OBD2 fault code question

[deano2469]

hi guys, i recently bought the following...
2014 Mini Auto Car V1.5 ELM327 OBD2 Bluetooth off ebay.
I also downloaded Torque pro on my android phone.What a great little unit. Had fun playing with it. I looked at the fault codes and got a bunch...Being that i had done an awful amount of things to the car over the last year i figured i would clear the faults and then drive a bit to see what came back. I have dual fuel and as yet have not changed plugs or leads in a while...i will get to it...it backfires occasionally when you take off to quickly from stop.The rest of the time it seams ok...anyway, i read the codes again a few days later...no faults, we drove last night and the car popped once, then was ok for the rest of trip. I read the faults again today and found the following. P0201-P0108 power train-injector circut and P1201-P1208 power train. I was wondering if these are because of the LPG tricking the injectors...the stall after backfire...or perhaps the cause of the backfire....any thoughts would be appreciated.

Deano

[TheTree]

Mate I never had an spurious codes like that on my LPG system

Maybe run it on petrol for a while and see if the codes recur ?

Steve

[glenhendry]

I havent seen those faults, but if you are having inlet manifold popping, then you are very likely to have damaged the MAF and/or the intake tubing or the airbox. These engines are very sensitive to correct MAF readings, and inlet leaks after the MAF sensor. The MAF are not durable against those backfires, also, they can get damaged and still give valid 'looking' values.

My suggestions:
1. Ensure intake tubing is in great (not good) condition
2. Clear faults
3. Run on petrol for days/weeks, check for faults and monitor fuelling
4. Check your long term fuel trims and close out faults one at a time
5. Be happy :)

What type of LPG system is it?

[deano2469]

Hi Glenhendry, it is an OMVL system, with a venturi ring inside the rubber air inlet.I have had an intermittant issue with this system since buying the car and have been through a few airboxes. I believe the air tubes to be perfect, I did have them just tight enough as to stay on and in event blow off rather than destroy themselves as backfiring was really bad. I changed plug gap about a year ago and have changed plugs every 10,000 since putting this engine in...had same issue with older engine too. Had no issues for that year then after being off the road for three months doing EAS problem has come back. I will change plugs again and leads then as you suggest drive on petrol for a while to check faults. As it stands i have an intermittent bad idle...when it starts to idle rough i am most likely to get a pop on take off...i think the faults come as engine cuts out but not certain.Once I have spent a penny i will check again, also want to invest in a steel , landrover discovery air filter in case issue persists.Thanks for response.

[Hoges]

Hi Glenhendry, it is an OMVL system, with a venturi ring inside the rubber air inlet.I have had an intermittant issue with this system since buying the car and have been through a few airboxes. I believe the air tubes to be perfect, I did have them just tight enough as to stay on and in event blow off rather than destroy themselves as backfiring was really bad. I changed plug gap about a year ago and have changed plugs every 10,000 since putting this engine in...had same issue with older engine too. Had no issues for that year then after being off the road for three months doing EAS problem has come back. I will change plugs again and leads then as you suggest drive on petrol for a while to check faults. As it stands i have an intermittent bad idle...when it starts to idle rough i am most likely to get a pop on take off...i think the faults come as engine cuts out but not certain.Once I have spent a penny i will check again, also want to invest in a steel , landrover discovery air filter in case issue persists.Thanks for response.

Before you go spending your hard earned $$$ on more plugs and leads: The leads should last for several years if they are kept clean and are mechanically "intact" i.e. they have not been mechanically damaged and both plug ends are solidly attached.

Re. Code P0201:

I find it curious that modern spark plugs would last only 10,00km ...

* When you removed the last set were they seriously worn? ..
* Are the plugs of the correct heat range?
* Have you checked the integrity of the wiring in the injector circuit? see http://www.obd-codes.com/p0201

Re Code P 0108:
A major trigger for this code is a vacuum leak. Are you sure you do not have a vacuum leak?
While your hoses maybe quite OK, the upper intake manifold may need to be re-torqued as it could be drawing air in around the gasket.

check your Long and short term fuel trim values on the Torque app when running on petrol? If they are constantly positive and higher than say 2-3% then you probably have a vacuum leak post MAF.

