420R in Virginia

[MV8]

2 hours ago, Austin David said:

That's an interesting idea.  Would it be reasonable for me to drain the tank down to an "OH NO" minimum like 2g, then set the float to bounce on E at that level?  That way I would know very well how much is left in there. 

Yes. You could leave the key on then watch the gauge as you seat the sender on the tank and tweak as needed. I wasn't suggesting running dry, just reminiscing; my mind wanders. The gerotor efi pumps do not tolerate running dry at all. A carb piston or diaphragm pump would be ok with that but I prefer a gerotor for carbs too. Carter makes an excellent inline/external, gerotor pump for carbs that is quiet and reliable. I can provide a part number if there is any interest.

[Austin David]

I'll just (some day...) bend the float.  No other plans to change the fuel delivery or otherwise further complicate things.

[Austin David]

uh, stupid question: where is the in-tank fuel pump?  Do I remove the Al panel from the boot to expose the tank, and in a very obvious place will find a cover, from which presumably hangs the pump + sending unit / arm?

[MV8]

No experience with your model.

In the top of the tank, you may find a large white plastic unit with a fuel line and an electrical connector. In this case, the level sender is part of the pump assy. It is under the boot floor and retained by a plastic nut ring. It will likely take a special tool to disconnect the fuel line from the assembly so you can remove it to bend the arm. The assy should be keyed to fit one way so the float is in the right location to swing freely. The seat and ring cover a large area and are not intended to be very tight in order to seal, so be careful not to break the retaining ring or force anything. I'm sure it is very expensive.

Other, older efi models should have separate pump and level sender assemblies in separate openings and secured by many small screws. Again, does not need to be very tight so don't strip screw heads.

Some carb models may have in-tank pumps.

[Croc]

1 hour ago, Austin David said:

uh, stupid question: where is the in-tank fuel pump?  Do I remove the Al panel from the boot to expose the tank, and in a very obvious place will find a cover, from which presumably hangs the pump + sending unit / arm?

 

Yes it is under - layer 1 - boot carpet then layer 2 - ali panel.   The tank is then revealed.  If you are standing at the back of the car the pump is obviously on the left side. 

 

 

Disconnect battery and wiring before removal.  Take the usual precautions when dealing with gasoline.  Break the seal and pull up out of tank.  Not sure if your car has the same type of seal as in the photo - I looked for a later photo.  Earlier cars used a thin rubber seal with blue hylomar sealant.  

 

The pump looks like this.  My car being older has a slightly different style and float but the principle is the same.  

 

 

You bend the float arm down so that it sits lower as the gas is used up.  The problem with this that others above have not noted is you cannot see if your bend is appropriate as once it is back in the tank as its position is again invisible.  I got close with some measurement and calculation of 3D volume of remaining tank.  You could reconnect battery and before resealing fuel pump see where gauge levels out at but I have never been a fan of that method given the nature of Caterham wiring.

[Austin David]

I'll make a post when I get to it.  I like the "float on 2 gals" method because I don't need to look at the gauge so much, assuming the float-deflection roughly matches the gauge deflection.

 

Thanks for the info & confirmation, it will help me plan that fun event.  In the meantime, I'll keep an eye on the trip odo.

[Kitcat]

Slightly off topic, but my ‘97 Caterham had an 8 gallon tank. The fuel gauge was never accurate, so I just filled it up every 100 miles to be safe

(Fortunately, the odometer was accurate:)).

 

On long trips I took a 2 gallon container  of gas(my own crude reserve system ).

 

Edited May 18, 2022 by Kitcat

[sainthoo]

On 5/18/2022 at 5:15 AM, Austin David said:

The ODB reader will help.  My idle was low on first crank, and the tach was way wrong.  I read the manual and found a switch configuration that works, eventually I "should" get the ECU flashed correctly, apparently.  For now it's right.

 

https://usa7s.net/ips/topic/13594-360s-in-charlestonish/?do=findComment&comment=125828

 

With an independent signal from the ECU (not the tach) you can set your idle correctly, and deal with the tach later.  Like when everything else is correct.

 

The fuel gauge seems very pessimistic, and mileage (mine at least, during break in) is absurdly high.  Below 1/4 it will maybe take 5 gals, and I believe capacity is near 10?   In the garage (as you are) I basically kept the needle where I could see it at all.  The first 2g was enough, then added more as I went around dealing with various coolant issues.

Set my RPM gauge to 1-7 off, 8 on. Now working. Will verify accuracy above 1100 when I have engine running properly.

 

If you find yourself in central Virginia, steak dinner on me.

 

[sainthoo]

In case anyone needs - module for 420R:

[wemtd]

Re: fuel float. IIRC when adjusting my VDO gauge I used an ohm meter to

read output as I adjusted float position. 
I also drove (casually) one evening with a jerry can and clocked ~40mi on an ‘empty’ tank before engine completely ran out of gas. So I know I have a little reserve distance.

[Austin David]

my usual method (motorcycle) would be the jerry can approach, drive till it sputters, get to a gas station, and measure with fair precision the volume of fuel between "full" and "uhoh".  But I don't want to starve the EFI motor...

[sainthoo]

New fun: little bulb inside headlights (seem pointless?) would not work. On the left- connection for bulb was bent. In the right- ground was faulty.

left:

right:

[Austin David]

I got the LED headlamps and I LOVE them.  I assume that bulb is for a "parking light" function?

 

In terms of the ground, you're going through a few layers of powder coat at the shock tower and at the headlight base -- it doesn't conduct well until you at least snug up the mounts at both ends of the little support arm.

[sainthoo]

26 minutes ago, Austin David said:

I got the LED headlamps and I LOVE them.  I assume that bulb is for a "parking light" function?

 

In terms of the ground, you're going through a few layers of powder coat at the shock tower and at the headlight base -- it doesn't conduct well until you at least snug up the mounts at both ends of the little support arm.

Yep all settled- just aggravating that this is necessary. 

[Austin David]

Tell me you're still early in your build without telling me... :-P

 

Count yourself lucky if this is the weirdest of it.  The upside is, having built it you'll be best able to debug it later.

[sainthoo]

So, I can’t believe it, I’m basically done.

(I still need to sort out speed sensor. I need to get brake pedal a bit more firm)

 

Josh sent me back my ECU with the most up to date tune (with this tune, I had to adjust TPS from 1.23V -> 1.33V). It was like magic- car running perfectly in 2-3 min.

 

Not quite on terra firma:

 

First time on the ground:

 

a beauty:

[sainthoo]

 

 

[Vovchandr]

Congrats!

[sainthoo]

Any advice on speed sensor or getting brake pedal more firm- I’m all ears.

[sainthoo]

On 5/19/2022 at 9:53 AM, sainthoo said:

Set my RPM gauge to 1-7 off, 8 on. Now working. Will verify accuracy above 1100 when I have engine running properly.

 

If you find yourself in central Virginia, steak dinner on me.

 

Well, after ECU tune, RPM gauge was terrible. Reverted back to factory: 1,2 and 8 on- now works perfectly.

I didn’t like electronics before this project, and this has done nothing to improve my disposition toward them.