Discussion
Ok then I've now tested the fuel pressure and on start up there is 30 - 40 but then instantly goes down to 0 - no pressure
Tried this on the origianl regulator and also on one of the FSE adjustably types
So question is what cause low presuere, checking hoses etc and all seem ok, other things could cause like
stuck open injector ? how to test ?
faulty fuel return ?
Dodgy fuel pump, although seems to pump under no load condition
Anything else ?
Would my spare Sagem 4FP 73351A also marked as Bosch 0 580 464 055 be up to the job as a replacement ?
Anyone know where my Wedge Bible is ?
Tried this on the origianl regulator and also on one of the FSE adjustably types
So question is what cause low presuere, checking hoses etc and all seem ok, other things could cause like
stuck open injector ? how to test ?
faulty fuel return ?
Dodgy fuel pump, although seems to pump under no load condition
Anything else ?
Would my spare Sagem 4FP 73351A also marked as Bosch 0 580 464 055 be up to the job as a replacement ?
Anyone know where my Wedge Bible is ?
gsx600 said:
That's what I thought so I tried 3 different guages all with the same results. Engine will idle but as soon as you put it under load it will die 
Thought you meant it would start but not keep running. You're saying it will start and idle but cut when you open the throttle? Please explain the symptoms in a bit more detail, including what's happening to the fuel pressure while this is going on.
Some more tests for you:
1. Idle engine then cut the ignition. What happens to the fuel pressure?
- It should remain high.
2. With engine idling, disconnect the vacuum line from the regulator and plug it.
- The pressure should rise.
3. If you suspect an injector, disconnect each electrical socket, one at a time, and see if the symptoms change. Of course if it's stuck open, this might not help!
1. Idle engine then cut the ignition. What happens to the fuel pressure?
- It should remain high.
2. With engine idling, disconnect the vacuum line from the regulator and plug it.
- The pressure should rise.
3. If you suspect an injector, disconnect each electrical socket, one at a time, and see if the symptoms change. Of course if it's stuck open, this might not help!
GreenV8S said:
gsx600 said:
That's what I thought so I tried 3 different guages all with the same results. Engine will idle but as soon as you put it under load it will die
Thought you meant it would start but not keep running. You're saying it will start and idle but cut when you open the throttle? Please explain the symptoms in a bit more detail, including what's happening to the fuel pressure while this is going on.
I've definately had some dodgy fuel as the fuel I drained out of the TVR I put in the Cav and it still ran poorly until I put more fresh fuel in their so the Cav now runs great.
I've now got £20 of shells finest optimax in the Wedge and was hoping it would solve it all, but I think something has happened to the fuel pressure. I'm currently taking of pump and what looks like the fuel filter (if that had too much crud in it would that cause presure to drop ? ) and going to try the spare pump and see what happens then.
There is also a stronger than normal smell of petrol, but I can't find any obvious leak , so again will need to jack up and shove me hammer in the flapper to get pump started and crawl underneath when there may be more pressure in the fuel lines or connect my air compressor up and see if I can hold 60 psi from the hose without the pump in line ?
Another way to keep the pump going is to connect a battery charger direct to the pump. make sure the switch is off, when connecting to not cause sparks.
or get some wire with spade conectors either end, and take the relay out and fit the wire so the wiring thinks the relay is on.
sounds like a faulty pump, or flow from tank is being restricted. or filter is blocked.
Most EFI pumps should work fine.
Also the Battery charger method will make the pump run a bit faster than normal, and the car may run ok on the battery charger, but then fail with standard car wiring. is this happens then the pump is knackered.
or get some wire with spade conectors either end, and take the relay out and fit the wire so the wiring thinks the relay is on.
sounds like a faulty pump, or flow from tank is being restricted. or filter is blocked.
Most EFI pumps should work fine.
Also the Battery charger method will make the pump run a bit faster than normal, and the car may run ok on the battery charger, but then fail with standard car wiring. is this happens then the pump is knackered.
So basically the fuel pressure drops to nothing as soon as you stop cranking? Surely that means the pump is stopping, so test whether you still have power to the pump and whether it still sounds as if it's running.
