Logo
FULL SITE MENU

2003 DF50 Acceleration Issue

D

Duckey

New member
Initial Problem.

Engine will not accelerate past 3k rpm. Engine started to idle rough in neutral then didn’t want to stay running after start up.

I’m thinking a fuel issue.

Currently I have replaced 10 micron Racor filter, and the low and high pressure fuel filter. (Fuel looked fine, no water or sediment). Replaced spark plugs. Also took off intake manifold to access VST. Opened VST and replaced hi pressure fuel pump filter. VST look fairly clean with exception of a white chalky build up near intake of filter. Filter did appear to be restricted. Should I replace the fuel pressure regulator in the VST? I removed float and needle valve. Needle valve looked fine as well as float (no cracks or fuel on/in float). I can hear high pressure fuel pump run when key is turned before starting engine. Is there anything I should check or replace while intake manifold is off? Am I missing anything?
 
There is a switch on the motor linkages.----If it is stuck in the NEUTRAL position the computer will not allow the motor to rev up.
 
If computer is told that motor is still in NEUTRAL it will not rev past about 3000 RPM.----Should be easy to test / eliminate that possible fault.
 
My manual also showed a neutral switch inside my throttle box on my console. I’m assuming the two neutral switch’s are linked to ECM.
 
Engine is back together. Starts up and idles great. Briefly ram engine up to 5k on the hose with no issues.

I changed the following parts. These were either due for change or just a had to due item since I had the engine apart.

New spark plugs
10 micron racor filter
Low pressure fuel filter on engine
Neutral switch on engine
Hi pressure fuel filter
VST gasket
VST breather filter
 
Engine is back together. Starts up and idles great. Briefly ram engine up to 5k on the hose with no issues.

I changed the following parts. These were either due for change or just a had to due item since I had the engine apart.
geometry dash lite
New spark plugs
10 micron racor filter
Low pressure fuel filter on engine
Neutral switch on engine
Hi pressure fuel filter
VST gasket
VST breather filter
Click to expand...
Hey,
Awesome to hear it’s running smoothly now! Sounds like all that effort paid off, especially catching that VST filter and the breather — those often get overlooked. Did you notice any visual issues with the old neutral switch? Wondering if that might’ve been contributing too. Planning to water test soon?
 
The neutral switch housing was cracked when I get some time I’ll take it for a test run. I was surprised how clean the inside of the VST was.
 
Finally power trialed yesterday evening. Been a bit busy! She ran just dandy. No hesitation. Here’s a picture of the cracked neutral switch I replaced, I’m can’t put my finger on exactly what the issue was but I’ll point at the high pressure pump filter and neutral switch.
 
Back
Top