1984 318i. Stock engine. It started happening a few months ago but the fix has been eluding me.
I was driving up the grapevine north of LA (steep twisty highway through the mountains) when I first noticed it. The engine would cut out for a second, similar to how it feels when a single coil on a car with individual coils per cylinder starts failing. It wasn't consistent, but it did seem to happen only under load. I have a 4.10 diff and an m10, so the engine had been sitting at 4K+ with pretty heavy throttle openings for quite a while when it started. I got over the other side to the Central Valley, and it was still happening, this time with less throttle and on flat ground.
I got to Buttonwillow Raceway and installed a new ignition coil. Got back on the road a few hours later and it was still happening. The temperature had cooled off from around 90 to about 75. I noticed it going down hill this time too, and it was starting to last longer, up to 4 seconds was the most I felt. The engine never stalls, it just cuts throttle like you're completely off the gas.
The car worked perfect the next morning, but my commute is only 3 miles each way so it barely has time to get hot. I changed the cap and rotor as they were getting slightly worn, but it didn't do anything. It only happens on hot days after the engine has been running for 45+ minutes. I've driven for over an hour in cool conditions and it never happens. Short trips the car runs normal. Both fuel pumps are working, I get 37psi of pressure at idle and 45psi with no vacuum.
I'm headed on a long trip this weekend and would like to have it sorted before I go. Has anyone else had this problem? Any suggestions? The fuel pressure seems a little low at idle, but I've watched it while I drive and it never goes below that.
Cliffs:
Engine cuts out randomly after driving in hot weather for 45+ minutes
Stock engine
New ignition cap, rotor, and coil. Plugs and wires are good
Timing is at factory specs
Tps is adjusted correctly
37psi fuel pressure at idle, 45psi with no vacuum. Fpr holds vacuum
No vacuum leaks
Valves adjusted to .009 intake and exhaust
Fuel tank level doesn't affect it
Coolant temp barely gets above the midway mark while this is happening, at worst
I was driving up the grapevine north of LA (steep twisty highway through the mountains) when I first noticed it. The engine would cut out for a second, similar to how it feels when a single coil on a car with individual coils per cylinder starts failing. It wasn't consistent, but it did seem to happen only under load. I have a 4.10 diff and an m10, so the engine had been sitting at 4K+ with pretty heavy throttle openings for quite a while when it started. I got over the other side to the Central Valley, and it was still happening, this time with less throttle and on flat ground.
I got to Buttonwillow Raceway and installed a new ignition coil. Got back on the road a few hours later and it was still happening. The temperature had cooled off from around 90 to about 75. I noticed it going down hill this time too, and it was starting to last longer, up to 4 seconds was the most I felt. The engine never stalls, it just cuts throttle like you're completely off the gas.
The car worked perfect the next morning, but my commute is only 3 miles each way so it barely has time to get hot. I changed the cap and rotor as they were getting slightly worn, but it didn't do anything. It only happens on hot days after the engine has been running for 45+ minutes. I've driven for over an hour in cool conditions and it never happens. Short trips the car runs normal. Both fuel pumps are working, I get 37psi of pressure at idle and 45psi with no vacuum.
I'm headed on a long trip this weekend and would like to have it sorted before I go. Has anyone else had this problem? Any suggestions? The fuel pressure seems a little low at idle, but I've watched it while I drive and it never goes below that.
Cliffs:
Engine cuts out randomly after driving in hot weather for 45+ minutes
Stock engine
New ignition cap, rotor, and coil. Plugs and wires are good
Timing is at factory specs
Tps is adjusted correctly
37psi fuel pressure at idle, 45psi with no vacuum. Fpr holds vacuum
No vacuum leaks
Valves adjusted to .009 intake and exhaust
Fuel tank level doesn't affect it
Coolant temp barely gets above the midway mark while this is happening, at worst
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