Cold Start Frustration!

[ScottCarsonCA]

Hi all,

I'm brand new to the board, but I've been a Bimmer owner since 1993 when I bought an E30 1984 318i 2 door.

It ran fine until about 2002. Since then, my wife and have replaced virtually every component related to cold start up to and including the engine! Through our cold start saga we discovered a cracked block.

Problem: When we turn it over, the car will occasionally take a while to fire. When it does, it dies unless we keep the throttle up. Once the car warms up, its just fine.

The last advice was to replace the complete wiring harness. Any help on this would certainly be appreciated. At 170k, its too young for the pasture!

Thanks,
Scott

 

[mjbst111]

could you list what was already replaced? distibuter, fuel injectors, fuel pumps, etc?

That way we won't give you ideas you already tried.

 

[echothreezero]

Engine Temp sensor problem is my first bet. Thinks car is hot when it isn't, so the ECU feeds the engine the wrong mix. Once engine is hot, the mix is right, so no prob. Very common problem.

Had this prob with my car - very cheap fix.

 

[ScottCarsonCA]

List of replacement parts

Let's see, I've replaced the engine, the distributor, the cold start injector (twice) the cold start module under the dash, the fuse block, fuses and several relays, the thermostat (for grins), the air flow modulator and the emissions oxygen sensor. When I replaced the engine, I ran new plug and coil wires, new coil and replaced the injectors. I thought that the temp control sensor was replaced, but I'd have to check my records. The Chilton was pointing to that way when I reading the other night and I going to try that next.

Thanks for the advice!

 

[Pink_Floyd]

It's your fuel pressure regulator. I'll bet good money on it. Cheap and easy fix. Let me know if that does it. Good luck!

 

[echothreezero]

If not engine temp sensor, try fuel probs. Regulator as pink floyd said, or pump, lines, filter etc.

 

[ldzpstnr]

I say its the coolant temp sensor. If I remmeber right there are two sensors right next to each other near where the top radiotor hose connects to the engine. I beleive its the brown one you need to check. You need an Ohm meter. Just disconnect the plug, hook up the ohm meter, start the engine and watch what the meter reads. THe number should increase as the engine gets warmer.

I do not have a repair manual with me to doulble check my instructions. I have owned two 318i's though and I am very familiar with them.

I had a temp sensor go bad and it was doing the oppisite... start up right away but after about 30 seconds start running like crap.

 

[ScottCarsonCA]

Coolant Sensor not it

I've got my Chiltons and checked the voltage for both of the sensors atop the water pump/manifold area. One is the Thermal Time Switch, the other is the Coolant. Both appear to drop voltage correctly per the guide. I'll check the fuel sensor next.

Thanks! I'll let you all know what comes of this.

 

[Pink_Floyd]

I still say fuel pressure regulator. Just buy one and replace it. I dont think you will be able to test the regulator because when running the pump you will get a constant flow of fuel. The problem is the the internals of the regulator go bad overtime and you don't get a good seal. Because of that fuel pressure will take a while to build up while you are cranking over your car. Let use know how everything works out!

 

[ldzpstnr]

I meant the thermo time switch. It could be the fuel pressure regulator as well. You dont check for voltage, you check for the OHM resistance. You can test the fuel pressure regulator with the right type of fuel pressure tester. Its an in-line one that does not restrict the fuel flow.

 

[Eeindee318i]

I am having the exact same problem!!
When started the engine seems to run at low revs, and unless you keep your foot down it sometimes dies. Once its warmed up, it normally starts first time thereafter

 

[bmwfanatic28]

Cold Start Valve?

I am curious if any one thought that it might be the cold start valve. I am having similar issues. My car doesn't have much power under 2k rpm's when the car starts (after a good long cranking). How do you replace the fuel pressure regulator?

 

[ldzpstnr]

THe cold start valve only runs for a few seconds, like 8 i think or maybe less. The fuel pressure rgualtor is on the fuel injector rail towards the front of the engine. Its an easy fix, just lossen the two 10mm bolts, the fuel line, and the vacum line and its off. Installs just as easy, JUST MAKE SURE TO NOT RUIN THE O RING SEAL. You can test the cold start valve by taking it out, putting it into a bottle while still hooked up and starting the car. If the injector sprays and fills up the bottle fast then it works. If it just dribbles then its shot/plugged.

The 1984-85 318i fuel injection computer DOES NOT handle the ignition timing, and a lot of repair shops DO NOT know this. They just assume that since its injected the computer handles everything. The injection on this car only just control the mixture, thats it. So make sure to check your timing. It is a bitch to do on the 318i to as you gotta use a timing light on the back of the moter, there is a small hole in the top of the bell housing so you can see the timing marks on the fly wheel. I never used a timing light on my car, I just set it by ear. I figure I was runing around 16 degrees of initial timing when stock calls for 8 or 10 degrees I think. My car would ping a little below 2000 rpm but hey you dont drive that little four cylinder at thows low engine rpms. My car would also get 35+ miles to the gallon, mainly in part to the exhaust header and the "hot" ignition timing.