Low power, some smoke, then no smoke

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Glenbob

Member
Posts
11
Hi fellow addicts,
I have a 1999 (late) P38 4.6 HSE, 180,000ks with LPG conversion. Today when leaving work it started normally but ran like it had dropped a cylinder, rough and down on power. My gas had just run out and was running on petrol. It belched grey/blue smoke from the exhaust, and some from the LHS engine bay. I fuelled up with LPG within about 2 ks from work then drove about another 10 ks. No smoke issued when on LPG, but still running like a chaffcutter.

Although power seemed down it still got up to speed ok. Some strange rattling noises from the engine bay and a distinct odour of gunpowder or fireworks remained throughout the journey home.

I randomly thought of catalytic converter failure but have no idea why. The muffler needs replacing and tends to mask or distort other noises. Till this point it has run very sweetly, serviced every 5000ks.

Does anyone have any ideas or similar experience? My mechanical resources here in Queensland are very limited where Rangies are concerned.

Thanks
 
Hi fellow addicts,
I have a 1999 (late) P38 4.6 HSE, 180,000ks with LPG conversion. Today when leaving work it started normally but ran like it had dropped a cylinder, rough and down on power. My gas had just run out and was running on petrol. It belched grey/blue smoke from the exhaust, and some from the LHS engine bay. I fuelled up with LPG within about 2 ks from work then drove about another 10 ks. No smoke issued when on LPG, but still running like a chaffcutter.

Although power seemed down it still got up to speed ok. Some strange rattling noises from the engine bay and a distinct odour of gunpowder or fireworks remained throughout the journey home.

I randomly thought of catalytic converter failure but have no idea why. The muffler needs replacing and tends to mask or distort other noises. Till this point it has run very sweetly, serviced every 5000ks.

Does anyone have any ideas or similar experience? My mechanical resources here in Queensland are very limited where Rangies are concerned.

Thanks
How often do you run it on petrol? when did you last change the fuel filter? I you think it's dropped a cylinder check the obvious first ie. H/T leads on, duff lead or plug. Oil leak on to leads/plug (smell of burning)? Is that enough to be going on with, keep us posted.:)
 
Sound like your exhaust system needs looking into, when you switch to petrol the system isn't as fuel efficient and extra fuel is delivered. With the gas system, the engineers are very careful to not provide too much gas. The smell sounds like you have a leak on the N/Side exhaust being a V8 most probably a gasket. As for the sewing machine noises, that's worrying and you must check or get someone to do it the oils condition. Hydraulic tappets need a regular oil change and the correct grade of oil.
You should consult someone with knowledge before you drive too far. These forums are fine, but we cannot hear or smell the engine. It could be a simple thing, lets hope so. Always trade your skills and befriend a tech. But not harass lol.
 
Petrol injector gummed up and sticking on a cylinder maybe from lack of use. Sounds like it was rich on a pot that may have zeroed a plug. Take a look.
 
Gunpowder smell : Are your brakes / clutch ok ? Go around the vehicle after a run and without touching feel for heat at the rims. The smell fits the sooty deposit from gas and can smell like that. Petrol does burn at higher temps than gas and you may be cleaning up the exhaust. I think you need to look for a leak of gases and if its the manifold fix it, otherwise on a long journey you will start to fall asleep from the fumes. You should run a system on petrol at least once a month. 10-15 mins to keep things together. Old petrol can rot seals and pipes etc.
 
Thanks for the quick reply guys.

It always starts on petrol, runs for about 3 or 4 k's before switching automatically to gas. Leads are only about 40 k's old and all secure. Fuel filter, not sure but would imagine it would only affect petrol running. The rough engine running/idling occurs with either fuel. No oil leaks (other than the usual of course!). The oil and filter are changed religiously every 5000.

I can't discern any exhaust leaks in the engine bay. The smell is quite distinctive, not strong but definitely fire-cracker-ish.

No messages appear on the display either, bit puzzling. Even though the symptoms have not got worse I am a bit reluctant to drive it too far. Could a failure in the exhaust system have caused any of this?
 
Thanks for the quick reply guys.

It always starts on petrol, runs for about 3 or 4 k's before switching automatically to gas. Leads are only about 40 k's old and all secure. Fuel filter, not sure but would imagine it would only affect petrol running. The rough engine running/idling occurs with either fuel. No oil leaks (other than the usual of course!). The oil and filter are changed religiously every 5000.

I can't discern any exhaust leaks in the engine bay. The smell is quite distinctive, not strong but definitely fire-cracker-ish.

No messages appear on the display either, bit puzzling. Even though the symptoms have not got worse I am a bit reluctant to drive it too far. Could a failure in the exhaust system have caused any of this?
Thought you had run out of gas and this fault occurred on petrol. Take the fuse box cover off and have a sniff. Is this your gunpowder smell ?
 
