Loss of power and running really badly

[Bass1st]

Mk2, Ph1 172. I have been suffering from intermittent loss of power, a bit like the car is going into limp home mode. Usually you wait and it corrects itself, but is getting more regular and also now does it on idle.

The RS tuner highlighted an O2 sensor fault so I swapped it today - made no difference!

Any ideas? When it is running rough it seems to run really rich and smells of fuel.

 

[!sean172!]

check the coilpack m8 mine just did that n it stunk of fuel .ijust recently bought the car n looks like some monkey has had the inlet n various parts off n hasnt put loctite or the right bolts bk into their appropriate place

 

[Bass1st]

OK, will try the coil pack. I have one on order already.

 

[Bass1st]

Changed coil pack and leads - car ran fine for a couple of hours then started developing the fault again, even on idle. I did a live data on the car when the problem happened and the only clue is the fuel trim (short term) drops like a stone to 3 when the problem occurs. All of a sudden the problem clears and it goes back to 128.

Any ideas? Do I have a fuelling issue?

 

[Bass1st]

Oh, and the ignition advance goes mad moving from 4.8 to 15... when running normally it sits between 11 and 12.

 

[Fastchip]

Have you looked into testing/cleaning the injectors ?

Cheers Henk

 

[Bass1st]

No, but I can do. I would have thought an injector fault would have shown up on the ECU? Any suggestions on how best to test/clean them? Also would be great to know what the 'fuel trim' actually means.

 

[RSsprint]

Have a read of this mate see if its anything like yours

http://www.cliosport.net/forum/showthread.php?609418-P0300-Random-Multiple-Cylinder-Misfire-Detected-and-fuel-trim-**HELP**&p=8172934#post8172934

 

[Freeman_1986]

Mine was like that. Turned out the timing was out

 

[Fastchip]

I would have thought an injector fault would have shown up on the ECU?

The mechanical part of the injector is not 'seen' by the ECU

 

[Chambers-182]

My 182 was like this a few weeks.. Injector 4 was f**ked.. £45 for an injector frm euro car parts sorted it.. Only took 10 mins to change

 

[Bass1st]

I changed the injectors and did a track day at Mallory Park today. Problem occured after an hour. I then changed the crank sensor and it worked fine for 4 hours, so hopefully I have found the issue.

 

[Bass1st]

Took my 172 to Donnington today for my first track day of this year- started playing up again with the same symptoms. Let me recap;

Car runs fine, then all of a sudden it will loose all power and run really badly. The car does not stall, but you get little or no throttle response. All of a sudden it will kick back into life and run fine again. It seemed to fail most often just after a heavy braking area and as you accelerate out of a corner.

The good news is today I have my RS Tuner with me. I managed to replicate the issue in the pits by getting the failure on track and coasting in. Sure enough, the car runs rough and then all of a sudden corrects itself. Attached is the screenshot where the change happens. Its definitely a fuelling/ignition related issue, but no clue what is causing it. Wriggling cables made no difference!



The only ECU errors showing are for the canister (which has been removed) and the front O2 sensor which has been replaced. I think this error is a symptom of the issue, not the cause.

I also took a video of the engine when the problem occurred and a few seconds before the end the engine corrects itself.

http://youtu.be/i5BMbkr8Mpo


To try and resolve this issue I have previously changed the injectors, coil pack and crank sensor.

Any ideas??

When the car is running its a joy, but this intermittent issue is a real pain in the bum!

 

[davemittell]

have you checked the map sensor? try popping it out and giving it a clean with some brake cleaner. if there is crap getting in there or is clogged will caue all manner of faults. I had asimilar issue with a megane the other week had been to 3 different garages, came up with similar faults to yours and was intermittent. Changed the map sensor and all was good again!
check wiring to map as well as it does break on the back of the plug too!

 

[Bass1st]

Thanks Dave. Interestingly I went to have a fiddle with the car this afternoon and it won't start at all now. The engine turns over, but unless you give it some revs it just dies. I cleaned the sensor up and it made no difference, however it I tried to run the car with it unplugged it fired up OK. The engine was reving to about 2.5k and it was a bit rough, but it worked.

I have order another one of ebay so will see if it makes any difference. If not, at least I have a hard fault now on the car to fix.

 

[bengtt5]

What condition are the spark plugs in
as in the tips of the plugs ( do they all look the same)

 

[benkay]

This sounds exactly like my problem, ph1 172 also.

So far I've changed coil pack, HT leads, spark plugs and front o2 sensor (i also got this fault on RS Tuner).

Have you got to the bottom of it yet?

 

[Bass1st]

Not yet Benkay. I will try changing the MAP sensor this weekend and see what happens. Will let you know...

 

[MullyBaby]

That data graph shows your O2 sensor isn't working, did you use a decent make? And did you plug it into the correct loom? Didn't plug the front into the rear loom etc?

 

[MullyBaby]

Unplugging the map sensor will just force the car to revert back to open loop so would run ok as it won't use any sensors. Ignition advance was going crazy, I'd start with the O2 sensor and check the knock sensor.

 

[benkay]

For what it's worth I was having exact same problem as OP.

I swapped the front O2 sensor (lambda) for one off a scrap car. This didn't cure it so I went off on a route of HT leads etc etc

Nothing worked so I bit bullet and bought a new Bosch lambda. There was always a O2 sensor fault showing on diagnostics but, like the OP, I assumed this was a result of spurious readings caused by the real problem.

Anyway, fitted new lambda yesterday. Fault code has been cleared and stayed away on RS Tuner. Car running great!

So, for what it's worth, that was the fault with mine.

 

[Xanda73]

For what it's worth I was having exact same problem as OP.

I swapped the front O2 sensor (lambda) for one off a scrap car. This didn't cure it so I went off on a route of HT leads etc etc

Nothing worked so I bit bullet and bought a new Bosch lambda. There was always a O2 sensor fault showing on diagnostics but, like the OP, I assumed this was a result of spurious readings caused by the real problem.

Anyway, fitted new lambda yesterday. Fault code has been cleared and stayed away on RS Tuner. Car running great!

So, for what it's worth, that was the fault with mine.

Did you also have a strong smell of unburnt fuel?

 

[benkay]

Honest answer I don't know as I never managed to get it to happen when I could run round the back of the car to find out.

Nothing noticeable from the cabin when it happened though.

 

[Junior Bear]

Having major problems like this yesterday and today, had a new exhaust system installed and it's running like a bag of shite, but comes to life full power intermittently

I've got an rstuner but it says it
Can't identify ecu?


Cleaned both lambda sensors and tried another postcat sensor and no joy


What's annoying is its all began since the new exhaust

 

[benkay]

You want to try a new pre-cat lambda mate. Post cat doesn't really do anything other than check emissions levels. Pre cat adjusts fuelling levels so is the one you ought to check.

 

[Junior Bear]

Can you remember how much you paid for the oem sensor?

 

[benkay]

Nope. There was/is a group buy in the marketplace section for them.

 

[Junior Bear]

Update

Just had a Bosch pre lambda sensor fitted and it has cured it so far

 

[Bass1st]

Update: Fault finally fixed! It was the connector between the O2 sensor and the main loom. One of the four pins had broken and was making an intermittent contact. I would never have found this without the help of the boys at Pyro in Barwell and an hour at Bruntingthorpe today doing a shakedown test.