92 replies to this topic

[BoyracerAU]

Okay, I've had my car for a week and with a lot of help from this forum, I've been busy doing all the things I figure I should so I know where I'm at with it.

On the third day of proud ownership, the car developed a reluctance to rev above 2,000rpm - but only intermittently.

I've cleared vacuum lines and replaced brittle and cracked elbows. I've replaced the plugs, leads, oil & oil filter. The fuel filter is currently being done by a mechanic because I get vertigo under cars.

One thing I discovered was a stainless steel pin that looked like it had started to slip out. It's located towards the front of the air filter. I'm not sure what it does or what it's attached to. It sits within and across the nozzle intake bit of the air filter. I used a pair of pliers to push the pin back into position and I'm beginning to suspect that this has caused all my grief.

Sprocket wrote the following and I think it might be related to the little pin I pushed in. I'm thinking the flap he's talking about is attached to the pin. And I suspect my little maneouvre has caused the flap to get stuck.

This capilary supplys vacuum to the air cleaner inlet air temperature control system which operates a flap inside the housing, drawing air over the exhaust manifold, heating it, to aid smooth running in cold and freezing temperatures.


Can someone tell me if I might be on the right track?

Edited by BoyracerAU, 31 December 2007 - 01:29 AM.

[BoyracerAU]

I thought I'd better put something up here so as to close this thread. The car was at the workshop when I wrote the previous message so I wasn't able to check things out for myself.

The little pin was indeed the pin that the flap hinges on. From what I can gather, vacuum in the throttle body causes it to open and close. My having pushed it back in did not cause any dramas. I've since got the car back and been able to check it out for myself.

I've been wracking my brains trying to nut out the intermittent 'no rev' drama based on all the info that Sprocket has kindly posted up. Unfortunately, the issue is still not resolved, but I am getting the fuel filter changed tomorrow and I have my fingers crossed. Failing that, I'll be sending the ECU off for code reading and resetting - also, with my fingers crossed.

We didn't get these cars originally here in Australia. The clubby was the last Mini sold new here back in the late seventies. There are a few Rovers that have come in as personal imports, but parts and servicing are not easily found, especially when you're new to the marque. As an example, I travelled 70kms (not in my Mini) round trip this morning to pick up the fuel filter and if I send the ECU off for code reading and resetting, it will be going to another capital city in another state and will have travelled 2,400kms by the time it comes back to me.

Ths forum has been incredibly helpful. I can't imagine what I'd be doing now if not for TMF - climbing walls and forking out money hand over fist probably. I'm guessing our American friends will have similar stories to tell.

[Sprocket]

Hi there, I really do understand your feelings about trying to fix this, And I am sorry that all I can offer is suggestions to the probable cause, I myself am still learning

With a little more thought on this, if this hesitation/ flat spot is a very short period after depressing the accelerator, this may indicate a problem with throttle position sensor. This sensor tells the ECU the rate of throttle opening. The ECU can then decide how much extra fuel to inject to compensate for a transient,'lean' condition.

Explanation of transient fueling (acceleration enrichment)

Baisicaly, the fueling is a closed loop control. The ECU injects a fuel amount based on the pre programed maps. this fuel then has to travel from the injector, past the throttle, down the inlet manifold, past the valves into the combustion chamber, where it is then burnt, and the waste gasses exit through the exhaust where it passes over the Lambda sensor, where the oxygen content is sensed, this signal is then fed into the ECU and calculates any correction tothe base map fueling.

All that takes time, something like half a second. Obviously the slower the air entering the engine at low engine speeds the longer this time will be, and the faster the air entering the engine at higher engine speeds, the shorter this time will be.

Wheres this going I hear you say. When you accelerate, there is a 'transient' lean condition as more air enters the engine with very little change in fueling. Without the addition of extra fuel the engine will hesitate, untill the ECU receives the feed back from the Lambda sensor to say that it is lean and then it would recover. To prevent this condition the ECU monitors the Throttle Position Sensor for the rate of change and adds a predetermined amount of extra fuel in relation to the rate. This prevents a transient lean condition and the engine runs without hesitation.

If the TPS is not working correctly, the ECU may not be adding transient fueling causing the engine to hesitate momentaraly

There, a little long winded, lol, but then I have always been Just thought you would be interested to know how the ECU controls the transient fueling so you could possibly understand your problem a little more.

