R400D: Curious misfire

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John Vine
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Thanks, James. 

Yes, I too was surprised that vapour lock could affect a modern injected engine like the Duratec.  It sounds as though your symptoms didn't cause a complete failure in firing, whereas mine cut everything for several seconds.  The ambient temperature at the time was 20-25C, so relatively cool.  By contrast, in 2019 I motored through France in 35C temps.  I was melting, and had to put the half-hood up for shade.  But the car behaved impeccably, so something has changed in the interim.  Ethanol-laced fuel?  Who knows.  I'm trying to work out what faults could cause a complete cut in firing.

You're a knowledgeable fellow regarding Easimap.  Do you think an in-flight logging session would throw any light on the problem?  If so, which panels should I include as a minimum?

JV

aerobod
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Hi John, I would include as many panels as possible, should be able to log at least 32 channels with the default 992 ECU used in the R400D. My 9A4 ECU seems to be able to go higher, currently at the following 36 realtime channels that are determined by the panels you have open on the active page:

James

7 wonders of th...
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Forget the fuel vapourisation the Duratec runs with a lage capacity rail the rectangular version used by Cosworth the pump prime is more than man enough to over come this.

David_Long
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The reason the Caterham Duratec is more prone to vaporisation than the Ford equivalent is that it is a longitudinal installation and the fuel rail and pipes runs hotter as a result. The fuel rail is also a single feed, so the only way for any vapour to escape is via the injectors. But only some cars do it and the reason for that is unclear. Re-mapping does seem to remove it but I suspect thats because the Caterham map is sensitive to the condition (posibly due to emissions requiremnts on the generic map, rather that best running that a custom map gives).

7 wonders of th...
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The fuel rail will be hotter still in a tin top, coolant temps are higher its tucked away under covers and cocooned in noise insulation under a solid bonnet -  Under bonnet  temps of a Mondeo touring Spain or the South of France towing your own landsnail will be much more of a challenge for a dead end rail set up than in a 7 where its in free air about 75mm below the bonnet louvres.

Did some R400's use the thin plastic fuel rail perhaps...? 

7 wonders of th...
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thus us the high volume rail I use, (Bosch green injectors though) the rail was standard on the ST150 - and can picked up on fleabay cheaply

AFAIK CC used this accross the Duratec range too.

 

https://www.burtonpower.com/cosworth-fuel-rail-hi-flow-injectors-ford-duratec-he-i4-kk3450.html

 

John Vine
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Re #13:

Thanks, James.  That's most helpful.

A couple of questions:

My misfiring symptoms appear only after I switch off the (hot) engine for, say, 15 mins, and then restart and drive off.  If I start logging and later switch off the engine, will I lose whatever I've collected up to that point or will logging pick up again when I restart?  (I'm assuming that, as switching off will interrupt the Easimap-ECU connection, I'll lose the log, but I'm hoping otherwise!)

Your graphic shows 36 panels/channels.  If my (locked) 992 will handle a max of 32, I propose to drop the four Manifold items (I have RBs and therefore no manifold).  Would that seem a good idea?  Also, I imagine I could drop Baro Pressure as I don't have a sensor (or map) for that?

JV

 

John Vine
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Re #17:

This is my fuel rail (with green injectors):

With this part number:

JV

aerobod
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Hi John,

As long as Easimap is left running on the laptop on the same page while the engine is off, it will resume logging when the ECU is powered up again, you will see the power cycling as events in the log.

It sounds as though dropping the manifold and Baro pressure measurements would be the right ones for your setup if you are channel limited. I would also add the crank signal if possible. With Easimap though, you may not see spiky transients less than 50ms or so, even though they may cause problems with a signal, if you have a duff sensor or coil dropout causing a misfire, you may need to use an oscilloscope, such as one of the cheap Hantek dual-channel USB ones that can also be hooked up at the same time as Easimap to the laptop.

James

John Vine
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Many thanks, James.  I'll let you know how I get on.  My misfire seems to be all or nothing at low engine speeds, yet disappears completely at higher speeds.  The upshot is I'm trying to work out what faults could cause that.

PS: I can't find a panel for crank signal.  What should I be looking for?

JV