TR4A running/fuel problem

[Z320]

On 6/18/2022 at 11:51 PM, eng622 said:

If I undo the supply pipe to carb and prime sometimes fuel does not come out straight away and when it does it spurts out with each prime. On putting the pipe back it still will not start except for the one bump start. The pump glass bowl is always full.

If I undo the inlet pipe to the in line filter (before the pump) fuel pours out. There must be debri in the tank because there are bits in the filter, it is a glass one that can be cleaned. So could that debri starve the pump. Above 2000 rpm it runs fine it is when coasting to a stop when there is less fuel needed that gives the problem.

The pump filter gauze is missing. Note the point regarding where to fit an inline filter but have had several classics with filter fitted before the pump and no problem.

 

In my opinion the key is already in this post.

This "cleanable" glas filter looks very worthy and I'm shure you have it still inline and no doubt about.

But it's a FAKE product. It is blocked long before you see any dust.

It CAN'T be cleaned and the nylon texture is heat sensitiv. Guess why I know.

A petrol filter is never to clean, it's a one time use product.

The bowl of the AC pertol pump works different:

mainly by sedimentation, and metal texture sieve indeed can be cleaned.

If you have this glas filter still fitted - kick it in the bin and be happy again.

Cheers, Marco

Edited July 8, 2022 by Z320

[eng622]

Tried another road test today just to lower the fuel level in the tank. As usual all started well then after some miles engine became lumpy at low rpm but blipping the throttle seem to clear it. Anyway just managed to get home.

Did idle in the drive but not smoothly and eventually stalled and would not restart. Took the fuel pipe off the front carb and cranked, no fuel to start with then did spurt out and engine would then restart. Stopped engine after a few seconds and would not restart. Took fuel pipe off again cranked and as before. So after endless tries when the engine does start and idles fine as soon as you switch off it will not restart. Would have thought there was sufficient fuel left in the carb float chambers to enable a start.

Took the air cleaners off to check the carb pistons lifting in sync and they do. Now with them off car started, stopped, started and appeared to be ok and putting the cleaners back stop/starting worked every time.

Got to be a coincidence. Maybe the problem is temperature related or some sort of vapour lock.

Reading before I'm going to check the two short rubber hoses and blow though the fuel line from the front with compressed air, what do you think. 

[Z320]

@&€!!@!!

[james christie]

You’ve nearly convinced me that you have an intermittent fuel blocage

1) Drain fuel tank

2) Disconnect fuel outlet from underneath the tank

3) Peer into tank with some kind of light or an endoscope if can lay your hands on one and be absolutely certain there is no crud in it - inevitably there will be some

4) Disconnect fuel arrival from fuel pump. Change the one way valves and the membrane on the pump if you haven’t already. 

5) Take off short rubber pipe connection at rear and be prepared to renew it. If you are courageous, make up a new length of fuel pipe from the tank, shape it and join it to the front pipe with a single compression joint. (It’s a fiddle but eliminates the rubber bit-and enables you to leave a bit more pipe projecting higher into tank, so sucking up cleaner fuel.)

6)Blow through pipework from end to end each way preferably with a compressor.

Put it all back together again. At least you will have eliminated a possible source of your problem.

Been there, done that, got the T shirt etc. Except that my tank was flaking internally and had some minor pinholes. I took it out and gave it the resin treatment. A much more laborious programme.

james

[keith1948]

Hello again Melvyn

It seems like you have resolved the electrical problems and now back to a fuel issue. James in the post above has made some useful suggestions. As I said much earlier I have done away with all the rubber connections under the car and now have one run of metal fuel pipe from tank to engine bay. If your rubber connectors under the car are old then they are unlikely to be ethanol tolerant. Much has been said about E10 but I have just replaced the floats on my Strombergs which were showing signs of blistering and softening with E5. When I removed my original rubber connectors under the car they were well past their best. The small change in diameter from metal to rubber to metal introduces a possible blockage point as well. Out of sight out of mind means these connectors are often neglected until they leak.

Like Marco I am confused by your description of an in line filter. Do you mean the one glass bowl next to the pump or do you have another glass tube shaped filter somewhere in line. For info if it is the latter they are directional with an arrow on them showing which way round they fit. I have one between the pump and the carbs on the pressure side of the pump and it seems to work ok but as Marco has said they can be blocked without visible sediment. Never had a problem with mine in that position. However if you have one before the pump then as Marco has said remove it. The original glass bowl one next to the pump is ok to take out sediment etc without blocking up. Having a tubular glass one on the suction side before the glass bowl is a bad idea because it is likely to block in that position.

