[Vwdiesel] Lusting after efficiency

Tue Jul 8 22:47:09 PDT 2014

If you can, try checking compression.  Yeah, should be higher when hotter but, if you have a tight valve/s then they'd get tighter when hotter, thus leaking.  
  I'm not so sure it's with the pump.  You could try recreating the situation in your driveway, put some ice water on the pump, to cool it down and see if that does it.  Not likely but at least testable.
  Only other thing I can think of is if your timing's off such that it's fine for a cold start but too far off for a hot start (advanced?).
    Loren

-----Original Message-----
From: Mark Shepherd <mark at shepher.fsnet.co.uk>
To: Bryan Belman <dieselwesty at yahoo.com>; vwdiesel <vwdiesel at vwfans.com>
Sent: Tue, Jul 8, 2014 4:55 pm
Subject: Re: [Vwdiesel] Lusting after efficiency

What's the break-even point for a diesel to be switched off, over the excess 
uel from a restart? For my QTD , I can increase fuel economy, if switched off 
or 
t least 30 seconds, say at traffic lights. Loading on the starter etc is 
ependent on number of turns to restart I would have thought.. My engine can 
estart 
n about a turn to about an hour, if it is hot!
This brings me to my question for this forum:
About 2 months ago my car developed a fault, that either hadn't been there 
efore, or had just not shown itself:
>From cold it is quick to start. 
fter a journey of a few miles, if hot car would not restart. 
o roadside jump leads, booster pack, or even ether, would start it. 
owever, if left till almost completely cold it would then start normally. 
irectly powering glow plugs made no difference. 
low through the pump is about half litre per minute [Although can't say I've 
hecked during the failure to start period]. 
Rebuilding engine revealed 2 pistons had aligned ring gaps. I decided to put in 
ew rings seeing as I'd bought 2 spare sets. New rings seemed to cure it for 
 few weeks.
hen the refusal to start when hot returned. 
racking fuel lines seemed to indicate fuel getting to the injectors but 
ossibly not much...
his was mentioned by 2 independent roadside mechanics. 
e jointly decided to check the stop solenoid. 
Removing the core brought about a cure, when car had cooled, but had still start 
inutes earlier. 
o it was interpreted that the solenoid was opening when cold, then shutting 
hen hot, but only partially re-opening when hot, or still warm. 
nspecting the solenoid core showed it to look like new, black and anodized, 
xcept for a wear[binding?] patch on one side.
hen I got home, I put in a spare solenoid, and all was well again; restarts 
fter trips were successful for a few weeks, until last week when after a 2 mile 
RUSHED trip I turned the car off for a couple of minutes and then it refused to 
tart. 
I removed the core again, but it made no difference, so I called Rescue. The AA 
escue man tried a near flat battery booster pack, and ether, but that didn't 
ork, 
e didn't show any empathy, unlike the previous 2 guys, and said it was probably 
 tired old engine, and that we could spend, or as he put it "waste" another 
our trying to start it; I insisted he take me back home. He asked if I wanted 
o leave the car! Crikey, I pay membership for a full relay service, why would I 
want to abandon my car? 
roblem started at 8.30pm, back home by 9.30pm, still not starting, but about 
0.15pm tried again, and the car started straight up with a few turns, a cloud 
f smoke and then normal idling. 
Last night I went out for a 20 mile round trip with 2 x 20 min stops. No 
roblems. 1 hour later I repeat similar journey. Stop for 15 minutes to pick 
omeone 
p, and car almost starts, .but doesn't and then as per usual no signs of 
tarting. I tried a few minutes later, but nothing. This time after 20 minutes, 
ar did 
tart, which is the quickest restart after a 'no start'!
t blew a cloud of smoke and then was happy to idle normally. Returned home.
Summary:
o car starts straight away when cold, but not when hot [pump hot to touch] 
t is not a lack of fueling to the pump, as it lifts 0.5 litre per minute. [not 
ure when failing to start, but I assume still so.]
ot glow plugs, as I have directly powered them up with a second battery during 
he problems with no difference.
The failure to start is usually commenced with a 'near' start, and then nothing, 
ntil it decides to suddenly start later after cooling down, so is it possible 
hat 
he problem lies with the mechanism that gives beyond maximum fueling for 
tartup and it is sticking when pump is hot, in it's idle, or running position?
Really sorry for the long post, but read slowly shouldn't take more than 2 days 
o read...
Mark

