engine stalls

[robert]

The engine stalls when releasing the throttle from higher rpm revs. It will do it when there is no load and when under load. It Idles fine however. I replaced the ISC and checked for vacuum leaks around the thtottle body and BISS. I'm at a loss and would appreciate any advice.

Bob

[XakEp]

Mods? It could be anything from plugs and wires to a bad turbo.

[robert]

There are a lot of mods but the turbo is brand new and so are the plugs and wires. I'm going to do an air intake leak test. Do you suppose it could be fuel pressure related?

[Hal]

Light weight flywheel?

Hal

[v413nc3]

Have you done any head work? If you have new valves and an old head and didn't lap the valves that could be your issue. A new valve job and new valves don't need lapped normally but an old/old combo does to seat the valves nicely.

[robert]

I did put in a Fidanza lightweight flywheel replacing the RRE lightened that was in there. The head work was all just done professionally including a 3 angle valve job and mild porting/polishing.

[v413nc3]

What's your Fuel pressure at? What are you using for management?

[robert]

My fuel pressure is at 31 lbs at idle. I beleive this is low so I have got a Walbro 255 to install and an Aeromotive AFPR. I am going to put them in now, but I just finished the assembly with the new Ross Pistons, Eagle Rods, head work, flywheel, etc. and did not want to risk having to wait too long for fuel before the initial startup

[hoffman]

correct me if im wrong, but FP is 40psi for a 1g and 43psi for a 2g.

[ryanman]

Originally posted by hoffmangsx
correct me if im wrong, but FP is 40psi for a 1g and 43psi for a 2g.

With vacuum line disconnected and plugged................. at idle of course

1G's N/A's - 47-50

1G turbo with manual tranny - 36-38

1G turbo with auto tranny - 41-46

2G turbo - 42-45

2.4 engines - 47-50


With vacuum hose reconnected............ at idle also

1G n/a's - 38

1G turbo manual tranny - 27

1G turbo auto tranny - 33

[v413nc3]

Keep in mind you generally want (with aftermarket injectors) to have it set at 43 base pressure with the line on at 0 vac. Just because it's easier to know what fuel delivery you're getting, MOST (not all) injectors are rated at XXX/cc @ 43.5psi

ie...

450cc @ 43.5psi
or
660cc @ 43.5psi


if you run a different base pressure you're getting different fuel delivery and your fuel trims will be all kinds of wacky and you'll have trouble tuning it properly unless you account for the difference.