R300 build – ignition problems

[Declan Ward]

I was hoping to fire the engine up, for the first time, on my R300 this weekend. Having connected everything (as far as I know), nothing happens when I turn the ignition key, no power to the stack dash, no priming of the fuel pump...nothing.

 

What am I doing wrong? When I connect the battery, the Shurlok immobiliser arms itself (single beep and the red light on the dash is flashing). I also have power to the lights and horn. I then disarmed the immobiliser using the black key fob thing (single beep and the flashing light goes out) however when I turn the ignition key…. nothing… not a sausage. Needless to say pressing the starter button is also met with resounding silence.

 

Bearing in mind that I am working from a position of total ignorance, I have checked that all plugs and earths are connected (well the ones I know about), the battery is fully charged, the ECU fuse (30A) is ok, have swapped the relay for the stack dash, the wires to the ignition switch and starter button are connected, the wires in and out of the MFU are as per the wiring diagram, all to no avail.

 

Any help or suggestions on what to try next would be gratefully received.

 

For reference the car is a R300 with master cut-off, stack dash and a nice red starter button.

 

Dec

 

[F355GTS]

Declan

 

Needs to be a process of elimination

 

Do you have 3 large connectors going to the VE+ on the battery? 1 x red and 2 x brown

 

Have you connected the two looms togehter (one connector on a thickish purple wire joining to a smilar sized brown wire)

 

Can you wire out the master switch? ie join the two large connectors together to ensure it's not faulty

 

try those then post again

 

Mark

[Declan Ward]

Mark, thanks for the input.

 

My wiring is as follows

 

Battery +ve

- Heavy red from master switch

- Large brown (black sheath) with ring connector

 

Battery –ve

- Black earth to engine block

- Five black wires on single ring connector

 

Starter solenoid stud

- heavy red from master switch

- two browns on ring connector

 

Starter solenoid spade

- brown with red trace female spade

 

Ecu power

- purple to brown

 

I notice you suggest that both browns should be connected to the battery +ve, so have changed the mine to reflect this. Unfortunately still the same problem.

 

If I remove the master switch it cuts power to the immobiliser (the red light stops flashing), lights etc. Turning the key returns power to the immobiliser, lights etc. I assume this suggests that it is working correctly?

 

Is it possible to eliminate the ignition switch from the equation? It is connected to two wires on spade connections, a brown and a white/green. Is there anything else I can check, obvious or otherwise?

 

Thanks again

 

Dec

 

 

 

[F355GTS]

Declan

 

time for a meter to see where the power's not getting to!

 

If you have lights etc then power is getting to that part of the loom, it suggests the problem is that power is not getting through the main loom to engine loom which i think is the Purple to Brown, is there 12v on the Purple wire? although why that should affect the Stack I'm not sure. Oddly mine has 12v here permanently irrespective of master switch or ignition!

 

Is there only two wires on the Ignition switch? sorry my car hasn't got one so can't check, if it is two then one assumes you can join them together which will disable the ignition switch, or having turned on the Master Switch and disarmed the Immobiliser check if there's power getting to the Ignition Switch, if it does to one of the connectors then turn the Ignition on, it should put 12v to the other connector. If that works then check you have 12v at the starter switch.

 

One other thing is have you checked the fuel cut off switch, not sure how far this stops things working other than the fuel pump

 

It's a bit difficult working blind and i'm not sure we're following the most effective route! if all else fails I'm around on Monday and could drop over (only 15 mins away) can't play tomorrow as I'm going to Donington for the Ferrari Festival.

 

Mark

[TorAtle]

Not much help here but let me say I've been through many electrical problems and know how frustrating this can be. Keep the faith

 

As Mark says, get that multimeter out. It is a big advantage to have the scuttle off so you have easy access to all the wires and can follow them. Check for 12V input on the ignition, then turn the key and check the 2nd output. I'm not sure, but I think the output is wired via the starter button (and possibly the fuse box) to the relay box.

 

Good luck!

[Declan Ward]

Mark,

 

I have power to the engine loom (12v on the purple wire at all times). I also have 12v into the ignition switch and 12v out when the key is in position 2, so that looks ok (I think ).

 

Thanks for your kind offer on help on Monday, unfortunately I am going to Thruxton for the Touring cars. I’ll give Caterham a call on Tuesday and see if they can add any more. In the meantime, thanks again for you help, and if you do think of anything, do let me know.

 

TorAtle,

 

Thanks for the words of encouragement. I am a novice to all this but learning (slowly) as I go. It’s always great to know that if you do get stuck there are plenty of people on Blatchat willing to offer advice and help…fantastic.

 

Declan

 

[Gridgway]

my R500 didn't start initially and it turned out to be one relay short of a race! The vital relay was missing and I swapped one of the others and it fired up. Sounds like you have checked the presence of all the relays, but if not, it might be it.

 

Graham

[Mr Locust]

Does the car have the shock senstive trip switch as per std cars. Rubber covered reset button high on the scuttle.

 

This would stop the fuel priming also.

[Declan Ward]

Gridgway,

 

I have all relays in place (4 small ones and one larger one) and have swapped the positions of the smaller relays, with no success. I do have a couple of questions relating to the larger relay.

 

The relay mounting has four wires attached, green/white, black, larger diameter brown and a larger diameter white however the relay itself only has three spade connectors. The relay does not seem to have a connection for the brown wire (the only wire with power). Is this normal?

 

When I turn the ignition switch to position two the green/white wire receives power (12v) however the white and black wires remain at 0v. Should I expect to see power on the white and black wires... or is this just the ramblings of an idiot.

 

Mr Locust

 

I initially had the inertia switch disconnected as I was only planning to crank for oil pressure however I have reconnected it and pressed the button to make sure it was not contributing to the problem. Out of interest, do you happen to know, in addition to the fuel pump, what else does this switch cut power to?

 

Thanks

 

Declan

 

[Chris W]

I don't have a stack system myself, but on the Caterham stack wiring diagram, the inertia switch ONLY controls power to the fuel pump.

 

Also the cct diagram only shows 3 relays and the flasher as per non-stack cars. The 3 relays being horn, headlights and indicators. Since relays have 2 contacts for their coil and at least 2 for the contacts, the three terminal jobbie has to be the flasher unit. The terminals will be marked on the case as 49 (+12v), 30 (earth) and 49a (flash out terminal which connects to the indicator switch middle terminal).

 

I can't see a fourth relay on the Caterham diagram.

 

BTW, you would normally exect to see power on any white wires. They are meant to be ignition switched +12v wires which are not fused.

 

Chris

 

1.8K SV 140hp see it here

 

 

Edited by - Chris W on 25 May 2003 15:01:25

[Declan Ward]

Success!!

 

The three pin plug is the flasher unit and not a relay as I thought (thanks Chris) and careful examination of the fuse box showed that Caterham had fitted the flasher unit in the wrong place (there is an forth relay, I assume for the stack dash). A quick change, battery connected and we have power and an engine that turns over.

 

Thanks for all that contributed I couldn't have done it without you

 

Declan

 

[F355GTS]

 

Mark