The TPS is the same as used on many of the Rover cars of around the same age, The Rover 100, or Kensington 1.1 would be your best bet as they were all single point. Dont know if these cars are that common in Oz

If you find it difficult getting hold of a TPS, flirt me over your Address on PM, and I'll send one out to you, I'll only ask the cost of postage

Worth elliminating this before you go to the expense of sending the ECU off for testing, its rarely the ECU, but they do occasionaly fail.

Again a diagnostic code reader would be able to show you the TPS volts or perceent, but its down to the user to determine if it is correct or not, not the code reader throwing up a fault. Same goes for the sensors Would it not be worth your while trying to get hold of one of these code readers from the UK Ebay. You could maybe then earn your money back helping others maybe in a similar predicamant, all be it having to post it out on an exchange basis?? Just a thought

Sprox

[Major Burkenshaw]

With a little more thought on this, if this hesitation/ flat spot is a very short period after depressing the accelerator, this may indicate a problem with throttle position sensor. This sensor tells the ECU the rate of throttle opening. The ECU can then decide how much extra fuel to inject to compensate for a transient,'lean' condition.

Is this process affected by the engine temperature?

I.e. Would this fault not be apperant when the engine is started from cold and only develop when the engine reaches opperating temperature?

Edited by Major Burkenshaw, 02 January 2008 - 07:16 PM.

[DaveRob]

We are all learning on here as Sproket says. My ref data about the Rovers MEMS and all its varients concides exactly with the statements that Sproket has written about the TPS. Rover did however also have in some of their MEMS systems, ( but I dont know if it was all of them).... and I would check for confirmation with Sproket......that is that the TPS does indeed indicate the RATE of change and its the RATE statement that matters here. However when the throttle is opened 100% and really quickly.......the RATE of change is excluded from the ECU map and the fueling reverts to a FIXED value. If that is the case and the TPS was at fault,...... by completly flooring the accelerator as fast as poss then you should be able to flip the ECU into a mode where the TPS isnt part of the equation and so see if the TPS is or isnt where you should be focusing attention.

Being here is an education.......

Tin hat on....etc etc

DaveRob

Edited by DaveRob, 02 January 2008 - 08:29 PM.

[Sprocket]

With a little more thought on this, if this hesitation/ flat spot is a very short period after depressing the accelerator, this may indicate a problem with throttle position sensor. This sensor tells the ECU the rate of throttle opening. The ECU can then decide how much extra fuel to inject to compensate for a transient,'lean' condition.

Is this process affected by the engine temperature?

I.e. Would this fault not be apperant when the engine is started from cold and only develop when the engine reaches opperating temperature?

Add to this further by saying that when the engine is cold, more fuel is required to sustain combustion in the cylinder. This is because fuel that would normaly be intended for this combustion, condenses out on the walls of the inlet tract and forms droplets of fuel that get drawn into the combustion chamber, which would, in a warm engine, normaly be vapour. Liquid fuel does not burn. The ECU is programed to add a certain amount of extra fuel at different temperatures during warm up. This is a balance with a properly operating system. If the manifold heater is not functioning, when you accelerate, transient fueling is added ontop of the warm up enrichment, and that ontop of the base map fueling, but there still may not be enough fuel to sustain propper combustion due to more fuel condensing out on the walls of the inlet tract. The programed norm, is not, because of the faulty manifold heater, this results in cold air and cold manifolds, propigating the condensation of fuel. When the engine is up to temp, the manifold heater is not functioning as the engine coolant circulates the manifold and heats it.

You would be surprised how powerful these heaters are. With my programable ECU I can turn on the heater, and I have used it to clear out a flooded manifold. Liquid fuel sitting ontop of the heater in a pool soon evaporated as i watched.

I recon this, as my first diagnosis, is the manifold heater, and then the second probabale is the TPS.

[BoyracerAU]

Thanks guys. I'll have to read your posts several times over. I'm very inexperienced when it comes to tinkering in engine bays. I couldn't have got this far if it wasn't for all Sprocket's posts.

I'll look into getting a code reader off ebay. Is there a particular model I should get? I had a quick look the other night, but all the ones I saw were ODBII which I didn't think applied to our Minis. I figured I was looking for anything that mentioned MEMS and I thought the numbers 1.9 particlarly applied to SPI's.

