18 replies to this topic

[humph]

Sorry I know this has been covered many times, but I can't seem to find anything that really helps me so far.

 

This problem has been an issue since the autumn now, and it's driving me mad as it's intermittent so tracing it is a struggle.

 

My 95 Sidewalk cuts out, usually where you least want it.  When the problem isn't there the car runs great, or seems to.

 

So when the problem happens the car loses power and starts to cut out, sounding rough and sounding as if it's running rich (but I may be wrong!). Try as I might I can't keep her going and inevitably she dies. Up until today this was normally happening about 10 minutes after starting the car from cold, but it happened at the end of a 50 mile journey today.  I'd say it normally happens whilst driving away from a junction, or just after turning a corner as I go onto the gas.

 

Once she's stopped she won't start at first, just cranks. After trying a few times she'll fire but not run despite my best efforts with the throttle.  After a couple of tries where she won't run she'll start, a bit roughly to start with, but then she'll be fine again. Today she did it after a mile of my journey, then again after 50 miles, both times pulling away from a right hand turn. After the first breakdown today (in a torrential storm) she ran roughly for a good few miles (a good 15 minutes) before clearing.

 

Car was serviced by me a couple of weeks ago and fitted with;

 

New Plugs

New Leads

New Dizzy Cap

New Rotor Arm

New Vapour Trap

All New Vaccum Leads (for an spi)

New Fuel Filter

New Oil & Filter

 

When I go her home today I ran a check with my Sykes Picavant, I'll get the video up shortly (hopefully). Problem is by the she was running fine. Whenever she plays up[ I;ve not been able to get a test on her to see if anything is amiss.

 

As and aside, not sure if it's connected, the idle can be a bit erratic. Today at times it raised to 1500 & 2000 revs whilst sitting at lights, but not when the cutting out issue occurred.

[humph]

Video of my diagnostic results

 

Diagnostic 21-05-18  on Flickr

 

[Henry's Dad]

Hi Humph. Is your problem anything like mine, which I raised in this topic : http://www.theminifo...en-cutting-out/ ?

I don't have an answer as yet, but a number of possible solutions have been suggested by other members which might help you. In addition to everything suggested so far, I also found a slightly loose spade connector on the coil (bottom right, nearest the front) last week (it's a two-onto-one connector) so I tightened it up a bit with pliers and sprayed every electrical connector I could find with GT85. He's been ok since, but he's ok for months on end before my particular problem recurs so I don't know if I've solved it until it doesn't happen again.

Good luck.

 

ps. Many many years ago I had a Hillman Minx MkVI which occasionally ran rough and then died for no apparent reason. Long story short, I eventually worked out that it only happened after I'd filled it with petrol and it turned out there was cr*p in the tank which got stirred up and passed to the carb. Any help?

[humph]

Hi, I did read your thread, and many others before posting mine. I appreciate you posting again. It is a similar problem, certainly as frustrating. Mine doesn't over rev and die, it just dies. The over revving happens at other times, so may or may not be connected.

 

I'll be giving the electrics a good inspection at the weekend as I suspect that it may be electrical. Have had a similar problem before and that was a broken wire to the O2 sensor where the loom rubs on the bulkhead.

 

It could be a sensor, mine's an injection car, but the problem there is that I can't get the diagnostics on it while the problem is there, and when it runs it runs fine generally.

[andyapanel]

I had a very similar problem-it only happened doing a sharp right on my commute. I eventually tracked it down to the coil. Replacing it sorted it immediately.

I was curious to find out what was loose and cut the coil open. There were no obviously loose connections, but there was a lot of oil-I guess it's a heat sink. I assumed the oil rushing to one end of the coil as I cornered was causing something to not connect anymore.

Anyway, good luck.

[humph]

Thanks Andy, that's interesting. Testing the coil was on my list of things to do, but I have a spare and may just swap it out and see how it goes. I can feel a frustrating day of electrical testing coming on.

Edited by humph, 22 May 2018 - 07:36 PM.

[phillrulz]

I had a very similar problem-it only happened doing a sharp right on my commute. I eventually tracked it down to the coil. Replacing it sorted it immediately.

I was curious to find out what was loose and cut the coil open. There were no obviously loose connections, but there was a lot of oil-I guess it's a heat sink. I assumed the oil rushing to one end of the coil as I cornered was causing something to not connect anymore.

Anyway, good luck.

 

probably the opposite, oil is used as an insulator as clean oil has a higher breakdown voltage than air. So no oil / contaminated oil is easier to flash over

[andyapanel]

That makes sense-my coil was cutting out on a right hand bend, which would have exposed the plug end of the coil internals.

