For hesitation problems, it may be one of the following: 1. Sticking or Binding air flow plate. If the airflow sensor plate binds on the way up, fuel flow will be limited and the engine will sag or stumble. 2. Sticking or binding Control plunger. If the control plunger binds on the way up, fuel flow will be limited and the engine will stumble or sag. 3. Incorrect System or Control pressure (you'll need a K-Jet gauge to measure this). If the system pressure is too high or if the control pressure is too high (high system pressure will usually cause a high control pressure) the movement of the control plunger will be limited and the engine will begin to run lean as the airflow increases. OR 4. Unequal injector flow. You can check 1,2 and 4 by removing ALL of the fuel injectors and placing them in a jar. Jump the RPM relay to turn on the fuel pump. Note the spray patterns on all of the injectors; they should be close if not equal. Next, with the air box removed carefully press down on the air meter flap and verify that there are no restrictions (should go all the way down). There should be a slight opposing force, that's the fuel pressure against the control plunger. It should go down smoothly and you should see more fuel (again close to if not equal amount) spraying from all of the injectors. The spray pattern should also be in a cone shape, should not be in a straight stream spraying out of one side. If it is spraying out like a straight stream then the injector is either dirty or bad. In order to check 3 you'll need a Fuel pressure gauge for the Bosch K- Jet system. That's the only accurate way to tell if the fuel pressure is too high in the system or if the Warm up regulator is bad. Steve --- In dmcnews@xxxx, Sacha Prins <sprins@xxxx> wrote: > Hi, > > I'm looking for Dave Sontos who sent me a URL once with directions to > solve 'engine hesitation' problems: > > > Hesitation, hard starting, backfire in engine, are all related to fuel > > startvation problems in a cold engine. Visit my web page at > > http://www.vabch.com/dsontos/Regulator.html for a full explination of > > how to fix your problem. > > Unfortunately the URL mentioned is not available anymore nor is Dave via > his old e-mail address. Since I'm going to take my #17115 to the shop > any time soon for a workover I'd like to have these directions to show > the mechanic in the right direction. > > Any info is appreciated, > > Sacha > #17115