Lucky for me the guy I'll be sending the ECU to is the local Aussie legend with these cars. Also lucky for me, I've been very fortunate to find a NSW Club member who is actually visiting this guy next week for a day trip. Even better, he has kindly agreed to take my ECU down and bring it back with him. That's as good as it gets in my books!

It's just bizarre how it came on. The car was great for the first three days and then I had the alarm installed (because Minis are getting stolen and disappearing completely here in Sydney) and I had a bit of time to start to get to know my car. That was when the drama started. I figured the alarm guy bumped something like a vacuum hose, but I've been through all these and the elbows that go with them and the problem still isn't sorted out.

The no revving above 2,000rpm scenario doesn't kick in till the car's been warmed up and driven for about 15-20 minutes. After this it's impossible to go above 2,000rpm in any gear, and I find myself suddenly appreciating just how hilly my area is and looking for the flattest roads home that don't have traffic lights to hold me up.

I'm booked in to visit my mechanic in one hour. He's going to change the fuel filter for me seeing as access isn't the best and my driveway really isn't set up to take a petrol spill.

Hopefully, I'll be back with some good news to report in a little while.

[BoyracerAU]

Well, I should've known it would happen.

The other day when I picked up the filter, I was told there were two types. Having travelled so far, I said I'll grab both of them. The guy said don't do that and assured me mine would be of a certain type.

So today, my car goes up on a hoist for the second time in two days only to discover the filter is not the right one!

I did another 70km round trip late this afternoon and picked up the OTHER filter. Got back too late to get time on the hoist.

Hopefully, tomorrow we'll get the filter installed!

Stay tuned.

Edited by BoyracerAU, 03 January 2008 - 09:06 AM.

[Sprocket]

Scratch, lets start again.

If the engine is running and idling well, I seriously doubt there is anything wrong with the ECU.

MAP sensor. ENSURE the vac lines are free of blockages, nicks, and cuts. Also ensure that the Elbow ends are the correct ones. The brown ones are incorrect, they are too short and when pushed onto the connection point can and do block off the line, there will be no MAP sensing and all sorts of bad running conditions will be pressent. I know you have checked this but humour me

Check this topic on how to ensure the MAP sensor is not liquid locked http://www.theminifo...x...st&p=774378

If this problem only occured imediately after the alarm was fitted, then its something simple.

What type of ECU is this? A two plug or a one plug?

The two plug ECUs have a switch on the throttle pedal, if this switch sticks, it gives the symptoms you describe.

Check the temp sensors for continuity, if it reads infinity or zero, the sensor is faulty, if it reads anything inbetween, it is still functioning but how well is difficult to decide without the code reader. Just see if the sensors are at least reading something.

Check the Lambda senso as described in the Pinned topics.

I really cant suggest anything else, though there is probibly something very simple wrong here, lol, it usualy the way.


Who is this 'Legend'? wouldnt be Mad Matt the Mini Man would it?

[BoyracerAU]

Hi Sprocket,

Thanks for all that. I really appreciate your giving my problem some thought. I know you must feel like you've posted all this a dozen times over.

My ECU has only one plug and the vacuum line that goes up to the fuel trap.

I've replaced the elbows with straight 3mm vacuum hose at the ECU and the fuel trap. And I have straight 4mm vacuum hose going from the fuel trap to the throttle body. I've got black rounded off elbows on the red vacuum line. The yellow line has the regular square elbows on. Perhaps these have been pushed on too far? I'll back them off a bit before I go out to get the fuel filter changed this arvo.

The only things I haven't done yet is (1) test the sensors and (2) shove some cotton wool up the MAP sensor inlet in the ECU.

The temp gauge reads just on or under halfway, so I'm guessing the coolant temp sensor is okay.

I'm sure you're right. It's going to be something really simple. In some ways, it's been good for me to learn a bit about the car I've just bought and whilst I don't mind a bit of character building, I'd love to be able to drive it with confidence sometime soon.

I've only been in the Mini World for two weeks. Who's Mad Matt? The legend I refer to is Steve at Brickworx. His business imports ex-Japanese cars for parts. He also brings in whole Rover Minis, but the powers that be have decreed that we're only allowed to have pre-1989 cars here, so anything after this is pretty rare. Steve has been very helpful. He's also been more than ready to try to help me out with advice over the phone.

I'll report back shortly.