You may well find that the engine will run without the pump, depending on the cam you can get enough manifold depression to pull enough fuel through for it to fire, as soon as you touch the throttle it dies though.
You may well find that the engine will run without the pump, depending on the cam you can get enough manifold depression to pull enough fuel through for it to fire, as soon as you touch the throttle it dies though.
Well after fiddling around with connections at the fuel pump and taking off and attaching to batt charger managed to get pressure back. She would then idle ok but still not rev past 3k.
Took filter out of equation and she now revs her arse off
So where is the best place to get a replacement filter, will try halfrauds later but I doubt if they have any of the shelf items as big as what came off
Took filter out of equation and she now revs her arse off
So where is the best place to get a replacement filter, will try halfrauds later but I doubt if they have any of the shelf items as big as what came off
gsx600 said:
Well after fiddling around with connections at the fuel pump and taking off and attaching to batt charger managed to get pressure back. She would then idle ok but still not rev past 3k.
Took filter out of equation and she now revs her arse off
So where is the best place to get a replacement filter, will try halfrauds later but I doubt if they have any of the shelf items as big as what came off
Paul, the Mann part number is here (fitted to my 400 last year)Took filter out of equation and she now revs her arse off
So where is the best place to get a replacement filter, will try halfrauds later but I doubt if they have any of the shelf items as big as what came off
http://www.pistonheads.com/gassing/topic.asp?h=0&a...
7.
Well went to halfrauds and they had the exact same filter on the shelf for a 3.5 V8 Rover / Landrover of some sorts. Got home put it on and wey hey all running hunky dorey
Go down the road on a road test round the block and all superb. Get back to pick up Michell and pop to Wokingham and then break down on the A329, guess wot
No bl**dy fuel pressure after a long right hand sweep going on to A329
Wait for an hour to get recovered home, and once home fiut my spare pump, so far all seems ok ,but not been on any large right hand sweeps. Going to VW now tomorrow as no time to prepare for car boot sale, so hopefully all will now be ok
Morale of story dont't be a cheapskate, and if you have the spare part to hand fit it whilst the other part is off
Go down the road on a road test round the block and all superb. Get back to pick up Michell and pop to Wokingham and then break down on the A329, guess wot
No bl**dy fuel pressure after a long right hand sweep going on to A329
Wait for an hour to get recovered home, and once home fiut my spare pump, so far all seems ok ,but not been on any large right hand sweeps. Going to VW now tomorrow as no time to prepare for car boot sale, so hopefully all will now be ok
Morale of story dont't be a cheapskate, and if you have the spare part to hand fit it whilst the other part is off
I think it does say in the service schedule you should change it every 30,000 miles, its amazing how clean it get the petrol.
You may want to check the pre-filter has not failed or missing, as this can damage the pump and also the clog up the main filter very quickly.
if you still have the old filter, you may want to back flush it into some rag, to see the size of any deposits that come out.
You may want to check the pre-filter has not failed or missing, as this can damage the pump and also the clog up the main filter very quickly.
if you still have the old filter, you may want to back flush it into some rag, to see the size of any deposits that come out.
Now that is what I was wondering why is there no filter before the pump ? Or as you say is there a pre filter - supposidly - somewhere between the tanks and before the pump.
Had a quick look around whilst on the stands but could not see anything apart from a swirlpot that looks like it could be replaced soon as well
Had a quick look around whilst on the stands but could not see anything apart from a swirlpot that looks like it could be replaced soon as well
Well most had a filter in the swirl-pot.
But these can come loose, or get pitted.
The only aftermarket one I have found that fits, i.e. has 12mm conectors and can flow enough is the systec one with the cleanable metal filter. I just did a order for me and Jeff and got a small discount, but was still 65 each inc postage and vat.
But these can come loose, or get pitted.
The only aftermarket one I have found that fits, i.e. has 12mm conectors and can flow enough is the systec one with the cleanable metal filter. I just did a order for me and Jeff and got a small discount, but was still 65 each inc postage and vat.
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