10 replies to this topic

[Perrylawrence96]

Hello

 

My mini was running rough, I got that problem fixed ( sort off ), by changing the water temp sensor.

 

now I have a bigger problem..

 

My auto SPI is running very very very high idle speed... and when I put it into gear, it then bogs down to the point off it stalling? it is automatic.. would anyone have any headers to the problem? as it missed its biggest show its ever had due to this

 

 

[spiguy]

Sounds like you have a vacuum leak. The leak would cause the high idle, and then when loading the engine the leak would result in an overly lean mixture which will bog it down.

 

As you have had the temp sensor fixed (did you do this yourself?) the vacuum lines will have been disconnected in the process of doing this, so they could be damaged or not properly attached.

 

My guess would be that it is the red vac line which runs to the underside of the air filter housing, which is the problem. Basically there are two outlets on the back of the inlet manifold. The red one as I mentioned, comes off the right most outlet (as you look at the front of the car) which operates a cold / hot air valve, and the other one on the left outlet, goes to the ECU via fuel trap. If the fuel trap one is disconnected you usually get a very lumpy almost stalling idle and the car is very rough, because the ECU does not see any manifold vacuum and adds lot of fuel.  However if the red one is split or disconnected this just provides a significant vacuum leak and draws extra air through it.

 

In any case, check all the vacuum lines, it's bound to be the cause of your problem. In summary, you have a short pipe to the fuel trap (left side) then a long pipe from the fuel trap to the ECU. On the other side you have a red pipe to the underside of the air filter box (to a valve) then a yellow pipe from that valve to the diverter flap on the top of the air box. check all for splits / disconnected etc, but my guess is start with the red one.

Edited by carlukemini, 31 March 2015 - 01:22 PM.

[Perrylawrence96]

Hello Mate

 

Thank you for the time to read and reply!

 

with the vacuum pipes... I've had all new ones put on with elbows too.  it seems like it can be that tho! when I take a look into the injector once the air fiter is off.. there is a constant spray off fuel going into the Butterfly thingy-ma-bob. so there is a massive problem off over fueling? now with a injection mini it could be anything that is sending the ECU to do what it likes.. I was thinking relay module or the fuel trap itself? im not too sure where to start this time To be honest its been off the road for a year now with problems.. I am giving up now. Thankyou for the post

[spiguy]

Hmmmm.. At idle, the injector does basically look like a continuous supply of fuel is being sprayed, don't worry about that it's normal. Don't forget the SPi is still a wet manifold system, it's really just like a carburrettor setup, only the injector is under ECU control.

 

Can I ask, are you DIY'ing this? Or do you use somebody to do the work for you?  If so, who is doing the work? Are you sure the vac lines are all connected up correctly?

 

Still sounds like a vacuum leak to me. There are a few places it could draw air - the vac lines as mentioned, also the brake servo hose runs to the inlet - this is a BIG potential source of a vacuum leak - it could be disconnected at either end (either servo or inlet manifold) - what's the brakes like?  Pedal hard to push? Also there are some breather lines which could cause it. All of the above would quite likely have been off / disturbed when getting the coolant sensor replaced, as most likely the inlet manifold would have been removed to do that work.

 

Did your temp sensor not give a reading in the past - was that the reason for changing it?

 

Don't give up! Is there a club near you?

[Perrylawrence96]

Hello

 

I was told a mist was suppose to be trickling into the injector by my mechanic? hmm!! haha!

 

erm its a mixture between me and my dad ( use to be a mechanic for years and years )..

 

it could well be a vac line is on the wrong part off the injector system giving a mis reading? maybe that is the problem indeed..

my next door neighbour is a mechanic and said he has a old Machine with the same fitting for the old rovers laying about.. yippee! so that could be a start to see weather or not a sensor is down..

