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Trouble starting
Hiya Mike,
You didn't specify year (or mebbe I didn't receive your 1st post), so
I'm sorta shooting blind here, but I'll give it a shot.
First, are the basics OK? Good plugs, points (if you have 'em), strong
battery, good turns from the starter motor? Clean A/F, recent F/F change
[<15k miles], recent oil and O/F change [<5k miles], good fuel, ignition
timing is correct, distributor cap and rotor not cracked or burnt or worn
out; all that good stuff..?
My first instinct is to look at fuel; but the Cold Start Valve (aka: 5th
injector) isn't really all that important in moderate temperatures, might
not even kick in.
You wrote that the car starts fine when hot, but poorly "when it's been
sitting a while".
Try this; before trying to start bridge the fuel pump relay. Uh... what
you want to do is get the fuel pump up BEFORE you crank the engine, if you
find that starting is easier that gives us a direction to go in for
troubleshooting. I'm thinking you might have a problem with fuel pressure
bleeding off when the car sits for a while; the delay you're having in
starting is the system having to bring pressure back up within specs.
On the older Mk1 Scirocco's the fuel pump relay usually had a fuse
mounted to it, on Mk2's I think you'll find the F.P. relay in socket #2 on
the fuse/ relay panel (with a separate fuse). I'm refering to the Bentley
manual ("VW Cabriolet, Scirocco; 1985- 1993" I also have the Bentley for
earlier cars but not right here at the moment), chapter 13 "Electrical
System", page 13-28, figure 13-2. If you have a Bentley manual, great. If
not, go buy it ASAP; this is the best source of information you'll find for
your VW. Spendy, but worth it.
Look at the electrical schematics; what I want you to do is bridge the
fuel pump. Bring it up before starting to ensure that the system pressure is
up to snuff. For whatever year Scirocco you have; you'll find a diagram for
the fuel pump relay, it shows connections, fuse, etc.
To make the jumper, you?ll need first to pull the relay. I think all the
terminal connections are stamped in the base of the relay, and might also be
printed on the side (in schematic format).
You want to fabricate a jumper lead with an in-line fuse holder. Yes, I
know there's a fuse already in the fuse/relay panel (in Mk2's), but if doing
this blows a fuse you have a 50/50 chance that it'll blow the fuse in the
jumper rather than the one in the fuse panel, which could damage the panel.
Install a 15 amp fuse (or higher/lower amp rating if that is what your
manual shows) in the holder and a male spade connector at each end (use the
blades on the relay for size reference for your spade connectors). There are
five terminals: 1, 15, 30, 31, and 87. Here's what's important [Bentley page
13-6, table a. Terminal and Circuit Numbers].
All terminals numbered 15 are hot when ignition switch is turned to ON
or START.
All terminals numbered 30 are hot ALL THE TIME (if Battery is connected)
regardless of ignition switch position.
All terminals numbered 31 are ground, no matter where they are on the
car.
Your jumper will connect two sockets in the fuel pump relay section of
the fuse/relay block; from terminal 30 (?always hot?) to terminal 87
("ground" by way of the fuel pump). When you make this connection, the fuel
pump will run until you remove the bridge or the battery is drained.
So plug it in... you should hear a low buzzing noise by the right rear
tire; that?s the pump running. Give it a minute or two to clear out any
bubbles (the Bosch CIS fuel system is a recirculating type), then try
starting and see if the beast starts easier.
If so, then I think you might have a bad accumulator, or vent problems,
or? ... I?ll need to know what year. We can then proceed to ID the problem.
Wow... that got out of hand. Hard to repair by remote control.
I hope you find this helpful.
Karl
>From: "C Boyko" <roccit_53@scirocco.cs.uoguelph.ca>
>Reply-To: roccit_53@scirocco.cs.uoguelph.ca
>To: "Mike Smith" <smithma7@gmail.com>
>CC: scirocco-l@scirocco.org
>Subject: Re: Trouble starting
>Date: Thu, 22 Jun 2006 23:37:21 -0400
>
>On 10:31:39 pm 06/22/06 "Mike Smith" <smithma7@gmail.com> wrote:
> > Lately I've had issues starting the car when it's been sitting a
> > while. Starts fine when hot. When cold, it cranks for a while and
> > eventually starts (30 sec or so). I don't crank it for that long at
> > once, BTW.
> > Anyway, thermo time switch / cold start valve? I used to have this
> > problem years ago (at least 4 yrs before joining the list) and
> > instead of fixing (was dirt poor then :) I just popped the clutch for
> > a year or so. Finally got it fixed and I believe that was the
> > problem then.
> > Should I order those items? BTW, anyone got part numbers for those
> > two items?
> >
> > --
> > Mike
> > '86 red 16v: Red 5 (aka der Jahrtausendfeierfalke)
> > "The world is my oyster soup kitchen floor wax museum." - King Crimson
> >
>
>Seems to me there's a pretty easy test in the Bentley for that, mind you,
>I've only ever done it on the 8V, no, wait.....I may have done it years
>back on the 16V. Anyway, you pull the cold start injector, which is not
>scary to do at all, (it's even easy to get to on a 16V, try it on a Fox
>manifold if you want fun, can you say firewall? I thought so) and aim it at
>a bottle and see how long it sprays and what the pattern looks like. The
>Bentley test will describe how to tell if it's a thermotime issue, or an
>injector issue. If I was closer, I'd help you, I gave up huffing pretty
>well cold turkey with that "new" fuel distributor. I kind of miss it.... :D
>Cathy, clean for, well, a few months anyway.......
>
>Oh, I can look up the PNs if nobody else does.....
>
>
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