16 replies to this topic

[macauley151]

I have a 94 sprite SPI and bought it knowing that it was over fuelling. now I have stopped the fuel issue I have now got to sort out the terrible idle.

 

the car runs smooth and without any problems. starts first turn of the key cold or hot, but when you blip the accelerator the engine sticks at the rpm you reached for a duration between 1-10 seconds. the accelerator cable is not at fault as when I rev the engine I use the bar on the inlet. I know there isn't any air leaks as I have had the car connected to a diagnostic machine.

 

since I have purchased the car I have changed the following:

vacuum hose from ecu to fuel trap

vacuum hose from fuel trap to inlet manifold

lambda sensor

new exhaust manifold

manifold gasket

inlet manifold locating rings

new K&N air filter

new spark plugs

 

I have also blocked of the port under the fuel lines as when I purchased the car there was no hose. I was told to do this by a mini mechanic as this is what he does on there race cars.

 

 

(above picture of blocked off port)

 

the breather rail on my car that connects a hose from the front of the inlet manifold and fuel purge valve is a little rusty (as shown bellow)

 

 

I have read some other topics to see if I could address this matter. the only thing I came across is the throttle position sensor. I tried testing this today. as mentioned in another topic I unplugged the sensor when the car was idling erratically to see if the revs would drop down but this only increased them. if I am honest when the engine picked up revs I plugged it back in again as it worried me. this brought the revs back to the sticking point and then they dropped down to idle.

 

I am still unsure on the condition of the sensor. I'm not even sure if this is the problem.

 

My MOT has now run out and I would like to get this sorted before booking the car in. if anyone could shed some light onto this is would be much appreciated.

[minisilverbullet]

Sounds familiar to what i experienced. 

 

I assume the port you blocked of was where the red vacuum line ran from (since you know have a k &N that is normal). 

 

You could try and bypass the fuel trap, i did this for a while and it seemed to cure the issue (until i bought a new trap). 

 

you know the vacuum pipes have different size elbows on each end. so they must be fitted correctly. I installed mine incorrectly and basically the elbow was blocking the vacumm to the map/maf sensor. 

 

you can also try and clean out the maf/map with some cotton. 

Edited by minisilverbullet, 17 June 2013 - 06:39 PM.

[wardyxxx]

As above, take the fuel trap off, blow all the junk out, dry it on a radiator overnight with some tissue in the holes.

Take the ecu off and do the same thing thing with the vac port on the ecu.

Don't worry, we'll work it out! Both me and SilverBullet have enjoyed the SPi erratic idle. So you're not alone!

[minisilverbullet]

As above, take the fuel trap off, blow all the junk out, dry it on a radiator overnight with some tissue in the holes.

Take the ecu off and do the same thing thing with the vac port on the ecu.

Don't worry, we'll work it out! Both me and SilverBullet have enjoyed the SPi erratic idle. So you're not alone!

Indeed! 

 

When the revs stuck on my mini, it would literally drive itself, Herbie style!

 

I assume when it sticks, you then turn the car off and restart and all is good again?

[macauley151]

Sounds familiar to what i experienced. 

 

I assume to port you blocked of was where the red vacuum line ran from (since you know have a k &N that is normal). 

 

You could try and bypass the fuel trap, i did this form a while and it seemed to cure the issue (until i bought a new trap). 

 

you know the vacuum pipes have different size elbows on each end. so they must be fitted correctly. I installed mine incorrectly and basically the elbow was blocking the vacumm to the map/maf sensor. 

 

you can also try and clean out the maf/map with some cotton. 

 

are you on about the red vacume hose that usually connects to the air box when not using a K&N? if you are, I have a non standard hose with a screw plugging the hole. I know this is working as the vacume is reading 38 when on a diagnostic.

 

 

As above, take the fuel trap off, blow all the junk out, dry it on a radiator overnight with some tissue in the holes.

Take the ecu off and do the same thing thing with the vac port on the ecu.

Don't worry, we'll work it out! Both me and SilverBullet have enjoyed the SPi erratic idle. So you're not alone!