FWIW: My 4.6 was running lean (high Short and Long FTs on the Torque app. 25%...max value!!!) and I finally pinned it down : discovered "by accident" that the plastic 1/4"BSP fitting which screws into the inlet manifold and accepts the breather hose from the RHS rocker cover, had a hairline crack just at the beginning of the threaded portion! It was drawing in sufficient air to exceed the 25% maximum fuel enrichment compensation available from the 'closed loop' fuel mapping. Replaced it with a $3 brass fitting from Repco (vs $8 for another OEM plastic one...) there's a write up on this earlier in the P38 section.

The following has some good info on Code P0108 which might be worth following up http://www.obd-codes.com/p0108

[deano2469]

Hi Hoges...glad for the response, firstly it highlighted the fact that can't read my own handwriting...the codes were P1201-P1208 and P0201-P0208. with regard to air leaks...I will check over again, not too sure how to use the torque app properly yet so those values i can check for now, cheers. Also I had issues with plugs getting a brown build up on them, I assume from my last engine which is now similar to the k's on this replacement, was getting water in the cylinders..when heads came off, bolts were loose..these plugs don't get like that but are very sooty and are not expensive so kept the habit. As such, the leads get pulled on and off a fair bit. I had the end of one come off in my hand at the 90 degree and am using a spare...i assume there could be a weakness in more of them so new leads.I use NGK BP5ES plugs at .9 gap. On old engine, as soon as i gapped them smaller, the backfires went away...thats why i feel the prob is electrical.the P0201 code is interesting, my LPG switch on the dash has on, off and LPG, i thought as the car backfired and stalled with ignition on, it may be the cause of the fault. I will however look into injectors as idle is rough but intermittently. On my car, the breather hose goes from the rocker cover to the airbox and the inlet on manifold is blocked off, was when i bought the car.
Heaps to look for, sorry for the bum steer with wrong code....will keep you posted, anything i've mentioned that you have ideas on , feel free, thanks again.

[deano2469]

hi again, I drove to work and back last night, 100 k's round trip.I opened the app, checked for faults...none. Looked at vacuum and was 12.9 as seen in pic test 1. I drove round trip on petrol.During this trip the vacuum kept bouncing between vacuum and boost and no data...it settled on 12.9 The trip home i did all again and the vacuum went to 10.3 and was constant...I figured ok i have a leak. This morning i drove again, this time on lpg, flicking between petrol to gas when warmed up as this also causes either a stall or backfire if done too soon, anyway, no backfires at all even tried to get it to do it to see if i got a fault, nothing....I stopped for fuel and remembered i had a little chip for economy/power(most likely crap but anyway) plugged into the air sensor at the airbox. I took it off and drove home with no noticeable change...the only thing was the vacuum now says 2.3 as per pic 2...so no leaks?..i am at the least confused. Is it possible for sensor to be stuffed?..i don't think the chip would make a difference...it hasn't before. It is supposed to tell the computer its got cold air all the time to change the advance but i don't know how true that is.Anyway, more to think about.

and I forgot, even with no backfires i got the same codes come up on the last trip from servo to home P1201-P1208 and P0201- P0208...car was on LPG and started on LPG after filling and no dramas...rough idle came and went with no issues.

[Hoges]

Hi Deano
suggest you read http://www.aulro.com/afvb/p38a-range-rover/172248-high-long-term-fuel-trims-why.html
Apart from vacuum, would be helpful to get info on the actual fuel burn as per Glenhendry's post with the thumbnail screenshot of the Torque App. If you can set up your App similarly and get some Short & Long Term Fuel Trim data it might well shed more light on the issues.
cheers

[peter51]

is this a gas injection system.? Is it a GEMS V8 or a Bosch one? Your obd faults are a wiring loom issue. Has someone hacked into the injector loom at all? Look for any stray wiring going into the main loom.

