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Discussion Starter #1
Gents
I have a British, 2002 K series elise, which I decided to upgrade by installing a reconditioned VVC head, and with the Piper solid cam conversion, although I chose not to install vernier pulleys.
I have the 285H cams, and its running a stock ECU (for the time being).
Having reinstalled everything, added a new cam belt, and checked the cam timing using dial test indicators (I have adjusted the inlet cam by 1 tooth position to obtain the closest valve lift measurement to the specification from piper); the engine wont start.
It turns over, and fires momentarily then immediately stops - i.e. there is no more ignition.
There is plenty of fuel - I can smell it.
I removed the plugs and proved that I have a spark when I hold the end of the plug against ground - I can see a nice fat spark.
One detail which is interesting.... the head casting from the VVC is taller than the original one. That means the cam position sensor which was pointing at the exhaust cam reluctor lobe is now about 14mm further away from the semicircular lobe on the cam. I'm guessing the hall-effect sensor can no longer read the cam position.
The crank sensor seems to be working, I tested the resistance and it meets the spec - anyway it was never disturbed during the work on the engine.
The IAC valve is functioning (I think so, it makes noise and gets warm).
Weird thing is that it wont even fire up with a good spray of easy-start straight into the inlet manifold. Always the same result - fires for a half a second, and then no more combustion.
My battery is now flat, but I tried it a few times with jump leads and it makes no difference.
I am trying to measure the engine compression at the moment, but my compression tester is too short to reach the spark plug threads - it needs modifying.
I don't have any computer diagnostic equipment to interrogate fault codes or the ECU.
Any ideas?
I can try to post a video of it turning over to see if that helps.
Thanks
Chris
 

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if i recall correctly, the ecu transitions from burst firing of the injectors to timing them with engine position during start up. also, there is a startup compensation that counts cam rotations to adjust fueling and ignition timing until the counter saturates (a short startup compensation). the cam sensor may also be involved in synchronizing the accounting of engine position. i think the cam sensor should be fixed.

here are some notes i made during code disassembly for the K4 ecu:

but you may get more useful help over on SELOC where more people will be familiar with that powertrain and mod path.

if you want to play with on-board diagnostics, you could use a laptop and vag com cable, or a cheap bluetooth obd dongle and torque application on android.
 

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Discussion Starter #3
Hi Obeisance, thanks for the swift response. I will take a look on SELOC, and also see if I can find the OBD port.
I'll report back if the OBD port offers any more clues.

Chris
 

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Discussion Starter #4
Seems like this topic is covered in SELOC.... SELOC Forums
Thanks for the hint.
Now I will try to bodge a longer Cam sensor to see if it will temporarily work
 

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Discussion Starter #5
All sorted - I cut a spare Cam sensor in half (3 wire, inductive sensor on top of the cam cover) and extended it 14mm. Glued it back together with some silicone. Now the car starts first time and can idle. It runs quite rough, but that's most likely down to the special cams, and the stock ECU not playing well together.
I will add more details on the SELOC forum if you are interested.
 

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thanks for sharing your solution; this will inevitably help someone in the future. was the original sensor also a three wire part?

Out of curiosity, what do you plan to do about the engine controls? Tune the stock ecu? Switch to an aftermarket solution? Do you tune the calibration yourself, or do you have a tuning shop help?
 

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Discussion Starter #7
Hi. The original sensor was a 3 wire sensor. I still have that one untouched on my bench. I tested the polarity of the new sensor, and it does have a polarity. If you invert the 12v and ground wires it wont start. Just to know for the future.

On the subject of what to do now...im thinking of getting an Emerald ECU. But i will have to save up a few quid first. In the meantime theres not a loy of "tuning" to be done on the stock system. The plugs are completely black, so i need to inveatigate that. I might start by reverting the adjuatment i made to the inlet cam back to it's stock position. I'll post an update about that later.
 

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i see that a lot of people on SELOC prefer to use Emerald ECUs, so i expect those to be quite capable and to have good support.

when you say that there's not a lot of tuning to be done on the stock system, what do you mean, exactly? what kind of changes do you need to make?

if you just want to adjust base fueling and timing, those parameters are easily accessible in the S2 k-series elise with a K4 ecu. (see the romraider definition that i linked to above).

although I'm no expert in tuning, adjusting flash memory in the ECU is something I'm comfortable with. after all, the K4 is just as unprotected as the T4 that I've spent a lot of time with. I even made a simple, free reflashing program, written in Java, to do so. the only issue remaining is the risk and my lack of expertise in tuning: I'm working up to adjusting my own car and in the mean time I'm looking for anyone else who wants to take a risk with self-tuning and participate in talking about this.

@steelypip seemed very close to being the first person apart from me to play with my DaftOBD reflashing program. but then god intervened and prevented the possibility of missteps.. make of that what you will...
 

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2005 Elise LSS Saffron Yellow
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I haven't given up yet - just haven't gotten to it. Might well take the car out this weekend for some basic poking at the ECU on the sparsely populated roads.
 

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Discussion Starter #10
Sounds intriguing...i was under the impression that the stock ECU is non adjustable. Ill read through your post in a bit more detail.
 
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