Car hesitant when cold

[Spotter]

Hi all, I'm hoping you may offer a solution for my sick car.

Vehicle : Fabia I, 1.4l, 16v, 100bhp, 2001, Engine code AUB

Problem: When the engine is cold, it is hesitant and lacks power and will die if the revs are allowed to drop, requiring a switch off and restart two or three times even when driving, until suddenly the hesitancy goes and the engine produces the correct power. This I am sure is temperature related. I've have fault codes relating to the front o2 sensor indicating heater and signal errors, but if the codes are cleared when the engine is warm, then no faults are flagged. I did have an issue with the radiator temp sensor, but this has been changed, and is working. I have also had faults with the EGR, however this is currently blocked off to eliminate it from the main fault.

My feeling is that the o2 sensor is at fault, but I don't have any experience in this area. If it is the o2 sensor could I replace it with a universal 5 wire one?

Thanks.

[fabdavrav]

Are you talking about the lambda sensor???

Clean the egr valve then refit as it should be.

Are you using Shell Vpower fuel or just plain unleaded?

Has the fuel filter, and crankcase breather filters ever been changed/cleaned??

Has the fuel rail been bled properly?

Is the battery up to charge at at least a 60ah type?

Are the sparkplugs the correct type and ok??

[sepulchrave]

You MUST have an EGR valve with this engine, suggest you fit a new one (ebay £60) and get it re-adapted.

The radiator temperature sensor you had replaced sounds like it relates to the electric fan so you should replace the main ECU temperature sensor (£20) which is blue and is fitted to the thermostat housing on the gearbox side of the engine at the front.

I would ignore the Lambda probe errors and focus on these other two issues first, the lambda errors will probably clear and not return if the other items are fixed since the cold-start is not affected by closed-loop lambda performance.

FYI a universal lambda probe is NEVER ok, there's a reason why they're so much cheaper than the real thing, I seriously doubt you need a new one anyway.

[Spotter]

Thanks for your replies.

Fabdavrav

Are you talking about the lambda sensor???

Yes

Clean the egr valve then refit as it should be.

Already clean, but will remove the blocking plate.

Are you using Shell Vpower fuel or just plain unleaded?

Bog standard Tesco stuff

Has the fuel filter, and crankcase breather filters ever been changed/cleaned??

Probably not. The car has only done 41k miles. I had to change the tyres last year due to perishing not wear, suspect they were original.

Has the fuel rail been bled properly?

Don't know

Is the battery up to charge at at least a 60ah type?

Not had any battery problems, always starts ok, the problems occur after starting.

Are the sparkplugs the correct type and ok??

Will check.

Sepulchrave

Will remove the blocking plate. How could I re-adapt the EGR with VAG-COM?

I don't suppose you have the part no of the ECU temp sensor to hand, to ensure I get the right part.

[fabdavrav]

Are you talking about the lambda sensor???

Yes

Are you using Shell Vpower fuel or just plain unleaded?

Bog standard Tesco stuff

Has the fuel filter, and crankcase breather filters ever been changed/cleaned??

Probably not. The car has only done 41k miles. I had to change the tyres last year due to perishing not wear, suspect they were original.

Has the fuel rail been bled properly?

Don't know

Is the battery up to charge at at least a 60ah type?

Not had any battery problems, always starts ok, the problems occur after starting.

Are the sparkplugs the correct type and ok??

Will check.

For the AUB engine the spark plus should be NGK make, type BKUR 6ET-10 only!!!!!

This engine needs to run on 98ron VPower, look in the fuel filler cap at the original sticker!!!

Best thing to do is to pour some "Cataclean" into the fuel tank and fill up with Vpower and then run car until the tank is almost empty then change filter (really needs doing every 4yrs) and when you refit the filter bled the fuel rail...there's a blue caped air valve on the fuel rail on passenger side of it...just use a rag to collect surplus and press centre stem in! have you got a haynes manual???

