choke/over running

chris · 15th December 2003, 12:41

my r series 1.6hls manual has a carb/choke problem starts ok ,choke shuts off, then when i've been driving for 20 mins or so engine starts racing as if the choke is back on when i stop and turn off engine over runs is this a choke prob ? and can i disconnect the auto and replace with a manual? i use standard lrp thanks

E_T_V · 15th December 2003, 13:13

Might be a duff cooling sensor telling the brain that the engine is cold. They are relatively cheap so bung in a new one and see if that helps. What does the temperature gauge say when the engine races? If it says it is cold it is either a duff thermostat (and the engine is cold) or the temperature sensor is dud. Otherwise try re-seating all the connections to make sure there isn't a loose one somewhere giving an intermitant contact.

I'm not sure if this applies to the R series (as I've not taken one apart yet) but also check the O rings on the choke as a split one might have this effect also and they are well known for perishing.

Hope some of this helps

G Force · 15th December 2003, 13:24

Hello there. It is possible that the fault is in the coolant sensor/ecu wiring etc. as already suggested. But it may be that the carburetor settings are wrong ie idle speed too slow or the fast idle speed too high. Check that there are no air leaks in vacuum and breather hoses, manifold gasket etc. before making any adjustments.

Cheers Gary

MaestroMatt · 15th December 2003, 15:09

Just to agree with E_T_V's points... Do check the seals on the auto-choke - my R series idled like a new engine when I renewed them, and it is a five minute job. Search these forums for a post by Gareth (MGTurbo) in which he quotes the seal size which, apparently, is a standard one). The ambient air sensor is a tiny black square of plastic between two spade clips just behind the offside headlight in the engine bay. Easy to find and replace and I'll bet it's cheap so try that.

15th December 2003, 16:08

BSO 13 in Viton.

Gareth

chris · 16th December 2003, 09:02

thanks for the pointers check i'll them out today , if its the ambient air sensor , would that explain why i get a constant cold air from the side air vents but hot from the screen demister . all the sliders to change the air direction seem to work ang the temp guage works fine

16th December 2003, 09:56

Quote:

Originally posted by chris
thanks for the pointers check i'll them out today , if its the ambient air sensor , would that explain why i get a constant cold air from the side air vents but hot from the screen demister . all the sliders to change the air direction seem to work ang the temp guage works fine

No, the face level vents are fresh air only.

Gareth

E_T_V · 16th December 2003, 11:18

Yes another maestro "Characteristic"! Mind you I've never needed or liked hot air in my face anyway.

Let us know how you get on

Simon · 16th December 2003, 12:07

I suspect the stepping motor O ring seals are the cause of my car's refusal to idle/perform properly when cold. Easily replaced, granted but surely I can get away with standard rubber ones as my car's non turbo?

That might have also been the cause of the same problem I had on my previous 1.6 when it was relatively new (3 years old/
30000 miles)and I went through virtually everything to cure the cold start/choke/idling problems. The only thing I didn't change was the O ring seals (wrote the car off before I had chance!). Changing the ambient air temp sensor did precisely nothing.

E_T_V · 16th December 2003, 12:32

No, I'd recommend against the rubber seals as they degrade quickly in service.

Normal rubber is cr*p at resisting petrol so no using any plumbing O rings you've got lyinh round either. They swell and stick (or break) quite quickly. There are lots of different rubbers that might work but viton is probably the most widely used and easy to get hold of. So as GK said go for the viton ones, they'll still be a lot cheaper than if you go to your Rover dealer and ask for some original ones.

As an aside I believe that LRP has a lot to do with the problem, as new petrol is very different to the old stuff. LRP is stuffed with potassium (I think) and benzene and lots of other weird and wonderful additions too. The same goes for unleaded (apart from the potassium). I think the old rings were resistant to normal fuel but not to the super fuels we are now using.

Landcrab1800 · 16th December 2003, 12:47

Hi,

Did you know that LRP does not have a British Standard and has been linked to damaging engine. Even Watchdog did an article on it.

I NEVER use the c

p. When flush I use full fat petrol, but normally I use Optimax with an additive (depends on the car I am using).
I can recommend Optimax as I can fel a difference in performance.

Cheers

Gordon

e692wtt · 16th December 2003, 13:01

He's right about the lack of a British Standard for LRP... I've started using BP Ultimate with Millers, and my Monty runs even better on this brew than on Optimax with Millers... as witnessed by several club members on the way back from the xmas meet at Oxford!

If I used LRP there's no way at all I would drive other than very gently, and only if it was the only stuff left (eg a Petrol Shortage).:laugh:

H48HPE · 16th December 2003, 17:21

I tried optimax on its own in my 1.3 and I noticed an increase in performance, unfortunatly my economy was not as good as when it was running with normal petrol, even though I was doing my best to drive as economically as posible.

andy

16th December 2003, 18:22

Quote:

Originally posted by Simon
I suspect the stepping motor O ring seals are the cause of my car's refusal to idle/perform properly when cold. Easily replaced, granted but surely I can get away with standard rubber ones as my car's non turbo?

That might have also been the cause of the same problem I had on my previous 1.6 when it was relatively new (3 years old/
30000 miles)and I went through virtually everything to cure the cold start/choke/idling problems. The only thing I didn't change was the O ring seals (wrote the car off before I had chance!). Changing the ambient air temp sensor did precisely nothing.

Turbo or non-Turbo, you still use the same petrol, which is what causes thr rubber O rings to swell, especially with a high octane fuel. When seals fail on the Turbo, it's worse because fuel is blown out from the stepper motor shaft.

As Dan has said, petrol has changed alot over the past ten year's, it took me ages to track down my problems, even replacement seals from Burlen would swell up. I did numerous tests to pin-point the fault down, and Viton seals seem to be the only decent soloution so far.

Gareth

Simon · 17th December 2003, 11:27

Thanks for the quick replies! Advice duly noted, I use nothing but premium unleaded, no additives because car has an unleaded spec engine, fuel and ignition ECU's. Right, so Viton it is then. When you quote BS 013, one assumes that is the size of the O ring seal, in other words 7/16" I.D. and 9/16" O.D. Am I correct?

Sam · 9th January 2004, 23:33

Quote:

Originally posted by Landcrab1800

I NEVER use the cp. When flush I use full fat petrol, but normally I use Optimax with an additive (depends on the car I am using).
I can recommend Optimax as I can fel a difference in performance.

Gordon, do you know which is the additive with Octane boost in it? I have been putting an additive in recently but the engine has been pinking a lot...most likely because of the lower octane.

10th January 2004, 09:32

Quote:

Originally posted by Simon
Thanks for the quick replies! Advice duly noted, I use nothing but premium unleaded, no additives because car has an unleaded spec engine, fuel and ignition ECU's. Right, so Viton it is then. When you quote BS 013, one assumes that is the size of the O ring seal, in other words 7/16" I.D. and 9/16" O.D. Am I correct?

That'll be correct. As long as you quote viton at the end when ordering otherwise you'll get a normal seal.

Gareth