R400D: Curious misfire

[John Vine]

During my trip north through France last week, the engine started misfiring badly after I switched off for 10-15 minutes (say, for petrol stops or shopping).  The engine would restart easily enough, but on pulling away, I’d get several seconds of absolutely no firing at all.  The misfire affected all four cylinders simultaneously, and it felt as though either fuel or sparks had been completely cut.   Suddenly, the power would come on again, albeit intermittently.  This would continue for several minutes, making smooth progress in towns a bit tricky.  After a while, the misfiring would eventually clear, especially when I gave the engine some beans.

I’m ruling out individual connectors to coils and injectors, and thinking instead of something that could stop firing completely, such as a wiring fault in the injector or coil looms, ECU earthing, and ignition switch.  I think the battery connections are ok as dash lighting etc remained working all the time.

The only recent work has involved fitting a new Banner battery.

I plan to hook up the ECU to Easimap to do a static check and then to record a 30-40min in-flight logging session.

So, a couple of questions for starters:

What do you chaps think might be causing this?

Which specific Easimap panels should I include for my in-flight logging session?

All advice much appreciated.

JV

[7 wonders of the world]

TPS..?

Could you still here the pump running when it misbehaved..?

Crank sensor - a little vulnerable and easy to snag the harness if you've parked on a verge or similar

power and earths to ECU, chassis etc

[Amos91]

Could also be the lambda messing around, particularly if it's fine on WOT. 

EDIT: try disconnecting the lambda before restarting in a similar situation and see if it runs fine on basic ECU control. 

[ECR]

Having mistakenly filled the Elise with  high ethanol fuel on my way back after our trip, the engine ran ok but felt down on power,. Unusually, the engine stalled after every restart ( normally it just starts and ticks over). This is a bit left field for you but .....

[John Vine]

Re #2:  Thanks Neil.

TPS:  I'll look at that.  I've heard they can disintegrate due to engine vibration.

Good question about the pump, but I wouldn't be able to hear it over my ear protection!  I'll check the loom and connections.

Crank sensor - hadn't thought of that.  I'll check the loom.

Re #3:  Good point.  Thanks.

Re #4: Interesting, Roger.  On the way down and back, I filled up with both SP95-E5 or SP95-E10.  The problem seemed worse on the return trip.  In other years, French E5/E10 seemed ok.  (Great to meet up at Pau.  We must repeat -- next year perhaps?)

JV

[Hampshire West AR]

I had a similar problem with my old car fitted with a Blackbird engine and the problem turned out to be a loose earth wire for the engine loom.  Worth checking all connections?

Nick

[Jonathan Kay]

Very interesting.

At the risk of falling into the trap of making educational suggestions on removing the contents of shelled zygote containers by applying negative pressure:

How many tank refills have you done since you've been back? Has the frequency of the problem changed with this?

What's the battery voltage while cranking? And do you have a functioning alternator warning light?

How many cables are connected at each battery terminal?

Does it have a master switch?

Jonathan

[Dave Hardcastle]

John, that sounds exactly like 1 of the issues I had when I purchased my R400D. The ECU was a Caterham locked variety which failed completely when Northampton Motorsport were examining it. A new unlocked ECU and map from NMS and the car is an absolute delight.

I have the strange feeling you already have an unlocked ECU though?

[David_Long]

Sounds like classic fuel vaporisation, which some R400s suffer badly from. It's difficult to cure without fitting a fuel pipe return system, but a little time spent heat shielding fuel pipes may help reduce it. Premium brand fuel (shell, BP etc) are also less problematic. 

[John Vine]

Thanks for the extra feedback, chaps.

Some answers to your questions and comments:

Re #7:

(I suppose that's what you might call la fate des grands-mères!)

How many tank refills have you done since you've been back? None

What's the battery voltage while cranking? 12.6v (just checked this)

And do you have a functioning alternator warning light? Yes

How many cables are connected at each battery terminal? -ve: one fat black, +ve: one fat red plus a smaller lead to 12v socket:

Does it have a master switch? Yes

Re #8:

I have the strange feeling you already have an unlocked ECU though? No, just the standard CC-locked 38L036A MBE992.

Re #9:

Sounds like classic fuel vaporisation, which some R400s suffer badly from.

Now that's very interesting.  When I mentioned the problem to my wife a few days ago, that was her immediate reaction (she used to run an MG Midget which suffered from the malaise).  I wonder if that's made worse by ethanol-laced petrol, which has a higher vapour pressure than unadulterated petrol.   I'm also wondering whether a good test would be to drain the tank (Mrs V's Fiesta would be more than happy with the transfusion) and refill with "E0" (if I could find it)?

Is there a reason why only some R400s suffer from this, rather than all?  And if ethanol petrol is the culprit, would a remap fix things?

 

In the meantime, I'll do more checks:

ECU and loom earths
Crank sensor integrity
TPS integrity
Lambda sensor and wiring (could a faulty O2 sensor cut ignition completely, though?)

One remaining question is:  Will an Easimap logging session help me diagnose my problem, and if so, which specific panels should I include?

JV

[aerobod - near CYYC]

Hi John,

Although there may be a fuel vapourisation issue, it shouldn't be a problem with a fuel injected car compared with a carburetted one, an issue that has the same sort of characteristics that I had with my R400 may be applicable. With my car, it only happened with high ambient temperatures (30C or higher) combined with slow speed running (such as in heavy traffic) and exacerbated by high altitude, leading to a too-rich mixture that fouled the plugs. It seemed to be due to poor mapping in the default map relative to coolant and air temperature and heat soak in the engine that needed to be evened out when the car gets some air flow into the engine compartment again, followed by the engine "clearing its throat" to clean the plugs off.

If you are able to stop the car at the side of the road when it does this and pull the plugs, the condition is characterised by sooty plug tips.

[John Vine]

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 - near CYYC]

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:

[7 wonders of the world]

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]

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 the world]

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 the world]

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]

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]

Re #17:

This is my fuel rail (with green injectors):

With this part number:

JV

[aerobod - near CYYC]

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.

[John Vine]

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

[aerobod - near CYYC]

I think the best one to use for the crank is actually inferred in the cam panels - "Measured Cam 1 Phase" which shows the phase difference between the cam and crank signals, so a loss of crank or cam signal should give an erratic output of this value.

[John Vine]

I must be dense but I can't find that one either.  I have:

Cam Signal Level
Cam Signal Status
Lower Cam Window
Upper Cam Window.

This is on Easimap 6 vR76

JV

[aerobod - near CYYC]

Hi John, I'm also on R76. It looks as though the extra functionality for the crank signal is only available on the 9A4 ECU (which is set as my default), unfortunately when I selected the latest 992 ECU software (992ac80b), I only see the options you have listed.

[John Vine]

Thanks, James.  That would explain it

JV.