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Fuel cell installation


sf4018
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Really neat installation.  I enjoyed this thread.

 

How do you trigger the fire extinguisher in emergency?  Is it just a hand held or is it plumbed in?

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It was plumbed in by Caterham, there’s a handle on the dash.

 

So I put 5 gallons in, set off the pump for a second but no gas flow or pressure. Maybe I have to put more fuel in or bleed it somehow?

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Moving on to the new ECU…it’s so nice to be able to go in and configure stuff. The RPM meter on the dash doesn’t work properly, it’s like it’s showing pressure or something, but I’ll figure that out later. The main issue right now is the engine doesn’t idle, anyone have a clue what could be the problem? Here’s a vid of the problem…

https://youtube.com/shorts/u2HwIthDE-g?feature=share

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It almost sounds like it's running out of fuel.  Is the pump still operating when it dies?  What happens when you immediately try to restart it?  Any change to the behavior shown in the video?

 

-John

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My Duratec will do that until warmed up - I have to sit and blip the throttle until it gets happy.   If you hold revs higher than idle will it get past this "cold" stage until it can idle on its own?  

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In the video, the idle seems very stable for the first 5 seconds, then slowly drops off.   I'm used to immediate idle instability when it's a cold mapping issue and a lumpy drop off.  

 

@sf4018 are you able to keep the car idling by blipping the throttle?  If so, then I'd start by looking for the idle settings in the map.  Typically that's handled by adding a certain amount of advance when the revs fall below a certain amount and fuel enrichment tied to coolant and air temp.  Emerald has some good guidance on how to attack this on their site.  The software interface is different, but conceptually the same process is the same.  I can dig out a link in a bit.

 

-John

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I blipped the throttle to keep the engine going for a while, then after it warmed up some it held idle fine. I also experimented with the 2 electrical control variations for the pump.

Here’s how the original on demand pump controlled by the ECU and pump control relay (same as original internal pump control) works…


…the pump runs for a second to charge the pressure, then I start the engine, fails to hold idle, then the pump is re-activated by the ECU. How it ever worked before i don’t know. Fuel pressure was around 30psi. I know the plumbing isn’t setup for on demand but I wanted to see what happened. So the relay is now chopped off and ECU signals taped off.

 

Next was running the pump full time by wiring YG154 and B10 to the pump…

 

…holds about 52psi. Engine was cold, even with this higher pressure idle didn’t hold.


So the electrical is sorted now. I’m gonna let the engine cool completely and see if it’s a cold start issue. If it is, which looks likely, I guess I’ll need help what to change in the ECU.

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The engine and hard idle sound very similar to my car and it's issues. I however had ITB's and a problem with IAC. As the car would get warm it would hold but it was very hard to start at the beginning. 

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On 8/24/2021 at 6:39 PM, Anker said:

Are the throttle bodies balanced?

I only see 1 throttle body at the entrance to the manifold, everything past that seems static, but I don’t really know.

 

On 8/24/2021 at 6:58 PM, JohnCh said:

If it is cold start, and the MBE manual doesn't provide much info, this guide from Emerald may prove helpful from a methodology perspective.  The most relevant section starts on page 9 "Coolant temperature injection corrections."

 

-John

That’s good info thanks!


So I started up the engine cold a few times now, it reliably holds idle either the first or second attempt, so I don’t think it’s a temperature thing, maybe air bubbles in the line working it’s way out. Whatever the reason, it’s pretty good now.

 

SBD Motorsport have been great so far, it’s so great to be able to send any data I want to the AIM system. They responded about the RPM meter not showing RPM correctly they said it was a setting for 4 pulses per cycle instead of 1, I’ll try that tonight.

 

Just gotta do fine tuning after that.

 

What a painful project, but the end result turned out pretty good. I appreciate all the help and support from everyone, it made a big difference! 
 

Thanks!

Simon

 

 

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Glad you are making progress.  Do you have a wide band O2 sensor feeding into the MBE?  If not, it's very useful for trouble shooting, particularly if you can log events vs. only seeing live data.  

 

-John

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Posted (edited)
On 8/26/2021 at 1:24 PM, JohnCh said:

Glad you are making progress.  Do you have a wide band O2 sensor feeding into the MBE?  If not, it's very useful for trouble shooting, particularly if you can log events vs. only seeing live data.  

 

-John

I believe so, I can pull up the raw O2 sensor value and lambda number on the ECU software, I’ll be able to send this to the Aim Solo2 for recording. Life is good with an unlocked ECU 🙂
 

Edit: Upon research it looks likely that it’s not a wideband lambda sensor, so I’m gonna replace it.

Edited by sf4018
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Has anyone replaced a standard lambda sensor with a wideband one? I believe it's 6 wires but there's only 4 on the current sensor connector (brown/blue/black/white).

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You cannot just swap to wide-angle sensors. Regular sensors are like a switch, they only work over a narrow band, rich or lean are the only choices. Wide band work as the name suggests over a wide range of values. Your ecu will not know what to do with the increased range of values the sensor will provide.

 

Graham

 

 

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As Graham notes, you can't simply replace the sensor, but you can buy a WBO2 system with controller and wire that to the MBE.  The instruction manual should identify any changes you will need to make to accommodate, but it could require a slight wiring change (e.g. the Emerald uses different pins in the harness plug for WB vs. NB and also requires a setting change in the software.)  

 

-John

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  • 2 weeks later...

SBD Motorsports recommended replacing the stock lambda sensor with an Innovate LC-2 Wideband System, so I went with that. Mechanically it swaps out easily without modification. Electrically this is the plan…136EF838-4A03-45ED-BEA3-85D764679611.thumb.jpeg.06c66899c3aba1b9b8eafe4f578f15d2.jpeg

The only unknown is whether the signal 0V NB8 should be grounded (probably to the chassis). Looking at the Caterham schematics the NB8 signal ground wire is shared with several other sensors, plus it’s close to 0 ohms to battery ground already, so right now I’m going to lean not connecting it. Ground loops are not good. 

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  • 2 weeks later...

Did the first ECU setup run with Steve of SBD Motorsports yesterday. A few relevant notes:

 

1. The ECU fuel pump run command signal can be programmed to run as long as the engine is turning over, which is safer than the "always on" mode that it's wired as right now (currently only killed by key turn out of position 2 or inertia switch trip). So electrically it would have been better to keep the fuel pump control relay and harness intact. I will re-install a new harness over the winter, but for the tracks days coming up next month it's gonna be fine.

2. Steve tuned the cold start perfectly, it fires up first time now. Awesome.

3. Idle and low speed tuning took several hours and apparently is the hardest part of the tune. He made some changes while I was driving around the neighborhood with the PC connected to the ECU with a desktop session to the UK via cell. It was really cool to see how even small changes to mapping can make a noticeable difference. If I can figure out how to tune it myself later on it'll be car nerd heaven.

 

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