Laguna II has developed a drinking problem....

Renegade Mechanic

If Jesus sees this :rolleyes:
My 03 Laguna with a 1.6 k4m engine without the variable inlet cam has gotten a bit hard on petrol and at an inopportune time too. Im doing rather heavy mileage at the moment (900mls per week) and at below 30mpg instead of 46, Its something Ill be looking to fix quickly!
I just cant get the time to fully investigate but heres what Ive checked on the quick so far.

Wheels and tyres ok.
All brakes are free.
No engine light.
Engine itself is not misfiring and sounds acceptably smooth at idle (coils are notorious on these)
Full service 7k (oil, air and plugs, every time) ago so not due for another 2k
Air filter is not dirty
Cat seems ok (No exhaust rattle at least)
No smoke when driving either. And oil level is fine.


Now the things I have noticed.
Took out a plug and its black which is to be expected I guess given the circumstances.
It will cruise easily and accelerate softly without a problem but it does feel a little restrained under hard acceleration. More pronounced when cold, sometimes even hesitating.
It has gotten a little lazier when starting. Though its a starter I bought and had reconditioned about two months ago so that might be a seperate problem :rolleyes:

Im off for three days next week so will have time to pour into it. What I need are more experienced fellas than I to give out a few Ideas so I can start somewhere clever and fix it quickly as I doubt those three days will stick.

Any advice at all is more than welcome and Im more than prepared for the quips that come with being the mechanic that drives a Renault:p

dieselbug

Get it read for codes and then you may have somewhere to start from.

Renegade Mechanic

Yeah, Ill have access to a clip so Ill use it on tea break tomorrow. If I see no faults, I might book it in altogether for a deeper look, read parameters and the like.

jayok

Not sure how you got on, but I had something with a knock sensor on a Honda. Basically the sensor was broke and giving false readings, so that the ignition timing wasn't able to advance to the optimal point, as such it was drinking fuel and sluggish to move. Eventually it gave up a P0325 code and once replaced, it was sorted.


Just another angle.

Renegade Mechanic

Thats a decent angle tbf, jayock. No faults on the clip but didnt get to look at parameters. Emission test shows the cat is struggling though. Absolutely no oxygen and a ppm of 360. More than Im happy with though CO is right at the limit. As a side note, I was running late this morning so I drove it on. Mpg for harder driving hasnt changed at all (~25mpg). Despite feeling choked over 4krpm. Have some time to myself tonight so Ill service it altogether and clean the throttle body. Pretty sure it wont be at fault, given I clean it every time but Ill get to have a proper look for anything obvious. At any rate, many thanks for that, I actually have a spare one at home from a laguna I striped a while back. Might stick it on

dgt

Could be a fecked oxy sensor.

Shove a bottle of this in the tank and see if it helps

dieselbug

If you have a spare map sensor it might be worth a try.

Surprising there no codes if it's running so rich. Was it genuine clip or a clone?

Renegade Mechanic

dgt, that looks good and I suspect Ill need it quite soon..

diesel bug, Im not sure on this but I think the Ecu's interpretation of the upstream O2 sensors have large emissions limits to allow for cold running and wide open throttle acceleration. Downstream just make sure there is very little O2 post cat, to let the ecu know its doing its job. (but none at all is not good).

At any rate Ive hit a rather unfortunate discovery:(
I noticed a little blue smoke during acceleration onto the motorway and pulled over soon after for a look at the oil level. I really, really should have checked the oil level more often.. I dipped it and the oil level was near the end of the dipstick. Pic below will show:

Ive taken just under 9.5 Ltrs of extremely thin and petrol smelling oil out of the car. Even cold, its more like water!
Video of cause will follow If I can upload the bloody thing:mad:

Renegade Mechanic

Ok heres the video. Its of the number one injector (four on everything else) disconnected from electrical power but left on the rail while the pump primed the system. It doesnt remain closed (fully), allowing fuel into the manifold between openings.

Not happy.. But its the cause at least. Ive done at least 1800mls like this, likely significantly more. I have a spare injectors so sorted there. At some stage, Ill be doing an oil pressure test, compression test and re testing emissions. Im expecting damage to be honest. Possible bent conrod and petrol isnt famous for its ability to lubricate cylinder walls.... Im hopeful the oil pressure might be good. Emissions might be better too. A few weeks from now mileage will be much more acceptable (~300mls). Is that an overly optimistic forecast? If damage is done, could I expect to get long out of it. I have no intentions of selling it. Ive spent far to much keeping it the condition its in and It hasnt missed a beat. Itll just be some time before I have time to swap an engine. (A bit funny really, just last week I was discussing swapping the engine for a bigger one but that wouldnt have been till mabye late next year..) Thanks very much for the replies people:)

Edit: Screw the video..

dieselbug

I would have thought this would have triggered a code for a rich condition as the o2sensor would have "seen" it as such.

