desperate need for emmisons help!

Hi all

I'm quite new on here and need some advice with my emmisons please

Car is a 1998 4.6 HSe with 200k miles

I could smell petrol while on tickover so though I'd get an emissions test done, here are the shocking results...

CO: 11.403% (limit is 0.300%)
HC: 435ppm (limit is 200ppm)
LAMBDA: 0.682 (limit is 0.970-1.030

The car wasn't completely hot which could play a part, also on tickover there is the slightest hint of rough idle (makes me wonder if an injector could be failing)

Could someone help me out please?

Thanks

Chris

New air filter, plugs and a good rag down the motorway for a start. Not a petrol man so don't know what the cold start device is on your motor but it could be overfueling. Over to anyone who has a better idea

Check out Range Rover P38 fire warning

Even if heat shields still in place that rubber pipe is a weak spot and needs changing. Two p38s last year went up here.

Heres another one, same message on another site but different replies so read all.

Don't panic its only a pipe - but a very very important one and needs doing correctly, also check the integrity of the petrol line from the tank and return lines to the tank. These messages cover the GEMS engines THOR engines have a different fitting and no return.

Lambda sensors & possible shot catalyst converters, need to fix the fuel leak first
Also worth to check rocker cover breather oil separator

See they only needed prodding

Druim said:

Lambda sensors & possible shot catalyst converters, need to fix the fuel leak first
Also worth to check rocker cover breather oil separator

Click to expand...

Good advice, when all done get a diagnostic to check and reset the fueling

Because the Lambda reading is so low and Co so high its clearly running way too rich.But the Hc's tell me the cats are trying hard to do their job.
The rough idle indicates misfires,which will drive the short term trims rich in trying to get the sensors to switch.Each misfire sends a large slug of oxygen and unburnt fuel down the pipe - which the oxygen sensor sees as a lean mixture - so it widens the injector pulse even more.
Fix the misfire - all your problems could be down to a couple of dodgy plugs or leads.DONT change the oxy sensors or cats until you have 8 cyls that don't misfire.Equally,dont get an adaptive reset done until after the misfire is sorted,a reset could make matters worse if the maf is reading low etc.

eightinavee said:

Because the Lambda reading is so low and Co so high its clearly running way too rich.But the Hc's tell me the cats are trying hard to do their job.
The rough idle indicates misfires,which will drive the short term trims rich in trying to get the sensors to switch.Each misfire sends a large slug of oxygen and unburnt fuel down the pipe - which the oxygen sensor sees as a lean mixture - so it widens the injector pulse even more.
Fix the misfire - all your problems could be down to a couple of dodgy plugs or leads.DONT change the oxy sensors or cats until you have 8 cyls that don't misfire.Equally,dont get an adaptive reset done until after the misfire is sorted,a reset could make matters worse if the maf is reading low etc.

Click to expand...

Agree that you should not do an adaptive reset until all the jobs are done but a diagnostic now with live data should show where the problems are or everyone is guessing. Fix misfire is good advice.
Druim is right though - fix that petrol leak first

stopover said:

Agree that you should not do an adaptive reset until all the jobs are done but a diagnostic now with live data should show where the problems are or everyone is guessing. Fix misfire is good advice.
Druim is right though - fix that petrol leak first

Click to expand...

If it was Motronic you might have a chance with live data,with Gems all you will see is massively positive fuel trims.
An inductive clamp on a scope looking at HT waveforms is more like it.

Wow thanks for the advice guys

Just to clarify though, I smelt petrol coming from the exhaust pipes so there isn't a leak upfront (thankfully)!

I had a look at the pipework between the Maf and the engine and noticed it had a crack... Which hopefully, now replaced will cure it? Although after I started it up, it still seems slightly rough. Would a good run tomorrow help with that or would it need to be reset?

I have a mate who has the odbc connection with some cheap software on his phone, if I exchange beer tokens is that likely to tell me if there is a faulty injector?

If none of the above works, is there a way to test for faulty injectors?

Again, many thanks for any help!

Chris

chriswood6725 said:

Wow thanks for the advice guys

Just to clarify though, I smelt petrol coming from the exhaust pipes so there isn't a leak upfront (thankfully)!

I had a look at the pipework between the Maf and the engine and noticed it had a crack... Which hopefully, now replaced will cure it? Although after I started it up, it still seems slightly rough. Would a good run tomorrow help with that or would it need to be reset?

I have a mate who has the odbc connection with some cheap software on his phone, if I exchange beer tokens is that likely to tell me if there is a faulty injector?

If none of the above works, is there a way to test for faulty injectors?

Again, many thanks for any help!

Chris

Click to expand...

What makes you think it's an injector? If it's been running very rich then the plug's are probably fouled up, clean/change them

Fair point

I have just bought a new set of plugs, leads and a new air filter - so will change them over this afternoon and see what happens...

Looking at the leads, some of them are red and some are black, suggesting they are of different ages - could all be down the the leads maybe?

Seeing as there is a franchise on my doorstep, I have also booked in a "Terra-Clean" on the engine next week. Has anyone used this system before? Home | TerraClean

Many thanks

Chris

Leads sound the likely culprit then if they are a mish mash set. Check the condition of the coil pack while you're changing them. Ngk plugs are the best.

Cheers for the input

How do I go about checking the coil pack - just look for anything obviously broken / fouled up?

Chris

Just check for corrosion when you remove the old leads. You have the same model as me, so the straight line coil pack tucked behind the plenum. I changed half of my coil pack soon after I got the rangie as 2 of the ports were quite badly corroded and had the same symptoms as you describe.

I have looked at the 'terra clean' franchises. I decided they are very effective to charge lots of money for very little value.

My opinion anyway.

Money would be better spent replacing plugs and leads as suggested. I always recomend an oil and filter change as well when its been running that rich, and clean out any engine breathers.

If its still misfiring get a 'good diagnostic garage' to interrogate the engine ECU, he will spot if you have a duff coil, or just a vacuum leak on hose. He wont be cheap if he is good, but lots of time saved and money saved on not replacing parts that didn't need it. I appreciate many people like to sort things themselves, but its not always cost effective!

If these cheap code readers and phone apps were reliable, why would a good diagnostice guy have 20 or 30 grands of diagnostic worth kit?

Like I said - my considered opinion

kevwill said:

Just check for corrosion when you remove the old leads. You have the same model as me, so the straight line coil pack tucked behind the plenum. I changed half of my coil pack soon after I got the rangie as 2 of the ports were quite badly corroded and had the same symptoms as you describe.

Click to expand...

Bugger, I was going to say hold the ht lead, stand in a bucket of water and get someone to start the motor. If you feel anything it's ok.

Check ignition system and compression

Hi Chaps,

Quick update...

Leads and plugs changed and the smell of petrol from the exhaust is a lot better, as it the Rickover - happy days!

But... I've just looked at a plug and it's pretty black, suggesting it's still running rich. Does anyone know if the car needs to be reset (and how I do it) or will the car adjust on its own with some time and mileage?

Thanks again

Chris

--------------------------------------------------------------------------------

Hi Chaps,

Quick update...

Leads and plugs changed and the smell of petrol from the exhaust is a lot better, as it the tickover - happy days!

But... I've just looked at a plug and it's pretty black, suggesting it's still running rich. Does anyone know if the car needs to be reset (and how I do it) or will the car adjust on its own with some time and mileage?

Thanks again

Chris