Fault codes !

ukadamwest · Apr 5, 2015

P38 Bosch Motronic. LPG/Petrol.

Hi all,

Last night the P38 misfired whilst running on LPG.. switched to petrol and no problem at all. good pick up, no mis-firing, smooth and clean..

Fault codes just read are as follows

6 showing.

1 - P0134 - 02 Sensor
2 - P1300 - Misfire
3 - P0303 - Misfire
4 - P1319 - Misfire - Low Fuel
5 - P0300 - Misfire
6 - P1000

Non are showing as persistantly present. Cleared the codes and will see what pops up again.

In the meantime, i'm wondering if this was OK on Petrol but not on LPG could this be as simple as the LPG filter needing a change ?

ukadamwest · Apr 5, 2015

Ok just ran it again on petrol, and fault codes are back up

1 - P0134 - 02 Sensor
2 - P1300 - Misfire
3 - P0303 - Misfire
4 - P1319 - Misfire - Low Fuel

And now showing as persistant !

Just had a thought.. it was running well and good but have just changed the waterpump, t-stat and Vicsous fan.. if the CPS got wet during the water pump change would that cause these faults being thrown ?

??

Saint.V8 · Apr 5, 2015

there is a good possibility of that...

The ECU detects misfires by analysing the knock sensors...and determines which cylinder by CPS position.

But also cos you have an O2 sensor fault and also misfires and a low fuel fault, I would strongly think the Lambda in question is dicky!

This will cause mis-fuelling and the potential for misfires due to incorrect fuel/air mix!

If you have access to live data, check the fuel trims and also the lambda voltages to see if they are switching or changing !

ukadamwest · Apr 5, 2015

Ok saint. i will do.

I sincerely hope its not the lambda sensors.. getting them out on the classic was impossible ! Bought the actual lambda sensor socket and it bent out with the breaker bar. and that was with the cats off the car - i replaced with new !

wammers · Apr 6, 2015

Code Psense on petrol engines means "Fit diesel".

ukadamwest · Apr 6, 2015

Pfft Wammers. !

ukadamwest · Apr 6, 2015

OK plugged up the faultmate, just running on idle.. only faultcode now is..

P0135 = OXYGEN SENSOR HEATER UPSTREAM CATATALYST BANK 1 DRIVE CYCLE C, WHICH HAS OCCURED ONCE
(SIGNAL TOO LOW, THE FAULT IS CURRENTLY PRESENT, THIS FAULT DOES NOT GIVE MIL LAMP ACTIVATION, THE FAULT HAS BEEN DETERMINED AS PERSISTENTLY PRESENT).

Now.. I wonder what that could mean.. Saint V8 is right again !!

Here's the screen grabs

Roughness and Timing:

Air and Fuelling:

O2 Sensor, cold from start up:

O2 Sensor warmed up:

ukadamwest · Apr 14, 2015

So changed the O2 sensor on bank 1.. it ran fine yesterday, lots of towing, then in the evening 'pop' misfire again.

Looked at the codes and getting ...

P0135 = OXYGEN SENSOR HEATER UPSTREAM CATATALYST BANK 1 DRIVE CYCLE C, WHICH HAS OCCURED ONCE
(SIGNAL TOO LOW, THE FAULT IS CURRENTLY PRESENT, THIS FAULT DOES NOT GIVE MIL LAMP ACTIVATION, THE FAULT HAS BEEN DETERMINED AS PERSISTENTLY PRESENT).

??? O2 sensors are Bearmach ones

Saint.V8 · Apr 14, 2015

If the Sensor is a known goodie....Check the wiring, connections/plugs, and trace the wiring to the ECU....bell out with a meter to check continuity...if all that checks out, a) Change the sensor for the opposite side and see if the fault follows or stays....then b) if it stays....check Cat for break up or if it follows....sensor fecked!

ukadamwest · Apr 15, 2015

Saint.V8 said:
Change the sensor for the opposite side and see if the fault follows or stays....then b) if it stays....check Cat for break up or if it follows....sensor fecked!

That's easier said than done !! it took me a couple of hours to get the bank 1 lambda out. heat, turn, realease oil, wiggle back and forwards, repeat and rinse, i haven't got bank 2 lambda out yet !

the lambdas were ordered from brit car (£30 ea) and they supplied bearmack, spoke to them yesterday and they are sending out a replacement one FOC.

Now here's a question.. on the P38 if the heater circuit one fails does it affect both (the reaon i ask is that the porsche has 4 and if one goes it can fault all 4) ??

Saint.V8 · Apr 15, 2015

ukadamwest said:
That's easier said than done !! it took me a couple of hours to get the bank 1 lambda out. heat, turn, realease oil, wiggle back and forwards, repeat and rinse, i haven't got bank 2 lambda out yet !

the lambdas were ordered from brit car (£30 ea) and they supplied bearmack, spoke to them yesterday and they are sending out a replacement one FOC.

Now here's a question.. on the P38 if the heater circuit one fails does it affect both (the reaon i ask is that the porsche has 4 and if one goes it can fault all 4) ??

Looking at RAVE, the wiring to the sensors from the ECU are independent of each other!

Common power feed from Fuse 26 though on an NK wire!....

ukadamwest · Apr 15, 2015

it's the same on the porsche, the sensors are all on separate wiring, and you can can get codes for sensors left and right bank pre and post cat, however the DME can read a fault on one and throw an error, for say the heater circuit, requiring trouble shooting to find which one it is..

so i was wondering if a heater circuit is faulty on one would it throw a code for both or the other ? i guess it's moot anyway as i have the sensors both left and right so guess will change both and see !

I'll keep you posted

mozz smith · Apr 15, 2015

hi lads , im having same problem now !!!!! obd2 check says = bank 2 lean ?????? so off to have it re-read on autologic at another garage so can get fault code etc etc ////////... what is part no for lamba sensor and best quality i.e. price and where from ??? are both sensors the same unit ???? desperate for help sainty cheers lads .... regards mozz oh just had full st of platinum plugs and compression test do9ne yesterday ???? still the same ???? £160.00 have I been smacked again ????

ukadamwest · Apr 15, 2015

Mozz i got my O2 senors from Brit Car, its a 4.6 Thor, Cost £29.30 Part Number is MHK100940A. There are two on mine Left and Right bank pre cat. Both Bearmach boxed

MHK100940A | OXYGEN SENSOR | Bearmach | | Britcar (UK) Ltd

Be prepared for some work to undo the old ones.. heat, turn, heat, turn with copious amounts of release oil.

Fault codes !

ukadamwest

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Saint.V8

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wammers

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Saint.V8

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