Austin David

Is the fan a single- or two-speed fan? I notice the electrical diagram shows two drops for high and low speed, but my fan has only two wire connection and as far as I can tell it's wired up to the cooling fan relay directly, which I assume the former ECU controls/ed with a simple on/off. As in, with the ECU disconnected I can ground the correct relay pin and the fan comes on and sounds fairly loud, and I don't see any obvious second circuit for a higher speed. Car is a 2021 Caterham 360S (Duratec) with new electronics. On OEM electronics it behaved "normally" as in "fan cycles at idle" between 90-95C" and I feel like it was very much on/off but I did not test it before I ripped out the old ECU and harness.

ok, for future sleuths: - it's on purpose - it should get hot while the little battery light in the tach is ON -- ignition on/engine off, or alternator no worky - it should not get hot while the engine is running normally (light is not illuminated) - it's there because the LED in the tach doesn't draw enough current on its own, so this will sink a few W (2? 5?) to keep the rest of the system happy. Thanks @sltous, I wasn't able to find that set of articles.

Yes! The batt light on the tach gauge comes on when I disconnect the resistor while running. I also noted it's not hot at long idle, but definitely gets hot if I leave the ignition on with engine off. Other than the battery light on the tach, everything seems fine with the resistor out

about 25-30 mph seems to muffle that beeper just fine

Some light googling says this might be something about LED lighting in the dash, and providing enough resistance to look like incandescent? But if I unplug it, things seem to work as expected. it gets HOT to the touch -- again, googling sort of indicates this is expected. 10k miles in and it doesn't seem to be causing any trouble, What is it? Is it important? It lives approximately above my steering column.

The first time I saw the interference I had the crank sensor line run a totally different path, nowhere near the alternator. It doesn't seem like it's interference from the control line? And, as near I can tell, those two lines are just a battery sense and the warning light on the dash, so I don't know why they'd even be noisy...

quick: notes: I think I've got everything sorted and am ready to start test driving. tl;dr: it was harder than I expected but definitely not out of reach. The ME221 was a good choice. CANchecked also good and would recommend standalone. Expect to use a LOT of wire, crimps, connectors, loom, heat shrink, etc. Invest in a crimper, good connectors, etc. - Alternator is noisy when plugged in (triggers false signals in the crank sensor), but the noise does NOT appear consequential. When disconnected it wasn't charging in any meaningful capacity, when connected it charges at idle. ECU still showing full 720-degree sync with the noise, I'll continue to monitor. - fuel pump : the driver module (old ECU harness #33) can be driven via PWM, 500 Hz signal. 5-50% duty -> 10-100% pressure. I wired in a 0-100psi sensor to the former MAP sensor lines, MEITE has a section for the fuel pressure sensor. I use a GPT to drive the FPDM from 35% - 100% based on ignition duty, or "off". The FP relay is wired to the ECU (low side output to fan relay), but currently just slaved to an "always on" signal. This has the FP prime on ignition on (default behavior from FPDM), then start when the engine starts turning. Added a mechanical gauge to help calibrate, but the expected calibration was correct: 0.5v - 4.5v == 0-100 PSI. - cooling fan: wired a second output (low side) to the fan relay, very simple on/off - tach: same 1-per-rev as stock ECU, plugged into former ECU pin 44. - throttle: the original cable doesn't even sort of work, and would hit the air filter backing plate. I got a 90* bend fitting, a make-it-yourself cable set, and a 1.5mm nipple from Amazon. Had to cut down the elbow to fit the throttle hanger on the ITB, then tap it for 5/16" (the nearest-size die I had handy). The pedal side was too small for the firewall hole, but a layer of heat shrink holds it still, with a nut to keep it from pulling through. The nipple doesn't fit inside the pedal tube, but the wire passes straight through and I snugged up the nipple. Full pedal travel (and more) for full TB sweep. - standard kit assumed EU-style Duratec, which uses external plugs. ME supplied a COP adapter harness, but basically just IGN1-4 + one wire, out to each of 4 COPs. Simple to set up, otherwise. - I opted for uprated 330cc injectors but probably didn't need it. The new fuel rail is much, much prettier though. Old rail is out, old injector holes are plugged with supplied injector-shaped plugs (provided with the kit) - I ended up basically rewiring the entire engine. This would have been easier with engine out, but was easy enough with coolant out (that top tube). The old ECU harness is tucked pretty hard up under the tunnel, which itself is insulated. I elected NOT to pull anything I couldn't reach, and will get to it if/when the motor is next out. Hopefully never. - In retrospect (see above) the only sensors and harness I reused were for the oil pressure gauge and starter/alernator. IF I had motor out (and the good fortune to do this job again) I might have saved time making a harness from scratch and just disconnecting everything from the factory. - CANchecked is the unsung hero here. I replaced the temp gauge (external submarine) with an MFD15. For reasons not yet determined either the gauge or the ME doesn't correctly terminate CAN, but a 120-ohm resistor at the gauge side took care of it. I had already added an oil temp gauge in the pan, and wired the "submarine" water temp gauge directly to two analog ports on the MFD15. I still have all my original Caterham gauges save one, and the "new" temp gauge now shows all sorts of cool things. Including temperature - while under the scuttle I rewired my AUX stuff for the 12V plug / USB charger, seats, roll bar light. I moved it all over to driver side, above steering wheel. Ran a ground lug through the firewall on the steering column brace, which incidentally helps stiffen the firewall. Cut a ~ 1" penetration in the firewall and made a shrouded grommet. Put 5 AUX fuses inside + relay (keyed to ignition), and 6 hot fuses outside on the firewall. Also moved my horn power line to the new fuse panel, previously on the hot side (above passenger footwell). It's much cleaner than my previous job, but required removing the scuttle to set up, and losing the original airbox. - new ECU is mounted on a custom mount (3D printed) on driver side footwell. For now I've removed the shims and lowered the battery, but it's on the same sheetmetal mount. - the oil dipstick (wet sump) needs a new home. Parking this to sort out "later". - have not yet cut the bonnet. The air filter plate was NOT cut. I ended up making a template (3d printed), then used that to locate the centers of each stack, then used a 60mm hole saw ($18, Amazon) and drill press with lots of clamps and a spoil board. Worked perfectly, but took me a couple days to figure out. The IAT is mounted in the center near the top, basically just in front of the throttle cable.

