up these marks by turning the distributor, nip up the distributor and try starting.

[DaveEFI]

Ok guys i'm stumped

Rv8 3.5

Set engine to no 1 cylinder TDC on compression stroke both valves closed. Aligned dizzy so No1 post was pointing at rotor arm. working clockwise fitted the leads in the correct firing order 18436572.

Getting a spark. Getting fuel. Still wont start, will only make popping noise when the pedal is floored.

Please tell me what to check next?

Timing needs to be set more accurately than that especially on an engine which may be off tune in other ways.

What type of ignition - points or electronic? If electronic, what type?

[Simeon]

Dave

I have Mallory dual point.

[DaveEFI]

Dave

I have Mallory dual point.

Turn the engine so the timing marks line up on the compression stroke.
Disconnect the lead from the dizzy to coil, and connect a DVM set to ohms or continuity from dizzy connector to a suitable chassis ground. Turn the dizzy in the same direction as the normal rotation until the DVM buzzes or reads a short - ie the points are closed. Then turn it the other way until you *just* get an open circuit - zero ohms or the buzzing stops. This is where the points open and trigger the spark. Make sure the rotor arm is still pointing to cylinder 1 on the dizzy cap.

(There is a procedure for fitting a standard dizzy so the rotor arm points in the 'correct' direction at TDC. But with an aftermarket dizzy this is unlikely to work so you will have to check the coil leads are correct after setting the initial timing as above.)

Once the engine starts, check/re-set the timing using a strobe timing light.

[Simeon]

Thanks for your help so far guys

Dave I can't see how your procedure would work. When I spoke to RPI yesterday they said that the rotor arm never comes into contact with the posts. It is designed to jump across as they put it. Just a furthe rbit of info, I'm getting 9.65 volts the coil on crank, does that sound right?

[Will Reeve]

Dave means the low voltage side, the HV spark jumps the rotor arm to the post of that cylinder, down it's lead and to the plug, correct you can't measure that with a multimeter. However the coil needs a trigger to fire the spark, that is low voltage. Depending on what Dizzy you have there are a number of ways to generate that signal, the easiest is with points (a simple mechanical switch with two strips of metal, like a micro-switch), you can measure this like Dave suggests.

[Simeon]

Dave

I've done as you said and it's still not having it.

Oh and Will thanks for expanding that for me.

[DaveEFI]

Thanks for your help so far guys

Dave I can't see how your procedure would work. When I spoke to RPI yesterday they said that the rotor arm never comes into contact with the posts. It is designed to jump across as they put it. Just a furthe rbit of info, I'm getting 9.65 volts the coil on crank, does that sound right?

Sorry - it's a bit difficult at this distance to work out the experience of an individual, and so I assumed things.

I meant connect the DVM to the low voltage side - not the plug leads.

How are you measuring the voltage at the coil? If between the + terminal and chassis, it should be the same as the battery volts when cranking. So likely 11v or so.

[Will Reeve]

How I tested (and this may be frowned upon) is pull off the main plug lead to the coil at the dizzy end and leave it laying on the engine. On cranking you should see a huge spark jump from it to the engine block, you know you are getting a spark to the dizzy if that works, now all you have to do is make sure that spark gets to the plugs and it's happening at the correct time!

[Simeon]

Will,
Definite health safety yellow card for you
I am getting at spark at the plugs, wether it's a good one or not I don't know, iv'e got nothing to compare it with.

Dave.
Yes I checked the voltage at the positive post on the coil and chassis earth. To get my cranking voltage I've spliced into the white & red lead that cranks the starter motor. If thats the wrong place then I'm not sure where to get the power. The solenoid has two spade connections. One to fire the solenoid which is for the white and red lead I mentioned earlier and the other seems to gice out 12v when ignition is on but not during cranking. Anyway the splice goes to the ballast resistorand directly on to the positive side of the coil and on the resisted side of the ballast resistor is connected a 12v ignitioned.

[Will Reeve]

Ok, not sure of your set-up by I used a ballast resistor with the old Opus system and I wired, like you, to the starter motor solenoid. Big mistake! Turns out what when not cranking my starter would ground that wire! So I had sparks on cranking and not when running!
I fixed that by using a relay to supply the 12v from the battery when cranking (relay energised by the starter solenoid feed).

p.s. I was getting a good 2inch spark from the lead to the block, guess that is typical, had a brand new coil and a good 12v straight from the battery terminal feeding it!

[Simeon]

So, could the fact that I only have 9.6v at the coil causing a weak spark prevent it from firing?

The engine turns over nicely it just does'nt even sound like it going to fire up.

[adamnreeves]

I had a starting problem with a Disco once it it was the similiar issue. I changed the coil and it didn't sort it. I was only reading about 9v also. I wired in a new supply and it the full 13v and it fired up.

[Simeon]

Cheers Adam I knew you would'nt let me down. I have a new coil, cap, condesor, leads, plugs rotor arm. I can't think of anything else.