No start, they flood easy
Thread Starter
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: May 2001
Posts: 14,697
Likes: 598
From: Las Vegas
Fuel pump off...crank...pressure drops....it fires...fuel pump on...runs happily.
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Oct 2001
Posts: 20,506
Likes: 566
From: Bend, Oregon
It seems like the 'problem' strikes those using high-flow toiletflush valves for injectors. With all the playing/working on my car in its life, I don't remember ever having evena hint of flooding problems when starting it. Except when the LH box started to crash. I suspect that this thread may not be relevant to the mere mortals among us.
Rennlist Member
Joined: Jan 2008
Posts: 4,078
Likes: 332
From: Friday Harbor, WA
It seems like the 'problem' strikes those using high-flow toiletflush valves for injectors. With all the playing/working on my car in its life, I don't remember ever having evena hint of flooding problems when starting it. Except when the LH box started to crash. I suspect that this thread may not be relevant to the mere mortals among us.
The fix is simple (with a Sharktuner), just change the cranking pulsewidth to a smaller number, e.g. 3.2 or 3.3 ms for 24# injectors. That setting is on Sharktuner's Fuel-Parameters page.
We got caught by this also, after changing injectors to 24#. Of course that provided the opportunity to dismantle and check over every part of the fuel and ignitions systems
Cheers,
Three Wheelin'
Joined: Nov 2008
Posts: 1,675
Likes: 4
From: TEXAS
Guys,
If next time your 928 floods please step back and check things before you try to turn the engine any further and take the fuel pump and injector relays out before you try to start again, if you only take the fuel pump relay out you will still have fuel in the fuel lines and the injectors will just flood the cylinders more.
The Alusil bores can get damaged easily from fuel wash. Imagine the cylinders get flooded and then you keep turning the engine, the extra fuel will splash around the cylinder and wash it dry from oil, with no oil on the cylinder walls your compression will drop down which could also help in making the engine more difficult to start.
Last month I was looking at a 944 S2 engine ( basically half a 928 engine same cylinder walls on our engine), the engine got flooded with fuel and he kept turning the engine trying to start it, the engine was completely stock, no big injectors. They end up taking the engine out and pulled the head, the fuel had made the cylinders dry enough to the point that the rings had gauged the cylinder walls badly, chunks of Alusil missing on all cylinders, I wish I had taken a picture to show you guys, it was horrific.
Also Tony,
check your oil, smell it, if the flooding had caused some fresh fuel to pass the rings you now have fuel mixed with your oil and it will bring the viscosity down, so change the oil.
If next time your 928 floods please step back and check things before you try to turn the engine any further and take the fuel pump and injector relays out before you try to start again, if you only take the fuel pump relay out you will still have fuel in the fuel lines and the injectors will just flood the cylinders more.
The Alusil bores can get damaged easily from fuel wash. Imagine the cylinders get flooded and then you keep turning the engine, the extra fuel will splash around the cylinder and wash it dry from oil, with no oil on the cylinder walls your compression will drop down which could also help in making the engine more difficult to start.
Last month I was looking at a 944 S2 engine ( basically half a 928 engine same cylinder walls on our engine), the engine got flooded with fuel and he kept turning the engine trying to start it, the engine was completely stock, no big injectors. They end up taking the engine out and pulled the head, the fuel had made the cylinders dry enough to the point that the rings had gauged the cylinder walls badly, chunks of Alusil missing on all cylinders, I wish I had taken a picture to show you guys, it was horrific.
Also Tony,
check your oil, smell it, if the flooding had caused some fresh fuel to pass the rings you now have fuel mixed with your oil and it will bring the viscosity down, so change the oil.
Three Wheelin'
Joined: Mar 2010
Posts: 1,307
Likes: 3
From: Colorado Springs, CO USA
It seems like the 'problem' strikes those using high-flow toiletflush valves for injectors. With all the playing/working on my car in its life, I don't remember ever having evena hint of flooding problems when starting it. Except when the LH box started to crash. I suspect that this thread may not be relevant to the mere mortals among us.
The problem has happened to me about four times in the 10 months I've had the car. The first time was probably a month after I got it home. It didn't happen for about a six month stretch until it bit again the other day.
On a side note: I don't understand why many people prefer to pull a relay instead of pulling a fuse. In my car, I can pull a fuse with one finger and a thumb. I have yet to pull a relay at all (I mean, I've tried, but they might as well be welded in). I have seen special Porsche and aftermarket tools for pulling them, but I don't (yet) own one. Namas GT's comment about fuel still in the lines with the pump not running is true, but the working pressure, and thus the delivery, will drop off very fast when cranking without a running pump.
