New engine won't rev past 2k

kasey200

kasey200

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Sep 24, 2006
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I posted this in my build thread too but i though i may get a little more help here.

Engine doesn't seem to want to rev over about 2 thousand RPM's. It idles great and sounds good untill 2k or so. Once it hits 2k it flutters and cuts out. Does this sound like an issue with my 4gsk or possibly still air in the high pressure lines? Any ideas? This is frustrating.
 
Got Smoke? said:
Got a fuel pressure gauge? Weak lift pump maybe?
Click to expand...

I have one but it's not wired yet. I will do that tonight and give it a try. Is this what I should be looking for?
18-24 psi at idle, 28-36 at 2000 rpm with no load
 
Got Smoke? said:
Got a fuel pressure gauge? Weak lift pump maybe?
Click to expand...

I wired my fuel pressure gauge quickly over lunch and it is idling at about 25 psi. It does raise when throttle is applied but it's hard to tell how much because the motor starts to flutter pretty bad above idle speed. Also, It starts really hard when cold (truck is in garage so it cooled to about 40* overnight, this isn't that cold). Once the motor has had a chance to warm up it fires instantly.
 
Re-check your timing. Check to make sure your grid heaters are getting power if its having probs starting in 40* weather
 
So.. Whats the fuel pressure doing when it flutters ? Does it stay up? How about the overflow valve?
 
when the engine flutters the fuel pressure stays up around 25 but does elevate slightly. I am not sure about the overflow valve? It doesn't have any problems idling (is't poor idling a characteristic of a bad over flow valve?)
 
Is the fuel shut off solenoid working properly? Does it pull the plunger up the whole way?
 
Try adding 2 clicks to your governor springs. You may have to lower your curb idle after. See how that does.
 
Sounds like a bad overflow valve. Pull it out and disassemble it and stretch the spring. And put it back together. Make sure you put it back together the same way it came apart. In reverse order.
 
Dumb question but Ive seen people do this. Did you happen to leave a rag or something in the IC tube or anywhere to keep stuff from getting in?
 
Is this before its warmed up fully? check your fuel filter, and try the gov spring mentioned before.

what color is the smoke? white? does it burn your eyes real bad?

if its any of those probly timing /fuel pump/filter issue. my timing slipped withing 10 minutes of running, i got a new washer and it solved my timing problems.
 
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