Thanks Tomcat. The gas warning beeper sounded pretty much as soon as I drove off, knew it was low and ready to run out. Switched straight away to petrol as I always do and that is when the smoke belted out. Switched back to gas once I re-fuelled and the smoke disappeared.

Started it again just now with a cold engine (it's about 9.45pm here). As it always starts on petrol I checked the exhaust and there was some grey/blue smoke issuing, though nowhere near as bad as when it first happened. Still running a tad rough.

No concentrated odour at the fuse box, either, the smell was general and at running temperature. Temp hasn't varied either. Buggered if I know...
 
Thanks Tomcat. The gas warning beeper sounded pretty much as soon as I drove off, knew it was low and ready to run out. Switched straight away to petrol as I always do and that is when the smoke belted out. Switched back to gas once I re-fuelled and the smoke disappeared.

Started it again just now with a cold engine (it's about 9.45pm here). As it always starts on petrol I checked the exhaust and there was some grey/blue smoke issuing, though nowhere near as bad as when it first happened. Still running a tad rough.

No concentrated odour at the fuse box, either, the smell was general and at running temperature. Temp hasn't varied either. Buggered if I know...

Blocked CAT?
 
Thanks Tomcat. The gas warning beeper sounded pretty much as soon as I drove off, knew it was low and ready to run out. Switched straight away to petrol as I always do and that is when the smoke belted out. Switched back to gas once I re-fuelled and the smoke disappeared.

Started it again just now with a cold engine (it's about 9.45pm here). As it always starts on petrol I checked the exhaust and there was some grey/blue smoke issuing, though nowhere near as bad as when it first happened. Still running a tad rough.

No concentrated odour at the fuse box, either, the smell was general and at running temperature. Temp hasn't varied either. Buggered if I know...[/quote Get the tinnies in the fridge, book my ticket and I will be over to have a look:):). Is it still smelling when up to temp? I remember a strange smell from my A/C compressor when its clutch burnt out, the engine ran strangely till the drive belt disintegrated. I know that doesn't answer your rough running problem but it must be past 10pm there so you should be drinking:D:D
 
Tomcat, you should know that owning a Rangie and NOT drinking are mutually exclusive occupations! Yes the fridge is now empty. The nearest service centre is about 55 k's away, I'll call them in the morning for advice, that is if they aren't all off surfing. Thanks for your help, and you too tnseal.

Wammers, I don't know what 'blocked CAT' means, can you please explain. Thanks to you as well.
 
No mention of the airline ticket then, what a bummer. Blocked catalytic converter (part of exhaust). Do not give up that easily, more advice may emerge when you are asleep. Regards Alan :D hope its not 55 km to top up with drink
 
Tomcat, you should know that owning a Rangie and NOT drinking are mutually exclusive occupations! Yes the fridge is now empty. The nearest service centre is about 55 k's away, I'll call them in the morning for advice, that is if they aren't all off surfing. Thanks for your help, and you too tnseal.

Wammers, I don't know what 'blocked CAT' means, can you please explain. Thanks to you as well.

I take it your car has catalytic converters fitted. One on either down pipe. They can break up internally and partially or sometimes entirely block the exhaust. Just a suggestion. Maybe a red herring but worth a thought. Specially if you have gases being forced out.
 
Thanks again to you all for the help. Now in the cool light of day I think I'll limp it down the coast to British Off-Road, the local wrecker-cum-dealer.

I'm on the Sunshine Coast, place called Noosa Heads, miles from Bundaberg and I agree with Alan; Bundy rum is a dangerous product.

I'll post a result once I've sorted the problem
 
Thanks again to you all for the help. Now in the cool light of day I think I'll limp it down the coast to British Off-Road, the local wrecker-cum-dealer.

I'm on the Sunshine Coast, place called Noosa Heads, miles from Bundaberg and I agree with Alan; Bundy rum is a dangerous product.

I'll post a result once I've sorted the problem
Good luck :beer2:
 
Just a follow up to the post last week regarding my P38. The Rangie ended up in the shop for three days before the surprising problem was discovered.
Turns out that the inlet valve on No 8 cylinder was stuck open, maybe due to a dislodged carbon deposit. Also a piece of ceramic surrounding the electrode on No 8 spark plug (NGK) had broken away, possibly lodging itself in the inlet valve port, preventing the valve from closing.
The mechanic used a product called 3 Bond Upper Cylinder Conditioner to flood the cylinder which cleared the obstruction, hopefully never to return. Don't know if it has the ability to vaporise ceramic, so just have to trust that all is good. The 4.6 is now running as sweet as ever.
Goes to show that as a mechanical diagnostic technician I make a pretty good gardener I guess. Still, surf's up and the tinnies are cold.
Thanks again for all your input. Glen
 
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