Audi 100 Won't Start: Finally Starts !!!!!!!
Marc Boucher
mboucher70 at hotmail.com
Thu Jan 29 16:54:56 EST 2004
I wired in 12 volts to the CSV and it started and ran first time.
After what I thought was a sufficient time with the CSV engaged, I
disconnected it. Car died instantly. Tried this and many variations and
here is the new knowledge:
The car will start and idle ok with the cold start engaged (albeit a bit
rich?) but without it it will not run.
For the first few minutes, any attempt to take it off idle, i.e. to press
gently on the accelerator will kill the idle.
After its warmed up a bit, I can operate the throttle to increase the rpm
however I feel that this is simply added air and leaning out the mixture.
If the throttle is opened too much it will die (presumably from too lean a
mixture)
During the idle I was able to check to my satisfaction that there were no
vacuum leaks.
During the idle, unplugging the wire to the ISV would kill the idle. (in
the past I seem to recall that unplugging the isv made it idle faster?)
During the idle, unplugging the connector to the differential pressure
regulator had no impact..
After the car was a little warmer (i.e. needle had just started to move on
dashboard sensor), once the cold start was unplugged the car would first
increase in rpm (as though the mixture had been too rich and was becoming
ideal) and then die a second later as it ran out of fuel.
So where does this leave me:
A thermoswitch that has no impact on the Cold start valve?
A fuel injection system that seems to meter fuel through the cold start
valve just fine but doesn't do much of anything with the other five
injectors?
Marc
----- Original Message -----
From: <McCohens at aol.com>
To: <mboucher70 at hotmail.com>
Sent: Thursday, January 29, 2004 4:27 PM
Subject: Audi Start Woes
Yes, unhook the CSV and wire in a 12 volt. I did it on my 4000Q and it
worked great! Here is what I did.
1.Get a momentary switch from radio shack. They come in a pack of two I
think. Save the extra one the switches are junk and go bad after a year or
so.
2. Tap into a power source like the cig lighter or such. Use a fuse if you
like.
3. Unhook or cut wires going to the CSV. I would advise unhooking and
finding a connector with pigtails for the new setup. Depends on how cold it
is, how much time you have to muck with it.
4. Connect power thru the switch to one side of the CSV. Doesn't matter
which side. Other side goes to a ground.
5. Push the button, listen for a faint click from the injector.
6. Cold start procedure will be push the button for 3-4 seconds, count to 5
and start.
7. You may need to "tickle" the switch for the first minute until it idles
on its own.
This is not the best fix, but it works. Actually its a pretty cool
limp home setup too. With no fuel going to the CIS system you can drive
slowly on the CSV alone.
Good Luck!
Randy Cohen
----- Original Message -----
From: "Robert Mangas" <porter_t_dog at hotmail.com>
To: <mboucher70 at hotmail.com>; <syljay at optonline.net>; <quattro at audifans.com>
Sent: Thursday, January 29, 2004 2:30 PM
Subject: RE: Audi 100 Won't Start: Breakthrough ???
I hope it's safe to energize it directly w/ 12v; that's how I start it every
time ;)
On my 4kq the starter portion of that circuit wasn't working, but the
starter was fine, otherwise. I wired in a momentary pushbutton to fire the
CSV manually when needed. Works good, and though kludgy was way cheaper
than a new starter.
$0.02,
Robert
>From: "Marc Boucher" <mboucher70 at hotmail.com>
>To: "SJ" <syljay at optonline.net>, <quattro at audifans.com>
>Subject: Audi 100 Won't Start: Breakthrough ???
>Date: Thu, 29 Jan 2004 14:26:38 -0500
>
>Today I discovered something that has a strong likelihood of being the
>problem with my car's starting.
>
>I decided to measure the length of time that the cold start valve was
>energized for.
>
>Previously I had done the 'output' test of the ECU which essentially just
>shows that it can be energized. I'd also measured the resistance voltage
>across the thermo switch which measured at about 3.5k Ohms and was
>consistent with data supplied by others in this group. Today I got out a
>couple of radio shack resistors I'd never used in order to test.
>
>The results: REGARDLESS of what resistance was detected by the wire coming
>to the thermotime switch, each time the cold start valve was energized for
>only about 1.5 SECONDS !!! I have Hayes manual that shows that at current
>temperature (50F) the cold start valve should be energized between 2 and 4
>seconds. Here is a table of my tests, my expected, and observed results:
>
>Test Description Expected Time
>Observed Time
>Thermotime Plugged in, 50F 2-4 seconds
>1.5 seconds
>Thermotime Plugged out...open circuit ?
>1.5 seconds
>11 KOhms resistor (simulates 15 F) 4-10 seconds
>1.5 seconds
>22 KOhms resistor ?
>1.5 seconds
>wire shunted...zero ohms ?
>1.5 seconds
>FI box of ECU unit removed ?