 

with the temp sensor, the car at first was running on a very bad miss fire for ages and over fueling, now we only changed this because after a cluedo investigation ( haha ) we come to a conclusion the car is reading that it is not getting hot and the ECU is telling the car to put in more fuel to warm up? it worked until this happened

 

who put such a modern unit into a mini -.- What was they thinking!!

 

my local club is Essex  Mini Club, spoke to a lot off people including a mechanic for the Mini Spares SPI racing team and they couldn't tell me what was wrong, maybe my car is cursed .... lol

[spiguy]

Certainly if you can get the codes read then that could save you a fair bit of time. It won't look like a mist spraying in there at idle. If you were able to see an individual injector spray for one cylinder on a direct injection car, then maybe it would look like a mist, but on the mini the injector is spraying enough fuel for all 4 cylinders into the throttle body.

 

If your temperature sensor was faulty, and the gauge read cold all the time, then that would definitely cause the overfuelling that you say you had previously.

 

So did you remove the manifold to replace the coolant sensor?  I take it you did, there isn't much access to it otherwise. Assuming you did, then you would have disconnected quite a lot of stuff in the process - the vac lines, servo hose, breathers, stepper motor connector...

 

You need to go through all that stuff and verify it is back on and in the correct position. I would suggest you read the single point sticky in this section, it describes in alot of detail how everything works and is connected up.

 

Also, I am happy if you want to take some pics of the engine bay showing how it's all connected up, to check it out for you, and / or send you some pics of mine too.

 

Oh - does the temp gauge read correctly now?

[Perrylawrence96]

Hello, once again thankyou for the reply :)

 

Erm yes the code Reader might be a good thing to have!

 

When doing the Temp Sensor it was all taken apart.. Prior to this I had a head rebuild... and a lot off things was re-newed for safety measures ( Like the Vac Pipes ) ... Everything seems too off all been put back correctly.

 

The only other main thing I could think off that is not kicking back is the stepper motor? but its doing all the signs I think by having a initial look off working correctly.

 

if you could get pictures that would be awesome!!! don't rush yourself Tho... the mini is a slow moving project ( that is sitting there burning away insurance money for F*** all )         

[spiguy]

A stepper motor fault could cause the high idle, but I can't see how it could cause a high idle (suggesting pushing on the throttle linkage too much) and also a tendency to die when in gear (suggesting not pushing on the linkage enough) - the two are contradictory.

 

Forgot to mention above when discussing sources of vac leaks, of course the inlet manifold gasket itself is another possible source of a leak. Some questions for you:

 

- Was the inlet manifold gasket renewed, and is it all up tight?

- Have you reconnected all the breather pipes to the inlet manifold?

- Have you reconnected the servo vacuum hose at both ends and is it in good condition?

- If you pump the brake pedal until it is hard then start the car, does the pedal go down as the servo applies vacuum?

- When you run the engine then switch off, can you hear the stepper motor cycling?

- Have you tried feeling at the back of the manifold where the vac pipes attach to see if there is a vac leak where the pipes attach?

- What happens to the idle speed if you disconnect the red pipe from the underside of the air box?

- What happens to the idle speed if you disconnect the vac pipe at the ECU end?

- Is the throttle potentiometer plugged in correctly?  Also was this removed from the manifold at any point?

 

Cheers

Craig

[Pierre Tardif]

Reading this one with interest as I have similar issue with mine, a 1992 SPI. Mine has been doing it 3-4 times in a few weeks and now permanently. Rev up to 3-4000k for no reason at traffic lights. But all I had to do is to shut and restart the engine 2-3 times and it would idle back to normal. Now stuck in the driveway I will check every vaccum lines tomorrow to make sure. Thanks!

[spiguy]

Pierre - with it being an early SPi you should also check the accelerator switch, that is what tells the ECU to idle. Should be closed when no accelerator being pressed, open when it is pressed. It is mounted down behind the accelerator pedal arm.

Edited by carlukemini, 10 May 2015 - 08:34 AM.

[Pierre Tardif]

Thanks, I will have a look at that and make sure about the leaks and will let you know!