Also check the breather hole in the filler cap is clear.

Keith

[eng622]

Drained the tank from the front short rubber pipe, fuel flowed out ok but there was a lot of ****/sediment. The inline filter is before the pump so not in the best place and the inlet/outlet holes are quite small so could block. The pump gauze filter is missing.

Used compressed air both ways into tank, from where pipe disconnected and then into tank via a rubber bung through the filler. Put fuel in/drained out 5 times and now only a little sediment observed. Did bounce the car up and down and side to side to move the fuel around the tank. So will put all back and try again.

Melvyn

[ianc]

The only way to get rid of the remaining particles in the tank and to stop further shedding of particles is to remove and thoroughly clean the tank, and then use slosh on the inside.

See my article in TR Action 144 (also in Section K3 of the Technicalities CD).

It's 24 years since I carried out this exercise, and I have not suffered any problems with shedding of particles since then - and I believe that the sloshing process has been improved since then.

I couldn't find the product on the Moss site (from which I purchased back then), but a search found this product:

     rust.co.uk/product/slosh-fuel-tank-sealer-7

Ian Cornish

[Pontious]

On 7/11/2022 at 3:08 PM, ianc said:

The only way to get rid of the remaining particles in the tank and to stop further shedding of particles is to remove and thoroughly clean the tank, and then use slosh on the inside.

See my article in TR Action 144 (also in Section K3 of the Technicalities CD).

It's 24 years since I carried out this exercise, and I have not suffered any problems with shedding of particles since then - and I believe that the sloshing process has been improved since then.

I couldn't find the product on the Moss site (from which I purchased back then), but a search found this product:

     rust.co.uk/product/slosh-fuel-tank-sealer-7

Ian Cornish

+1.  Your engine issues are identical to mine. There’s the solution.  The Slosh guys are very helpful if you need advice. 
 

David

 

 

[eng622]

Still getting the same problem. Ditched the washable in line fuel filter as when tested could not blow through it. Fitted a plastic one larger than average. Car started ok then ran ok for 35 miles then stalled at a junction. Got it going and got it home but it hesitated like never before at low rpm. Stalled in the drive and would not restart.

Now the fuel check with pipe off front carb and no fuel coming out on cranking. So tried the hand primer and fuel did come out, so back to cranking and still none then eventually did spurt out and it started.

I do not think it is anything to do with blockages prior to the pump and the pump bowl is always full so it must be the pump valves. Have had the top off recent and all clean but noticed the inlet valve had been replaced but the staking butchered. So guess the best way forward is to replace the pump as do not have the tools to change the valves. Perhaps the problem is due to heat as it started from cold easily.

[rcreweread]

Melvyn  - I have a few refurbished AC Delco pumps done by Dave Davies if you prefer a better option than the modern repros.

I can also supply a new alloy fuel tank, if you need one as I think this could very well be part of your problem, but I only have a few left following Alicool shutting down, so when they are gone, they are gone!

Have PMed you more details

Cheers Rich

[Lebro]

Sounds like a fuel pump problem, but not the valves, pull it out & check the lever which contacts the cam is ok, & check for any "slop" in the linkage.  A new / refurbished pump is probably the answer.  Recommend the Dave Davies pumps as offered above.

Bob

[eng622]

OK understand it cannot be the pump valves, not taken it off yet. Ordered a cheap one and if that solves the problem then can get the original one refurbished.

Melvyn

[eng622]

Fitted a new pump and result is the same so assume not the pump. Appears to be temperature/distance related. Starts ok and idles well. So ran the car in the drive idling, it was already warm, and ran for several minutes then the idle got slower and it then stalled and would not restart. It is a fuel problem as undid the fuel pipe from the front carb and tried priming and cranking and no fuel came out. Left it for several minutes to cool down, cranked again and fuel came out. Reconnected pipe and car started.

So baffled as to what is going on. The glass bowl is always full of fuel but this fuel cannot get to the carb on cranking (same for the original pump)

[Hamish]

Tank not breathing 

or

pipes closing up check all the rubber

has you blown through whole fuel pipe run from engine end 

[RobH]

5 minutes ago, Hamish said:

Tank not breathing 

Just about the only thing left.  You could try repeating the last idling test but leave the filler cap loose. 

