Wiring help

[jlumba81]

2004 caterham 7 with svt engine. Ok got the 7 back together but no power to anything. Got the battery cable connected to the starter. Is there anything else supposed to be connected to the starter? I just have the battery cable and the solenoid wire. Where does the ecu and ignition hook up to power? Got a good ground and voltmeter confirms that. Been staring at wiring diagrams for other engine models, but it isn't helping so far.

[s2k7]

This is not SVT engine but almost all starter has the same wiring: http://i60.tinypic.com/2eckdwl.jpg

[jlumba81]

Battery 12v cable and solenoid wire is hooked up. I don't have a seperate solenoid like in the picture. I'm just stumped as to why I don't have any power to the ignition or lights or anything.

[scannon]

My 2004 Caterham (Miata engine) has the main power to the rest of the car coming off the same terminal on the solenoid as the cable from the battery. Its not battery cable size but IIRC a 10 gauge wire.

[jlumba81]

That's what I was thinking but the only extra wire I have with a ring terminal on it is pretty thin around 16 gauge. That wire triggers one of the relays when I put it directly to battery +, but still no lights or power to anything. I think I'll unhook every wire and look again.

[jlumba81]

Well figured out what an extra cable that I thought was an extra grounding cable. It goes from alternator to the starter. Still no power to the fuses, ignition, lights, ecu. Got 2 extra connectors (that don't match each other or anything else), 1 is taped up and the other is one the same wire as the o2 sensor but has no loose wires near it. Still stumped as to where the main power comes from.

Edited July 5, 2014 by jlumba81

[xcarguy]

jlumba81,

 

Just a thought; do you have a main (50 amp) fuse? If so, is it blown?

[jlumba81]

Fuses at the fuse box were 20 amp or lower. All were good.

[xcarguy]

Fuses at the fuse box were 20 amp or lower. All were good.

 

Look for a 50 amp fuse; external of the fuse panel. :smash:

[jlumba81]

Looked and didn't see anymore fuses outside the fusebox other than fuses for 12v outlets. All the caterham wiring diagrams for, k-series, sigma, duratec, crossflow engines don't include a 50amp fuse. Unfortunately there's no diagrams for zetec powered caterhams.

[jlumba81]

Seriously wish caterham used the same standard as the US does for wiring diagrams. Or even what Subaru uses. My subaru electrical manual has the routing for every wire in my car.

 

Biggest issue is that I took apart the 7 back in Feb of 2013 (5 month delay on transmission parts and lost motivation), and unfortuantely didn't take pics on disassembly.

[xcarguy]

Time for a volt meter. Gotta find that power interruption.

[s2k7]

So, when you turn the ignition switch to 2nd position, not a single accessories (light or any 12V attached to the system) is on?

Totally no juice ?

 

The 2nd position switch (ignition key) should be connected to the main in order to power up all your accessories, the ignition system, the cluster gauge and all.

If you can poke under the steering and test the juice of the wire at the 2nd position switch, you can follow that wire all the way to the engine bay

and troubleshoot from there. Usually the Brits uses big 12ga brown wire for +12V....U.S. usually use red wire.

 

The 3rd position is for cranking the engine, No need to test the cranking wire if you don't get any juice at the 2nd ignition switch position.

Edited July 5, 2014 by s2k7

[Off Road SHO]

Work backwards from your fuse block. Look for the big wire that feeds it and trace it back to where it is probably dangling. If no big wire, find the post on the fuse block where it should be and run one.

 

Can you post a pic of the fuse block?

 

Tom

[catracer]

As S2k7 says, Brown is "British" for unswitched power, meaning hot +12V all the time. There should be a large diameter 10 or 12 ga solid brown wire with a 5/16" ring terminal coming off the chassis harness in the engine bay at about the same location as the connector for the engine harness. That wire powers up some of the unswitched chassis circuits (horns, lights) and then, through the ignition switch, powers the switched circuits. It should be connected to the large terminal on the starter solenoid (the one opposite the terminal that is connected directly to the starter). That same solenoid terminal should have 2 additional connections, one to the alternator, the other through the battery cable to +12V on the battery.

 

From there it follows the chassis harness, penetrates through forward section of the the transmission tunnel, then is ganged with several other solid brown wires on the right hand side, under the scuttle, just behind the hazard switch. One of those brown wires, in turn, goes to the ignition switch and provides the +12V to energize the rest of the *switched* circuits.

 

We have had some issues with the connectors at the rear of the ignition switch also. There are a lot of them in a small space. If you can locate and hook up the brown wire in the engine bay, and still have in issue, check the ignition switch connectors.

 

Hope that helps.

[jlumba81]

Thank, catracer. That's the info I'm looking for. Haven't seen that wire yet tho. Having about 50 wires wrapped up in several looms occupying the same space makes it a headache to trace. Coming out of the trans tunnel in a 4" gap from the bellhousing underneth the airfilter. I think the SV has the transmission farther into the trans tunnel than the S3.

[jlumba81]

Thanks for all the help. Got a family reunion to go to first then I'll need to limber up before diving underneth the dash.

[jlumba81]

Thanks for everyone's help. I found the correct wire, it had black sheath over it and looked like a ground wire. The wire split off from the main loom right at a 1" gap underneath the intake manifold so it was a pain to spot.

 

Other note that new first gear in my transmission seems to work ok when in the air. Reverse is noisy and 5th gear pops out. I'm hoping reverse will smooth out and that 5th gear issue is because it was in the air. Still need to weld up the crack in the exhaust and figure out why my wipers and windshield washers isn't working.

[jlumba81]

Well she runs and the first gear is fantastic. No more big rpm jump between first and second. Wiper and squirter started working by themselves, guess that's to be expected w lucas parts. Still have trouble finding 3rd and 4th gear, but its liveable. No 5th gear so will probably live with 4 gears until winter downtime and teardown. Should've used new sychros and blockers for the 5th gear.

 

PS: I got the longer 1st gear from SP Components Ltd. They are quick to reply, but if its not in stock it may take a few months.