Air purge pump and another connection
Moderator: Board Moderators
- DWH
- Senior Poster
- Posts: 248
- Joined: Sun May 06, 2012 11:27
- Model: Excel SE
- Colour: Monaco white
- Year: 1987
- Location: Bury St Edmunds
- Contact:
Air purge pump and another connection
Hello. Some help please.
Having had the sports exhaust and some other work carried out at Lotus Bits last week, the car is running very well and the 120 miles journey back was totally uneventful and smooth, except for the potholes in the roads.......
I did however notice after stopping for some food that the air purge pump was not operating. Having opened the bonnet when I got home, I found that all the pipe work to the pump was missing and after removing both the fuses in the relay housing that is cable tied to the purge pump, found that one had blown.
The fuses were both originally 2amp but the closest I have spare is a 3amp fuse. I have yet to run the car up to temperature to see if this has solved the non-working pump but what do these fuses and the relay control ? And where should the missing tubing connect to on the air-box ? and does the pump suck air out of the air box or blow fresh air into it ?
Also, I found that the lower spade terminal on the "thing-a-me-jig" at the front of the engine was not connected.......what is the "thing-a-me-jig" and should both wires be connected ? Photo shown below
I emailed Lotus Bits last week but haven't had a reply.
Thanks
Having had the sports exhaust and some other work carried out at Lotus Bits last week, the car is running very well and the 120 miles journey back was totally uneventful and smooth, except for the potholes in the roads.......
I did however notice after stopping for some food that the air purge pump was not operating. Having opened the bonnet when I got home, I found that all the pipe work to the pump was missing and after removing both the fuses in the relay housing that is cable tied to the purge pump, found that one had blown.
The fuses were both originally 2amp but the closest I have spare is a 3amp fuse. I have yet to run the car up to temperature to see if this has solved the non-working pump but what do these fuses and the relay control ? And where should the missing tubing connect to on the air-box ? and does the pump suck air out of the air box or blow fresh air into it ?
Also, I found that the lower spade terminal on the "thing-a-me-jig" at the front of the engine was not connected.......what is the "thing-a-me-jig" and should both wires be connected ? Photo shown below
I emailed Lotus Bits last week but haven't had a reply.
Thanks
- amarshall
- Moderator
- Posts: 8296
- Joined: Tue Nov 01, 2005 18:09
- Model: SE
- Colour: Monaco White
- Year: 1990
- Location: Darlington
- Contact:
Re: Air purge pump and another connection
The relay switches power on when the ignition is off, and off when the ignition is on - the power goes through the thermal switch on the cylinder head so the pump should only run when the engine is hot and not running.
I can't remember if it sucks or blows (suck would make sense - weaken the mixture by removing it rather than adding more air to an already rich mixture), but the rear tube vents down through the bottom of the engine bay and the front one connects to a spigot on the underside of the airbox. Chances are that yours won't work as the motors burn out. There's a thread on how to replace it in Technical Articles.
The "thingamajig" is the throttle jack used to keep revs up when the aircon compressor is running. (may also prevent throttles closing too quickly in some circumstances). Yes, both connectors should be on it - but one may have been taken off because it isn't properly adjusted.
I can't remember if it sucks or blows (suck would make sense - weaken the mixture by removing it rather than adding more air to an already rich mixture), but the rear tube vents down through the bottom of the engine bay and the front one connects to a spigot on the underside of the airbox. Chances are that yours won't work as the motors burn out. There's a thread on how to replace it in Technical Articles.
The "thingamajig" is the throttle jack used to keep revs up when the aircon compressor is running. (may also prevent throttles closing too quickly in some circumstances). Yes, both connectors should be on it - but one may have been taken off because it isn't properly adjusted.
https://www.lotusexcel.co.uk/
SORN - just say NO!
SORN - just say NO!
- DWH
- Senior Poster
- Posts: 248
- Joined: Sun May 06, 2012 11:27
- Model: Excel SE
- Colour: Monaco white
- Year: 1987
- Location: Bury St Edmunds
- Contact:
Re: Air purge pump and another connection
Thanks Angus. The pump was working fine when I delivered the car to Lotus Bits. I'll try and take it out tomorrow for a run and get it up to temp to see if replacing the fuse has sorted the problem.