[keith1948]

Hello Melvyn

Have a look at the recent post about cylinder 3/4 misfiring when hot in the 4A forum. That problem turned out to be Stromberg floats disintegrating and possibly valves in float chambers sticking when hot. Mine have had problems recently that I put down to use of E5 fuel over last few years. Not sure what carbs you have but carefully inspect the floats for softening, blistering or cracks. Also check that the valves in the float chambers are working and not sticking. If the floats have swollen slightly that might be enough to make them stick. Worth eliminating this as a cause.

Keith

[eng622]

Carbs are SU and have had sticking float valves and fuel leaks but both taken out, cleaned plus bowl and sure that is not the problem now. The problem is no fuel getting to the float chambers.

Where does the tank breath from is there something to check.

Fuel comes out the pipe that feeds the pump. Did disconnect the inline filter before the pump but made no difference. 

Pipes blown through with compressed air.

[RobH]

28 minutes ago, eng622 said:

Where does the tank breath from is there something to check.

There should be a small breather hole in the filler cap. It was referred to in a couple of the early posts on page 2, by BFG and Keith1948.

[eng622]

Checked the fuel cap breather hole it is clear and over 1 mm D. As said before have put fuel into tank bounced the car up and down and drained from the front. Repeated 5 times. There was sediment but a lot less after. Used air compressor to blow back to tank from front end and also pressurised the tank using a rubber grommet at the filler to blow out at front. When connecting the inline filter fuel gushes out the feed pipe.

Not sure about what has been said about inline filter before pump needing to have fuel in it. What I have noticed is sometimes the fuel drains back so it becomes empty but still starts.

On the road it appears ok for about 10 miles and ok beyond that if the revs are kept up. At low revs you can sometimes feel a slight hesitation if in top OD. And as said foot of pedal and it just stalls. But did find a fault, I think the idle adjustment screws have unwound, the springs are quite weak. I had to turn in 3/4 turn to increase the idle which was too low. But this has not cured the problem. 

Melvyn 

[stillp]

I had a problem with fuel not reaching the Stromberg carbs on my 4A after a few miles. Eventually cured it by removing the float bowls and the needle valves and cranking the engine over, which dislodged a bit of **** that must have been lodged in the carb between the needle valve and the fuel pipe. I'd already checked - several times - that fuel came out of the pipe when it was disconnected from the carb.

Pete

[Tr4aJim]

With the stock fuel pump, doesn’t the outlet pipe pass right up next to the block? If so could the pipe be getting hot and vapor locking? I believe modern fuels are more susceptible to this than in the past. I have an electric pump in my TR4A, so my fuel lines are routed well away from heat sources (as much as possible). You could try some heat wrap on the fuel lines and see if that makes a difference.

Late to the party here, so sorry if it’s been suggested.

Jim

Edited July 21, 2022 by Tr4aJim

[eng622]

Ran for 20 minutes in the drive and all ok however there was a weep of fuel at the top of the front carb float chamber. Found some **** between the needle and seat but the needle has a wear groove so ordered a new one. So will replace and try again. Also think I'm running the tank too close to empty.

The outlet pipe does in fact contact/close to the block for some distance, there is a short length of sleeveing insulating part of it.

Melvyn 

[keith1948]

1 hour ago, eng622 said:

Ran for 20 minutes in the drive and all ok however there was a weep of fuel at the top of the front carb float chamber. Found some **** between the needle and seat but the needle has a wear groove so ordered a new one. So will replace and try again. Also think I'm running the tank too close to empty.

The outlet pipe does in fact contact/close to the block for some distance, there is a short length of sleeveing insulating part of it.

Melvyn 

Hi Melvyn

If float needle sticks closed that could stop fuel supply. If needle and seat have a wear groove then replace them. While they are removed, blow through the pipe to the carb as suggested a couple of posts above by Pete. Don't think vapourisation of fuel is your problem.  Badly seating float valves and a bit of crud could be part if not all your problem. Fuel weeping shows float is not closing off the needle valve properly.

Keith

[eng622]

Forgot to ask, regarding the filler cap see the metal disc has an edge to it which I assume closes onto a seal in the filler neck. There looks to be something there but it has a rough surface and does not look like rubber.

[Z320]

Deleted 

 

Edited July 22, 2022 by Z320