Maybe im missing something, my brain is tired.

Renegade Mechanic

dieselbug wrote: »

I would have thought this would have triggered a code for a rich condition as the o2sensor would have "seen" it as such.

Maybe im missing something, my brain is tired.

Possibly. I remember a 2.0 espace on another website doing 25mpg at best. No engine light and no fault but it turned out to be that sensor anyway. They just changed it and it worked.. Granted that was in reverse to my O2s scenario but my point is theyre hard to trust for the importapart. The very millisecond the heater wire stops though :rolleyesş

Renegade Mechanic

Update. Fuel economy is acceptable now at 40mpg, nothing more. Oil pressure was good enough for me at around 6 bar and power wise, it's ok too. Its burning a little oil but no real smoke, about a litre every thousand miles. Compression test not so good either.. again just under 200psi across pistons 1-3 with a fluctuation of 8psi. Cylinder number 4 however peaked at 165psi. Its damaged Im afraid. Though the engine still cruises alright, its just hard acceleration(overtaking) thats not what it used to be. Personally, I dont see this presenting a big problem for a good while yet. Im just wondering can the "teaspoon of oil" trick, used to differentiate between worn rings or worn valves, be used to tell between worn rings or a bent conrod? At any rate, Im a free man for a while now and Ive got a game, some drinks and a warm room so for now, Im good:) Thanks for the tips lads and Ill definitely be using cataclean before the nct!

galwaytt

Dang- that's familiar territory to me: albet on a 'bike............

Long story short, you've got borewash. Mine caused by a faulty (from new) thermostat. Basically on my 'bike the 'stat isn't letting the engine warm up properly, and it's more or less on cold start settings all the time, so over-fuels. This then, like your car, sees oil level rising, is fuel is being washed past the rings into the sump.

In the 'bike I have the oil pump is driven by a plastic gear which is.......you guessed..........not immune to attack by petrol.......... yes, (really....), teeth part company with gear, pump skips a few rpm every now and then and............oil pressure goes to zero every so often. Cue 1 x fubar'd engine.

http://galwaytt.smugmug.com/Motorcycles/test/10479236_hnNX7M#!i=752585794&k=CT98qZx

galwaytt

Renegade Mechanic wrote: »

Update. Fuel economy is acceptable now at 40mpg, nothing more. Oil pressure was good enough for me at around 6 bar and power wise, it's ok too. Its burning a little oil but no real smoke, about a litre every thousand miles. Compression test not so good either.. again just under 200psi across pistons 1-3 with a fluctuation of 8psi. Cylinder number 4 however peaked at 165psi. Its damaged Im afraid. Though the engine still cruises alright, its just hard acceleration(overtaking) thats not what it used to be. Personally, I dont see this presenting a big problem for a good while yet. Im just wondering can the "teaspoon of oil" trick, used to differentiate between worn rings or worn valves, be used to tell between worn rings or a bent conrod? At any rate, Im a free man for a while now and Ive got a game, some drinks and a warm room so for now, Im good:) Thanks for the tips lads and Ill definitely be using cataclean before the nct!

Out of curiousity, why do you think the conrod is bent - did it hydraulic ? If it did I'd have thought your timing belt would have gone awol...........

I'd be inclined to think it's bore or ring wear. A hone and a new set of rings might cure it sufficiently.

Renegade Mechanic

galwaytt wrote: »

Out of curiousity, why do you think the conrod is bent - did it hydraulic ? If it did I'd have thought your timing belt would have gone awol...........

I'd be inclined to think it's bore or ring wear. A hone and a new set of rings might cure it sufficiently.

I was toying with the idea that mabye the cylinder had a little petrol in it on start-up but given that its burning oil, it dawned on me that it must be the rings/wall. Should be able to do it without removing the engine. Did it ages ago on a clio by removing the head and dropping the sump. Only replaced the big end bearings, never removed the crank. (170k miles and still running fine:D) Tbh, If I have to remove the engine, itll be to stick something rather bigger in its place. As it stands though its running well, consumption is ok and emissions are good again. If I get next year out of it (will only be doing about 350mls a week from August and I can be a very light driver) Ill be happy and will "s**t or get off the pot" re any engine work.