[peter51]

The codes are related to all your injector circuits,so it points to either a poor earth or some hack into the ECU. the injector circuits either have voltage present when they should not, or a disturbed/ poor earth path. The ECU uses a transisor to provide an earth path for each injector in sequence.
Look for some evidence of wire hacks into the ECU or ECU earth main earth.Look also for a hack into an earth path on the ECU loom itself.
These sort of faults should never manifest themself in a good wiring loom. They are very rare codes.

[glenhendry]

The lpg system cuts the fuel injectors. I also get 8x injector faults when running on lpg.

[peter51]

I assumed even the simplest LPG systems would have a simple emulator to simulate the operation of the petrol injectors to ensure the vehicles ECM detects no change to its injector circuit. I thought the majority of LPG systems had a slave ECU to do this job.Obviously not with glenhenry,s car.
However,If there was an LPG slave ECU then such faults might occur with poor electrical work. So glenhenry does not have one and I assume you do not have one as well.
Sorry about the misinformation..

[glenhendry]

You are right, they do have emulation, but the THOR ecu is too clever, it is not fooled by the emulator. Also, the O2 sensors get emulated by the LPG, but the THOR ecu sees through that too, it tries to tell the engine ECU that the lamdba is 0.45v (not rich or lean) and keeps the real value for its own mixture measurements, but the THOR ECU gets suspicious and throws faults. I even went to the LPG ecu manufacturer folks and we changed the type of emulation, there are several (square wave, flat line, etc) and it still expects to see more 'real looking' changes in the signal and eventually throws O2 faults and injector faults, eventually it goes into open loop mode.

I can clear the faults and all is good again, but for the last 2 yrs I have abandoned LPG entirely, and just use petrol. I must add, that LPG systems better than mine, may well do a better job of fooling the THOR.

The LPG system taps into the O2 sensor wire and the earth for the fuel injectors, and I have often wondered if the extra wiring and connectors are affecting the signal coming back from the (sensitive) O2 sensors, and causing my rig to have LTFT of ~+18% on both banks. I have chased every air leak, and replaced the sensors.

[deano2469]

Thanks to all players...I have run a few tests over the last few trips to work...I did a fault check...none, started on petrol and switched to lpg and back during a run, fault check...still none. the obd2 has a different vacuum value every time i drive..last time was 7.9...Hoges, I tried the fuel trim thing...stays on 100, probably got the wrong one. Glenhendry could you please give me a guide to which apps to add as there are a few. My MAF reading goes from .1 at idle to .4 at cruise at 100kmh.Peter51,I will endeavour to go through the wiring now that the switching doesn't seam to give the faults.Mine is a 96 GEMS as well, might be different to set up for a THOR.O2 sensors stay at zero and not working.loving the journey though, having to run on petrol is a pleasure to everything but my wallet...

Cheers

[glenhendry]

We need some units for those MAF values.

GEMS o2 sensors are 0v-5v. Wideband.
THOR o2 sensors are 0v-1v. Narrowband.

MAF sounds way wrong, mine goes from ~5->~100 (I thing grams/sec). Like I said, any popping or backfiring (even once) is possible to damage the delicate MAF. Strange that you are not seeing MAF faults tho. Here is all the MAF values (http://www.aulro.com/afvb/p38a-range-rover/165502-thor-maf-values-how-test.html#post1820908)you need to test.

Text your number to 0414 678 88eight and I will shoot you a torque screenshot. I will try to add a screenshot of all the value later tonight.

[peter51]

deano2469
My advice deano is to get a obd pid parameter recorder. They are on the internet for PC. GLM software is good - Australian company you can call.
You need to record a data stream as shown below. Forget about codes. They dont show the full story. They just cause false conclusions. You need the data steam to do the detective work as to why the ECU " thinks" it has the correct code.

