Did we ever figure out the "Hot Start Problem"

[venom40]

Where should I search for the cable in 93' E36 M42 Coupe? Does it have it? I read the thread from BMW club Malaysia  and  I've tryed with the Fuel regulator from my old engine and there is no difference with it.
The problem is that when I turn off the car for example for 5 to 8 minutes. When I start it ,she runs like she's out off fuel and  if I let go the gas pedal and she turns off.Then 1 minute she is trying to start  with no sign of life  and then it starts and working the same(like no fuel) way 2-3 minute.After that the engine runs perfect with perfect idle.
I've tryed with other: TPS ,air flow meter, temperature senzor(water-it was broken)Idle speed sensor and other things.
The engine is not the original one on the car. This engine is from a 92 IS coupe . Are they any differences between  92 and 93 ECU ?
Becouse i run the car with the ECU from the original engine?
edit: Sorry about my english..!

sorry double post

[venom40]

sorry double post

Problem solved,
The car Has a LPG system, the problem was a gas valve.
The other problems was a water temperature sensor - the blue one on the cyl. head.

[jdirty]

hello everybody, i've been dealing with this no start issue for awhile now. i just wanted to find out if anybody has some suggestions so here goes. Here's a list and current condition of my m42 in my E30 318is.

Replaced (in total)

• o2 sensor
• took care of mess under intake manifold
• changed sparkplugs
• replaced air filter with a K&N drop in
• swapped out ICV (no change with cleaned original and replacement)
• throttle body (no change with cleaned original and replacement)
• put in injector cleaner
• put in a new fuel pump
• put in a new fuel filter
• replaced fan clutch
• replaced thermostat and gasket
• replaced timing chain tensioner

the car starts after long periods of time being off.
like over night. or sometimes after 20~30 mins after being started and turned off. i had a problem before with sporadic idling where as my icv would cause 2k-3k of idling. what i've noticed is that the car is getting flooded with fuel. you could smell fuel and after those periods of rough starts white smoke will come out of the exhaust smelling of fuel. another note is when i got the car, it had no cat converter. idk really if it has anything to do with this but i figured i'd mention.

what i've been doing lately is opening the airbox, and then close it back. out of all the times i've done this, the car would start with the help of the gas pedal being stepped on. usually halfway open throttle body.

i have done no tests whatsoever with the sensors and such though. haven't gotten around to getting a voltemeter and learning how to use one. lol
any input would be appreciated.

[jdirty]

either a replacement dme or it was because i cleaned up my CPS which was so gunked up with what i believe was power steering fluid running from the reservoir and somehow got there. :confused:

[dunny]

I've only had my 318i running for a week or so and noticed this issue....same as everyone has described, it would start right up when cold but after it was warmed up it would require me to hold my foot on the gas pedal to keep it running but after a few minutes it would run fine.  I found that the little wire was connected....and I just disconnected it.  This did help the idling, but I still have to use a little bit of gas pedal to get it to start right away.  So I'd say this is another success story, thanks for posting this information!

[kimmerkaze]

Hey everyone,

New to the forum and picked up a '91 318is a couple of weeks ago. Been busy finishing school but this hot start problem has been bugging me ever since I got it. Previous owner swapped DME's, replaced O2, as well as several other components until him and his mechanic got stumped. He just did the old stomp trick to get by and advised me to do as well but I figured I'd try to get to the bottom of it.

I was suspecting TPS or AFM but stumbled across this thread and man, what a great fix! Best fixes are free ones like these! Wire was plugged in on my car too and yes the problem has gone away also. Thanks again Racer

[DesktopDave]

hello everybody, i've been dealing with this no start issue for awhile now. i just wanted to find out if anybody has some suggestions so here goes. Here's a list and current condition of my m42 in my E30 318is.

