Another Stupid Question
Discussion
Well maybe two - and I should know the answer to both.
My 280i has been standing in my garage for years. A month ago it started up okay but built up a lot of pressure under the fuel cap. I am guessing a vent is blocked. Any ideas?
Today I put fuel from a can and it blew back at me; probably same problem as above. Then I fired her up, and surprisingly it started almost immediately - for two seconds - then died. I repeated this many times with the same result. I noticed the bellows from the fuel distributor to the throttle body collapsed when it was trying to run. Does this mean a problem in the fuel distributor?
btw it did sound good while it ran!
Wjlf.
My 280i has been standing in my garage for years. A month ago it started up okay but built up a lot of pressure under the fuel cap. I am guessing a vent is blocked. Any ideas?
Today I put fuel from a can and it blew back at me; probably same problem as above. Then I fired her up, and surprisingly it started almost immediately - for two seconds - then died. I repeated this many times with the same result. I noticed the bellows from the fuel distributor to the throttle body collapsed when it was trying to run. Does this mean a problem in the fuel distributor?
btw it did sound good while it ran!
Wjlf.
Hi Mate...For the air intake hose to collapse you must have a problem with either a blocked air filter or possibly a stuck sensor plate as it sounds like there is not enough air being allowed in, The build up of fuel pressure sounds like an inoperative "Rollover" valve, I believe thats what the US cars had rather than just an atmospheric type like UK cars have.
I think the valves should be at a particular static position..Horizontal or vertical with none at an angle?...As always please be careful when dealing with flammables...Cheers...Ziga
PS:Forgot to say...Its probably starting easily as it has a very strong fuel pressure being "Close looped" due to the non operation of the valve, However the lack of air is suffocating the engine and thats why its stalling...(Possibly)
Always check the condition of fuel if a car has sat for years and pay particular attention to fuel tanks..Accumulators..Fuel filters, Pumps and fuel distributors as rust can inhibit all of these, There is an ultra fine metal mesh filter that is inside the fuel head, This can fail and also the plunger can stick..If the mesh fails and you havent checked for rust in the system then it will get pulled through to the injectors.
Hoses should be checked also for condition.
I think the valves should be at a particular static position..Horizontal or vertical with none at an angle?...As always please be careful when dealing with flammables...Cheers...Ziga
PS:Forgot to say...Its probably starting easily as it has a very strong fuel pressure being "Close looped" due to the non operation of the valve, However the lack of air is suffocating the engine and thats why its stalling...(Possibly)
Always check the condition of fuel if a car has sat for years and pay particular attention to fuel tanks..Accumulators..Fuel filters, Pumps and fuel distributors as rust can inhibit all of these, There is an ultra fine metal mesh filter that is inside the fuel head, This can fail and also the plunger can stick..If the mesh fails and you havent checked for rust in the system then it will get pulled through to the injectors.
Hoses should be checked also for condition.
Edited by mrzigazaga on Saturday 14th September 20:05
Thanks, Zig.
For now I have the fuel cap very loose, so no pressure build-up. The tank was almost empty and I put in three gallons of new fuel.
I disconnected the bellows; it starts well and now will run for half a minute or more if I don't touch the throttle; but the rpm varies from 400 to 2500. Maybe I am running on the cold start injector.
I have a new temporary in-line filter between the swirlpot and the pump. I have a new main fuel filter up front. Also a brand new pump. I assume the accumulator is bad as I can blow straight through it.
I have not yet messed with the fuel head. Is it easy to check the mesh filter?
So are you still planning that Caribbean trip? Cruises leave from Fort Lauderdale frequently.
Wilf.
For now I have the fuel cap very loose, so no pressure build-up. The tank was almost empty and I put in three gallons of new fuel.
I disconnected the bellows; it starts well and now will run for half a minute or more if I don't touch the throttle; but the rpm varies from 400 to 2500. Maybe I am running on the cold start injector.
I have a new temporary in-line filter between the swirlpot and the pump. I have a new main fuel filter up front. Also a brand new pump. I assume the accumulator is bad as I can blow straight through it.
I have not yet messed with the fuel head. Is it easy to check the mesh filter?
So are you still planning that Caribbean trip? Cruises leave from Fort Lauderdale frequently.
Wilf.
Let's see.....
My '82 280 blows back if you try to fill it too fast at the petrol/gas station, so I do have to pause now and again - I think the original twin tank plumbing isn't that good to start with, without any extra emission stuff !
The positive pressure in the tank - there is a tank breather on the UK ones, and I agree with Zig that something sounds blocked up with the tank. Remember the fuel pump also pumps excess fuel back to the tank, so pressure could build up that way.
Starts and stops at idle - could be blocked pipes or fuel filter - could also be faulty safety switch for the fuel pump ? I know later cars had the Ford system, which is supposed to run for about 2 secs before stopping, if unit doesn't see a spark (it's connected up to same place as the tacho).
Cold start injector should only be enabled whilst cranking, as far as I know.
It could be that the main injectors aren't atomising properly, which causes very rough idle.
Might be worth some injector cleaner?
Hope this helps !
My '82 280 blows back if you try to fill it too fast at the petrol/gas station, so I do have to pause now and again - I think the original twin tank plumbing isn't that good to start with, without any extra emission stuff !
The positive pressure in the tank - there is a tank breather on the UK ones, and I agree with Zig that something sounds blocked up with the tank. Remember the fuel pump also pumps excess fuel back to the tank, so pressure could build up that way.
Starts and stops at idle - could be blocked pipes or fuel filter - could also be faulty safety switch for the fuel pump ? I know later cars had the Ford system, which is supposed to run for about 2 secs before stopping, if unit doesn't see a spark (it's connected up to same place as the tacho).