catching up: the ME221 takes a fuel pressure input, but it's not particularly prominent in the interface. This input appears to do the right thing, when calibrated. I put a 0-100 psi sensor on the fuel rail, along with an analog gauge, and calibrated the fuel pressure sensor. I've got the fuel pump driver module (FPDM) working and slaved to a general purpose table, driven at 35% idle, which corresponds to about 40 PSI, then linear up to 100%. That table's input is injector duty, which I figure is the most linear guess about fuel pressure demand. I assume there will be some tuning required, I doubt to see such a linear relationship between FPDM duty and fuel pressure.

is that 620 dash (with all the switches) the reason I have about a million extra wires and unused (but terminated) connectors under my dash scuttle, and maybe half that many under the hood bonnet? nice color scheme, that's gonna be pretty sweet on the road

@sf4018 that's a great writeup. Reading between the lines, it really does sound like Caterham has some magic juju burned into their ECU. I tried to get an unlocked model from SBD for my ITB project but wasn't able to make headway, and I'm so far pretty happy with the flexibility in this ME221 unit. Like you, I probably underestimated the effort required before starting but I definitely know the car a lot better now than I did before...

Thanks, I'll take a look! Last night I figured out how to drive the FPDM from my ECU, I've got a sensor + gauge on order, and I think I can set up a feedback loop to maintain constant fuel pressure... I should know more this weekend. I'll post final configs when I've confirmed consistent pressure, but it looks like 10 000 Hz cycle, "negative" sense on my ECU. 75% is indeed off, and the full sweep is indeed 5-50% duty cycle, which definitely ranges from "FP barely running" to "sounds like full blast". I've also got the ECU taking over the fuel relay. Pending confirmation over the weekend (and hoping I don't jynx anything) I should be able to have the ECU enable/disable the FP entirely, and drive it from 10-100% to maintain a target pressure.