 

 

I had a very similar problem-it only happened doing a sharp right on my commute. I eventually tracked it down to the coil. Replacing it sorted it immediately.

I was curious to find out what was loose and cut the coil open. There were no obviously loose connections, but there was a lot of oil-I guess it's a heat sink. I assumed the oil rushing to one end of the coil as I cornered was causing something to not connect anymore.

Anyway, good luck.

 

probably the opposite, oil is used as an insulator as clean oil has a higher breakdown voltage than air. So no oil / contaminated oil is easier to flash over

 

[humph]

Update on this, just in case anyone has any further ideas.

 

Spent today looking for broken wires, dodgy connections, & coil testing.

 

No broken wires found.  Re-made a couple of connections at the coil where there was bare wire out the back of the connector insulation. Cleaned some earth points. Coil tested ok, pretty much bang on with the parameters in the Haynes manual for primary & secondary windings. I also put the front end up on ramps and had a look at the O2 sensor wiring and this looked fine.

 

So stories of today's driving & incidents.

 

Picked the car up and within a mile of collecting the car I'm on the motorway, all good. Off at the next junction and through a residential area. Half a mile off the motorway and as I sat at some lights the revs rose to 1500ish and held there. As the lights went green and I pulled away the car struggled and started running rough, lacking power & stuttering. I thought it was going to cut out, but I managed to keep it going and it ran great for the remaining mile home.

 

Having done all the tests above I let the car idle on the drive. Apart from a blip where the revs rose for a moment, probably as the car went from clod running to warm, the car idled no problem for a long time.

 

Having been switched off for half an hour or so I set off back to the storage place, all urban roads this time. After a mile or so whilst driving at 30 and starting to slow for a round about the revs stuck at 1500. Having taken the roundabout, pretty quickly due to the revs I pulled over, and a blip of the throttle sorted it. Another mile of steady 30 mph the engine started spluttering and started running rough. This time, and this is different to usual, the revs were bang on but the car was running awfully, seemingly very rich, but kept running. I jumped out to get the diagnostic from the boot, but by the time I'd got back to the front the car had righted itself.

 

It's getting damned frustrating.

[andyapanel]

The coil usually misbehaves when it is warm rather than cold.

I hope you identify the problem soon.

[Fast Ivan]

have you checked your earths?

[humph]

I have checked & cleaned the one at the top engine steady & the one on the clutch housing. All seemed ok.

[humph]

Couple of videos of a diagnostic taken yesterday just after the car had played up. Car was idling ok at this point but lambda sensor readings seem to be sticking/off.

 

In the first video the car is idling. I took the video because after a 2 hour (100 mile) drive the revs rose, then dropped off and I struggled to keep the car going, it ran rough, seemed rich to an uneducated man like me.

 

Diagnostic 1 - 09/07/18 

 

After that I took this one. It's me adjusting the engine speed using the throttlebody, not the car itself. 

 

Diagnostic 2 09/07/18

 

 

From what little I know, and I've read every thread I can find on the matter, this sensor seems to be sticking high, rather than fluctuating high/low. Is this the case, or will it stay high like this in certain circumstances?

 

If the sensor fails is there a default value the car will use? Having disconnected the sensor later in the day the car seems to use 0.8V as the default, so from the videos above it doesn't seem that the car is missing the signal in this case, suggesting that the sensor is powered and sending readings.

 

Finally would the readings be like this if the wiring was knackered,as it was last time, or is this definitely a duff sensor?  Could be that there is a blockage somewhere that is starving the engine of fuel and causing it to lean out, keeping the readings high.

 

I'd appreciate any help given.

[Wiggy]

I have a suspicion that the ACR4 doesn't read the O2 sensor voltage properly. My MPi has a constant error code for high 02 sensor voltage. The live data jumps around all over the place. Sometimes sticks, sometimes goes upto 3V. But the car runs great, and passed the MOT on emissions.

Sprocket has a thread on how to test the O2 sensor properly with a multimeter.

[humph]

Thanks Wiggy, I have read Sprockets excellent thread, and posted the same in there.  My ACR4 seems to read the O2 sensor fine, and I don't get errors showing, I seem to get a constant coolant temp sensor fault. Normally my O2 sensor cycles between 0.2V & 1.6V quite happily with no sticking which is why I noticed this so quickly yesterday. I did do a few more readings at various point on my way home and the sensor was cycling again, but was holding at 0.0V & 1.6V for longer than it normally would, & longer than it was on any other reading.