L400 diesel surge

Installed new set of injectors. Found drivability to be similar. The van will surge upon throttle getting up to speed. Rpm doesn’t slip, van just is slow to make power with demand experiencing random surges. I notice that since the pump rebuild and calibration, my egt numbers are extremely safe. Van also is experiencing ~20% loss in fuel economy. I now believe it is time to tune this van. Diesel shop told me it is ok to give full load screw a quarter turn in. Van makes no smoke when wide open throttle.
 
Update, today I replaced the in-tank fuel filter, all fuel hoses on and to the fuel tank, installed a new oem fuel filter, housing, water sensor, and inspected all of the suction side for diesel fuel delivery to the fresh rebuild injection pump and injectors. I bled the system as per shop manual and the van fired right up. Upon test driving approx, 50 miles, I have only felt three small surges. Most likely, these surges were remaining air in system after the bleed. So far so good! All egt values staying below 1200*f (wot up hills in heat). I did not adjust anything since injection pump calibration during rebuild. Now to observe the long term
 
Did you try and "see" the air in the return fuel or just replaced as the parts are 26 years old?
 
I just replaced all the parts due to age and admit I went to laziness on this diagnosis. I look back and wish I did observe the air.
 
As I have not had to do much under the van. Is there a easy access to the return line under there?
 
Yes there is, now that I think of it. Between hardline and tank is a 6mm return line hose. Question is there a fuel hose that is clear that could be semipermanently installed. To add, after seeing the whole fuel delivery system to the pump, I believe my air leak was near the fuel filter and housing area.
 
I do not know of a clear hose for semi permanent installation. Plus you you kinda have to have it in a loop to really see.
 
Hello guys, I know this is an old but super interesting thread, I have decided to adjust my tps sensor following the instructions in the PDF and when I look for the signal on the 3 cables, 2 show me 0.00 and only one shows me 5.00 , which is the blue and red wire, I have doubts about moving it or I don't know if the sensor is bad, who can help me?

I must add that since I have had the vehicle I have had the A/T light flashing, I got the flashing code and I have a code 11 that gives me a TP sensor failure, is there any way to verify if it is really damaged? The vehicle drives well, without failure and no problems, the RPM only feels a little high about 3k to 100k/h
 
Growlerbearnz said:
Fingers crossed for a bad chassis ground being the cause? I haven't heard of a bad earth causing trouble for years. Bad earths were all the rage on '60s and '70s British cars, pretty much any time something went wrong you could cure it by putting a jumper lead between the battery and engine block.

Oh god. I just realised: I'm really old.
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Lukas Prince of Darkness. I am old too. My kid found a can on a website "Smoke to refill your Lukas wiring".
 
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