Fuel Pressure reg

[G Force]

Checked both,there seems to be something rattling in the ecu which is not a good sign
Russ

Agreed! should not rattle

[Russ]

This is really doing my head in now!! Changed ecu ,just the same. Ive now ordered a fuel pres guage to do some more tests. Ive had the fuel line disconnected both ends today and blew it through with an air line still no change.
Whats on the end of the pick up pipe in the tank? I blew a bit of air down that and the fuel bubbled. Im wondering if the new pres reg is no good but it sealed with no vac where the old one didnt.
Thus far ive done
Change air flow meter 5times
Changed map sensor
Changed ecu
Changed pot
Changed fuel pres reg
Dizzy cap
Rotor arm
King lead.
Fuel pump twice
Fuel filter
I recon its fuel side as when I blocked off the return it ran ok

[G Force]

Whats on the end of the pick up pipe in the tank?

On the end of the pick up pipe is a plastic gauze filter. The pipe is sat in a swirl pot, the return pipe also terminates in the swirl pot. The swirling effect of the warm return fuel draws cold fuel from the tank to where the pick up pipe is sat. This ensures cold & denser fuel is always available at the pick up pipe & also help stop fuel surging away from the pick up pipe on accelartion & cornering.

Im wondering if the new pres reg is no good but it sealed with no vac where the old one didnt.

The fuel pressure regulator must be wrong type as the regulator has always been duel pressure on Maestro Montego. If the fuel pressure regulator has an adjusting screw like a FSE or Jaguar type then you can use it if you adjust the fuel pressure to 2.5 bar. Make sure you get the right combination of ECU part no. and fuel pressure regulator. I think I'm right saying your particular car should have an AUU1051 OR AUU1313 with the 2.5bar regulator.

Don't rule out glazed or faulty injectors or contaminated fuel.

Gary

[Russ]

Im wondering if i can get that gauze filter off, the pres reg is the right one for the car as I saw the part no.s on the screen your right about the ecu its auu1313 . The injectors have just been reconditioned and its had about 3 tanks of fuel since i got it,and contaminated fuel would cause other running problems.
Im thinking that the original pump was noisey (still had the flat spot) so was changed by the garage,the second was one of those cheap non genuine ones off ebay ,that seized. Now it has a new bosch one which is also a bit noisey.So im thinking are these struggling to suck the fuel from the tank?
Theres no way to remove the pick up pipe from the tank is there? I wonder if i can use a flexible drain unblocker to poke the filter off the end of the pickup pipe? As that would prove my problem without costing anymore money,and it would float and not block the pipe.Are new tanks easy to come by?

Cheers

Russ (on suiside watch!!)

[G Force]

Im wondering if i can get that gauze filter off, the pres reg is the right one for the car as I saw the part no.s on the screen
Russ (on suiside watch!!)

Hi Russ don't let it beat you, you can't fix it hanging from the ceiling :laugh: & it would not be fair on whoever inherited the car

Joking aside, I would not try remove the gauze as that will certainly lead to more pump failures (I have had this problem first hand with a fairly new car). It would be worth looking into the tank as ETV has mentioned the possibility of the pickup pipe drawing air somewhere due to corrosion.

The FPR has always had a vac connection, so if yours does not then it is wrong and could have been boxed wrong.

It could be worth you describing the flat spot as it accurs now, as when reading through your other postings it sounds like you have made improvements to the drivabillity along the way.

Try describe flat spot in terms of Engine hot/cold, what revs, what load, full throttle / light throttle, duration of flat spot. You never know it might just make someone think.

I think you will find the fuel pressure gauge a useful diagnostic tool once it arrives.

Stick at it

Gary

[Russ]

Right

The flat spot happens whether the engine is hot or cold.
Set off apply full power,1st gear no problems ,up to the red line if you want. Into 2nd pulls ok ,then about 3500rpm power dies then picks up again but the engine does not seem to be making full power,ease the throttle and reapply slowly and all is ok. This also happens when dropping a gear for overtaking. Ive had this before on another car and that was an airflow meter which is why I tried 5 on this!
Im pretty sure ive got low fuel pres as when I removed the pump to bus rail hose today there was hardly any presure and the engine had just been shut down.
There is a vac hose on the pres reg.
My theory of what is happening is
Car sets off from idle slight vac to regulator,pump has had time to get bus rail up to a reasonable pres- engine powers ok. Gear change, throttle shuts,lots of vac ,regulator dumps fuel ,throttle wide open ,regulator shut ,pump cant supply enough fuel ,engine dies.
I cant remember what access you have to tank,they dont seem to be available .Are montego saloon or estate ones the same?

Cheers

Russ

[G Force]

Im pretty sure ive got low fuel pres?

The symptoms you describe do seem to point towards a fuelling problem, & could very easily be fuel pressure.

The fuel pressure gauge should be able to prove this definitively.

It sounds to me as if the engine is probably leaning out when demand for fuel is high i.e. max torque & power. This could be fuel pressure / delivery rate or low delivery due to an injection problem or fuel quality.

The Max fuel pressure test I described should prove any fault with the pick up as the fuel pressure should rise up to 60psi imediately once you clamp the return hose, any slight delay would suggest that the pick up is either restricted or drawing air or a pump problem. You will also be able to rig the gauge up so you can see what is happening to fuel pressure when your driving.

If the gauge is going to be a while coming I think I would bite the bullet and get the tank off and inspect it.

Dont know which tanks are interchangable as I don't have access to a parts list, but hopefully someone else who has can help there.

