Jumping Rail Pressure on startup

[Ozymandias]

Hello

I've got a question about railpressure, always when I start my truck the railpressure jumps between 2000-4000psi, sometimes drops to Zero for a microsecond, just as long as the needle needs to drop to zero and back to 2000-4000psi.

Truck starts after 2-4 Seconds of cranking on normal winter temperatures.

On my Trip in January to 71° North with great cold I mentioned this behavior the first Time.



Do I need to worry about that?

Ozy

 

[JJPage]

Ozy, Do you have an Edge EZ or similar on your truck? When my EZ started to fail, the first evidence presented was erratic rail pressure at idle and light throttle. In park/neutral and in gear, like coasting up to a stop sign, my rail pressure would drop to 2/3k, bounce to 5k and repeat, drove me crazy, started replacing FCA, COV, etc.

It was my EZ, it only is failing on setting 2, but I would not trust the other 5 settings any longer, so I removed it. My TST failed in much the same manner, had it upgraded, but I no longer utilize it either.

If you do not have a fueling box, feel free to smack me for (as Bill O'Reilly would say) bloviating :-laf. Jess

 

[Ozymandias]

Hi Jess
I don't have any Tuner in my Truck, the Engine is bone stock.
If the engine runs the railpressure ist fine and steady, max pressure is also at 28000psi WOT.

 

[Ozymandias]

Does no one have e railpressure gauge installed in his Truck and can tell how his truck acts when cranking?

Can't believe it.

 

[cerberusiam]

Is this fluctuation during cranking or after the engine fires?

 

[Ozymandias]

Only when cranking, after it fires up the pressure is solid at around 7000psi idling.

 

[cerberusiam]

Only when cranking, after it fires up the pressure is solid at around 7000psi idling.

The problem with jumping during cranking may just be the draw down the starter places on the electrical system. Normally trying to read exact values while cranking is hard to do, especially with external gauages that rely on a clean adequate electrical source. The stepper motor gauges are very sensitive to fluctuations so the solution may be it just doesn't work well during cranking.

 

[Ozymandias]

Ok, so you wouldn't worry about it.

At which point do I need to have an eye on it, I mean hard start, after which time is it a hard start, 5 second cranking, 10, 15 ???

I just want to be prepared for it.

 

[cerberusiam]

Mine has always started before the end of slow count of 2. Basically, if you go beyond a slow count of 3 it is time to start thinking about looking for problems. Manuals start differently but the auto should start pretty fast.

 

[Ozymandias]

Thank you for this info, I think I'm behind a slow "2" in counting.

So I need to check some things, and I'll start with the connector tubes.

 

[JJPage]

Only when cranking, after it fires up the pressure is solid at around 7000psi idling.

I did not understand it was only while cranking, my bad.

 

[Ozymandias]

No worries, I appreciate every comment that could may help me.