I'll put the lower spade terminal back on and see what happens......the car hasn't got air-con and don't think it ever did so it seems odd to have a "throttle jack" fitted or was it fitted to all cars ?
Thanks
I'll put the lower spade terminal back on and see what happens......the car hasn't got air-con and don't think it ever did so it seems odd to have a "throttle jack" fitted or was it fitted to all cars ?
Thanks
- amarshall
- Moderator
- Posts: 8296
- Joined: Tue Nov 01, 2005 18:09
- Model: SE
- Colour: Monaco White
- Year: 1990
- Location: Darlington
- Contact:
Re: Air purge pump and another connection
A little voice is telling me that is has something to do with emissions control as well - hence my comment about stopping the throttles closing too quickly. It isn't present on all cars - just the HC with all the messy plumbing for emissions control systems.
Discussion from 2005 : http://www.lotusexcel.net/phpbb/viewtop ... w=previous
Discussion from 2005 : http://www.lotusexcel.net/phpbb/viewtop ... w=previous
https://www.lotusexcel.co.uk/
SORN - just say NO!
SORN - just say NO!
Re: Air purge pump and another connection
the purpose of the purge pump is to suck hot air out of the plenum chamber after switch off thereby enabling easier starting. personally i think it is a waste of electricity as i never found it made any difference. it would switch off after a few minutes and heat soak probably put the temperature up again. mine has been binned.
- Lotus-e-Clan
- Senior Poster
- Posts: 4454
- Joined: Thu Nov 30, 2006 13:25
- Model: Excel SE - EWP/Waterless!
- Colour: Not Blue or Green
- Year: 1989
- Location: Swaledale
Re: Air purge pump and another connection
I disagree.
The purge pump IS worthwile for hot starting - the issue is they run too long and eventually burn-out.
The purge pump IS worthwile for hot starting - the issue is they run too long and eventually burn-out.
Peter K
- DWH
- Senior Poster
- Posts: 248
- Joined: Sun May 06, 2012 11:27
- Model: Excel SE
- Colour: Monaco white
- Year: 1987
- Location: Bury St Edmunds
- Contact:
Re: Air purge pump and another connection
Could someone out there with easy access to their car please confirm which wires should be connected to the top and bottom terminals of the throttle jack please so I make sure it's round the right way.
Thanks
Thanks
- Doc Si
- Regular Poster
- Posts: 184
- Joined: Tue Nov 15, 2005 13:47
- Model: 86 SE
- Colour: RED
- Year: 1986
- Location: Lowestoft, Suffolk
Re: Air purge pump and another connection
Mine is connected the same as yours....the yellow wire to the top terminal.
- DWH
- Senior Poster
- Posts: 248
- Joined: Sun May 06, 2012 11:27
- Model: Excel SE
- Colour: Monaco white
- Year: 1987
- Location: Bury St Edmunds
- Contact:
Re: Air purge pump and another connection
Thank you.
I'll reconnect and see if there's any difference. As I said at the beginning, the car has never run so well as it is at present, so thanks to Lotus Bits for that. The flat spot that was evident at around 2,400 rpm has gone and the car picks up cleanly and smoothly.
Looking forward to getting some proper use from the car this year.
Here's hoping for lots of decent weather this weather......unlike today sadly..
Thanks
I'll reconnect and see if there's any difference. As I said at the beginning, the car has never run so well as it is at present, so thanks to Lotus Bits for that. The flat spot that was evident at around 2,400 rpm has gone and the car picks up cleanly and smoothly.
Looking forward to getting some proper use from the car this year.
Here's hoping for lots of decent weather this weather......unlike today sadly..
Thanks
-
- Senior Poster
- Posts: 832
- Joined: Sun Nov 13, 2005 19:27
- Model: Excel SE
- Colour: BRG
- Year: 1992
- Location: Hampshire/Surrey/Berkshire
Re: Air purge pump and another connection
I think the purge pump only helps on a hot day - when a build up of petrol vapour in the airbox causes an over rich air-fuel ratio upon re-starting?
