Author Topic: Warm start stall (Read 17348 times)

AcSchnitzer318is · « **Reply #45 on:** September 15, 2008, 11:04:55 AM »

Well, checked the 3 wire plug at the TPS and the 2 wire one at the ICV. Both are fine and wiring actually looks fairly new. I want to check the long plastic box under the intake that houses all the wiring for any problems, but I'm not holding my breath. Waiting on my new engine ground to get here...

I swear I can hear a whistle, like a vacuum leak from in front of the intake. But all those hoses/lines were replaced. I'll inspect all those lines VERY carefully next time I have the intake off to check those wires.

Anyone else make any progress?

Burnall4 · « **Reply #46 on:** September 15, 2008, 01:58:28 PM »

I really think the OP problem is a sensor, thinking about it:

1. Only on hot starts he has a problem, if it was a vacuum leak it would happen every time you start your car, like mine

2. Cold starts he is fine, there is a signal that is able to be read when cold, but hot not...

I would really lean toward sensor on this one.

My problem exist whether the car is cold or hot -> leads me to sensor & vacuum leak
Only time it doesn't do anything is when its really cool outside, temp , and the car has been sitting for a while like overnight

cjshelley · « **Reply #47 on:** September 17, 2010, 06:30:42 PM »

My car has been doing funny things ALMOST like this. It started just like the OP described and got worse from there. By the time I started getting massive power loss as I accelerated and the inability to re-start the motor after shopping on the hottest day of the year, I decided to take care of "the mess under the intake." no change. In fact, I think it's even worse. I also replaced the O2 sensor, so I'm thinking fuel pressure (or AFM... or temp sensor... but the stomp test gives the all-clear)

DesktopDave · « **Reply #48 on:** September 18, 2010, 07:49:57 AM »

Massive power loss...get the tester on fuel pressure. Let us know what you find.

I wonder if this has something to do with the BMW resistor pack on the AFM harness? I had one installed on my e30, does anyone else? It's an extension plug that BMW installed as a TSB...might be that it's changing the intake air temp sensor reading. If the IAT is wrong, the car will run pig rich, spark plugs won't fire & you'll get no start and strong smell of gas.

I'll test my TSB resistor pack later & report my findings.

dblhelix · « **Reply #49 on:** August 31, 2011, 10:06:15 PM »

I recently bought a 1991 318i (M42) for my son's first car and it had the same problem. It started fine cold but after being shut down hot for more than a couple of minutes it would start fine then begin to idle rough and if you attempted to drive it would surge and come close to stalling. If you let it idle for a minute or reved it up over 3000 RPM OR shut it off and restarted it would clear itself and be fine until the next hot start.
The solution turned out to be a very simple one. There is a single wire connector in the wiring harness under the cover on the firewall covering the DME/Fuel Pump/O2 Sensor relays that should be disconnected if the car has a catalytic converter and connected if it doesn't. I disconnected this connector and everything is fine! I wish I did this first however on the bright side I have a spare of pretty much every sensor plus a ECU (Luckily I got them cheap on ebay).
We have only had the car a couple of months and I must say I've learned a lot about it and love it. It is excellent to work on and a pleasure to drive. I'm looking for a clean '91 is for myself! I hope this helps someone as it seems we weren't the only ones troubleshooting this snag.

DesktopDave · « **Reply #50 on:** August 31, 2011, 10:28:37 PM »

There's a long post somewhere about that CO plug in the harness...I'm glad you've fixed it though. Post your spares up in the WTB classifieds section.

Welcome to the 'club, BTW...we're always looking for new members, especially if they're decent mechanics!