Gurgle, gurgle, chug, chug...! I think I have a carb' issue!

G

grifterkid

Member
Right then... As is always the case (or in my case anyway) once you get one thing done something else peeks over and catches your eye! Well ever since I bought my 1974 P6B there was some kind of sporadic problem that caused the engine to splutter and cough, the revs to drop and then, ultimately, the engine cut out... On occasions pulling the choke out whilst the splutter was occurring and then putting it back in would cause the problem to cease. Trying to re-start it immediately after the event sometimes worked but more often than not the car would need to sit for about half an hour then be re-started to resume normal service...

Anyhow, I digress! After two thorough services and a carb' dis-assemble/re-assemble (on the side my mechanic thought was causing grief) I thought we'd got out of the darkness of this problem as I had a fortnight of beautiful, trouble free, service (even commuting in the old brute!)... All was fine until this weekend when the problem re-appeared... :shock: The splutter appeared briefly on Saturday morning but after getting the car started again and letting it run for a minute to clear its throat (there was a touch of smoke emitting from the exhaust clearing as the engine smoothed) I had no problems until Sunday evening... The splutter came back, the power went down (even with the pedal to the metal as it were), there as a distinct aroma of petrol then the motor died... Re-starting did not help so it was a sorrowful walk home (thank the Viking I was only local!)... I returned a couple of hours later, jumped in, turned the key and we were off, back to normal...!!!

What my mechanic thought was the problem originally was something to do with the float chamber being clogged and not letting fuel through (or something along those lines)... The smell of petrol and lack of power really make me think it is a carb problem but the sporadic nature of it coming and going is really confusing me to the point of despair...!!! Do I need to perform a thorough carb' rebuild...! Could the tank be crud filled causing said crud to be pulled through the 'system'...? When I bought the car I was told it wasn't used thoroughly for some time so I think it could be some dirt somewhere messing with my motor...

Well, can any of you well weathered Rover drivers help...?! You folks have always been so damn helpful in the past I am hoping for the best now...!!! Thanks to one and all in advance... Sorry for the ultra long post by the way, just trying to be discriptive :wink:
 
The behaviour of mine has been similar - with one important difference - it seemed to be pouring oil through the crank breather to the point where there was more oil than petrol, hence my decision to swap the engine - thinking is that the piston rings have gone. No blue smoke but cant really see anything else to try. removing the breather from the air intake stopped the carb misbehaving. It also sounds like it's running on 5 or 6 rather than all eight and is very cammy or a valve is hitting but that's an aside...

On mine i think oil was getting stuck in the carb. turning over or leaving it for a while helped when it stopped running. To see if this part is similar to yours you could try temporarily removing the breather pipe and putting it somewhere where it wont put oil on your windscreen.

I'd point out that i'm not the most experienced roverer on the forum by a long shot - but i can share what little experince i have!

Rich,
 
Hello Ash,

What type of fuel pump do you have fitted?

So far the problem sounds decidely like fuel vapourisation, all the typical symptoms are there.

Ron.
 
I'd agree with Ron if it weren't for the fact that you had an experience of this immediately after a start from cold.

So lets run through the options.

First up is (as Ron says) fuel starvation / vapourisation. P6b's are very prone to vapourisation, especially if used in traffic - but of course it only occours when hot. In the same vein, if you have a dodgy mechanical pump you might well get symptoms like this. You could rebuild the pump if you liked (a simple operation, kits available from the usual suspects), but I'd be more inclined to assume the worst and simply fit an electric pump. If it is starvation even a 100% pump is unlikely to cure it.

Next along, you mention smoke from the exhaust. Aside from the usual suspicion of the rings etc (blue smoke), if it is white smoke then you might well have a leaking servo, with the leaked fluid being carried over into the engine via the vacuum hose. To check, pull the fitting on the servo vacuum tank where the vacuum hose connects, away from the servo. You will then be able to get a finger or dipstick into the servo chamber and check whether you have a puddle of hydraulic fluid in there. If you have then this could well explain your symptoms.

Finally, you mention a smell of petrol. That would be consistant with one or both float chambers on the carbs flooding due to a stuck open needle valve. Again not too difficult to renew as a DiY job and overhaul kits from the usual suspects. You'd also find out whether you had any crud being carried over from the tank at the same time - it'd be collecting in the bottom of the float chambers.

Since all these involve a certain amount of investigation I'd change the fuel filter and the flame traps (2) at the same time (they are service items after all). You should have both fitted to a P6B and again replacements from the usual suspects. Relevance of the fuel filter is obvious. The flame traps (and the hoses associated) are known to get blocked with carry over carbonised oil and if that were the case the engine would breath heavily and could upset compression etc etc.

Hope that gets you started!

Chris
 
Grifterkid, I'm sure this is vapourlock that you're experiencing given that it wil restart easily after an hour or so.

Usually, it's caused by running in traffic, and the ambient temperature doesn't have to be that warm either, just a warm engine. Mine did it on Friday on the way home from work and the water temp gauge didn't even get to 85 degrees but the heat soak from the engine to the fuel pump and lines coupled to the slow running was enough to vapourise the petrol before it got to the pump.

The smell of fuel under the bonnet could be the petrol vapour escaping from the carb overflow pipes. Black smoke on restarting is probably just an over rich mixture left from before the engine died.