Saving some info here, for posterity: https://www.scannerdanner.com/media/kunena/attachments/417/fpdmtheory.pdf Electronic Returnless Fuel Systems (ERFS) utilize a Fuel Pump Driver Module (FPDM) to control fuel pressure. The PCM uses a Fuel Rail Pressure Sensor (FRP) for feedback. The PCM outputs a duty cycle to the FPDM to maintain the desired fuel rail pressure. During normal operation, the PCM will output a FP duty cycle from 5% to 51%. The FPDM will run the fuel pump at twice this duty cycle, e.g. if the PCM outputs a 42% duty cycle, the FPDM will run the fuel pump at 84%. If the PCM outputs a 75% duty cycle, the FPDM will turn off the fuel pump.

My plan is to run this one "bang bang" for now; 100% on (bypassing the fuel pump control module), driven by the ECU. This ECU has a way to run a general-purpose map and PWM, so maybe it's possible to drive that FCM somehow. Docs are pretty scarce so I'd be guessing... plan "b" would be a $100-150 self-regulated in-tank unit, or a regulator at the rail + return line. I don't think I'd want to bother trying to fake out that FCM, rather than just rebuilding the fueling with something better understood. If this blows up or causes me any trouble I'll be sure to speak up

there are only 4 wires headed down into the tank; I assume (based on other cars) two are for the sender, and two are for the pump. Is there a feedback mechanism between the fuel pump, and that controller? if that's a new photo, can you stand a little further back and get shots of the wiring up to the socket at top?

for reference: the "stock" 360/420 setup includes a control module up by the tank, next to the fuel pump. Also the alternator generates not-insignificant noise that is heard by the crank sensor. It's the OEM sensor still, so I assume the original ECU either ignored the noise, or was able to filter it better. Once I get fans and fuel pump sorted, I'll figure out if I need to do something about the charging system.

I know several of those terms To my knowledge there's a regulator in the tank. If I blow up my fuel pump in the next 8 years I'll look at a return line and regulator up by the fuel rail. For now, based on what I've seen and touched, there is no regulator outside the original tank and no sensors. It's a single soft line coming off the fuel tank, clipped straight into the fuel rail, and the rail doesn't have a regulator on it. My setup has a wideband sensor on it, and I will be watching AFR pretty closely. If I burn a fuel pump early, or if I feel like I'm getting starved for fuel, I'll look at adding more $$ magic in line. From what I can see so far (famous last words...) I should be OK with the simpler solution.

My car has a Ford fuel control module on a Ford engine. I could speculate why it was included on this car, but mostly I'm trying to puzzle out what I miss out on by ditching it entirely. In theory (hard to test) the Caterham ECU would use it to modulate the fuel flow. In practice... ? I'm sanity-checking with the ME guys to see if they can drive this fuel pump module, but I assume the recommendation will be to simplify and add lightness, by removing it and splicing or repinning a couple connectors.

https://www.fordflex.net/forums/viewtopic.php?t=20842 Confirmed the "bypass" method works. My limited research says basically the same thing: it's used to modulate pressure, based on sensors we don't use, or can cut fuel based again on sensors we don't use. Odd. With the bypass in place, the fuel pump runs when the relay is on (ignition on). this might be my best option, I don't see a straightforward way to engage the fuel controller without inventing something worse than a bypass... Thanks for the tips, @JohnCh

Yep, pin 33 is the signal wire to the controller. Did some more research, that controller wants some sort of duty cycle. I can sort of trick it into running if I cycle that pin, but nothing I can obviously make my new ECU simulate. The new ECU will happily just run a fuel pump via relay, so I'll look into what's required to just bypass this controller entirely, and let the ECU drive the fuel pump as nature intended. Any idea why that controller is in use? We already have the inertial, and in some cases an external cutoff. What does this controller provide that we wouldn't get from an ECU-managed relay?

Ah yeah this definitely explains the problem. I'd like to drive that extra control module with my new ECU, any idea where I can track down that connection? I'm using a whole new ECU, the MBE is disconnected entirely. The new ME ECU has low side signalling or I can tinker to get the FP running. Worst case I could bypass the controller entirely and run the relay directly from my new ECU.