 

I shall take the trap off and disconnect the ecu and leave it out to dry off and I shall see if that works. thanks

[macauley151]

 

As above, take the fuel trap off, blow all the junk out, dry it on a radiator overnight with some tissue in the holes.

Take the ecu off and do the same thing thing with the vac port on the ecu.

Don't worry, we'll work it out! Both me and SilverBullet have enjoyed the SPi erratic idle. So you're not alone!

Indeed! 

 

When the revs stuck on my mini, it would literally drive itself, Herbie style!

 

I assume when it sticks, you then turn the car off and restart and all is good again?

 

 

YES!! exactly that

[minisilverbullet]

 

 

As above, take the fuel trap off, blow all the junk out, dry it on a radiator overnight with some tissue in the holes.

Take the ecu off and do the same thing thing with the vac port on the ecu.

Don't worry, we'll work it out! Both me and SilverBullet have enjoyed the SPi erratic idle. So you're not alone!

Indeed! 

 

When the revs stuck on my mini, it would literally drive itself, Herbie style!

 

I assume when it sticks, you then turn the car off and restart and all is good again?

 

 

YES!! exactly that

 

I also took your strategy of changing parts out. So I am not 100% sure what solved my issue! I am sure it was cleaning the maf sensor hole out in the ecu / replacing the fuel trap / fitting the vacuum lines the correct way. 

 

Regarding the fitting of the vacuum lines, you can test this by running the engine with the vacuum lines at the ecu end off and feel for it sucking...

 

I was also advised to change the two temp sensors (water and air), not sure it helped. 

[macauley151]

ok thanks. I have removed the ecu and fuel trap out of my car and tried to blow the rubbish out that was in the fuel trap and only a little moisture came out. I shall place them on  the radiator and try again in the morning

[macauley151]

results:

 

I left the ecu and fuel trap on a radiator over night to remove any moisture, made sure the hoses were connected correctly and there was suction at the ecu end. re-fitted and tested. car started fine like usual and the sticking throttle still occurred. the car needs a good run but due to no MOT I cant take it out, plus I haven't got a licence anyway. I am changing the oil and coolant soon and I don't think this will affect anything  but it needs a good flush.

 

not sure on what to do now though.... car doesn't really seem to get hot either. going to put in a new thermostat while I'm changing the coolant so maybe this will help.

[minisilverbullet]

I also changed the coolant temp sensor! I found it at northwest minis for a tenner.

[macauley151]

i have been doing some research during work/college and does anyone know if the two pipes from the front of the injection unit could do have any affect? I know that the right hand pipe (when looking from the front) is connected to the emissions breather rail and i doubt this has anything to do with it. the other pipe (left) thats connected to the fuel purge valve. do these pipes have to be air tight? i have been reading some other forums and this has been mentioned brefiely before.

 

So does the purge valve pipes need to be air tight?

if so will this affect the revs?

[Fast Ivan]

something is slow in its reaction, you say you have plugged it in to a diagnostics but did you take note of the live data, not just look for faults?

[zony]

Have you got your heating on in this weather.  (left on a radiator overnight)

[macauley151]

something is slow in its reaction, you say you have plugged it in to a diagnostics but did you take note of the live data, not just look for faults?

 

The diagnostic was a while ago now but from what i remember everything checked out to be correct. the only issue i had found on the diagnostic was a fault in the throttle sensor and that was cleared and the lambda was reading 1.8 but thats now sorted. the coolant temp started at 27 degrees from cold and warmed up to 55 when we removed the diagnostic. the rest i can not tell you

 

Have you got your heating on in this weather.  (left on a radiator overnight)

 

my house is really warm during the night so there was no need for the heating.

[FlyingScot]

Best to test the lambda sensor and check it is changing voltage. Also TPS could be "noisy" again you can test.
Both of these can be tested with a multimeter if you look at the stickies done by sprocket. Best is to use a diagnostic if you can borrow one. Not sure which one was used but you need to get the engine up to temperature to be sure that the fuelling changes from enrichment (equivalent to choke on a carb) to maintaining the correct fuelling under the load conditions.

FS