HARD start then sputter and die...

[clavinZERO]

On colder days, I start the car and the idle jumps up and down really hard and then the car usually dies, sometimes a few times in a row. If I get on the throttle just a little bit, I can usually save it from dying, just gotta hold it for 20 seconds or so at like 1500 RPM. No warm start problems but idle does fluctuate randomly. Tried searching a bunch, and didn't find much help so far, just stuff about the ICV mostly.

Here are details on the car...
-90 325is
-170,000 mi. +/-
-recent maintainence: timing belt, water pump, front seals, plugs, cap n rotor, ALL filters, all other belts, misc hoses, thermostat + updated housing, and I think the Temp Sender that's on the thermostat housing, etc.
-Valves NOT ADJUSTED yet (at least not since ~20K miles ago when purchased car)
-20/50 castrol
-New Fuel Pump
-throttle-body cleaned up a bit, lubed
-cleaned ICV with "electronics-friendly" solvent
-AFM electronics checked for clean contacts
-JimC chip
-91 octane Chevron gas (always)

Ideas so far:
1) valves
2) ICV took a crap
3) posessed by Satan

Thanx guys, anything you can think of would be great! :D

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[grlaneriejr]

Cold start Valve.

[clavinZERO]

time to learn about tha now, thxt. searchy searchy.

[clavinZERO]

Ok I read up a lil bit... seeing many mentions of cold start VALVE and cold start INJECTOR. kinda confused between the 2. Also the ICV and ICM... I know what the ICV is, but not the IC MODULE. Going to check the the Water Temp SENSOR and the Water Temp SENDER when I'm at the shop next. I guess one is 2-pin and one is 1-pin... forget which one I replaced. Gonna check the throttle body AGAIN and check for vacuum leaks again. I know she wants to run smooth, I know she does. :P

[grlaneriejr]

I call mine a cold start valve. On my M10 engine, the idle control valve is mounted right by it on the intake manifold. It is supposed to shoot gas into the manifold for 8 seconds or something like that.

If it's bad, it won't shoot the gas into it, basically trying to start a carberated car without the choke.

Hope this helps.

[clavinZERO]

i think that helps. thx.

[grlaneriejr]

no problem

[Jordan]

This is all fine and dandy, but m20b25's (Calvins engine) don't have cold start valves.

Instead the ECU simply adjusts the fuel sprayed by the 6 injectors during cold start conditions.

[clavinZERO]

Thanks Jordan for that info. Now I don't have to feel like an idiot looking around in my engine bay for something that's just not there. Got any other input besides that? Anything is always appreciated.

[EverWiser]

Check your temp switch(es) that are mounted on or near your thermostat housing. If it's shorted (i.e. very low resistance) the ECM thinks the car is already warmed up and doesn't kick in any extra fuel at startup. Just a thought; a Bentley would have some info on how to check it/them.

[grlaneriejr]

Sorry about that. Didn't know that they didn't have the injector like mine.

[clavinZERO]

Dove into the Bentley Manual. I ended up cleaning out the AFM for shits and giggles. Took a look at the throttle body and I adjusted the throttle plate screw so that the butterfly valve had the appropriate .0015" clearance from the inner wall of the throttle body. After reading misc. info on the scan tool, I noticed the IDLE SWITCH/FULL THROTTLE SWITCH was now working properly. The past 3 cold starts have been perfect. Hmph.

On another note, the AFM had taken a shit. The CO (carbon monoxide) levels were too low on the sniffer machine... running way too lean. Had the AFM turn full FAT and it didn't even pick up the CO levels at all. New AFM this morning (damn 250 bucks) and we fattened her up right; now she runs smoother and at the correct .4 - .8 on the CO.

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