Have a read of these two articles that Brian-Northampton has recently uploaded

http://www.p6roc.co.uk/download.asp?fil ... +23-28.pdf

http://www.p6roc.co.uk/download.asp?fil ... 2+8-12.pdf

Apparently electric fuel pumps cure this, I bought one yesterday so I'll let you know in a few weeks.
 
It certainly sounds like it to me also, pretty sure I have the same issue and if it is one thing to note is that the engine need not be very warm at all, had exactly the same symtoms from an engine that from cold only ran about 4 to 5 minutes max (and only at idle at that).

Graeme
 
The first thing I need to ask is what do I do if there is already an electronic fuel pump fitted...?!?!?! To add to the sporadic nature of the problem I took the beast out for a bit of a blast last night and it ran as sweet as a nut...

From what you have all said I feel it could be fuel vapourisation but seeing as I am already running an electronic fuel pump shouldn't this solve all that...?! Is there a way to test to see if the electronic fuel pump is working as it should...? I think that that could be causing the problem...

The one thing that confuses me is that I ran the car for 2 weeks (on one trip through Putney on Easter Sunday the engine was so hot, due to insane stop-start traffic, I overheated and had to stop but there was not annoying stuttering to signal fuel vapourisation!!!) with no problems whatsoever and all of a sudden it all goes horribly wrong again, darn it...!!!
 
ghce said:
Where is the fuel pump located? in the engine bay or under the fuel tank?
Click to expand...
In the engine bay on the inner right hand (drivers side) wing... It's quite a noisy old thing click-clicking away all the time!
 
My electric pump is located on the passangers side of the engine bay up high, next week I will look at placing it lower where it will be cooler in the hope that it will reduce my vapour problems. You are right about noise!!! I think I will also rubber mount mine in the hope of reducing the damn clack clack clack that it makes, are you still using the fuel return line?

Graeme
 
Hello Ash,

Having an electric fuel pump already now makes the vapourisation angle a touch less likely although the location of the pump as Graeme pondered will add weight one way or the other. It is not beyond the realm of possibility that the fuel itself is the problem,..maybe a bad batch.

It could also be moisture in the fuel, when it comes through it won't burn so the engine will stutter,...grab some methylated spirits and pour a good few cup fulls into the tank. It will remove any moisture that maybe there, and if there is none then it won't do any harm.

Ron.
 
Arrr....in the engine bay,...well if the fuel in the line turns to vapour prior to the pump, then that could well be a possibility. Some electric pumps pull the fuel through while others push, and the latter are usually placed beneath the tank. This design significantly reduces the possibility of vapour lock occuring, as the fuel is constantly pushed through.

Ron.
 
I agree with Ron - a pusher pump at the rear is a much better option. But I still think you ought to work through my suggestions before you get to that point.

Chris
 
josephp6man said:
hi,
all pumps should be mounted on a couple of rubber bobbins, it will stop any clatter clatter noises.

joseph
Click to expand...

Mine is mounted under the back seat (outside of the car) and is fitted on two rubber mounts. It clatters away like a good un.

I am thinking of fitting it inside the boot, or perhaps boxing it in where it is with some sound proofing.

Richard
 
Hi guys
I am a newbie on this forum but I noticed this cry for help with an apparent carb problem. I had much the same problem the pump on my car was the old Lucas type with the black case held on by the locknut which also served as the power entry. When this cover is removed there is a pantagraph arrangement with contacts fitted this clicks in and out and operates the diaphram internally. These pumps were cr-p when first fitted, I solved the problem by fitting a goldtop pump to push the fuel up to the carb from close to the tank, in line further up in the engine bay I fitted an adjustable fuel pressure regulator I drilled and tapped the outlet port and fitted a fuel pressure guage set it up at 4 PSI and all was well , it also has the affect of stopping the pump dumping fuel into the V and becoming a fire hazard. Hope this helps if you havent already fixed it , all these parts can be obtained from Real Steel. I am not in anyway connected to this firm.
Regards
John Lancaster
 
firebug6 said:
Hi guys
I am a newbie on this forum but I noticed this cry for help with an apparent carb problem. I had much the same problem the pump on my car was the old Lucas type with the black case held on by the locknut which also served as the power entry. When this cover is removed there is a pantagraph arrangement with contacts fitted this clicks in and out and operates the diaphram internally. These pumps were cr-p when first fitted, I solved the problem by fitting a goldtop pump to push the fuel up to the carb from close to the tank, in line further up in the engine bay I fitted an adjustable fuel pressure regulator I drilled and tapped the outlet port and fitted a fuel pressure guage set it up at 4 PSI and all was well , it also has the affect of stopping the pump dumping fuel into the V and becoming a fire hazard. Hope this helps if you havent already fixed it , all these parts can be obtained from Real Steel. I am not in anyway connected to this firm.
Regards
John Lancaster
Click to expand...
Wow, you're describing an SU type pump. Don't recall seeing one on a P6 :?
Welcome to the forum anyway :)
 
GrimV8 said:
Wow, you're describing an SU type pump. Don't recall seeing one on a P6
Click to expand...
Had one of those on one of my cars when I bought it! Mounted on the inner wing. Starting to wish I'd kept it! Quieter than the facet and it will self prime when it runs dry, something the facet has failed to do several times. Now have a lead and cigarette lighter plug attached to it, very handy for emptying fuel systems prior to work (have emptied my white V8 more times than I can remember), priming diesel filters (no primer fitted - saves cranking till the battery dies), as well as getting petrol out of diesel tanks!!Every workshop should have one!
Regards,
Dave
 
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