Electro magnetic choke

[ian65]

the choke on my silver car doesn't work on the magnet and hasn't done so for years according to the previous owner. The choke works the linkage to the carb but the magnet is inoperable. I've changed the entire unit for another one and still it doesn't work.
I know on 1st gens there are 2 water sensors... the first being the temperature sender located behind the oil pressure switch... this sends the signal to the temperature gauge... the 2nd is a temperature switch loacted near the thermostat housing which controls the choke. I've tried unplugging this sensor in case it was faulty and I've also tried bridging the wires in the loom plug to this sensor but still the choke doesn't hold on the magnet.
Anyone got any thoughts on what's causing the fault?.... I'm completely mystified by it.

[Steve-A]

Hmmm sounds like youve tried most things!

I can't remember off the top of my head (no wiring diagram to hand) is the choke magnet powered directly or via the emissions ecu? I have a feeling it is. Worth checking it's getting it's power etc?

[ian65]

Hmmm sounds like youve tried most things!

I can't remember off the top of my head (no wiring diagram to hand) is the choke magnet powered directly or via the emissions ecu? I have a feeling it is. Worth checking it's getting it's power etc?

thanks Steve, that's a good call. You're right, I've just checked the wiring diagram and it shows a wire coming from the ECU, to the water temperature switch and then on to the choke magnet.
I'll have another look at it on the car later.

[Steve-A]

If you need a known good emissions ecu mine shOuld be going spare in the next few weeks.

[KiwiDave]

Ian

Did you ever solve this? I have the same issue. Now obviously we get around it by using something to hold the choke out (a 5p coin in my case) but I hate it when things don't work properly.

[ian65]

I dunno yet Dave,
I've changed the choke unit (twice) and it still didn't work and I've now changed the ECU under the carpet in the front n/s footwell and I'm hoping this will do the trick. I haven't tried it yet though as I've got loads of electrical stuff disconnected due to the rebuild so I don't want to put a battery on it and power things up until I've put everything back together and checked the wiring.
If it still doesn't work, then it must be a problem with the wiring somewhere.....

[mpk490p]

Never known one that works!

Rip it out and put a 48IDA in there

[KiwiDave]

I did mention it to Tim @ RX Motors a while back. He suggested a relay in the engine bay - next to the hot start assist device. It's actually labelled Check Relay.

And no, I haven't changed that yet as I haven't found one. Will look for this ECU thing then as well.

I'm guessing a little cheaper than an IDA

[codge]

It's actual name is 'Choke and Check' Relay so maybe something in what Tim says.
It's the metal dome can relay with 6(?) connections at the bottom. Next the Hot Start motor.

It's main function is to oversee the dash warning lights at start up.

[KiwiDave]

I dunno yet Dave,
I've changed the choke unit (twice) and it still didn't work and I've now changed the ECU under the carpet in the front n/s footwell and I'm hoping this will do the trick. I haven't tried it yet though as I've got loads of electrical stuff disconnected due to the rebuild so I don't want to put a battery on it and power things up until I've put everything back together and checked the wiring.
If it still doesn't work, then it must be a problem with the wiring somewhere.....

Did you ever get yours going Ian? I've swapped my choke unit out for another and I've swapped out the 'Choke and Check relay. No change Exactly where is the ECU located in the passenger footwell? I need to check the fuse in that.