Background: 2021 Caterham 360S, Duratec motor. I'm swapping out the electronics (ECU) and intake with an ITB kit. Before I unplugged the original ECU, it ran perfectly. How does the fuel pump work? - I can hear it prime when I turn on the ignition. I can also feel the relay engage. Removing the relay, fuse OR unplugging the inertial switch will prevent this. So I feel like the FP is engaging when the ignition is on, and is continuing to receive power. - I do NOT hear the pump running when I try to start the car. - I cannot find any direct connection from the original ECU to the fuel pump, and as noted I think the FP is controlled by the ignition, not the ECU. Based on the fact that the relay closes when the ignition is on, and it stays closed. In the old (2015) manual there are 4 connections shown to the fuel tank; two black (B10 / B11), one GB148 which terminates at the fuel gauge, and one YG168 which terminates at the inertial; other side of inertial is marked YG167. Confirmed, inertial has two identical-looking yellow / green wires. As above, with ignition on / ECU disconnected, I can repeatedly prime the fuel pump by toggling that inertial switch. I have been able to "milk" the pump to hold an idle, by unplugging/plugging the inertial every second or so, to engage the FP priming. Otherwise the FP doesn't seem to want to run consistently, and (without fuel) the engine won't idle. Based on all the above I feel like the FP isn't running enough, but I'm not sure how to trick it into running more. What am I missing?

Great review! I still love my original Beeline. The routing / app is great, better than others I've tried (like, a dozen different apps) especially for longer, mutli-point routes. Anyone can use the app "free" without a device, if you'd like to try it. The upside of the device is (as noted above) it's small and easy to mount, and it is designed to work well in direct sunlight. My phone does NOT handle direct sunlight well, or even almost-direct like under the tonneau cover. @JohnCh i'm curious what you think of battery life; or more specifically, if the Moto II retained the "way more than actually needed" battery. My Moto claims "30 hours" ish, but that's ACTIVE hours. I only actually charge it every month or so. I worried that I would need to solve a wiring problem in my car, but that has not been a concern.

more significant update: starting my ITB project. Background: I want street (low-end) cams like my 360, but want to fatten up the curve a little. At one time Caterham had an "R300" build or somesuch, RBTB without the cam swap, but with the locked ECU they no longer offer the package and I was not able to find anyone who would / could fix the ECU. I got an ITB + ECU package from ME: AT Power mechanical, ME221 ECU and a pre-wired harness: https://motorsport-electronics.co.uk/product/at-power-ford-zetec-direct-to-head-itb-and-ecu-kit-copy/ I won't go into gory details here unless someone is particularly massochistic, but I will catalog the surprising gotchas. 0) if you are ever doing anything with wiring, spend a few hours making the scuttle removable. There are videos, you basically drill out 26 (?) rivets and replace them with m4 rivnuts. If you drive without a helmet, think about rattles while you're reassembling (strategic foam tape). 1) the CANchecked gauge is fantastic. I would recommend this upgrade regardless. It can take six analog inputs, CAN input (from my new ECU), OBD2 etc. At the very least, would be a replacement for the water temp gauge, and could incorporate oil temp. Not as pretty as the analog Caerbont, but it's a close match and not hard to integrate. 2) the factory ECU is pretty small. The ME221 won't fit in the same location. It MIGHT be made to fit if I changed the battery mount a little, but I'll probably just move it over one of the footwells, and lower the battery. 3) the old harness is wired in pretty hard, I assume I'll have to be cutting it out at some point, and re-wrapping a lot of old wiring. Looking under the scuttle there's also a lot of extraneous, unused wiring; I assume Caterham has one or possibly two types of harnesses used for every flavor of build. I'll also be removing a lot of this. 4) The new harness is pretty different. Might be easier to just get a naked harness and crimp on my own connectors. I think I'll be able to directly use a few (like 1-2) as supplied, but most will get replaced: injectors, coils, TPS, etc. I assume this is not shocking for anyone who's rewired an engine, but I was hoping* a "duratec" loom would fit a "duratec" motor, but ... here we are. At the moment I'm reassembling my intake and will do some additional "homework" with the car running. I'll be proactively checking ALL connectors, I've got some light mechanical work to fit the throttle cable, etc. I basically disassembled everything: ECU out (harness still in), battery/heater/scuttle out, airbox/plenum out. Got some notes on what to modify or fix. Each new discovery requires either a domestic or occasionally international shipment, so I'll do the homework under a running car, rather than just leaving it out of commission for a few extra weeks.

FYI that flickr link is not open for viewing. Maybe the album needs to be shared?

you're right, that is quite attractive