I just took my '92 cabrio on a 2400 mile trip from Austin to St. Louis, Kentucky bourbon trail, Nashville, Memphis, and back home. Ran fine at speed on highway when we left home, but once warmed up really good, when I would slow down (for gas, stoplight, etc.) the engine would hunt idle sometimes. Also, the check engine light would come on and go off randomly, never throwing a code. I had just done the timing belt, WP, thermostat, spark plugs, valve adjustment, new intake boot and various hoses, and I thought immediately vacuum leak. I tightened all hoses under the hood; it didn't change anything, and everything seemed tight, anyway. By the time we got to Nashville, the symptoms worsened to missing on highway at speed and when slowing down at a light, hunting idle and not responding when I applied throttle. I thought it was electrical in nature, so I checked engine connectors, cleaned them up, but it didn't help. By the time we were on our way home from Memphis, the car would only run smoothly with the throttle planted to the floor. Let up on the throttle and check engine light would come on and it would start missing. When I had to stop or got in stop and go traffic, I had to rev the engine to keep it from dying. Quite the PITA. So, now I'm thinking fuel supply issue.
One other time several years ago, the car would literally die while at speed, or when slowing down, begin stumbling and die. This turned out to be corrosion on the MAF meter connector. I thought it was a fuel supply problem, so I replaced the fuel pump and fuel pump regulator, to no avail. I know, I know. Throwing parts at the problem is a bad idea.
IWhen I did the engine work before leaving on this last trip, I had swapped the fuel pump regulator to the original BMW FPR. Why? I'm embarrassed to say because it was black, and the new OEM (not BMW branded) I had put on several years ago was anodized a yellowish golden color. I decided to change them since there hadn't been anything wrong with the original.
The day after we got home, I swapped to the newer and uglier FPR and voila! Car runs great! I am sure that the diaphragm in the original FPR rotted a little while in my hot shop building. Then it started giving up the ghost on the trip, until it was pretty much inoperative.
So if you have symptoms like I did, check the fuel pump regulator. Make sure it's operating properly first. Way too easy to do.
Ken
One other time several years ago, the car would literally die while at speed, or when slowing down, begin stumbling and die. This turned out to be corrosion on the MAF meter connector. I thought it was a fuel supply problem, so I replaced the fuel pump and fuel pump regulator, to no avail. I know, I know. Throwing parts at the problem is a bad idea.
IWhen I did the engine work before leaving on this last trip, I had swapped the fuel pump regulator to the original BMW FPR. Why? I'm embarrassed to say because it was black, and the new OEM (not BMW branded) I had put on several years ago was anodized a yellowish golden color. I decided to change them since there hadn't been anything wrong with the original.
The day after we got home, I swapped to the newer and uglier FPR and voila! Car runs great! I am sure that the diaphragm in the original FPR rotted a little while in my hot shop building. Then it started giving up the ghost on the trip, until it was pretty much inoperative.
So if you have symptoms like I did, check the fuel pump regulator. Make sure it's operating properly first. Way too easy to do.
Ken
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