New 420R kit won't idle, running rich

[dmansr25sd]

Hi folks, I'm building a 420R kit with roller barrels and can't get the thing to idle right.

 

The car turns over fine, builds oil pressure. After connecting the immobilizer to get fuel is when problems happen. The engine doesn't spark at idle, only with throttle do I get ignition and then the engine spews out unburnt fuel. It runs so rich that I can disconnect the immobilizer after this and the engine runs fine for close to a minute on residual fuel.

My dealer took the ECU back thinking it was mis-calibrated or something and after several months(!!) wait I get it back from Caterham direct and the same situation is happening.

 

My only thought is the TPS is wrong making the engine think it's at WOT fueling level, but I've tried adjusting it to no avail. I also haven't been able to get a hold of an MBE985 cable as they were sold out at SBD motorsports last they asked, but I'm trying again. I will try jerry rigging some fly wires into the TPS to see if I can get some readings. I've read some competing information on what voltage or resistances I should be looking for, anyone have the source here? Any other  thoughts on what to try next?

 

Thanks in advanced for the help!

[KnifeySpoony]

My guess is you have the green injectors in? If so, go back to the standard black injectors. 

[dmansr25sd]

38 minutes ago, KnifeySpoony said:

My guess is you have the green injectors in? If so, go back to the standard black injectors. 

Yes.... should the bigger green boys not be the ones to use with the roller barrels? Potentially dumb question, what are they for then?

[KnifeySpoony]

The new roller barrel tune is designed for use with the standard black injectors. However, neither Caterham nor its dealers seem to know this somehow...

 

My roller barrel kit, new in 2021, came with the green injectors. I installed them as well because no one told me not to lol.

[dmansr25sd]

wow. So yeah, I just swapped the injectors and after a little of fiddling with the throttle position sensor I got it running on its own! Thanks so much!

 

Any tips on how to properly set the TPS? There seemed to be a really narrow range where it didn't bog down and where it was burning clean(no tail pipe smoke). Seemed to idle ~1750 at that setting.

[sltous]

I got this document from Rocky Mountain Caterham at one point for roller barrel TPS setup.

 

WRNOT 608 - Roller Barrel Setup Ford Duratec Engine.pdf

[KnifeySpoony]

If you have the cable to hook up to easimap you can set the idle voltage there, or just read off the back of the plug and set to 4.62V (as per above instruction). I will say that I never adjusted the air bleed screws however. 

[KnifeySpoony]

1750 is very high. Mine idles around 1100. Another common problem is tachs reading high or low. Also another problem that Caterham doesn't know how to fix. If your tach seems off, check the dip switches on the gauge itself to make sure they're set correctly. The info is on this forum; should be easy to find with a search.