1987 325e Starting Problems.

[Mr. Tasty]

Hello there, as the title states, My 325e has problems starting cold. Could that be a fuel related issue? As I do also have a rough idle, slow dropping rpms, and also hesitation through lower-mid rpms. I believe I read something about 325e's have an extra cold start valve? I don't know, any help is grateful.

[jlevie]

A 325e does have a cold start valve, but taken all together the symptoms suggest intake leaks. A smoke test will find them.

[Mr. Tasty]

Even if it pretty much starts up when warm? I will give the smoke test a try. Where should I put the smoke? Brake booster?

[dnguyen1963]

You can make an adapter for the AFM location or a cone to fit into the intake boot to supply the smoke to the engine.

[jlevie]

Even if it pretty much starts up when warm? I will give the smoke test a try. Where should I put the smoke? Brake booster?

Do you realize that you'll need a real smoke machine intended for this particular purpose. To properly run the test the smoke has to be a long persistence oil smoke. A fog machine that uses water won't get the job done. The process is to plug the exhaust and introduce the smoke via an adapter that goes where the AFM connects to the intake boot. Smoke is fed in until a pressure of 2-4psi is reached and that pressure is held for at least 5 minutes to allow the smoke to work it's way to leaks distant from the intake.

If there are significant leaks that show up immediately it usually necessary to fix those and repeat the test. It may be difficult to reach and hold the necessary pressure and a lot of smoke coming out will obscure the evidence of small leaks elsewhere.