[sepulchrave]

EGR adaptation here:

http://wiki.ross-tech.com/wiki/index.php/Exhaust_Gas_Recirculation_%28EGR%29_Valve_Adaptation

I bought my new ECU temperature sensor from my local auto factors, they will probably have it on the shelf, a pattern part is fine so no part number is really needed.

[Spotter]

I've got the egr fitted properly, however I cannot get the adaptation to succeed, the voltage is always just over the max value. Is this indicative of a broken egr?

[sepulchrave]

Yes.

[Spotter]

Hi Guys, I have an update.

I cleared the faults last night, and found the EGR was adapted OK. Today the car was slightly better, seemed to warm up a little quicker. When I got home tonight I checked the faults once more to see that the EGR was no longer listed only the following two for the O2 sensor:

17591 P1183 Linear 02 Sensor / Reference Voltage Short to B+

17604 P1196 O2 Sensor Heater Circ.,Bank1-Sensor1 Electrical Malfunction

Does this change any of your previous - and very welcome - advice?

[fabdavrav]

17591 P1183 Linear 02 Sensor / Reference Voltage Short to B+

17604 P1196 O2 Sensor Heater Circ.,Bank1-Sensor1 Electrical Malfunction

Does this change any of your previous - and very welcome - advice?

Defo problems with one of the lambda sensors (one nearest the engine..under the exhaust manifold in engine bay) or wiring to it best to check the wiring to the sensors....inspect for breaks etc then use a multimeter to check continuity etc. Ignore the Bank1 as your engine is not a "V" engine eg V6, V8, V10, V12!!!!

[sepulchrave]

Hmmm, bad luck Spotter, looks like your expensive O2 sensor has failed after all, probably caused by overfuelling from the EGR being blanked off for so long.

Try here for proper O2 sensors at keen prices:

http://www.sparkplugs.co.uk/

[Spotter]

Thanks for your help guys. I may not have helped the situation by having the egr blocked off, however I did have the fault codes beforehand. Anyway it's time to check the wiring, and probably end up digging deep and buying a new O2 sensor.

Cheers.

Spotter

[rum4mo]

Hi all, I'm hoping you may offer a solution for my sick car.

Vehicle : Fabia I, 1.4l, 16v, 100bhp, 2001, Engine code AUB

Problem: When the engine is cold, it is hesitant and lacks power and will die if the revs are allowed to drop, requiring a switch off and restart two or three times even when driving, until suddenly the hesitancy goes and the engine produces the correct power. This I am sure is temperature related. I've have fault codes relating to the front o2 sensor indicating heater and signal errors, but if the codes are cleared when the engine is warm, then no faults are flagged. I did have an issue with the radiator temp sensor, but this has been changed, and is working. I have also had faults with the EGR, however this is currently blocked off to eliminate it from the main fault.

My feeling is that the o2 sensor is at fault, but I don't have any experience in this area. If it is the o2 sensor could I replace it with a universal 5 wire one?

Thanks.

My advice would be to check the price at dealer before buying on line, taking postage into consideration, when I priced one up, the dealer was within a £ or two - so I took the easy route, by the way, I'd stick with what the car maker fitted at factory, ie NGK or whatever NGK's Lambda trading name is - maybe NTK but you will find that on any seller that trades in NGK stuff. By the way, these codes do tend to mean that the probe has failed, mine went slowly at first, just the odd faults being logged and clearing with time (multiple engine starts with no more faults), then it became a hard fault - car performance never changed though, though maybe I caught it quickly, ie fault became permanent while I was waiting for the ordered probe to arrive. When it started to fail, did you find that the fault light only came on (if it had been previously off) after the car warmed up - for a probe failure that is what should happen as its action is inhibited when the engine is cold.

Edited 7 July, 2011 by rum4mo

[Spotter]

Hi, finally fitted the new sensor. It was much easier than expected. Solved all the problems. The readiness now shows a clean bill of health. Thanks for everyone's advice.