This data stream below shows a bad MAP. You will get the idea by following the clues. look at the MAP voltage, and you see it is far lower than it should be. 0.4 instead of 1.0 I know you have MAF but it is the same principle.And remember how important the load sensor is when setting the basic injection pulse width? So with a low value for MAP, the whole computer calculation would give us a lean mixture all the time. Even the O2 wouldnt be enough influence to fix it. Although it may try, and you may see the LFTRIM go rich to try to help. This is a very common problem to fix by the way, and if you dont know the exact values for the MAF sensors you are working on, you wont be able to catch it. Check RAVE. By the way, the easiest and most reliable way I have found to catch a bad MAF sensor it to check the value with the key on, engine not running. Compare it with what the value should be with no vacuum or the throttle wide open, and you can get the first clue. Anyway hopefully you get the idea and maybe someone can post normal values for you from their vehicle for you to compare.
Please post you O2 values. Are they swinging rapidly from .45 to .8.
BTW I am on the sunshine coast and may be able to help out next week - but in the interim get yourself a data stream to investigate- you will work it out.

[TheTree]

MAF Readings

At Idle...................... 20 kg/hr (5.5 g/s) ± 3 kg\hr (8.3 g/s) (^)
At 2500 rpm............... 61 kg/hr (16/9 g/s) ± 3 kg\hr (8.3 g/s) (^)
At 3000 rpm............... 90-100 kg/hr (25-27.8 g/s) (*)

22-25kg at idle,90-100kg at 3000rpm in neutral,engine hot all loads off.

At Idle 20 ± 3 kg/hr
At 2500 rev/min 60 ± 3 kg/hr ..

Steve

[glenhendry]

MAF Readings

At Idle...................... 20 kg/hr (5.5 g/s) ± 3 kg\hr (8.3 g/s) (^)
At 2500 rpm............... 61 kg/hr (16/9 g/s) ± 3 kg\hr (8.3 g/s) (^)
At 3000 rpm............... 90-100 kg/hr (25-27.8 g/s) (*)

22-25kg at idle,90-100kg at 3000rpm in neutral,engine hot all loads off.

At Idle 20 ± 3 kg/hr
At 2500 rev/min 60 ± 3 kg/hr ..

Steve

There is an error in these values, I created them and screwed the maths. Please find the correct values here (http://www.aulro.com/afvb/p38a-range-rover/165502-thor-maf-values-how-test.html#post2283423).

At Idle...................... 20 kg/hr (5.5 grams/sec) +/- 3 kg\hr (0.8 g/s) (^)
At 2500 rpm............... 61 kg/hr (16.9 grams/sec) +/- 3 kg\hr (0.8 g/s) (^)
At 3000 rpm............... 90-100 kg/hr (25-27.8 grams/sec) (*)

Bibliography:
(^) - RAVE & MAF Values (http://www.rangerovers.net/forum/7-range-rover-mark-ii-p38/18164-maf-values.html#post161516)
(*) - P38A P38 4.0 HSE MAF SENSOR DATA Is it working? Whats wrong? Please help. - Page 2 - Land Rover Zone (http://www.landyzone.co.uk/lz/f10/p38-4-0-hse-maf-sensor-data-working-whats-wrong-please-help-194493-2.html)

[deano2469]

hi again all, merry xmas. I get a bad reading when MAF is plugged in and no reading at all when its not. It runs the same either way...i will have to get a good used or cheap new MAF in the new year, bit short currently. thanks for all info guys, I will reassess when I get the new one.

[TheTree]

hi again all, merry xmas. I get a bad reading when MAF is plugged in and no reading at all when its not. It runs the same either way...i will have to get a good used or cheap new MAF in the new year, bit short currently. thanks for all info guys, I will reassess when I get the new one.

Mate

have you tried some MAF cleaner on it?

Steve

[deano2469]

Hi Steve, yes mate, just today i did oil and plugs.while I had Maf removed for access, I sprayed some carby cleaner on it and blew out with air..now I get a posative reading of .1 g/s at idle and .5 g/s at about 2000rpm. Not right but at least its something. Idle is not as rough now either but that could be the plugs.

NB, g/s from memory as i sit upstairs, the reading from the OBD2 and torque pro.

cheers.