Engine cannot rev when it is driving?

[Thomas_hmlo]

The problem occurred this morning. When I was driving at 70 to 80 km hour, the car started running like a horse. Gas padal the car cannot rev.
Stop the car at the side, engine still at idle. Give gas the engine rpm increases OK. When start driving, the problem comes back after a short while.

Gas padel wires not loose. Coolant level is enough. Engine oil OK. 9 deg spark plug burns OK. Change to 6 deg even worse.

Dump valve opens at 4K rpm. My mechanic two ERA dump value opens at 6K to 7K rpm. Is dump valve opens at 4K rpm normal?

I checked the value located at the top of the master brake cylinder. It functions when short
the connectors - fuel line, spark plugs, engine oil are OK.

Any possible cause to this problem? Please help.

[Thomas_hmlo]

Checked this valve. It is ticking when shorting the connectors together



The one at the water radiator have not yet looked into.

[an old original]

1) Try this....
On the first valve, take off the pipe that goes to the side of the carb and block up with a bolt or similar.

This valve can be a tricky thing, working one minute and not the next so taking it out of the equation will determine whether its ok or not.

[an old original]

also check out this pipe that loops from the side of the carb to the top of the manifold for leaks

[Thomas_hmlo]

Checked the carb rubbings. They are OK.
For the value, my mechanic guy replaced the value by exchange another valve from his ERA. The problem is not going away. I will check the valve tubing. That method is a good suggestion.

I know there is a ECU in the dash, what is wired to the ECU?
Also trying to open the carb to check

[an old original]

have a look at the wiring diagram in the Technical section in the menu on the left. That shows what is connected to what.

The part with the 2 wires and one pipe attached to the top of that radiator bracket is the boost modulator.

As far as I know it works a bit like this... when accelerating under boost the wastegate would normally open at about 4psi (0.2 bar) and that would be all the boost you would get, but the boost modulator allows a little pressure to leak, making the wastegate stay closed until you get to about 7 psi (0.5 bar) of boost. However I notice that yours has the end broken off and a bolt put in. I haven't got a picture of a complete one as mine is the same as yours! but this may restrict the boost you'll get.

This (and the ECU) should not cause the problem you have.


On my earlier advice regarding putting a bolt in the end of the pipe from the carb to the valve on the brake cylinder. I've run mine like this for 10 years but the idea of this valve is to stop the engine "running on" and to also help with starting when the engine is hot. Over here I haven't had problem with either but in your warmer climate it could cause a problem.

[paul]

Get a lo guage, used to test vacuum and low pressure systems, this should come with a T piece, and T it in to the fuel line, just before the carburettor, you may need a short length of fuel hose to do this, then connect up so the gauge come out of the bonnet vent and tuck it under the wiper and take it out for a high speed blast till symptoms start, check for fuel pressure, needs to be 3.5 to 4.5 PSI from memory, sure some one will quote exact figure, but if its in that area then it confirms the pump is still able to get fuel into the carburettor.

Will rule out.

Lazy pump, only able to provide fuel for tick over.
Partially blocked fuel filter, (not uncommon on imports from Japan to find they have been dry docked(PK term) or laid up for years as almost museum pieces and the old fuel varnish once used again dislodges and blocks filter or lines or pump..

Bad connections in wiring the in line fuse holder behind the carburettor is a known area where a bad connection can give these symptoms.

Fuse box, a corroded fuse box (under neath not visable can give similar symptoms)

Check and confirm fuel pressure is good or not and report.

Paul

[G96LUE]

Check that there are no splits in the hose from the carb to the anti run on valve too.

I guess you have already checked this too but to be sure, there is oil in your carb float damper isnt there?

A problem i have is my vacuum to the distributor. I removed the thin pipe from the little elbow connector next to the carb and blocked it with the solid end of a small 3mm drill bit.
This will prevent the manifold from sucking in too much air and your timing will stay static.
This seems to get mine running ok-ish as it was over advancing

Definitely remove the bolt from the boost regulator valve.
You will be running at half boost. The bolt should be a sort of air stone (similar to what you use in a fish tank) but with a plastic threaded connector and allows pressure to be released as mentioned above.

hope you get it sorted soon

[Thomas_hmlo]

Showing some photos. The problem is due to rusty tank and the rust was caught and stuck in the fuel pump. Mine fuel pump is not original type and has a mesh filter inside. Rust stayed at the bottom of fuel pump and more fuel pressure sucked the rust and clogged the pump.

Some rust removed from fuel pump and gas tank.





More in the tank

[G96LUE]

The grot in the tank would most certainly cause you some problems.
I guess its ok now, but what's with the screws?