mix and match

[mr b]

Just built 8v engine using 1.4 block injector and ECU ,1.2 head and put a kent cam NV062 in it and i tell you it will go and is quick hitting the limiter only trouble is getting it to idle. The ECU can handle the revs but struggles with the cam at idle tends to over fuel any ideas? running an external fuel pump as in tank was faulty

[mk1nova_rich]

Is it SPi? If so an external pump is probably feeding too much fuel

[Jon_nova1]

so everything is from a 1.4 apart from the head and Cam? does it smoke when accelerating?

[mr b]

Its spi, yes all is 1.4 except head and cam get a bit of dark smoke from idol while it burns excess fuel then runs clear. Thought the regulator in the throttle body would keep the pressure constant at the injector .

[Jon_nova1]

i'd suspect a sensor more so if you are using an injection engine with an injection tank, they have regulators yes?

[mowgli]

so you are running the spi injection with an mpi pump... overpressure will be causing a fair few problems..

[mr b]

no its just an inline fuel pump of the bay runs at about 3 bar

[mowgli]

an spi doesn't run at anything like 3bar, probably nearer 1bar..

3bar inline pumps are for mpi.

It will be causing problems

[mr b]

ok ill try a different pump, or fit a regulator then i can play about with the pressures cheers

[mowgli]

no need to play with pressures.... spi runs at .76 bar, thats 11psi, or about a half decent fart

the mpi is 3 bar (44 psi or a transit van tyre pressure)). it also flows 1.4 L/min, which is way too much for an spi to cope with.

[mr b]

solved the problem still runs a bit lumpy but thats the cam turned out to be the temp sensor. Left the pump on seems they run better at high revs with more pressure have to adjust the fuel pressure regulator next but will need it on the rollers to do that. Also advanced the timing by about 8mm from the mark made a noticable improvment worth trying