20 replies to this topic

[bradderz]

hi i have a 1991 Mini Cooper 1.3 spi.

when i start the mini from cold the engine sounds like it is stuttering and when i try to drive it it struggles to accelerate, but after a couple of mins it goes back to normal. also the idle speed wont make its mind up. sometimes its high, 1500 -2000, and sumtimes its normal, around 900.

does anyone have any ideas what might be wrong? its really starting to annoy me now

thanks

brad

[digger.9]

Hi all,

It sounds like I am hhaving exactly the same problem, during the summer when warm it started fine, as got a little colder ran bit rough till engine heated up and could be started on a warm engine. But now the engine is cold and the temp is cold I cant get it to start at all.

Im guessing must be a sensor for temp or something that has failed, not sure if your thinking same about your car?
Any help or suggestions would be appreciated tho as I am at bit of loss now thanks

[bradderz]

nah mine starts fine when its cold or warm, it just running really rough when cold.

[digger.9]

ah ok, sorry to jump on your thread then. will start a new one.
good luck with it...

[xrocketengineer]

nah mine starts fine when its cold or warm, it just running really rough when cold.

Hi,
If all your troubles appear to happen only when the engine is cold and go away as soon as it warms up, you need to check the operation of the Thermac valve on the air box intake snorkel. There is vacuum pipe from the back of the intake manifold to that valve underneath the snorkel and another short one from there to a flapper that allows warm air in from the stove around the exhaust manifold. If these pipes or the flapper actuator leak your mixture will lean out while the engine is cold causing your problems. Check that the pipes are not cracked or loose. Also, make sure that the flapper closes the inlet of the snorkel when running cold and opens immediately after warming up.
If you are still not getting any clear results out of the steps above, try disconnecting and plugging the pipe coming from the back of the intake manifold and see if your problem goes away.

Hope that helps,

Ivan

[bradderz]

ok i just tried your sugestion and the flap definately opens and closes, i tried the plugging of the vacumm pipe and i couldnt really notice any difference, also all the vacumm pipes have no cracks in them and they had recently been replaced.

could the problem be my lambda sensor by any chance? i just disconnected it to see if anything happened and it didnt make a difference, i did it a couple times to make sure, any thoughts? could this be my problem then?

thanks

[Miniature]

Hi there,

I have a 1993 Mini Mayfair 1.3 and I am having exactly the same problem as you. The car does start ok in the cold, but it just doesnt have any acceloration in the cold for the first few mins, and stutters quite a bit. As you have said though, once it has warmed up a bit it is absolutely fine. If you do find a solution to this problem could you please post it up here, as I am interested in what is causing this. I havent checked the things that xrocketengineer has said, I will check that tonight, but if you come up with any other ideas please let me know

Cheers.
Miniature.

[AVV IT]

I have a 1993 sprite with exactly the same problem. When it's cold I have to run it with the choke fully out until it gets warm otherwise, it's almost undriveable. I can't try the suggestion by "xrocketengineer" as I don't have an air filter box or vac pipes to the inlet manifold as I'm running a K&N cone filter & alloy inlet. The guy at the rolling road I went to seemed to think it was a common problem with high mileage A series engines (mine had done 88k at the time) and he mumbled something about the cam probably being worn?? If anybody has any other suggestions then I would also like to hear them, it's interesting that this problem seems to be shared by three early 90's models though, I reckon there must be something in that surely??

Edited by AVV IT, 27 October 2010 - 11:31 AM.

[xrocketengineer]

Well, outside of my own experience but based on "Sprocket's" vast knowledge, maybe the thermostat is in the wrong place. Reading from his threads, the thermostat should not be installed directly on the head. Instead, it should be installed on the sandwich plate. If I am not mistaken, this allows coolant flow from the head to the intake manifold (where the the temp sensor is) while the thermostat is still closed. This way the ECU gets an accurate temp reading of the coolant and adjusts mixture and timing as the engine warms up before the thermostat opens at 88 degrees C.

[Sprocket]

Cold running (rather than cold starting) problems that disappear when warm to hot can also be attributed to the manifold heater or PTC heater as it sometimes called. Check that the fat brown wire is attached to the spade terminal on the base of the manifold (directly under the manifold if you were looking down at the throttle from the top( the underside of the silver knobly bit at the bottom of the inside of the manifold, under the throttle disc)). It is fairly common for this connection to be burnt, loose, or even disconnected. Also check the relay pack large connector for similar scorching/ burning of the same wire (brown/ blue? from memory) as well as the circuit track on the inside of the relay pack. If this all looks fine, it could be that the heater itself is faulty. The heater should read an ohm value between the spade terminal and the manifold somwhere in the 100's depending on the temperature. If there is infinity ohm resistance with a cold heater, the heater is faulty.

Starting issues most likely down to coolant temperature sensor. Also If the air temp sensor is open circuit, disconnected or missing, can cause starting issues. An assumed value of 20 degrees is used, and if its cold out, will make it difficult to start first time. The problem improves when the engine is warm as the assumed value is more realistic with a nice warm heat soked engine. Coolant temp sensor also assumes a temp of 70 degrees if it is open circuit, missing or disconnected, again issues are less evident as the engine warms up as the assumed temperature is more realistic.

Edited by Sprocket, 27 October 2010 - 06:10 PM.

[bradderz]

turns out the manifold heater wasnt even connected up, after eventually getting it connected ( was a real strugle to get my hand under) turn the engine and nothing change! stupid spi, i new i should of went for the carb!

[bradderz]

so surely the problem lies on a faulty manifold/ptc heater, which is ok i suppose as i am gonna be replacing the throttle body and inlet from a job lot i just bought, and im pretty sure the heater is still on it

[bradderz]

managed to get hold of a multimetre to check the resistance on the manifold heater, turns out to be about 2 ohms lol pretty sure its buggered

[Sprocket]

Not necessarally.

Basic electrics states V=IxR where V is the voltage, I is the current and R is the resistance. You know the voltage with the engine running is roughly 14.5v and you now know the resistance is 2 ohm. transpose the equasion to give you I=V/R and the result is a little over 7 amps. Not an impossible figure for something like an electric heater. My initial advice regarding the ohm reading, thinking about it again, is not as accurate as it should have been. It hs been quite some time since I got real dirty with an SPi, now that i have four injectors, another two cams and an extra 8 valves

If there is still no improvemnet when the heater had been re connected, you need to check that the heater is infact getting power when the engine is running and cold. The power drops out at around 55 degree coolant temp. If there is no power at the heater end, check the relay pack connector and its internal printed circuit.

[bradderz]

i found a throttle body with all the sensors, inlet manifold,, ecu, and enigne mangement relay on ebay and was told that everything was working perfectly, so i bought it and have replaced it all yesturday and nothing has got better, still stuttering and crappy acceleration, and also a slight high idle when cold.

what could be wrong?

also noticed a few days ago that there is a hissing, sound sort of like air but not sure, when i press the accelerator pedal and gets louder the further i depress it, but it stops about halfway in down, any ideas about this?