Caterham Inertia Switch

[MichaelD]

Has anyone experienced a intermittent loss of all power while driving that may seem like a fuel loss issue only to have the motor kick in again? This loss of power may coincide with hitting expansion joints in the highway or bumps while rounding a turn.

 

All ground wires are secure. Fuses are secure. Fuel pressure is a constant 61psi.

 

The end of this video is exactly what happens except that the car will start immediately. I may drive for 30 minutes before it occurs.

 

 

I think it could be the inertia switch. Anyone know how to test the switch?

 

Thanks for your thoughts,

 

Michael D.

Edited September 6, 2011 by MichaelD
typo

[yellowss7]

Michael, I assume you know that you just press it on the top to reset it, right? Sorry, I didn't see that you said it will restart immediately without you resetting it.

 

Can you just disconnct it or bypass it to see if it's the culprit?

Edited September 6, 2011 by yellowss7

[Fimi 7]

It would have to be a faulty switch, since most of them you have to reset to get it going again. How is it mounted, do you lose all power? If the switch flips and is wired correctly should just kill all power.

[MichaelD]

I am trying to figure out the cause for intermittent power loss. Fuel pressure remains steady at 62 psi. Ground wires all seem tight.

 

Power loss is complete and may occur upon acceleration or it may cut out after crusing for 30 minutes without any problem. I can pull over and restart it. However it cuts out almost immediately. If I let it cool down for 20 minutes, it may drive for 10 to 15 minutes. I replaced the crank sensor this morning. It drove about 5 minutes before it died the first time. BTW I do not have to reset the switch to restart the motor. In fact, sometimes I simply depress the clutch as soon as I see the gauges flatline and the let the clutch out to restart the car.

 

The switch is mounted to the bulkhead just behind the battery. I always thought the switch was either off or on but never internittent. I have pushed down on the top of the switch. It does not seem to have any movement. Could the inertia switch have a short in it?

[MHKflyer52]

Hi Michael D,

 

I have been following your thread and you might want to remove the inertia switch from the equation by just making a jumper wire that will plug into the wires from the switch and then drive the car and see if it is the cause.

 

The initeria switch is usually a switch that that will only open if the vehicle exceeds something like 5G (very sudden impact) or turns over and then it kills the power to the ECU which shuts down the system.

 

I don't know what type of setup you have with your electrical system but I would start looking at any components that have been modified to be used in your car such as the wire harness as if it has been shortened you could have an intermittent connection that once the vehicle heats up could cause it to create an open or that the normal vibration or motion of the engine of the vehicle could also cause the problem but I do not think this is your problem from what I have read in your post.

 

I would look at the ignition system for the problem and could be as simple as a bad ballast resister or even a bad coil or coil pack. If you have someone close to where your located that has the same setup you could swap parts and see if it solves the problem.

 

Hope these thoughts help and I will continue to follow this thread to see what you find is the problem and so that I learn from your trouble shooting of the problem.

 

Do you have an electrical tach if so you could have a bad one as I do know of one situation where the tach would kill the iginition as an adjustable rev limiter but that was on a training vehicle that limited the number of RPMs that one could use while learning to drive a race car and kept students out of trouble

Edited September 6, 2011 by MHKflyer52
New thought in blue text

[bsimon]

Michael,

 

How are you monitoring fuel pressure?

 

I fought a similar battle for two years. As it were, the fuel pump was intermittently shooting craps. I would always see good fuel pressure on the under bonnet gauge. It wasn't until I had buttoned up the engine bay that the fuel pressure would drop out.

 

With the assistance of several mates on the Yellowstone tour, we finally caught the pressure dropping with the bonnet off. A replacement pump fixed the issue once and for all.

 

If I'd had a cockpit FP gauge, I'd have caught the problem long ago. I would have saved considerable gedas on unneeded replacement sensors as well.

 

I now have a temporary cockpit FP gauge and have discovered that my replacement pump is marginal at full chat...but that's a whole 'nother problem

[MichaelD]

Thanks for the good tips. I am off on business for the next three weeks. Hope to look try some of your suggestions when I return.