Alternator causing Mid RPM missfire??
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Alternator causing Mid RPM misfire??
I have a mid RPM misfire at about 2000 rpm after the motor warms up. Idles super smooth. Have replaced ECM, injectors, fuel filter, MAF, TPS, water temp sensor, O2 sensor, fuel press is perfect ignition is perfect. Compression is perfect. All has been investigated!! I'm running out of magic bullets so while reading on the INTERNET I came across an interesting account of what may cause a misfire like this.
" Try temporarily removing the belt from the alternator and see if the is still there. If it is not, you have a bad diode in the alternator. A bad diode allows AC voltage to get through to the computer which is not made to run on DC voltage only."
...at http://www.2carpros.com/topics/misfires.htm I'm going to try this. Wonder if anyone ever had the Alternator cause a misfire???
[Modified by GRX, 8:25 AM 10/29/2003]
" Try temporarily removing the belt from the alternator and see if the is still there. If it is not, you have a bad diode in the alternator. A bad diode allows AC voltage to get through to the computer which is not made to run on DC voltage only."
...at http://www.2carpros.com/topics/misfires.htm I'm going to try this. Wonder if anyone ever had the Alternator cause a misfire???
[Modified by GRX, 8:25 AM 10/29/2003]
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Re: Alternator causing Mid RPM misfire?? (MrNuke)
Well, its like one of the cylinders is just barely missing...like a small hickup. Nothing major like a backfire though intake or exhaust. Gets worse as temp and RPMS go up.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Alternator causing Mid RPM misfire?? (GRX)
It would be easier to unplug the connector on the alternator to see if it is alternator ripple causing your trouble rather than taking the belt off.
