Engine never starts on first time cranking

[tdmkr496]

I have an 88 Mustang 5.3 4L80E COS 5 411 PCM swap that never starts on the first time cranking the engine, but always starts on the second try, doesnt matter if the engine is hot or cold. Any suggestions??

[andysc3]

are you giving the fuel pump a chance to prime the system? try tuning the key to the on position 3-4 seconds then crank it over.

[tdmkr496]

Yes, pump is usually off by the time I start to crank it.

[andysc3]

do you have a fuel pressure gauge? Try posting your tune and some logs

[tdmkr496]

I do not have any logs of cranking, I will make one. I do have a fuel pressure gauge on it and it reads 38 psi at key on.

[andysc3]

seems low, Base fuel pressure should be around 58. How od is the pump?

[tdmkr496]

The pump is only about 6 months old, I'll try turning the pressure up.

[andysc3]

how does it run once it starts?

[joecar]

As andysc3 said, 38 psi rail pressure is incorrect... this has varioous implications, including the IFR table will be all wrong (it is based on 58 psi);

another question: is your FPR manifold referenced, or un-referenced...? (this determines whether the IFR table is flat or sloped).

[tdmkr496]

Thanks guys, I upped the pressure today and the problem went away. The FPR is referenced from the compressor housing.