[Russ]

Thanks for that,I was hoping gauge would be here today but it isnt.
I was wondering what can you see inside the tank,does the swirl pot go to the top of the tank or just rise a couple of inches from the bottom? As new tanks seem impossible to find I was thinking of replacing the pick up pipe (with the tank full of water) but i need to know if its just secured where it enters the tank .Then I would need some way of inserting a union in the outer skin and using copper pipe for a new pick up pipe ,but the problem is there would be no access to the inside of the tank.

Cheers
Russ

[G Force]

I was wondering what can you see inside the tank,does the swirl pot go to the top of the tank or just rise a couple of inches from the bottom?

The swirl pot is approx 4in tall and spot welded to the bottom of the tank. The pick up pipe is braized to the tank but I can't remember exactly if it is secured elsewhere, but I dont think so. The pick up is not easy to see but with torches and mirrors in the tank unit hole and filler tube you can just get an idea of the condition.

I had to cut into a fuel tank to find the problem with the efi I had eating fuel pumps because I could not see the gauze filter. It was a car under warranty and had had 2 new pumps fail. The problem turned out to be the gauze had a hole in it where it had melted. Obviously what had happened is during manufacture when the pick up was braized in place, the welding torch had been wafted over the outer end of the tube & the flame had travelled down the tube and melted the gauze. All it took to ruin the pumps was just minimal particles of rusty debris that had accumulated in the two years of running. Of course then I had to fit a new tank and another new pump.

Gary

[Russ]

I take it you were an austin rover mechanic then?
My plan is when i get the pres gauge,test the presure at the bus rail blank off the return see how long it takes for pressure to build. Then if still not satisfactory test the pressure between the pump and the pipe to engine ,if this is ok then the problem is in the pipe.
If still no good take the supply pipe from the tank off the pump and see how easy the fuel flows with a syphon pump. If its hard to syphon remome the tank (after draining) .Remove the sendor and clean inside tank,inspect pick up pipe repeat the syphon test with cleaner or water, if still no good remove pick up pipe and make new one from copper refit tank and come back crying on here saying my car still doesnt run right. Then get very drunk and walk off into sea!!!
Whats the best stuff for cleaning the tank and reducing risk of explosions?
Cheers
Russ

[G Force]

My plan is when i get the pres gauge,test the presure at the bus rail blank off the return see how long it takes for pressure to build. Then if still not satisfactory test the pressure between the pump and the pipe to engine ,if this is ok then the problem is in the pipe.

Hi Russ I thought it might be useful to summarise how you should test the fuel pressure, you might want to print it for referring to as you do the checks.

Connect the gauge in the fuel feed line between the fuel pump and the inlet of the fuel line. Depending on what adapters come with the gauge the best spot is T into the unions at the fuel rail inlet or you might have to T in just after the fuel filter. The gauge connections must be 100% secure and leak proof (fire warning)

Switch on the ignition and the priming period of 2-3 seconds should bring the rail up to full pressure in the rail (2.5bar) (approx 36psi). If you have lost a lot of fuel during connection of the gauge full pressure might not be achieved until turning off the ignition wait 15 secs and prime again.

You run the pump constantly by turning the ignition without running the engine by earthing the pink brown wire on the fuel pump relay if desired.

With the gauge installed you can easily see what the pressure is at idle (2.0bar) (approx 29psi) and with the vac pipe removed (2.5bar). If you briefly clamp the return hose the pressure should rise to approx 4.5bar, this tests the max output pressure of the pump; and no more than 6bar, if the pressure rises higher than this the fuel pump overpressure valve is faulty.

The Max fuel pressure test should prove any fault with the pick up as the fuel pressure should rise up to 60psi immediately once you clamp the return hose, any slight delay would suggest that the pick up is either restricted or drawing air or a pump problem.

You will also be able to rig the gauge up so you can see what is happening to fuel pressure when you’re driving, the pressure should never drop below 2.5bar when you accelerate or when under load.

You should also check that the pressure is holding in the rail when the engine is turned off. If it is not holding then clamp the return hose, if the pressure then holds then the regulator is faulty.

If the pressure still does not hold with engine off, then clamp the fuel feed pipe before the gauge, if it then holds the fuel pump non return valve is faulty. If the pressure drops with both feed & return pipes clamped off, you must have an injector leak.

Gary

[Russ]

Thanks for that Gary,The pres gauge still has not turned up
So cant really progress until it does,shame as its a lovely day down here.

How much crap normally sits in the tank? As it may be worth cleaning anyway

Cheers

Russ

[G Force]

How much crap normally sits in the tank? As it may be worth cleaning anyway

If it is the original tank I would expect there to be enough to justify cleaning it.

The tank that I cut up was only 2 years old and suprisingly there was enough silt to destroy 3 pumps.

[Russ]

Ive found a place in Norwich that will clean the tank and replace the pick up pipe for £40 ,ill wait until ive done the pressure tests before taking it down there. As there is still achance its the pipe from the tank to the engine. As the old pump was noisey and this one is not the queitest (compared to my metro which you can barely hear) does this mean that the pump is probably not full of fuel or its working too hard,ie trouble sucking from the tank or difficulty in forcing it up to the bus rail.

Russ

[G Force]

As the old pump was noisey and this one is not the queitest (compared to my metro which you can barely hear) does this mean that the pump is probably not full of fuel or its working too hard,ie trouble sucking from the tank or difficulty in forcing it up to the bus rail.

Russ

Tank clean & repair sounds promising.

If the pump was drawing air, then that would be one explaination as to it being noisey. The pump should be mounted with the large electrical connection uppermost for quietness. The pump gets noisey with wear also.

Gary