ndndndnd

Hello,

I have an 85 IROC L69, with a qjet from which the choke had been removed. I've just replaced the existing carb with a reman qjet (complete with choke) but the connector for the choke is missing from the wiring loom. There is a blue wire in about the right place but can anyone tell me the best way to check if this is the right wire, or how to identify the correct wire, using a basic multimeter? The car isn't really running at the moment (still awaiting a new coil), and I think I read the choke wire should only have voltage when the engine is running?

Any advice or help welcome,

Neil

Damon

That's basically right, if memory serves. It's powered off the ignition switch and should be hot in the Run position of the key. BUT I think it's qualified through the oil pressure switch and/or the choke relay which means it won't be powered unless the engine is actually running.

ndndndnd

So if I check the wire's dead with the car switched off and with the key in position 2, then check if there's 12v between the wire and ground with the engine running I should be good to get out the soldering iron? Is there any way to check without firing up the engine - I just need to wait for more parts to arrive if there isn't...

Damon

Probably best to get a wiring diagram if you want to be absolutely certain and/or want to bench test it with the motor off. I recall there was somebody who was offering up wiring diagrams for... basically everything. Over in the General Tech section of the board there was a thread titled something like "Wiring diagrams- I got them all".

nhgator

It should be powered with the key on,motor not running,I arced mine off a header accidentally during my motor swap and popped the fuse.

naf

iTrader: (7)

Choke wire will not have 12v without the engine running. It was designed this way so that the choke would not begin opening with the engine off/key on.

sofakingdom

iTrader: (1)

Choke wire is blue... kinda a light blue. Connector originally was grey.

It is powered by the choke relay, which only supplies power when the alt is charging. Obviously the engine has to be running for this to be true. Only hack I know of would be to disconnect the alt and short from batt to the brown wire to simulate charging. Whatever wire you want to test, should have no 12V until said short is applied.

Unfortunately, when the alt quits working, a light labelled "Choke" comes on; too bad it isn't labelled "Alt" like it should be.

ndndndnd

Thanks for the reply! Good advice there.

Is it possible to simply check continuity from the choke relay to the possible wire? My car's an 85 L69 - does anyone know if the choke relay is located in the cabin or under the bonnet?

My Haynes manual only shows wiring diagrams for the TPi engines... and my Chilton manual doesn't seem to have any at all!

Thanks for the help!

sofakingdom

iTrader: (1)

It's in the "convenience center"; a sort of tray arrangement under the dash, with the diagnostic connector on the end of it.

ndndndnd

Ah, no real chance of shorting it directly with the multimeter, then. I had heard the relay is sometimes located under the bonnet? I'm not sure how I'd recognise it though - some of the wiring has been butchered by the previous owner...

sofakingdom

iTrader: (1)

Sorry that has happened to you; there's LOTS of just blatantly WRONG ideas floating around out there about stuff. It's a shame people tell each other things that simply aren't true.

It's where I told you it is. Go find the diagnostic connector, access the assembly it's mounted on, observe the relay, you'll have no trouble recognizing it.

ndndndnd

Thanks sofa, I should get a chance to look at the car tomorrow. Should be fairly straightforward to connect to the choke wiring now.

Funny thing about the misinformation - I've got a lot of conflicting advice on my car from people. Keeping the CCC qjet has raised a few eyebrows - I've been told severally to ditch it and buy an Edelbrock. I mentioned reattaching the charcoal canister to a nearby corvette specialist (I'm in the UK) and he thought I was nuts, saying I should just cap the vent to the tank and let the float bowl evaporate to atmosphere. Having read about how the canister works, that just sounds like a waste of fuel. As for the Edelbrock, it seems a pity I need to chose between performance and economy, when a qjet (properly tuned, natch...) should give me both. As for the choke, the response was 'what do you need a choke for...?' Baffling...

sofakingdom

iTrader: (1)

What a shame...

The Q-Jet is an excellent carb, when properly maintained and all that sort of thing. FAR better than the Edelbrock. And, the emissions stuff like the cat, canister, EFE valve, and AIR, cause almost ZERO performance reduction, yet people CANNOT WAIT to hack them all off and in the process cause even more problems. The only emissions system on the kind of car you have that you can detect a performance gain from disabling, is the EGR; and that, only at cruise, and it's TINY. Not worth the trouble of actually doing it.

Over here, those of use without dinosaur brain learned long ago to nod politely to people who tell us to do things like ... hack on that stuff, thank them kindly for their concern and willingness to offer their thoughts, and then IGNORE every word they say.

ndndndnd

Thanks for the advice, but when I opened up the loom under the bonnet it all got more confusing, finding three different light blue wires. I tore into the under dash to get at the convenience centre (seriously, why the hell is that thing called convenient??!), but stopped when I realised I didn't really know how I'd identify the wire in the engine bay when I got there. Plus the sight of the previous owner's horrific bodge using domestic three-core flex kinda took the wind outta my sails... I think I need to get the wiring on this car professionally sorted.

I'm very acutely aware that most of the work I'm doing to get this car back on the road is trying to put right previous owners' stupidity!

sofakingdom

iTrader: (1)

Look at the loom on the pass side of the carb (the US pass side) that runs along the inside of the valve cover; the one that's part of the car as opposed to part of the engine's computer control, i.e. NOT the one that comes from over the pass side strut tower. Should only be red & brown wires going to the alt, the choke wire, and maybe the fan switch wire, in there.

Yeah the "convenience center" name is a bit misleading; I suspect it was convenient for the FACTORY, whether or not for anyone else.

ndndndnd

Thanks Sofa!

I've just got myself a better multimeter (that can measure dwell too!) so I'll take a closer look at the weekend and probably solder to the most obvious wire with my fingers crossed...

If the shoes fits...

ndndndnd

Thanks for the advice!
I got back to the car today to have another go at identifying the right wire and found my prime suspect was actually in the part of the loom coming from the strut tower. I then investigated the smaller loom running along the engine and back towards the firewall and found a light blue wire looped away down the back of the engine. I pulled the wire out from the depths and, hey presto! a broken choke connector emerged!

New connector is now soldered on and awaiting next weekend's test-firing.

Thanks for your help sofa, you got me out of a hole there!

sofakingdom

iTrader: (1)