Date: Sun, 26 Aug 2012 23:06:26 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Poor Hot Start Discovery - midway through solution
In-Reply-To: <1977916528.963320.1346032463092.JavaMail.root@sz0094a.emeryville.ca.mail.comcast.net>
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The fuel pump is either on or off. No power control except the relay. The temp 2 sensor itself rarely goes bad but the plug contacts and wiring are often a problem. The Temp 2 sensor actually sinks the ECU input to ground so any voltage drops at the grounds connection make the ECU think the engine is colder than it really is which can cause hard starting. When extreme this can also cause the engine control to go open loop. The system you described while driving can also be related to Vanagon Syndrome which can either be an O2 sensor problem or another issue related to grounds. On the 1.9 liter engines the O2 sensor can sometimes be cooled especially during wet weather from road spray from the left rear wheel. Especially since the original insulation is most likely missing.
For the hot restart problem you need to confirm you do not have leaking injectors or the fuel pressure regulator. The regulator is easy to check. Just remove the vacumm hose while the engine is running. If there is any sign of fuel there at all the regulator is bad. For the injectors remove them, jump the pump to build pressure and look for any signs of leakage. Then you should also check them for spray pattern. Ground out the ignition coil wire and have someone crank the engine while watching the injectors. Any weird spray patterns like a stream means time for injectors.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Skip
Sent: Sunday, August 26, 2012 9:54 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Poor Hot Start Discovery - midway through solution
Wow! David, your knowledge and clarity (and generosity) of writing has me in awe, and your sense of humor has me in stitches! Not sure if the shipyard reference regarding the emergency brake is the funniest one (my company does business with EB, btw), or your statement that my theory is as close to being right while being totally wrong.
Well, perhaps additional reinforcement for the poor Temp II connector. We just returned from SO's sister's (1.5 hour drive that should take 1 hour). It's been raining all day, temps in the 70's, so the roads were wet. Guess what? While driving home - two-lane hwy, 50 miles/hr, the engine "lost power", mumbled, and we exited to the shoulder (safely, fortunately). Prior to this happening I hear a constant whine from the fuel pump (while driving at speed...above the road/engine noise). I lifted the engine lid, took a look around, the engine was "fluttering" (about to die), SO reached her left foot over to rev up a bit, keep it going. I had my IR gun with me so I shot both heads (left - 4/3 was at 195F; right - 2/1 was at 215F). I shut the engine down (radiator fan ran for awhile), then started it back up (still no power and the engine ran rough). After 5 minutes or so (engine on and off) - never had difficulty starting the engine, btw, it had power and we were off and running at 50/55 mph. This happened two more times (last time in our driveway and I was able to coast to the garage.
Note - this happened prior to me reading the comments about "wet/loose" Temp II connector, so did not take the opportunity to jiggle the connection, etc. I was thinking, at the time, that it was a failing fuel pump, so I hit it with a large screwdriver just for good measure...
Theory on the above: Assuming the fuel pump is OK (it's new +4,000 miles/8 months), then the whining fuel pump may be indicative of being told to pump a bunch of fuel (which didn't whine, btw, after we got going again...then started to whine before we lost power again), then it's the faulty Temp II female connector (maybe not defective, but wet and bad connection), that indicated to the ECU that the engine is cold while it is hot and rolling down the highway, thus causing an excessive rich condition, thereby flooding the engine out causing loss of power. However, is the fuel pump "on/off" or "variable speed"?
What say you?
So, to test theory, I'm going to leave the Temp II connector disconnected, engine should start right up cold, drive around (we live in the country - not much traffic, assorted farm field entrances to ditch a mumbling Vanagon) a bit, and see if I can recreate the fuel pump whine and the "loss of power" phenomena.
Then (or perhaps before), I'll load the connector with dielectric grease and tighten the female ends on the connector. How about some high-temp tape to wrap the connection?
Thanks,
Skip
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