Not mine but- code 18 and a 35. It is a 94 3500HD, heath pmd less than 6 months old, rebuilt injection pump less than 2 months.

Pump is a 5068.

Injection pulse width is a steady 1.66 does not change when you hit the gas.

Fuel rate on scanner is 1mm.

Fuel oressure is good, ops, lift pump, filter harness swapped it with mine,all checked.

I would say the optic is bad, What else to check , and should i warranty the pump or replace the optic, its a hassle either way.

DTC35 is the 1.66ms pw - aerated fuel, bubbles, inadequate fuel supply - wrong Inj Pump?

1mm fuel rate indicates IP problems - the 5068 IP requires it's own eprom, won't interchange with any other IP or eprom

What's the story leading up to the replacement - oem original, any previous replacement?

this is the second pump in 6 months, guy i work with, previous pump ran fine for about five months don't know what happened, this second pump is when i got involved. i set the timing on it when he installed it everything looked seemed fine, don't know how he set the timing on the previous pump. when i set the timing he did have a fuel leak i fixed for him going to the filter.

there did appear to be some water in the fuel. when i was checking ops and what not. but i didn't think this would effect the fuel rate.

these have been NAPA reman pumps.

Be better if you could upgrade to a 5521 with corresponding eprom - should be some info in Parts Point

Give member Diesel Pro a PM, see what he has to say