| Author | Message | ||
     Corey (Discobro) Senior Member Username: Discobro Post Number: 341 Registered: 12-2002 |
I just replaced the stepper motor in my 96 because of a CE code that was P1509 - IAC Motor Circuit Short. I was having starting problems so I assumed that this was related. Once I replaced it I started it up without a problem (several times) with a very consistent idle. Then the test drive.... Got to the end of my street and it just dies. No idle. Start it back up and it revs over 2000 RPM for at least 15 seconds and then back down to nothing and dies again! Well my starting problem has been fixed but now I can't keep the damn thing going! In the end I just put the old stepper motor back in and everything is as good as new (almost - still the starting prob but idle is great). Help!! Is this a bad stepper motor or something else? | ||
| Randall Smith (Mr_smith) Member Username: Mr_smith Post Number: 229 Registered: 04-2003 |
Corey: Precisely what do you mean by "starting problem"?? Is your new stepper motor Lucas or from Pep Boys? Just for your reference: It takes 15 minutes of driving for the ECU to learn a new stepper motor. I suspect that there is an electrical problem with the idle control circuit, and not a fault wih the actual IAC valve. You may also have more than one problem, which is complicating the diagnosis. Randall | ||
| Jack Leitch (Liveattheedge) Member Username: Liveattheedge Post Number: 118 Registered: 12-2003 |
my idle was crap and stalling, bad fuel pump, it did run and go when u held the revs up, but u couldn't stop. Cheers Jack | ||
| justin monnin (Ineedthissale) Member Username: Ineedthissale Post Number: 41 Registered: 12-2003 |
sorry mate but it sounds like you will have to take it to the dealer to have the idle reset | ||
| Corey (Discobro) Senior Member Username: Discobro Post Number: 342 Registered: 12-2002 |
Randall - my starting problem has been this (to sum it up): about 50% of the time when I start the engine (temp doesn't matter) it hesitates to start and I need to give it gas and rev it a little until the idle can take over by itself. It always idles fine after it gets going but it takes a few minutes. If the stepper motor isn't the problem then how do I go about diagnosing the idle control circuit (without getting the dealership involved  )? So 15 minutes huh? I probably ran it for 5 min. then stall - 5 min. then stall - 2 min. and stall - was home by then and said the hell with it and put the old stepper back in. Should I try that again? The starting problem seemed to be OK except for the wacked out idle. Oh and I am not sure if it is Lucas or not (the new stepper). Got it from Nathan at DiscountRovers. All of the markings are the same and box said "Britparts" with a UK flag deal... | ||
| Randall Smith (Mr_smith) Member Username: Mr_smith Post Number: 232 Registered: 04-2003 |
Corey I don't believe that anyone in the Rover parts business would sell the wrong elec part just to undercut the other resalers on price. But a quick comparison of the two stepper motors using a multimeter should tell if they are identical parts. When i have checked those alternate steppers mentioned on these BBSs, they all are not the same as Lucas. They don't idle engine consistantly either. About the 15 minutes of learning: It's worth a try. but the important thing is that if nothing is wrong with your engine, and you install a new stepper, idle will be wierd for a few minutes. The ECU has to figure out how much juice to apply to new stepper to get the correct rpm feedback from the ig coil. You can diagnose IAC circuit at home with the electronic troubleshooting manual at hand. Testbook may be the easiest way though. Your description of slow starting 50% of the time is troubling. There may be more than one problem happening at the same time. The ECU controls the engine speed whenever the car is not moving(which includes starting engine). So that really needs to be working to have good clean starts and warm ups. That's one of the main advantages of EFI. Easy startups no matter what the circustance. Randall Randall | ||
| thom mathie (Muskyman) Senior Member Username: Muskyman Post Number: 596 Registered: 11-2002 |
the starting problem sounds like injectors are leaking down and causing a overly rich situation. this can also cause a fluctuating idle as the system trys to go into closed loop mode If so ...I'll bet it starts right up after sitting for a long time...and if it has been run and then sits like a hour or two you have to floor it to get it started? MM | ||
| Peter J Blatt (Peteb) Senior Member Username: Peteb Post Number: 331 Registered: 10-2002 |
Just for fun, How is the battery and alternator? if you have a low volt situation it can cause your engine to run like crap, and still start the truck, Look for 12.5v without the engine running, and 14v or so running. |
