13 replies to this topic

[mini.rich]

Car - 1998 MPi

 

Hi guys, 

 

hoping someone can help me on this one as I'm not sure!!

 

To cut a long story short I have removed the BMW twin cam engine and gone back to a standard engine apart from the exhaust system, it's basically a maniflow system with a standard CAT, this all ran on the car prior to the twin without issue -different engine but basically the same. I've had the head off to check the bores etc and de-coke it all, bolted it all back together with new gaskets etc etc.

The problem comes after letting it idle for 10-15 minutes the manifold gets very hot and the centre branch is glowing, well you can see a red tinge to it when its in shadow. 

I have relocated the lambda sensor to the Y-piece, extended the wires(all done correctly as I used this before without any problem), although this time I used a 45 degree mounting boss, the sensor still protrudes into the exhaust pipe by 10mm or so, the straight connector I had on before meant the sensor was occasionally hitting the tunnel.

 

I've checked the tappets this morning haven't been set and are a bit rattley..

 

My thoughts are there is a problem with the sensor and the fueling? either too lean or too rich??

 

If anybody can confirm this or point me in the direction of some things to check? voltages/resistances etc? 

 

I assume the mounting of the sensor @45 degrees will be ok?

 

Many Thanks

 

Richard

[Spider]

I don't know much about the inner workings of the brain from the MPIs (or SPIs for that matter) but what you've described is usually from very late - retarded - ignition timing. I know that the MPI has a crank sensor and then it sends that info off to it's electronic brain where any advancing and retarding of the Ignition part of it is done.

 

There's bound to be someone here who will know what the specific problem is.

[Steve220]

Are you using mems?

[JetBlackEreg]

This also happens when they run lean, I've seen it before and it was caused by the oxygen sensor giving the wrong information. You could try making sure its not corroded, dirty etc. 

[mk3 Cooper S]

Yep, as stated either too retarded ign or running lean - Have you got an airleak ?

Edited by mk3 Cooper S, 27 July 2015 - 03:52 PM.

[Archived1]

Had this from a leaky brake master vacuum nut on the inlet manifold. Caused too much air to ingress and was super lean. ran hot as hell.

[jagman.2003]

Yes, In my opinion instead of 'mini rich' it's 'mini lean' that would cause high exhaust temperatures!

[mini13]

the ecu should only use the lamda rading to trimm the fuel by about 5-10% which should not have this effect,

 

also there should be a limit to advance  adjustment if any at all, as this normally requires a knock sensor which I diont think is present.

 

I agree with the airleak theory, start checking the pipework,  and disconnect the servo and bung the hole to check that.

[mini.rich]

Many thanks for the reply guys!! 

 

I will take a look on Wednesday and see if there are any leaks on the system, I did have a quick look, but didn't notice anything, but I'll check the master cylinder etc. 

 

One thing I forgot to mention is that I've not got the charcoal canister thing fitted under the passenger side wing? don't know if that would cause a problem? I blocked the pipe from the purge valve but made no difference.

 

 

Are you using mems?

 

Completely standard Rover kit yes.

 

 

Yes, In my opinion instead of 'mini rich' it's 'mini lean' that would cause high exhaust temperatures!

 

 

HAHA!! 

 

 

Thanks again

[Guess-Works.com]

I'd check the cat is not blocked.

[IainStallard]

I'd check the cat is not blocked.

I second this

[mini.rich]

I'd check the cat is not blocked.

 

It did have some gun gum in it from where I used it on the 'Y' piece, so I thought I'd change it for the 'sports' cat that I used on the twin cam engine, but this has made no difference.

 

I have checked for air leaks but I can't seem to find any, so I'm still none the wiser.

 

Something else I noticed but didn't mention is that its idling at 1100-1200rpm.. should be about 800?

 

Theres a part, I believe its the air inlet control valve? to the left of the inlet manifold, could this cause my problem?

Can anyone explain how this is suppose to work? I'm guessing its a sort of variable/servo type valve? If I unplug it it makes no difference... But if I cover the hose to it partially the revs drop.

 

Any thoughts?

 

Thanks again

[mini.rich]

Hi guys,

It would appear I have fixed the fault now. I thought some of you might like to know, and incase anyone has the same problem in the future!

As I mentioned about the air inlet control valve or stepper motor I did a little research on the internet last night to find out exactly how it works. I decided to take it off and turn the ignition on as by my reckoning it should operate either opening or closing, but either way it should move! The one on the car didn't! so I luckily have a spare, plugged this in and guess what?! It moved, bolted it in and fitted the charcoal canister aswell, started it up, idle sounded better, ran for 15 minutes, didn't seem too hot, revs dropped to below 1000, I'm pretty confident that's it sorted now!

So I've just got to fit the grill and bumper and other bits and pieces and it'll be ready for an MOT!!! It's been a long time since I've had a mini on the road! I'm really looking forward to it!

Thanks again for the help!

[jamesmpi]

Good effort. Any photos of the mini? Threads are always more enjoyable with a photo haha!