| Author | Message | ||
     James4hand (James4) New Member Username: James4 Post Number: 13 Registered: 02-2003 |
This question is on a '94 RRC LWB with the 4.2L, but should apply to other Rover V8s. I got Code 48- the Stepper Motor- and had a low, rough idle. I first cleaned the stepper motor, didn't help. Then I replace the stepper motor, didn't help. Then I went to adjust the base idle. I unpluged the stepper, clamped the hose from the throttle body to the plenum with vise grips, and screwed out on the appropriate place. As I adjusted it, there wasn't a very big effect of the idle speed. But once I got to a certain point and unclamped the hose, there was a whistle noise coming out of the cone on the air filter housing. What does this indicate? A dirty plenum chamber or throttle body? Am I adjusting the idle correctly? When I reconnected the stepper, it really didn't have an effect at all on the idle speed. Thanks all. | ||
| Dave Thomas (Dthomas) New Member Username: Dthomas Post Number: 17 Registered: 11-2003 |
I have heard that 'whistle' before. I think it happens when the screw for the idle adjustment is un-screwed too far. How many turns 'out' do you have the adjustment? | ||
| James4hand (James4) New Member Username: James4 Post Number: 14 Registered: 02-2003 |
Good question. I turned it out at least three times, probably more, b/c I seemed to be having little effect on the engine idle speed. I screwed it back inward until there was only a faint whistle when I released the vise grips. It still idles at what seems to be just below 500, and I would like it to be up at least to 700 before I go to clear the code. | ||
| Shaun Power (Shaunp) Member Username: Shaunp Post Number: 214 Registered: 05-2003 |
I reckon you may have a blockage in the idle circuit. The base idle screw does make alot of difference to the idle speed when the stepper is blocked off. It is quite a fine adjustment but you should have no trouble winding it up 650rpm and then the ecu will maintain it a round high 600 to low 700 rpm. The error code means it the stepper is faulty or out of range. | ||
| Jim Macklow (Macklow) New Member Username: Macklow Post Number: 28 Registered: 03-2003 |
I just did the same exercise today. Clamped the bypass hose, turned the screw in but it had no effect. Turned the screw out until it came out, screwed it back in a bit. Un-blocked the bypass hose, got the whistling noise. Screwed the adjustment screw back in until the whistling went away. Turning the adjustment screw didn't change the idle at all. I have '95 Disco. | ||
| Shaun Power (Shaunp) Member Username: Shaunp Post Number: 215 Registered: 05-2003 |
I never clamp the hose. I remove,plug it and fit a short piece of hose with the end blocked to where it came from (infact these items are part of my tool kit). This is the way the book says to do it. If you have the small air leak in the clamped hose the stepper will still bypass air. I have never had a problem doing it this way. |
