Find the misfire
Turbo Mini Forums

Stupid car!!


Im struggling with a misfire with the car, im pretty sure its fuel related.

I can put boot the car and its fine and boost doesnt make a difference to the problem, but if when i travel a long enough distance the misfire occurs which makes me believe its emptying the fuel chamber.

The pump isnt changing tone, im still yet to check the fuel filter, the carb is clear, all fuel lines appear ok.

Ive checked the fuel pressure and this is fine, driving the car shows it rises as it should, when the misfire happens it drops down to where is was on idle.

Ive checked the compression and they are all fine, the plugs are new, but it did it on the old set too

When driving it will die, and you can hear the engine chuffing away and a slight rattle (but this may be just the sound of the engine). No action with the accelerator makes a difference, the car will then come back after 5 seconds or so

It doesnt make a difference under load, or do it under an particular situation, only after a period of running it where it would have chance to use a bit of fuel

The only changes to the engine this year is a new head with bigger inlet valves (and i havent had it on the rollers yet, i dont want to take it on there until it is working ok)


Arghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!

Edited by Nic on 27th Apr, 2008.

Sounds like mine!!

I'm thinking my guides are binding up.. Do you have a wideband? does it go lean when it misfires?

Edited by Turbo Tel on 27th Apr, 2008.

website:- http://www.terryhunt.co.uk

sounds similar to the problem i had dude, definately check your filter or for any crushed/dodgy looking hoses.

Have you checked the little gauze filter before the needle valve ?

WWW.TURBO-MINI.COM

may be you need the float jet mod regarding drilling it out to 2.9mm and lapping the seat back in again Nic........

Edited by BENROSS on 27th Apr, 2008.

I havent got a wideband unfortunately, im going to have to sort something soon,

i dont think its my guides as it dies on all 4

Im planning on taking a look into that nick, good to know it sounds similar to yours if you know what i mean

Yeah ive cleared that gauze filter, there was a bit of rubber in there so i made sure i got everything else off and cleared it through

Do you think that could be the case steve? its always been fine before but has been playing me up since putting it back on the road

may be Nic
you now have a bigger valve head......
if you have checke all others out it wont hurt

just a thought, could it be a vacuum leak anywhere, that could potentially cause a faulty signal being sent to the fpr.

Unlikely i know, but worth a punt. Just trying to think of things that would have changed from when it was working...

it might be your coil pack nic

always looking for them bigger bunches of bannanas

https://www.facebook.com/pages/Fusion-Fabri..._homepage_panel

www.fusionfabs.co.uk



1/4mile in 13.2sec @ 111 terminal on 15psi

ive just pulled apart the fuel filter-it had a fair amount of blue sponge from my tank in it

Fingers crossed this is the problem

Any suggestions in the pump will be ok?

Suck it and see!

My favourite method-along with trial and error

hmm its still there

however i did manage a race with a cossie powered westfield, it was fine off the lights but not so good on the open road

mine actually had similar symptoms a couple of years ago. turned out to be the old pump not flowing enough, although it sounded ok and was producing enough pressure when i tested it at idle but couldnt match the required flow rate when driving for a while (20-30 mins).

might be worth measuring it to make sure the pump is ok. should be easy enough to pull the feed pipe of the carb and time 1l of fuel. should be 1l a minute according to an old thread on here.

im wondering if its the pump, i think the £10 pump has come to the end of its life

does the rpm drop to zero when the missfire occurs?

1152cc turboed mini clubman, most powerful 1.1L a-series?

http://boostmini.justboard.net/

hmm if there was debris in the gause filter i think that was the cause,

i'd give the fuel lines a good blow through from a compressor, then swap the pump.

Nic.

When I was diagnosing a misfire setting up the wasted spark ignition on my van, this is a potted summary of the advice from all sources, including Phil Ringwood at :

www.ExtraEFi.co.uk/support

1. Plugs - make sure resistive 'R' plugs are used, correctly gapped.

2. If using coilpack ignition - fit the standard Ford 20 microfarad capacitor (suppressor) that usually comes with the coil when you get it from a scrappy. The capacitor is fitted to the centre +12v feed wire to the coilpack and just tees into it with the earth for the capacitor being the bolt that mounts it onto the coilpack bracket or as close to the bracket as you can get it (assuming you've got the bracket mounted to the chassis). This sorted my misfire as soon as I fitted it.

3. Sensor - make sure your sensor air gap is 0.7-1.0 mm as this effects the amplitude ands strength of signals and that it's shielding is good.

4. Megatune (if using Megasquirt) or other similar tuning software - modify the 'xxx.ini' file to show battery voltage on the display.

Whatever tuning software you've got interfaced with the ECU, make sure it shows you're getting a clean RPM signal.

Do a datalog when you're taking your car out and the misfire is detected. The trace will probably help to show where it's coming from, or at least where it's not.

Also, see if Megatune, or similar, resets itself after each misfire - it counts the resets in the bottom RH corner of the screen and on every datalog when you run one. Certainly helped me.

4. If it's fuel pressure related - Tee in and mount a small fuel gauge onto your wiper arm so that you or a passenger can see it whilst driving and make sure the pressure isn't dying with boost or is at least continually 3-4 psi greater than boost pressure.

5. Ensure ECU and sensors have got good earths, preferably at the battery, using the same earth point / wire.

6. If you don't have some of the stuff above fitted, then ask your dyno man to do a diagnostic run rather than a power run. After all, his kit should at least detect fuelling CO and ignition signals at the sort of speeds / runs you're doing at home.

I was going to do something like this later but, hey, hope some of this helps.

Richard.

Minivanless, but reluctantly happy living with the decision. There'll be another one day.
http://www.youtube.com/profile?user=minimadmotorman#p/u

Cheers guys, i will have a bit more of a play tonight and see if i can get to the bottom of things with your suggestions

i've had this a few times, always been short on fuel one way or another!

got a trip to the states this week so think i'll be getting a new pump!

Id say definatley fueling ?

Make sure the lines are clean but id say either pump has finaly had it or fuel filter?

Rick

website:- http://www.terryhunt.co.uk

Yeah the boost gauge swings round in the positive as you said

I was thinking that this could just be extra fuel escaping in the the cylinder and burning on the wasted spark?

is your fuel filter before orafter your pump just wondering if foam in pump.

no longer a series, but still 1.3 turbo.