hard to start then revs up high

[comanche13]

my truck every time i start it takes a long time to start then when it does it revs super high then goes all normal what could be the cause of this?

thanks tim

[dasbulliwagen]

We need more details... engine size, trans, year etc. My 2.5 does this, I think I read once that it takes three revolutions for the computer to get a proper crank signal, and after that it will start, and the high rev at least on my 2.5 is the throttle actuator that revs it up more at startup on a cold engine, it also bumps up the throttle for AC operation and high power steering pump pressures. Let us know what you got! :thumbsup:

[comanche13]

my truck is a 1990 4.0 ax15 pioneer

[Eagle]

The title of your post indicates it's hard to start. The text of your post, however, says it takes a "long time" to start, but doesn't mention it being hard to start. What's your definition of hard to start, or takes a long time? Your 1990 is a Renix model -- the injection/ignition system was designed by Renault and Bendix ==> Renix. This system does not "learn" as you drive. Every start is a "cold" start as far as the ECU is concerned, and every start requires several revolutions of the flywheel for the ECU to register sensor input and get things synchronized.

 

This is normal. You will NEVER get the "one touch of the key" starts that are sometimes seen in other vehicles. So if all you're reporting is that it cranks over a couple of times before it fires -- that's not a problem.

 

For the high idle, try cleaning the idle air controller and throttle position sensor.