Prawny12009 said:

I was starting to wander if it could be an issue with trigger phasing,

But people on here seem to swap 899-1.1 etc ECU from ohv to ohc engines without issue so the trigger must line up the same at tdc.

Can you adjust the air gap on the trigger?

Click to expand...

The gap can be made larger. I was wondering if orientation of the pickup matters. There was no markings that I could see on it, if it was picking up an inverted signal it may end up a few degrees off.

If the slots are elongated/offset on the sensor then there is a good chance orientation matters.

No adjustment, just drops into the hole and has 2 bolts that secure it in place.

Is your trigger pulley lined up correctly? There should be a peg to locate it in the correct position.

If it isn't lined up properly the ECU will spark and inject fuel at the wrong time.

I've not got a clue. I'd assume it's located by a Woodruff key so shouldn't be out of place. I'm going to check that there's no bass ackwards wiring for the pickup, possibly get my scope on it to check the signal out.

*replies to own reply*

Wiring is fine, not checked signal out but sensor is brand new so cant see that being at fault. Maybe the crank pulley is wrong for the engine, earlier one on a later engine possibly?

Never mind I was assuming the 899 used the same set up as the fire engine.

I just compared pictures of the ohv Vs ohc pulley, one is solid with a single bolt (ohv)
the other is held on by three bolts to the main timing pulley (ohc).

I can't imagine the ohv pulley is capable of going on in any other position, without the pulley or Woodruff key being damaged.

I have seen the keyway wearing on Vw engines in the past allowing the timing to go out though so not an impossibility.

May potentially have found the cause, need to add a return to tank.

Do you have your return line between the tank and pump or between the pump and engine?

A filter with an integrated return line fitted before the pump might be a good option, if it syphons back it could cause long priming times though.

I've been trying to find either a two spigot pick up/sender unit or a 1-1.2 bar in tank regulator.

Most I can find are 3 bar+, with an in tank pump and regulator you can use a single output from the tank,

the original return could be blanked off at the throttle body or used for a pressure guage fitting.

I think the hole in the robin tank could accommodate an intake pump (approx 50-55mm opening).

Could you run the return into a catch can to see if you still get the knocking

Return goes back to the pump inlet. I'll get a catch can on it and see how it goes this weekend.

Well it wasn't the fuel supply, however I've found out today that the throttle doesn't open all the way. Not enough travel from the throttle pedal. Does the IAW16F self-calibrate the throttle position?

At a wall with it now. Done ignition system, map, water temp, ECUs, fuel supply, crank sensor, throttle position sensor and now stem seals and head gasket with a decoke. All that's happened is I've used the entire Christmas holiday and got nowhere with it. It's still knocking at specific load conditions.

I would change the injector and pressure regulator but it seems to be only available as the top part of throttle body for stupid money.

Kind of a dead post now but I'll share the solution for anyone else.

Turned out to be only 0.5 bar of fuel pressure, looks like the regulator had been tweaked in the past as there was pretty much none of the wax seal left. Hooked up gauge, tweaked the screw ands knocked it up to 1.2 bar. Struggling to run properly at trhe moment as I've significantly increased the fuel flow through the injector but hopefully all will be well now.