MicroSquirt.com read only forum (Jan.15,2018)

I'm running a 1.8 litre Zetec with Jenvey throttlebodies and Bosch Green 803 injectors. The car was MOTd friday, and yesterday was spent trying to get it running right, which I managed to do. This morning I went out and it was fine, but it seemed to be overfuelling/running rich.

I've read that the 803 injectors flow at 330cc/min or 382 depending on where you read it, it was set at 330 so I swapped to 382 and went for a drive. The engine flooded after 50 feet. I've changed the setting back, and I just can't get it started. The cylinders are just getting full of fuel.

I took the plugs out, and turned the ignition on (I've set the fuel pump to pump when the ignition is on, rather than when it's cranking) and I could see fuel being pumped into a couple of the cylinders. I disconnected the power wire to the injectors and looked, and it had stopped. This, to me, says the injector isn't stuck open.

When the engine isn't turning over, but the fuel pump is running, shouldn't all the injectors be closed?

Has anyone come across this kind of thing before?

And does anyone know for sure the flow rate for an 803 injector?

Cheers

Mike
(Moderators:I've posted this in the european forum, so feel free to remove it from there, as I think I'll get a better response in this forum)

Are you running a v2.2 board by any chance? This sounds like a classic flyback failure on an original v2.2 board.

Those injectors are low-z aren't they - as such you need to setup injector PWM and ensure you have the hardware for active flyback protection. On the v2.2 board this requires a second board, on the V3 it requires that all the parts be installed (they usually are.)

Either way, strip the Megasquirt and check for burned injector drive components.

James

Thanks for the reply James. Yeah. they're 4.5 ohm and it is indeed a v2.2 board.

Looking at the board, it looks like the q1/tip42 transistor has fried. Now, how do I go about fixing it as I didn't build the 'squirt in the first place. Is there anyone in the UK who can supply the necessary components, or one fully built? Reason for the urgency is I'm going on holiday on Wednesday, and I'm needing the car running for a show I'm going to a couple of days after I get back! (It's the Classic Ford show at Santa Pod. You may be there, James, if you've got a Cortina!)

You need the flyback board or inline resistors. You _may_ get away with getting a new TIP42 and bolting it to the case.

Bill Shurvinton or Phil Ringwood are worth contacting for a flyback board and a repair while you are away.

I could repair it and likely source resistors, but don't have a flyback board.

James

Thanks again. I've emailed Bill to see if he can do anything for me.

I found a post on the UK Megasquirt yahoo group with a link to someone in the UK supplying boards (http://www.americanv8engines.co.uk/shop ... cts_id=194)
so hopefully either one may be able to sort me out.

Cheers

Mike

Just another question, if I were to switch my injectors to high impedance ones, and then change the PWM settings according to the megatune manual, would my megasquirt with the blown flyback circuit work? ie: by changing the PWM settings to 100% does that tell the megasquirt to ignore the flyback circuit?

The damaged components on board need replacing whatever. However, if you did switch to high impedance injectors you wouldn't need the inline resistors or flyback board.

James