Stumble off idle when cold, flat spot

[Leiden]

Yup they looked exactly the same as the rods I pulled out of the motor, even weighed the same!

Only difference between them was the ST246 were slightly different in colour.

I was going to use ST185 rods in the rebuild as they looked alot beefier but it turned out one of them had spun a bearing and killed the big end. Couldn't find anyone wanting to part with their ST205 rods either

[t0ms]

I've been thinking about removing the pulsation damper as I've heard these can become a problem and cause lean conditions, would make sense because the FPR is intank and thinks the fuel lines/rail is pressurised to 62psi when its actually the pulsation damper being a restriction.

Theres a little screw on the top of it that I had a play around with, as far as I can tell it practically does nothing until it seats against the rubber o-ring, then I think it assists the fuel in pushing the damper upwards to flow onwards into the rail. I've thought about adding a small washer to try and relieve some more pressure, any thoughts on this?

The pressure regulator and the dampner are two different things with 2 very different functions.

FPR regulates the pressure up to the require pressure for the system

pulsation dampner helps to maintain a smooth consistant pressure in the fuel rail.
every time an injector fires off the pressure in the rail drops slightly as the fuel escapes. the dampner is a preloaded spring applying the same pressure to the fuel as is required in the rail. so as the fuel exits the spring compresses the remaining fuel to maintain the rail pressure. remove it and you'll get wider fluctuations in the rail pressure making it harder to maintain constant accurate metering of the fuel into each cylinder.

the other thing is it shouldnt be any sort of a restriction because it is not "in line" with the fuel flow. it mearly acts on the fuel in the rail. theoretically the only "restriction" on your fuel system should be the FPR....

[Leiden]

I saw a exploded view of one and it looked to me as if the fuel had to push past the valve (hence push against the spring) to get into the fuel rail therefore making it inline i.e. between fuel pump & fuel rail

[t0ms]

yeah but if you see the rhs of the "neck" as such is lower than the lhs. this will allow fuel past but when it is running i think you'll find that the plate is actually like halfway up inside the cover allowing for much greater flow. remember you have 70 odd psi pushing up aghainst it holding it up there and it will only be moving like 1 - 2 mm

[Leiden]

Ah ok, so the chances of it failing and becoming a restriction in the fuel system are pretty slim if anything then?

[matt dunn]

Ah ok, so the chances of it failing and becoming a restriction in the fuel system are pretty slim if anything then?

I doubt it would be able te restrict flow unless something got in there,
but if you have a fuel filter it wont.