Replaced (in total)

• o2 sensor
• took care of mess under intake manifold
• changed sparkplugs
• replaced air filter with a K&N drop in
• swapped out ICV (no change with cleaned original and replacement)
• throttle body (no change with cleaned original and replacement)
• put in injector cleaner
• put in a new fuel pump
• put in a new fuel filter
• replaced fan clutch
• replaced thermostat and gasket
• replaced timing chain tensioner

the car starts after long periods of time being off.
like over night. or sometimes after 20~30 mins after being started and turned off. i had a problem before with sporadic idling where as my icv would cause 2k-3k of idling. what i've noticed is that the car is getting flooded with fuel. you could smell fuel and after those periods of rough starts white smoke will come out of the exhaust smelling of fuel. another note is when i got the car, it had no cat converter. idk really if it has anything to do with this but i figured i'd mention.

what i've been doing lately is opening the airbox, and then close it back. out of all the times i've done this, the car would start with the help of the gas pedal being stepped on. usually halfway open throttle body.

i have done no tests whatsoever with the sensors and such though. haven't gotten around to getting a voltemeter and learning how to use one. lol
any input would be appreciated.

Glad you solved your problem...but I read this & had to chime in...get a multimeter & start testing.  You'll save a ton of time, money and frustration.  Even a $4 HF cheapie is better than nothing.

Grab the e30 electrical troubleshooting manuals (ETM) too.

Mine had the same problem when I got it...the cam PS and cam cover gasket was leaking enough oil to cover the CPS with a thin layer of oil & rust.

[Burnall4]

I will step out of the shadows for a second...


My thread became a sticky



Made this picture a long time ago just never posted it...better late than never




Completely different note, about to get back into e30's after a 3 year dry spell...

[sailer6460]

Has anyone thought of taking a look at the fuel pressure regulator. Could be that it's stuck wide open.

[DesktopDave]

I will step out of the shadows for a second...


My thread became a sticky

Made this picture a long time ago just never posted it...better late than neve
Completely different note, about to get back into e30's after a 3 year dry spell...

Nice picture, makes it easy to find.  Welcome back to the e30, it's a hard habit to kick, eh?

I'll bet this "CO pot mod" (plugging this cable makes the AFM CO adjustment screw active) could be used in engine swaps, especially where a catalytic converter or O2 sensor wasn't originally installed or isn't planned (like on the track).  Say you're swapping an M42 into a Locost or an M10 BMW (320i/2002/2000cs) with a custom exhaust...then enabling the CO adjustment in the AFM by plugging in this wire...it would likely help a lot with idle control and emissions.

While it'd be sloppier than the OEM Cat/O2 system (and I'm all for cleaner air), it'd make resurrecting an old Bimmer that much simpler.

[jdirty]

the cause for my warm start (engine was getting drowned in fuel, it would smell of fuel if i kept trying to start the car) was a faulty FPR since i had already replaced my fuel pump, filter, fuel pump relays, and took care of the hoses under the intake. all i need now is a new ICV.

[goml23]

I'm having pretty bad issues with this as well, I'm about to head outside and check up on that even though it's almost 11pm over here. I really hope this wire's plugged in.

[wazzu70]

Well I know what fixed mine and it will only help you if you hooked the mystery wire up like I did. I disconnected it and all is well.

Lower left corner of this graphic.

Thanks for this, I have been having a random hot start issue that has been frustrating the heck out of me. Everything tests fine going to the starter, but still no start. Idle sometimes is horrible as well.

When I pulled the M20 and dropped the M42 in I connected those wires as I had never seen a M42 harness before and figured they had to be connected...right?

Thanks a ton!

[ic455]

Well I know what fixed mine and it will only help you if you hooked the mystery wire up like I did. I disconnected it and all is well.

Lower left corner of this graphic.

This is exactly what was wrong with mine!  The PO put a clutch in and mentioned moving this harness around, I assume he connected the wires when the cover was off.  I unplugged the wire and voila! Much thanks sports racer great to have diagram too!

[E36Coupe]

Just wondering, if i decat my car, and decided to lose to o2 sensor, what would plugging this wire in do?

and if i decat my car and keep the o2 sensor and leave it un plugged, would it run ok with no cat? surely o2 sensor reads wrong or something?