1986 535i automatic; car won’t stay on but will crank

[Tavian21]

I’ve already posted once about my tps. But I own a 1986 535i automatic. I’m having some problems with my car. Every time I cut it on, it cuts right back off, I have to keep my foot on the gas for it to stay on. It has no power at all when driving it. I’ve gotten to fuel pressure regulator checked and the fuel pump tested, both checked out good. One mechanic told me I had a worn I cam... but 3-4 weeks before him so call telling me I drove the car to Memphis Tennessee and back which is like 8 hours one way. So that made no sense not including the fact the I bought the engine in August and only had 90k miles on it. They never took my valve cover off either. But in really trying to figure out what the problem is.... I do know my tps is bad though.

[tn535i]

Sounds like a big air leak or AFM, connection to it, or cracked boot for example. A big vacuum leak from a hose popped off on the ICV, seen that too. The AFM meters the air and determines how much fuel the engine needs. So if ANYTHING is leaking air into the system between the AFM and engine it cannot run properly. I forgot to mention the crankcase vent system also since it has a big hose that goes to the downstream of the throttle body from the valve cover. Even losing the oil fill cap will make it run poorly.

A good practice on these old cars is to replace all the vacuum hoses which could be original.

[Tavian21]

Sounds like a big air leak or AFM, connection to it, or cracked boot for example. A big vacuum leak from a hose popped off on the ICV, seen that too. The AFM meters the air and determines how much fuel the engine needs. So if ANYTHING is leaking air into the system between the AFM and engine it cannot run properly. I forgot to mention the crankcase vent system also since it has a big hose that goes to the downstream of the throttle body from the valve cover. Even losing the oil fill cap will make it run poorly.

A good practice on these old cars is to replace all the vacuum hoses which could be original.

Thanks man. I’m going to give it a try!