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nelmo

Misfire

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it maintains an equal pressure difference between the fuel rail and the inlet.  Are you on a stock zetec ecu or aftermarket?  If aftermarket and has been mapped as it is now will be fine without, if it is stock ecu it will run better under cruise and part throttle conditions with it connected.

 

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Emerald ECU but not professionally mapped - but it runs closed loop with the wideband lambda sensor, which maybe is why it's never been a problem?

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Fuel pressure reg is left open to air  no vac pipe connection 

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I know my engine is old school petrol injection but my understanding of engine control is knowing parameters of how it is operating. 

The more information the controls get for spark and fuel supply the better it will run under the many various loads the engine suffers.  Obviously with later engines the controls have been transferred to electric rather than vacuum and that was my main query.

My application has knackered a new set of injectors due to over pressure of the fuel regulator, in this case reaching over 10 bar which should not have happened with the max pressure of the regulator set at 3.5 bar. However the vacuum connection reduces a properly working regulator down from the maximum to 1 bar or lower when vacuum at maximum during low load/tick over. Also I had the reverse of your malady happening as fuel was feeding back through vacuum pipe making tick over massively over rich and fast running strange.

Just trying to help!

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So, replaced HT leads, spark plugs and coil pack - misfire still there 🙄. I've also re-wired the plug into the coil pack.

I started up the Emerald software but I cannot see anywhere that might show up errors - does anyone know if it has diagnostics? I will email Emerald about that...

To summarise; Ford Zetec, FI, plenum (no TBs). Start-up, idle and gentle acceleration all fine. Hard acceleration and anything over 3k revs, engine misfires quite badly.

What do we reckon next? I can't think of anything else to replace on the ignition side so injection? HP fuel pump? Injectors?

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My 2 cents.

Any overheating or chance that the crank and/or cam sensors are loose? 

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No over-heating and I unplugged the crank sensor when replacing the starter motor (yeah - expensive month) and it seemed firm enough, although difficult to tell, I guess. Actually, that's an idea - try wiggling it while the engine is idling and see if it misfires?

This is probably a stupid comment but I'm not using the cam sensor, I don't think ☺️ - just googled where that is and I don't think I'm using it...

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Not sure on the cam sensor? My Mazda motor uses one. The Ford may not? 

I'm sure someone will chime in shortly.

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OK, panic over - all seems ok...

I went out to use the datalogger function in the Emerald software but I had to sit on the drive with engine running for ages while I tried to work out how to start the logger (Emerald could do with improving their manual) 😳. Drove off and...nothing....smooth as silk (well, as smooth as it gets).

I can only assume I had some dirt in an injector and either the extended warm-up period washed it through or it just washed through eventually?

Have to see if it's still ok next time out, before I get too excited 😉

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Did you find the diagnostic page?

Looked on my Emerald this morning and found the page by accident.

Helped me find my problem. I think it was under the help menu button.

Glad its now sorted but may be worth fitting a fuel filter to the pressure side to stop and more dirt.

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Have you not had it on a rolling road to check the timing is all doing the right stuff in the right places? I can't believe how much the driveability of mine improved after a day on a dyno getting all the fuelling and timing tweaked (also had a hard acceleration issue where I couldn't stomp the throttle but had to build it up). Literally went from hard work to drive to an absolute pleasure again.........Or at least so I could realise that suspension is next on my hit list haha.

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4 hours ago, jmspec said:

Did you find the diagnostic page?

Looked on my Emerald this morning and found the page by accident.

Helped me find my problem. I think it was under the help menu button.

Glad its now sorted but may be worth fitting a fuel filter to the pressure side to stop and more dirt.

There aren't any diagnostics in the Emerald ECU, just a data logger. Emerald suggested I use that and if I saw breaks in the signal for anything, that could suggest where the fault was. As it happened, I didn't need it - but interesting to use.

@Zac, no, never done a RR. Too many other things I can spend £350 on....my worry is, will the session kill my car and will I notice the effects enough to justify the money? I'm perfectly happy with how my car runs now and while I'm sure it could be better, £350 better? I have done this before, spent a lot of money on something and afterwards thought, "well, it's a bit better but not a huge amount"...

Edited by nelmo

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Did a group rolling road several years ago with CKC , "near" Exeter.   All was fine, it just proved that Florin was running as she should.  Told the tester not to exceed 5K rpm as we needed car for the 135 mile trip home.  Think the cost was around £50 -- so worth the cash to us but maybe a complete set-up would need a lot more time & effort by the tester.

Was the only car on the rollers that had a picnic basket on the back.

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Money spent on a rolling road is money well spent as far as I am concerned. Strap it down and give it hell,  if it survives that then it will survive anything I can give it on the road. The old engine i had in had scorching on the top of the pistons, probably caused by too lean a mixture, something that would have shown up on the rolling road if the previous owner had bothered. My distributor was giving too much advance at low revs and to much retardation at high revs or the other way round, I forget which. The owner of the RR whipped it off and adjusted the stops and hey presto another 26 horsepower. Changed the chokes for some bigger ones too as I knew it would take him a lot less time than me. A couple of hours work for him and it only cost me 80 quid.

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34 minutes ago, kevin the chicken said:

Strap it down and give it hell,  if it survives that then it will survive anything

And if it doesn't survive? 😉

 

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