Surging O4 Lb7 At About 70mph

J

J7 DIESEL

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Feb 1, 2008
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I put some new injectors in at 204k miles and it ran better no white smoke and idles great. Now I am having a surging problem at 65-70. You guys know whats going on with it, or how I can check was-up. Thanks
 
Check balance rates in drive at idle. Should be within ±4

Datalog rail pressure commanded, and rail pressure desired.

Normal crappy behavior for injectors is rough idle, high balance rates, white smoke that smells like fuel, and rising dipstick levels. You do not need all to have a problem.

You can also check return rates, but it's a PITA.
 
It has brand new injectors in it now, with about 300 miles, does this test still apply? Thanks
 
Have you checked that you do not have a leaking return line?
 
dumb question, are the return lines the ones that are under the first cover, that hook to the smaller side of the injectors? Thanks
 
J7 DIESEL said:
dumb question, are the return lines the ones that are under the first cover, that hook to the smaller side of the injectors? Thanks
Click to expand...

Yep.
 
do you have fuel in the oil? If no, its hard to say leaking return line. Maybe a sticking regualtor?
 
no fuel in crankcase either, Ok I have checked return lines and they are ok. Also I am having no fuel economy problems and it runs great when giving it throttle. I checked the water today and it was low, the water pump looks dry, holds a vacuum and does not leave any spots on concrete so.... head gaskets got to be ok right?
 
Day later about half a gallon low on water. Cannot see any leaks from weep hole motor is dry and holds pressure test. It does not smoke and runs great??? Head gaskets would show a pressure loss correct? The surging is slowly going away and I have the fuel pressure switch on the way. Thanks guys.
Jason
 
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