7747 in a 1980 Sand rail

[chadapcb]

I am lost. Just did a full swap in a boat and everything runs great.

Doing swap wan on my sand rail idles and revs great in park but no power in gear.

Basically this his is what I have.

1980 sand rail with a 350. Had a qjet carb.
New fuel cell 20 gallon not sure if it baffled or not.
New external fuel pump.
I replace all sensors so all is new.
Tps and iac been replaced.
New distributor and coil and wires.
Timing set at 0 cranks real easy.

Fuel pressure is 14lbs idling and same revving up.
idle is 650 rpm
put in gear still idles great once start moving and rpm gets
above 1200 rpm then it just falls flat on her face.

Swapped ecm from my boat and swapped chip. Boat works great.
Still does same on sand rail.

The he chip is not been modified in any way for sand rail. Using a chip
from a 1990 Chevy 1500 350 5.7

Any suggestions is greatly appreciated.

[Six_Shooter]

What is the engine in the sand rail exactly?

Have you verified that the ECM is controlling timing?

Where is the ECM grounded? Is the ECM case isolated from the rail's chassis?

[chadapcb]

The ecm is actually inside of a fiberglass box.

As far as ecm controlling I believe it is.
It appears to jump around.

Is is there a way to verify it.
I have disconnected the set timing and it goes back to zero at idle

the engine is a 1990 5.7 rebuilt to stock with vortec heads and intake.

[sturgillbd]

the engine is a 1990 5.7 rebuilt to stock with vortec heads and intake.

Vortec heads will require more spark advance and more Acceleration enrichment. Vortec heads have different flow characteristics and timing requirements compared to TBI heads. To make this engine run correctly, you will have to datalog and tune.

There are several threads on this forum that deal with tuning using vortec heads.

Hope this helps,

Brian

[Fast355]

Its the Vortec heads causing your problem. You will need 454 injectors or about 30 psi fuel pressure and alot of tuning to make it run correctly. You can bump the timing 8-10* and get it to run a little better, but you will need ALOT more fuel.

[chadapcb]

So basically I take and put my timing at 8degrees btdc and turn my fpr up to 30 psi
all should be good.

[Fast355]

So basically I take and put my timing at 8degrees btdc and turn my fpr up to 30 psi
all should be good.

Going to need to dial in the chip, but you will have enough fuel at that point for it to run correctly. As for the timing, I always set the timing about 8-10* at the distributor on a vortec head engine then make the timing changes in the chip to make it run correctly. There are places that my Vortec likes ~50* of timing at cruising speeds. Set at 0* the stock distributor will only allow 42* total timing and the stock timing map only delivers about 20* of timing at WOT and often retards past TDC aka timing goes negative advance when you stab the throttle from idle. With Vortec heads this often gives a nice pop or fireball from the intake.