engine and drivetrain Tii hot start issue

[cosm3os]

Twice in the last week, my tii has failed to start.  When it's cold, it fires up.  When it's a normal operating temp, it fires up.  When I sit idling for a few minutes and the engine temp gets a bit hotter than normal (but still under 3 oclock on the gauge), it cranks but no fire.

 

Saw this thread while I was waiting for the flatbed (Haggerty roadside FTW!):  http://www.bmw2002faq.com/topic/106546-tii-cold-idle-and-hot-start-question/  I already have the cold injector button.

 

Any thoughts?

[wegweiser]

a) the cold start injector is designed (originally) to squirt for one second even on hot starts a weeping cold start injector can dribble fuel in to the throttle body while engine is stationary and cause hard / wonky hot starts (thanks to Ben T for this tip!)

 

 

With that said... give it a thorough tune up:

 

ignition parts (points/cap/rotor/Copper plugs)

properly set the linkage and warm up plunger/regulator (special tools and some knowledge required)

 

...and while you're at it... check your ignition timing and valve adjustment. I just did all of these on my own car the other day, getting ready for SPRING!

 

A tune up = virtually FREE horsepower.

Edited April 11, 2015 by wegweiser

[cosm3os]

It got a tune up (including Kfish) two years ago (5k miles), so maybe it's time.  Conveniently, it's going to Ben T this week for rear bushing work.

[wegweiser]

Remember: Ben functions on a higher plane than the rest of us. You will indeed be in superb hands. He makes fun of me, for checking my linkage and valves so often...but it works on my car. 

[cosm3os]

I bought the car knowing that whatever went wrong with it, it was a 5 mile flatbed ride to Yoda.

[ray_]

Heheh.

 

If it strands you in the meantime, floor it and crank until it fires.

 

If you are continually on the starter for brief periods, you're injecting a lot of fuel with each turn of the key.

 

Otherwise, what Paul said.

 

Cheers,

[OriginalOwner]

been havin' that problem on & off for 40 years ...... ain't never figured it out.  Throw a million-dollar tune-up at it:  starts every time, no problem.  Then another million-dollar tune-up a while later, gets wonky (I like that term).

 

these days, I got a brand-new (rebuilt) engine and that hot-start thang is back.  My solution now:  I don't press the gas pedal.  Crank a few cranks and if it doesn't fire up, then I turn off the key.  Count to 3, hope for the best, I don't press the gas pedal, and turn the key ..... so far, it then starts.  I'm thinking the secret is to NOT press the gas pedal when cranking the engine. 

     The carb guys get accustomed to using the gas pedal to help things along, but in my marginal experience us tii guys can't do that.  I don't know enough of the "what & why" but in my experience, staying off the gas pedal and just cranking it till it (hopefully) starts has worked for me.

 

Cheers,

 

Carl

 

p.s.  note that ray_ says "floor it" .....  that's what a carb guy does when the engine is flooded.  In my experience as a tii guy, I don't do that, and it fires up.  If I knew why, I would explain.  But I don't know why ..... I only know that not pressing the gas pedal works for me.

Edited April 12, 2015 by OriginalOwner

[ray_]

I don't disagree with Carl, about (not!) touching the pedal during cranking. Unless it doesn't start.

 

Then, floor it

 

That always worked in my experience, on my tii.

 

Cheers,

[02Les]

I don't disagree with Carl, about (not!) touching the pedal during cranking. Unless it doesn't start.

 

Then, floor it

 

That always worked in my experience, on my tii.

 

Cheers,

Ha. I had a Touring tii back in the 80s. Same thing with hot start.....mash the pedal to the floor and crank. Worked everytime.

[cosm3os]

Thanks guys.  Floor it it is!

[photocrasher]

Hi Guys - I've got a weird variation of this issue. If I drive my '74 Tii for longer than about 35 minutes, upon stopping it will not turn over. All of the electrical devices work fine in the car (lights, radio, etc.), but the engine doesn't even attempt to turn over. If not for the other electrical items working beautifully I would suspect dead battery. If it sits for several hours it will turn over and fire right up.  Any thoughts? Thanks in advance.

[wegweiser]

Clean the connections at the starter first. Clean ground connections at inner fender and at engine block, from battery. You SHOULD have a two tailed ground wire off the negative terminal of the battery....if you don't... now is a good time to get one from BMW.

 

Other tests - try manually jumping the starter (at the starter itself) Make sure it's in neutral!!!

 

I suspect the starter is on it's way out. Works cold... gets wonky when hot from ambient engine heat. Common problem for cars with starters mounted directly below exhausts....but not unheard of, for BMWs.

[PaulTWinterton]

For the pros...

What about starter relay? Do they go bad?

What about ignition switch behind key?

On my 73 there is no relay so all the juice goes through the key. The switch gets hot and eventually dies. The first thing to melt is the starter circuit.

[bmdubl02]

Make sure the engine is grounded to the chassis via the large braided strap. What is happening is identical to what happened on a regular basis with my tii - realized the grounding issue and problem was gone.

[photocrasher]

Thanks all for the suggestions. I checked out the grounds and as far as I can tell, the repaint may have just been a bit heavy on the body. I sanded down that area and am planning on doing some longer testing this week.