Cold start injector should only be enabled whilst cranking, as far as I know.
It could be that the main injectors aren't atomising properly, which causes very rough idle.
Might be worth some injector cleaner?
Hope this helps !
Edited by RCK974X on Saturday 14th September 20:45
Thanks, Andy.
Mostly I am being lazy. The weather is very hot this afternoon and I have to leave it until the sun goes down. (I know it's your winter, but it doesn't look too bad)
Mine is US spec, listed as 1988, but more likely it's a 1987. The fuel pump on mine does not have a return to the tank. If there is too much pressure build-up it sort of circulates the fuel inside the pump. My thinking is that when the fuel distributor sends surplus fuel back to the tank(s) there is some vent which on mine is blocked. Now I think of it, it doesn't make sense; as it it is only replacing part of the fuel the pump has taken.
US cars have a cream coloured Engine Run Sensor instead of the purple one in UK. Mine has a problem and I have partly bypassed it. It controls positive voltage to the fuel pump and the coil. I don't think this is my problem, although obviously I am not ruling it out (mostly since I have messed with it)
My next step is to enjoy the air conditioning and read the manual; I will look for any venting system.
I expected the problem to be in the fuel distributor. Who knows?
Wilf.
Mostly I am being lazy. The weather is very hot this afternoon and I have to leave it until the sun goes down. (I know it's your winter, but it doesn't look too bad)
Mine is US spec, listed as 1988, but more likely it's a 1987. The fuel pump on mine does not have a return to the tank. If there is too much pressure build-up it sort of circulates the fuel inside the pump. My thinking is that when the fuel distributor sends surplus fuel back to the tank(s) there is some vent which on mine is blocked. Now I think of it, it doesn't make sense; as it it is only replacing part of the fuel the pump has taken.
US cars have a cream coloured Engine Run Sensor instead of the purple one in UK. Mine has a problem and I have partly bypassed it. It controls positive voltage to the fuel pump and the coil. I don't think this is my problem, although obviously I am not ruling it out (mostly since I have messed with it)
My next step is to enjoy the air conditioning and read the manual; I will look for any venting system.
I expected the problem to be in the fuel distributor. Who knows?
Wilf.
1- I didn't know there were '88s over here. I though the last few '86s were titled/re-titled as '87s.
2- Take the rubber-ish dome off the air/fuel and check the mixture plate. I get (for some reason) an oily contamination with the consistency of honey (and the same color) on the plate. When it's there, the engine will not idle for long and chokes out unless you boot it.
3- I think there is a tank return. Yours might be stopped or pinched - hopefully not cracked and leaking.
4- Are you describing the main ribbed hose for the fuel/air supple collapsing? Mine recently developed a mess of cracks (so it didn't hold pressure,collapse or start). It needs to be air-tight.
5- The swirl pot - as I understand it - it is a combo first stage filter (screen) and an accumulator so the pump will have a steady supply fuel to draw from regardless of the status of tanks. Basically a 'lower than the tanks' sump.
6- Filling both tanks is unlikely and there are some old threads on this so I'm not alone. I can get about 7.5 gallons in- max. And at that the gauge goes from empty to full. I don't do long rides so I haven't explored. My 2 cents. Grady
2- Take the rubber-ish dome off the air/fuel and check the mixture plate. I get (for some reason) an oily contamination with the consistency of honey (and the same color) on the plate. When it's there, the engine will not idle for long and chokes out unless you boot it.
3- I think there is a tank return. Yours might be stopped or pinched - hopefully not cracked and leaking.
4- Are you describing the main ribbed hose for the fuel/air supple collapsing? Mine recently developed a mess of cracks (so it didn't hold pressure,collapse or start). It needs to be air-tight.
5- The swirl pot - as I understand it - it is a combo first stage filter (screen) and an accumulator so the pump will have a steady supply fuel to draw from regardless of the status of tanks. Basically a 'lower than the tanks' sump.
6- Filling both tanks is unlikely and there are some old threads on this so I'm not alone. I can get about 7.5 gallons in- max. And at that the gauge goes from empty to full. I don't do long rides so I haven't explored. My 2 cents. Grady
Edited by Grady on Sunday 15th September 06:26
more good ideas above....
Just thinking - the early Colognes in UK were wired up very simply with just a switch on the metering head to stop the pump when no airflow - this was changed to the 'purple realy' system as the flap could stay open if vehicle turned over in accident...
So for testing, you should be able to wire coil/ignition amplifier and pump straight to 12v live via ignition key (remembering the resistor for the coil of course)...
If engine still stalls, then at least that proves there's a fuel flow/inject problem somewhere.
Fuel filter on mine only affected full throttle (when I noticed it) so I don't think it should affect idle much - could also be one of the pressure valves I guess (metering head, pump, etc)
[ Winter - we just had the worst windstorm in about 40 years - power down in lots of places, debris everywhere, broken trees,... It's gone now but still cold and frosty - at least Sun is shining as I type this ! ]
Just thinking - the early Colognes in UK were wired up very simply with just a switch on the metering head to stop the pump when no airflow - this was changed to the 'purple realy' system as the flap could stay open if vehicle turned over in accident...
So for testing, you should be able to wire coil/ignition amplifier and pump straight to 12v live via ignition key (remembering the resistor for the coil of course)...
If engine still stalls, then at least that proves there's a fuel flow/inject problem somewhere.
Fuel filter on mine only affected full throttle (when I noticed it) so I don't think it should affect idle much - could also be one of the pressure valves I guess (metering head, pump, etc)
[ Winter - we just had the worst windstorm in about 40 years - power down in lots of places, debris everywhere, broken trees,... It's gone now but still cold and frosty - at least Sun is shining as I type this ! ]
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