Robert K
06-29-2004, 05:59 PM
I'm having a idle/low RPM problem on my 1991 535i. The idle is a bit rough and I have a strange surging that occurs at steady state cruise speeds. Also, when the engine is hot and I shut it down for a few minutes to go in a store, when I restart and begin to pull off, I get a strange lope that goes away after about 10-15 seconds.
This started after I changed the plugs and adjusted the valves. At first, I suspected a vacuum leak and did eventually replace the little hose that goes between the valve cover and the hose between the air flow meter and throttle body. In the process of removing the valve cover to adjust the valves, the original hose cracked, being very old and brittle. I really thought I'd found it, but replacing the hose didn't fix it.
So now, I've rechecked all the vacuum hoses, regapped the plugs from .028 to .033, checked all the valve lash (all set at .013 cold). I've also checked the resistance between the pins on the idle bypass valve (it checks out good) and checked the throttle position switch. Everything on it works except the wide-open throttle switch. I know that that switch is used to initiate the stomp test, so I used a couple of wires to simulate the signal the switch should have been giving. Anyway, that's when I got a strange reading from the check engine light. It goes on for about a second and a half, goes off for a second, then comes on for maybe half a second, then repeats the pattern. I left the key on for quite a while and it just keeps repeating the pattern. Therefore, I am getting no codes from the computer, unless the one it's flashing is an "everything's ok" type of signal. Anybody got any clues what it's flashing? I'd welcome opinions as to what's going on with my engine too. It's about to drive me nuts. I'm beginning to wonder if I've got a fuel pump about to give up the ghost.
Grace and peace,
Robert K
This started after I changed the plugs and adjusted the valves. At first, I suspected a vacuum leak and did eventually replace the little hose that goes between the valve cover and the hose between the air flow meter and throttle body. In the process of removing the valve cover to adjust the valves, the original hose cracked, being very old and brittle. I really thought I'd found it, but replacing the hose didn't fix it.
So now, I've rechecked all the vacuum hoses, regapped the plugs from .028 to .033, checked all the valve lash (all set at .013 cold). I've also checked the resistance between the pins on the idle bypass valve (it checks out good) and checked the throttle position switch. Everything on it works except the wide-open throttle switch. I know that that switch is used to initiate the stomp test, so I used a couple of wires to simulate the signal the switch should have been giving. Anyway, that's when I got a strange reading from the check engine light. It goes on for about a second and a half, goes off for a second, then comes on for maybe half a second, then repeats the pattern. I left the key on for quite a while and it just keeps repeating the pattern. Therefore, I am getting no codes from the computer, unless the one it's flashing is an "everything's ok" type of signal. Anybody got any clues what it's flashing? I'd welcome opinions as to what's going on with my engine too. It's about to drive me nuts. I'm beginning to wonder if I've got a fuel pump about to give up the ghost.
Grace and peace,
Robert K