Therefore you should see no difference at this time of the year (February).
On a hot summer day it should make re-starting easier as you are pulling in fresh air to the carbs, so getting the correct air-fuel ratio.
I agree: ( 'it sucks') it removes the air-fuel vapour from the airbox, pulling in fresh air.
Therefore you should see no difference at this time of the year (February).
On a hot summer day it should make re-starting easier as you are pulling in fresh air to the carbs, so getting the correct air-fuel ratio.
I agree: ( 'it sucks') it removes the air-fuel vapour from the airbox, pulling in fresh air.
- amarshall
- Moderator
- Posts: 8296
- Joined: Tue Nov 01, 2005 18:09
- Model: SE
- Colour: Monaco White
- Year: 1990
- Location: Darlington
- Contact:
Re: Air purge pump and another connection
Checked mine - yellow wire at the top.
I've definitely found that the purge pump helps, in all weathers - mostly when filling up on the way to somewhere else. As long as it gets to run for 5 minutes or more it eliminates the embarrassing churning and WOT manouevres that used to be required to start it.
(but then, I'm also one of those freaks who starts it from cold with the choke rather than pumping the throttle pedal)
I've definitely found that the purge pump helps, in all weathers - mostly when filling up on the way to somewhere else. As long as it gets to run for 5 minutes or more it eliminates the embarrassing churning and WOT manouevres that used to be required to start it.
(but then, I'm also one of those freaks who starts it from cold with the choke rather than pumping the throttle pedal)
https://www.lotusexcel.co.uk/
SORN - just say NO!
SORN - just say NO!
- Lotus-e-Clan
- Senior Poster
- Posts: 4454
- Joined: Thu Nov 30, 2006 13:25
- Model: Excel SE - EWP/Waterless!
- Colour: Not Blue or Green
- Year: 1989
- Location: Swaledale
Re: Air purge pump and another connection
I'm the same sort of freak Angus ...I just need to get out more, then I'd be exactly like you..except I have no hair, and I'm smaller.
Peter K
- amarshall
- Moderator
- Posts: 8296
- Joined: Tue Nov 01, 2005 18:09
- Model: SE
- Colour: Monaco White
- Year: 1990
- Location: Darlington
- Contact:
Re: Air purge pump and another connection
I'm getting there - on both countsLotus-e-Clan wrote:I'm the same sort of freak Angus ...I just need to get out more, then I'd be exactly like you..except I have no hair, and I'm smaller.
https://www.lotusexcel.co.uk/
SORN - just say NO!
SORN - just say NO!
-
- Junior Poster
- Posts: 79
- Joined: Sat Jan 29, 2011 18:01
- Model: Excel SE
- Colour: Red
- Year: 1986
- Location: South Wales
Re: Air purge pump and another connection
We also start the car by pulling the choke out. We also depress the clutch. Was told many many years ago that it took a little pressure off the engine! Must be getting old
Kerry
Why make it simple when you can make it difficult!
Why make it simple when you can make it difficult!
-
- Regular Poster
- Posts: 191
- Joined: Fri Dec 14, 2007 12:02
- Model: Excel SE H.C
- Colour: Yellow
- Year: 1988
- Location: Norwich
Re: Air purge pump and another connection
my purge pump has always been disconnected and sometimes crank over a bit to start when hot but not such a problem that i really feel i need to do anything about it.
I have also left the throttle jack disconnected as i find it just hold too many revs on, between gear changes it will still be reving 2-3000rpm
Also dont like the way that it acts on the end of the throttle linkage,in my mind it feels like its twisting the throttle linkage unevenly and more likely to put the carbs out of balance.
Cheers Terry
I have also left the throttle jack disconnected as i find it just hold too many revs on, between gear changes it will still be reving 2-3000rpm
Also dont like the way that it acts on the end of the throttle linkage,in my mind it feels like its twisting the throttle linkage unevenly and more likely to put the carbs out of balance.
Cheers Terry