Failing Relay?

[islandcat]

Has anyone else had a similiar problem to this? ....
I have recently replaced the fuel pump and starter motor on my 1987 Austin Maestro. The fuel pump is brand new and
the starter motor was from a H reg Maestro in the scrappers. A couple of days after fitting these, my car became very
unhappy with cold running. It will start perfectly and idle reasonably well. If I try to get it to pull, however, my
rev counter goes bananas, flicking between 0 and 2000rpm very erratically. Also I can hear one of the relays under
the dash clicking like fury. If I drop the clutch and let it idle, it sits there quite happily. If I wait until the
engine warms just enough to start registering on the temperature gauge, I hear a little click and the car becomes its
normal well mannered self. It pulls aways and drives as it should.
I am rather confused about why the engine temperature appears to be a factor in this. Any suggestions for tests
gratefully received! I've swapped the engine management unit for a spare and exactly the same happens. I haven't
swapped out the fuel ECU as I've had the engine converted to manual choke so didn't think that unit would cause this
problem. Thank you in advance :)

[MaestroMatt]

Do you have the S Series engine? If so, it could well be the fuel cut-off solenoid. Disconnect it and forget about it - you don't need it anyway!

[islandcat]

I do have an S series but if that solenoid you're referring to is part of the automatic choke assembly, thats all been removed. If its located elsewhere, I'd be happy for directions :)

[MaestroMatt]

I don't think it is anything to do with the auto-choke as my R series has an auto-choke but no fuel cut-off solenoid. My friend had a similar problem ages ago and that was the cause of it. There was a discussion a short while ago about this so try searching this forum for mention of it. There is definitely a long thread on the old forums about it, started by SIR, The MVDP Fan, so have a search there as well.

[islandcat]

Originally posted by MaestroMatt
I don't think it is anything to do with the auto-choke as my R series has an auto-choke but no fuel cut-off solenoid. My friend had a similar problem ages ago and that was the cause of it. There was a discussion a short while ago about this so try searching this forum for mention of it. There is definitely a long thread on the old forums about it, started by SIR, The MVDP Fan, so have a search there as well.
Thanks for your help, I will continue my search there

[Wonko_The_Sane]

"however, my
rev counter goes bananas, flicking between 0 and 2000rpm very erratically. Also I can hear one of the relays under
the dash clicking like fury"

A relay under the dash...rules out the fuel solenoid anyway IIRC. It doesn't have a relay..:)

I had this in the distant past with mine..and it was truly weird...again, when left it was good, as soon as drive was selected and wellie applied...hah. Going somewhere? I doubt it..

I fixed it..umm..does the engine rev with the rev counter, or is it the counter flicking on it's own?

I'm trying desperately to recall..but heres a suggestion..look at the front bulkhead, under the carb...you should see a BIG red wire...the manifold heater. Try disconnecting it..I'm sure thats what i did...the relay clicks still..but the heater can't do squat.

Doesn't seem to affect the car in the cold..:) That heater draws a HUGE current.."If I wait until the
engine warms just enough to start registering on the temperature gauge, I hear a little click and the car becomes its
normal well mannered self."

That little click is the heater cutting out..it's the same click I hear...and it happens at a preset engine temp. The fact it behaves after cutout but not before...I say disconnect the heater and see, my friend..:)

[e692wtt]

I'd put money on a fault with the Inlet Manifold Heater or its wiring, as referred to above. It consumes 16 Amps, which is enough on my Monty to cause the engine to stall while the IMH is still on but not immediately after it has gone off (after the 'click' from below the dashboard, at a coolant temp of 30 deg C).

Try taking the fuse for the IMH out of the fusebox, or removing the relay for the IMH, or disconnecting the feed to the IMH, and see if this corrects the faulty running. References to 'a big red wire' being the IMH feed wire, to the side of the carb, are correct - you can't miss it..

The other other Rich.:)

[islandcat]

Thanks guys, you've all been an excellent help. I've taken your advice with the manifold heater and with it
disconnected its far better behaved. I now need to trace whether its the relay or the heater itself. You've got
me looking in the right place and thats excellent, thank you. I will appreciate the smoother journey and my employer
will appreciate me being on time again :)

I'm off to have a good old tinker now :) Thank you