Exige S1 won't start, no spark - new engine

Topics relating to the series 1 Exige
trackrod
Posts: 271
Joined: Sun Aug 21, 2016 10:43 am
Location: Germany

Re: Exige S1 won't start, no spark - new engine

Post by trackrod » Wed Jun 06, 2018 12:09 pm

While chasing my drivability issues I checked the crank sensor on my car wiring too. Maybe it is of use for others so I share what I've found.

The crank sensor signal is very improtant but also very sensible as it is a low voltage signal (only caused by inductive effects) and changes with up to 5 kHz. Lotus uses a twisted pair cable but that's not enough signal protection. Better to use a high quality shielded cable and earth the shielding at one (!) end to the ground (preferable to sensor earth at the ECU side but engine ground will work too). Run the cable separately from the rest of the wiring. In the original loom it runs parallel to the injection and spark driving cables which cause a lot of noise input into that wiring. I routed a new cable via the fuel filler side from the sensor to the ECU to get a clean crank signal.

I've found older reports on this forum about the ECU speedo sensor not working properly which causes the 5500 rpm rev limit to cut in. The speedo sensor works with the same principle and is prone to signal disturbance as well. A shielded cable to this sensor has been reported to solve issues there too.

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thommo
Posts: 4016
Joined: Tue Jul 13, 2004 12:50 pm
Location: Lancs

Re: Exige S1 won't start, no spark - new engine

Post by thommo » Thu Jun 07, 2018 6:53 am

Congratulations..All a bit technical for me but I followed your progress with great interest.. Great result,

Francelise
Posts: 58
Joined: Sun Nov 20, 2016 8:40 am
Location: Lincs

Re: Exige S1 won't start, no spark - new engine

Post by Francelise » Fri Jun 08, 2018 9:51 am

thommo wrote:Congratulations..All a bit technical for me but I followed your progress with great interest.. Great result,

I once thought I want to build my own house (my dad was a master builder), I was not trained in this domain but, guess what? I did it.

Started in the foundation, then floor, then builder put the structure up (economics), I did the rest, piece by piece.

My point being, don't look at the whole thing, piece by piece most of us can do it, with help/time.

My car should of been finished at Christmas, time....

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thommo
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Joined: Tue Jul 13, 2004 12:50 pm
Location: Lancs

Re: Exige S1 won't start, no spark - new engine

Post by thommo » Fri Jun 08, 2018 1:15 pm

Thanks for those kind thoughts . . .

EXG932
Posts: 12
Joined: Sat Mar 27, 2010 6:09 pm

Re: Exige S1 won't start, no spark - new engine

Post by EXG932 » Fri Jul 20, 2018 4:14 pm

Hi Gents- been a while - 2 years ? and i can see this January - May i suggest looking at the low tension circuit in the boot . there is a little black connector on the left of the engine that feeds the Coil . I have had one instnace where it worked itself loose .. the engine cut, all else seemed good... found the wire clip on the connector had broken , push it down hard and secured it temp with zip tie ... and instant ignition... that was 4 years ago - blush - must fix that properly HAG w/e

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