No start has finally gotten worse, maybe able to diagnose?

[MarkEkberg]

2003 305hp/6speed, smarty.

Yesterday it was 60 degrees and it would not fire without a shot of ether.

I am at 230K. I installed a smarty at 200k. Makes no difference if it is in, on various settings or completely disabled.

It started out not starting at cold temps without being plugged in. Over the last 15K miles it gets warmer and warmer on the no start. Once it fires the first time it starts great from there on out. About three seconds of crank to fire at that point.

I have noticed that there is a surge at low speeds (about 25-30mph). If your just cracking the throttle to maintain speed it is a rhythmic surge about every 4-5 seconds just enough to feel in the seat of your pants.

Injectors are OE. I know I will need them, but I am not convinced it is as cut and dry as a set of injectors.

I have read about many people throwing 3K worth of injectors at a truck only to have had a sensor bad or some other issue.

 

[p-Bar]

It probably is injectors . As the the heat is applied to the injectors (plugging it in) the tolerances are tightened up allowing the rail pressure to increase during cranking to get it to fire. Watch what you buy in the way of injectors , stay away from rebuilds . They are all not created equal. Think about some better fuel filtration before you put new injectors in.

 

[promisedland]

Agreed^^^^^

 

[Bob4x4]

Watching the rail pressure will give you a good picture of what is happening at start up.An injector return test will confirm it.Long crank time is abusing the Starter,batteries and charging system............pay me now or pay me more later..

 

[MarkEkberg]

Watching the rail pressure will give you a good picture of what is happening at start up.An injector return test will confirm it.Long crank time is abusing the Starter,batteries and charging system............pay me now or pay me more later..

I agree. If it does not fire in about 5 seconds I spray my filter with ether and crank again. Fires as soon as it ingests it.

I had rail pressure checked couple years ago when this first started happening. Was high enough to start, but fluctuated while at idle. I think the slight surge has something to do with it?

 

[cerberusiam]

Depends on how much fluctuation, 600-800 psi fluctuation at idle is pretty normal. More than that the FCA is suspect, at an idle it should not be bad. Part of the problem is you can never be sure the RP sensor isn't flaky unless you replace it. Age and heat cycles effect the sensors and they drift.

If you want to be sure it is injectors, do the return flow test on them. Test PR relief valve for leakage, test the CP-3 return flow, and get a contribution test with rpms drop done with a scanner. Or start buying parts and guess at what next.

 

[Motorhead]

Ether really isn't a good idea with a grid heater.

 

[MarkEkberg]

Ether really isn't a good idea with a grid heater.
If you want to be sure it is injectors, do the return flow test on them. Test PR relief valve for leakage, test the CP-3 return flow, and get a contribution test with rpms drop done with a scanner. Or start buying parts and guess at what next.

I disable the grid heater when I need to fire it on ether. I do want to make sure it is injectors.

I have replaced the FCA (I think that was the name of it). What does a shop need for a scanner? Good snap on? My trusted mechanic for things I don't have time for is not a diesel guru, so as long as I tell him what numbers to grab and a 6pack of beer he will.

 

[cerberusiam]

A SnapOn scanner with the correct modules should do the contribution tests and kill test. Injector and return flow is more manual but requires the test cycle if you want to do it per current specs, not sure if the SnapOn has that test cycle.

 

[Bob4x4]

Yes the most accurate return test is when the rail pressure is turned up to duplicate real world conditions