cold start issue... help please!

[jimmyc607]

I'm very new here and to e30's in general. I recently purchased a 91 325i and got a steal on the car. My thoughts are to daily drive it but i'm currently having a sold starting issue and I will be the first to admit I know nothing about these cars.

When cold the car wants to crank over for quite awhile before starting up... the car always starts but it just seems to want to crank over too long IMO.

I have replaced the plugs, cap, rotor etc, just for a tune up but i'm not sure what could be causing this cranking issue... the car ran fine when I bought it and this issue has just popped up in the past week or so. When the car is warmed up it starts up just fine.

Any help would be greatly appreciated! Thanks ahead :)

[2.5-12]

check the Cold start valve?

[jimmyc607]

I literally know nothing about these cars... what and where is this cold start valve?

[2.5-12]

I believe it is under the throttle body on the M20

the CSV injects more fuel into the cold engine to get it to start quicker

[JMPAuto]

91 dont have cold start valve. its only for old model eta.

Change your coolant temp sensor and fuel filter and see what happens.

[jlevie]

The most common cause of this problem is intake leaks. The only sure way of finding all intake leaks is to have a smoke test run on the intake. There's no point in considering other possible causes until you can prove that there are no intake leaks.

[jimmyc607]

Thanks guys I will look into these and see if any help. I did check the intake for leaks but did not do a smoke test so that might be next.

I did read about the coolant temp sensors causing issues as well so for like $20 that's definately worth a shot.

[hotballs]

You can find a coolant temp sensor for $7. A smoke test is a little overkill for an OBD I car and pretty simple emissions.There are only like 5 hoses you have to check. Change your fuel filter, clean your ICV with some throttle body cleaner. Check for visible vacuum leaks. The leak is going to have to be big to create issues. I have a tear in my boot and have no issues.

Could also be the FPR. Check your fuel pressure. If you don't have the tool maybe see if someone has a working FPR near you that you can try.

Good luck!

[jlevie]

[QUOTEA smoke test is a little overkill for an OBD I car and pretty simple emissions.There are only like 5 hoses you have to check.][/QUOTE]
I beg to differ. Any fuel injection system is extremely sensitive to intake leaks and they are the most common cause of starting or idle problems. And there are a few more places for an intake leak that just the hoses. The complete list of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hoses, valve, and expansion tank
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

[jlevie]

[QUOTEA smoke test is a little overkill for an OBD I car and pretty simple emissions.There are only like 5 hoses you have to check.][/QUOTE]
I beg to differ. Any fuel injection system is extremely sensitive to intake leaks and they are the most common cause of starting or idle problems. And there are a few more places for an intake leak that just the hoses. The complete list of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hoses, valve, and expansion tank
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

[jimmyc607]

Just wanted to say thanks for all the info here guys it is much appreciated. I managed to fix the issue... I'n not entirely sure what it ended up being but I changed the coolant temp sensor, installed new fuel filter, new distributor cap and rotor, and some new plugs and now she runs like a champ again :) My guess is fuel filter as it honestly looked like it was the original!!!