Inventor
Rennlist Member
Rennlist Member
Joined: Sep 2002
Posts: 10,219
Likes: 469
I -truly- hate no-start problems.
After a lot of cranking (to clear a flooded engine) you can quickly run the battery down to <10 volts when the starter is engaged. Then you have too much fuel -and- the computers won't wake up.
BTDT²
After a lot of cranking (to clear a flooded engine) you can quickly run the battery down to <10 volts when the starter is engaged. Then you have too much fuel -and- the computers won't wake up.
BTDT²
Addict
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Feb 2009
Posts: 18,061
Likes: 10
How does one know it is flooded ? and not an ignition issue? Both will make the plugs wet. And the ignition has a relay or two 
And we all know relays go bad ! You have less juice when cranking on the battery yet when it starts and runs it may see 14 volts to the relays so a degrading relay can be intermittent.
And we all know relays go bad ! You have less juice when cranking on the battery yet when it starts and runs it may see 14 volts to the relays so a degrading relay can be intermittent.
Three Wheelin'
Joined: Mar 2010
Posts: 1,307
Likes: 3
From: Colorado Springs, CO USA
How does one know it is flooded ? and not an ignition issue? Both will make the plugs wet. And the ignition has a relay or two And we all know relays go bad ! You have less juice when cranking on the battery yet when it starts and runs it may see 14 volts to the relays so a degrading relay can be intermittent.
And we all know relays go bad ! You have less juice when cranking on the battery yet when it starts and runs it may see 14 volts to the relays so a degrading relay can be intermittent.Rennlist Stories
The Best Porsche Posts for Porsche Enthusiasts
Six Genius Porsche-Themed Gifts That'll Make Any Dad or Grad Smile
Joe Kucinski
10 Used Porsches Are Selling for Way Too Cheap
Joe Kucinski
Tuner Is Converting Porsche 911s Into Shooting Brakes
Verdad Gallardo
This Coachbuilt Creation Is A Modern Take on the Legendary Porsche 917
Verdad Gallardo
Is This Convertible Cayenne A Steal, Or A Returnless Investment?
Verdad Gallardo
10 Best Non-Flat Six Porsches You Can Buy For Under $100K
Joe Kucinski
Porsche's Top 5 Most Questionable Naming Decisions
Verdad Gallardo
Pogea Racing's 964 Porsche 911 Reimagination Stands Out in a Crowded Field
Verdad Gallardo
6 Convertible Top MYTHS Most People Don't Understand!
Michael S. Palmer
Rennlist Member
Joined: Jun 2005
Posts: 3,261
Likes: 53
From: Park Ridge, IL (near Chicago)
I had similar no start problem on my 84 l-jet. I cleared it with full throttle cranking and had gradual return to function then rough running that finally smoothed out. This works fine on my MB LH-jet as well. It assumes a fully charged battery that can handle 20-30 seconds of continuous cranking. Very cold weather would probably spoil this method as well. I ran a can of Techron through it and it did not misbehave since. I assume a leaking injector may have played a part.
Good luck,
Dave
Good luck,
Dave
Race Car
Joined: Dec 2003
Posts: 4,477
Likes: 5
From: Atlanta, GA
On a side note: I don't understand why many people prefer to pull a relay instead of pulling a fuse. In my car, I can pull a fuse with one finger and a thumb. I have yet to pull a relay at all (I mean, I've tried, but they might as well be welded in). I have seen special Porsche and aftermarket tools for pulling them, but I don't (yet) own one. Namas GT's comment about fuel still in the lines with the pump not running is true, but the working pressure, and thus the delivery, will drop off very fast when cranking without a running pump.
Trying to start a flooded car continually without taking any other action (and further flooding it in the process) is stupid. If you pull the fuel pump fuse and crank, there isn't enough time for any damage to occur before the engine starts. Why would anyone want to press the accelerator to the floor and crank the car for 30 seconds !!! and then have the car run rough when pulling the fuse and starting will have the engine running after 5 seconds?
Dan
'91 928GT S/C
475hp/460lb.ft
Rennlist Member
Joined: Apr 2006
Posts: 35,695
Likes: 511
I had similar no start problem on my 84 l-jet. I cleared it with full throttle cranking and had gradual return to function then rough running that finally smoothed out. This works fine on my MB LH-jet as well. It assumes a fully charged battery that can handle 20-30 seconds of continuous cranking. Very cold weather would probably spoil this method as well. I ran a can of Techron through it and it did not misbehave since. I assume a leaking injector may have played a part.
Good luck,
Dave
Good luck,
Dave