========================================
essage Received: Jul 08 2014, 03:19 PM
rom: "Bryan Belman" 
o: "Tad" , "Mark Shepherd" 
c: "mailing list" 
ubject: Re: [Vwdiesel] Lusting after efficiency
GREAT summation.  I had not thought about those issues, I would agree, TDI would 
ot make sense in a hybrid.  Possibly if they would let the motor idle 
nd that defeats the purpose.  While sitting in a traffic jam, dead stop closed 
ighway last fall, in 28F weather, my 1.9NA motor consumed almost a gallon of 
uel in 1 hour of idling, but it was able to keep heat in the van since it was 
t road running temp.  An idling TDI in cold weather will not warm things up, 
ut 
hey could over come this with electric coils in the heater box.

ll and all, it is not the best idea.

Bryan Belman, Pt. Pleasant, NJ
4 Jetta Wagon TDI PD BEW, 100hp, 5sp -- running :<)
4 Golf TDI PD BEW, 100hp, 5sp Tiptronic Auto -- running :<)
2 Diesel Westy 1.9NA 1Y -- running :<)
0 Type 1 Beetle -- Under Restoration forever:-) 

n Tuesday, July 8, 2014 1:17 AM, Tad  wrote:

(sorry, Atkinson, not Miller, and apparently the answer is yes. )

n Mon, Jul 7, 2014 at 10:09 PM, Tad  wrote:
> Doyt, interesting you don't mention it by name, but we have one too, and
 it's a good car.  Quite different from a VW diesel, but good in it's own
 way, and basically equivalent MPG.

 As for the diesel hybrid... I think there's a good reason we haven't seen
 one of those on the market.  For one, diesel wouldn't gain as much from the
 start/stop technology because it's far more efficient at idle.  Two, I
 suspect longevity issues from the stop/start due to, among other things,
 issues with keeping the system up to temp (which is hard enough in cold
 weather with a conventional diesel).  Third- cost.  The additional cost of
 a diesel plus the additional cost of a hybrid setup is a double-whammy.

 It makes me curious  though, is there such thing as a miller-cycle diesel?

 On Mon, Jul 7, 2014 at 5:36 PM, Mark Shepherd 
 wrote:

> And then there is Stirling- Electric
> If ever I found a Syncro Q, over here, I'd probably try make it electric
> drive on the back with regenerative braking. Diesel powered with a Stirling
> Engine recovery of the
> exhaust...Germany did a 1.8 gasser syncro.
> ========================================
> Message Received: Jul 07 2014, 06:32 AM
> From: "Stephen Kraus"
> To: "Doyt W. Echelberger"
> Cc: "vw fans"
> Subject: Re: [Vwdiesel] Lusting after efficiency
>
> Diesel electric can beat it. VW was testing a 70 MPG diesel hybrid.
> On Jul 6, 2014 8:21 PM, "Doyt W. Echelberger"
> wrote:
>
> > Back in the eighties I pampered an overwhelming lust for efficient
> > transportation by acquiring a 1985 Jetta TD. I drove it until a few
> years
> > ago, and then moved the turbo to a naturally aspirated diesel engine in
> a
> > pristine low mileage 89 Jetta chassis. Part of that long relationship
> with
> > the 85 Jetta involved learning as much as possible about diesel
> technology,
> > largely by conversing with people on this list. But I recently
> encountered
> > something that rivaled the diesel solution. And you might find it
> > interesting. A rival car joined our family and returned a 47 mpg
> > performance using regular gasoline, over the same roads that I've been
> > clattering around on for almost 30 years.......and that equals or beats
> all
> > my diesel experience with efficiency. I was pleasantly surprised to
> > discover gasoline/electric engine technology invading that space.
> >
> > It gives me more choices. I like both of them, and look forward to a
> > diesel/electric hybrid at some point in the future.
> >
> > Doyt Echelberger
> > 89 Jetta TD
> > 2014.5 Camry Hybrid
> >
> > _______________________________________________
> > Vwdiesel mailing list
> > Vwdiesel at vwfans.com
> > http://www.audifans.com/mailman/listinfo/vwdiesel
> >
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