[Sprocket]

I would have thought that you would have heard of Mad Matt, lol, he is Mad, lol

http://www.users.big....au/TheMiniMan/

http://www.ausmini.c...5e1427685f409fc

[Sprocket]

http://www.miniman.com.au/default.htm

[BoyracerAU]

Hi Colin, I hadn't come across Mad Matt before now. Since I got this problem, 95% of all my websurfing has been looking up your threads.

Anyway, Mad Matt is roughly 1,000kms due north of me and Steve, the bloke I mentioned before, is 1,200kms south west. by the way, I'm going to my first local club meeting tonight. Hopefully, there'll be someone there who can sort this car out. Beyond replacing all the sensors including the TPS, I think we've reached the uppermost heights of my technical abilities.

This afternoon I finally got the fuel filter changed successfully, but the intermittent splutter is still there. (


I had a mad thought this morning. I wondered if I could've mixed up my red and yellow capillary tubes on the underside of the air filter.

Currently, I have the yellow one going from the little round thing on top of the air filter housing underneath to the outlet closest to the centre of the air filter.

I have the red one going from the inlet closest to the outside edge of the air filter to the right hand side of the throttle body.

I have the left hand side of the throttle body connected to the black inlet on the fuel trap and the green inlet heads out to the ECU.

Does all this sound right?


Interestingly, I had a really nice test drive in the Mini this morning after I backed off all the elbows a bit. I didn't have the guts to go too far from home, so I did laps of my block for about 20 mins. I'm sure the neighbours were wondering what was going on. The car behaved perfectly throughout this run and I dared to hope the problem was solved. Alas, it started to cough and splutter not 500m after leaving the mechanic this afternoon.

Whenever it splutters, there's a fast clicking noise which seems to coincide with wild movement of the tacho needle. The needle acts like it's bouncing off a glass ceiling and reverberates between idle speed and say, 2,000rpm at a very fast pace, accompanied by this clicking noise. I wonder if this clicking noise is the TPS?

[Sprocket]

Ok something else to consider

Because there are few people that know how these things work over there, it wouldnt be too difficult for some one to try and adjust the ignition timing by moving the distributer. The problem with this, is that the SPi distributer is a simple mechanical device that distributes the HT voltage to the correct plug. It does not control the ignition advance. you could move it 35 degrees towards retard or 35 degrees towards advance and the actual igntion advance wouldnt move. This is becaus the ECU determines when to fire the coil.

If the distributor is not set correctly, what can happen is that the rotor arm may pass the electrode in the cap before the ECU fires the coil, the gap between the rotor arm and cap electrode increases, the HT has to jump a bigger gap and the resulting spark is weeker. The bigger the gap gets the weeker the spark gets. Tell tail signes of this are burnt out dizzy caps on the corners of the cap electrodes.

Just a possability

Is the fuel pump inertia switch securely fastened to the bracket on the bulkhead? and are the connections on the coil clean free of corossion and tight?

The TPS is a symple variable resistor with only one moving part which is attatched to the throttle spindle

[BoyracerAU]

Hi Colin,

Thanks for even more tips! It's very much appreciated.

The electrodes inside the dizzy cap do have like divots cut out of them. I'm not sure if this is what burnt out electrodes look like. I'm waiting on a new rotor button and dizzy cap which should turn up early next week.

The fuel pump inertia switch is secure and I have cleaned all the contact points on the coil. I've also swapped the relays - no difference there.

Today I thought the clicking noise that I hear when the car is playing up sounds very much like the indicators except a it's a lot faster. It does sound a bit like the flasher can.

Today the car thought one of the indicators had gone out. It ended up being one of the two wires (that go to the front driver's side indicator )had come loose. I'd been mucking around in that corner getting the ECU out to clean the MAP sensor, so I guess I bumped an already dodgy connection. I've crimped a new plug on, so that's good now.

I really just can't fathom what has happened. The car went well for three days. I had an alarm installed. I travelled something like 20k's immediately following this and this is when the drama started.

The intermittent nature of it makes it even harder to work out. This morning I drove it for 25mins before the drama kicked in well and truly after the car had reached normal operating temperature. This afternoon the drama kicked in quite some time before it had reached normal operating temperature.

By the way, did my description of the vacuum lines sound like they were hooked up correctly?

Another question: Am I doing damage to anything having the car running like this? I read in another thread that someone had melted a catalytic converter. Am I in danger of doing this?

Edited by BoyracerAU, 05 January 2008 - 07:48 AM.