>0 seconds
>
>So unless I'm missing something, the cold start valve is not being
energized
>correctly according to the temperature. Is there something that I could
>have missed in order to get the cold start to be energized correctly
>according to the temperature?
>
>Would it be safe to energize the cold start valve with 12 volts directly
and
>try to start?
>
>Anyone have any tips on where to go from here? i.e. anyone have a wiring
>diagram of the ECU's I guess the next step it to trace the wiring ???
>
>
>Marc
>
>
>
>----- Original Message -----
>From: "Marc Boucher" <mboucher70 at hotmail.com>
>To: "SJ" <syljay at optonline.net>
>Sent: Wednesday, January 28, 2004 8:03 PM
>Subject: Re: SJ Audi 100 Won't Start (Vacuum Leak?)
>
>
>It may be a few days before I can get starter fluid and a spark tester so I
>thought I'd add some further information. Each of these may be irrelevant
>but for what its worth, here goes:
>
>In lieu of an 'inline' spark tester, I pulled a plug wire, plugged it into
a
>spare spark plug, and turned the engine over a few times. Each time, the
>spark plug generated a healthy spark from the time at which I engaged the
>starter until when the engine finally died. I know its hard to tell
>visually but it really seemed more like the engine died and so the sparks
>stopped, rather than the sparks stopped and so the engine rolled to a stop.
>
>I pulled one plug to check its condition. It had a thin coating of black
>suit, as I'd expect from a car that's been turned over for several days but
>rarely starts. Otherwise the plug was in good condition, the gap was
>correct, and there was no gap bridging or heavy deposits. Plugs are Bosch
>platinum 4477 with about 6000 miles on them.
>
>While working on the car I noticed fluid underneath the tranny on the
garage
>floor. Confirmed it was transmission fluid. Not a lot but a noticeable
>amount. This car has never leaked a single fluid and the driveway and
>garage have until now been pristine. I wonder if repeated starting
attempts
>can cause transmission fluid to leak?
>
>So I went and checked the other fluids...hydraulic fluid has dropped from
>max to middle of fill line in less than a month despite never going down
>before. Again I wonder if the repeated starting attempts, or the time we
>had to push it and steer without power assist can cause a leak to begin?
>
>One more point to add: almost the last day that I drove the car
trouble-free
>also happened to be the coldest weather the car's ever been exposed to. It
>was parked outside for about 6 hours in -30C (-22F) temperature. After 6
>hours it turned over slower than usual but started on 2nd try (usually
>starts on 1st) and took me home fine. Its been in a warm garage since.
>Maybe one or two other short successful drives, but something just didn't
>'feel' right with how it started even then (given it was in a warm garage).
>
>Before I had any trouble, there was an interesting 'tick tick tick' during
>idle (actually a couple of them). One could be recognizable as the tappets
>and that would sometimes go away. But the other one was the fuel
injection.
>I guess I'm gonna have to read up on fuel injection because I'm convinced
>that the problem is that fuel isn't getting through the injectors into the
>cylinders. I'm tempted to try adjusting the mixture or pulling an injector
>and if that doesn't work then getting it to a mechanic, or just shooting it
>:-)
>
>You asked if I had Bentley. No unfortunately. I have Hayes, which doesn't
>cover adjusting the mixture of the fuel injection.
>
>Marc
>
>ps below when I said "Thus the current flow would be about 100mA once the
>ignition was engaged," this was poorly explained. A clearer explanation:
>
>Once the ignition was engaged, the current flow was a steady 100mA. While
>cranking it remained at 100mA. Once the key was released (released because
>it seemed like the engine was starting) the current essentially followed
the
>rpm...ie.descended from 100mA to zero just as the rpm descended from 1000
to
>zero. Time between releasing key and zero rpm was almost always under 1.5
>seconds.
>
>
>
>----- Original Message -----
>From: "SJ" <syljay at optonline.net>
>To: "Marc Boucher" <mboucher70 at hotmail.com>
>Sent: Wednesday, January 28, 2004 5:03 PM
>Subject: Re: SJ Audi 100 Won't Start (Vacuum Leak?)
>
>
> >
> > Here are the results of today's testing (pulls out his log book :-)
> >
> > TESTING OF THERMOTIME SWITCH:
> > Both pins measured about 3.5k Ohms from ground to the pin. At about 50F
> > this is quite close to your results.
> >
> > TESTING OF IDLE and FULL THROTTLE SWITCHES:
> > Confirmed...on idle the switch is engaged (zero ohms) between pin 1 and
2.
> > On full throttle we get zero ohms between pin 2 and pin 3. (I know its
>not
> > technically zero ohms...guess that's called 'closed circuit' ?)
> >
> > TESTING TO ELIMINATE FUEL PUMP RELAY AS CAUSE:
> > This had been done yesterday and results reported. Key point is that on
> > removal of the relay and shunting, the fuel pump can be heard to
operate,
> > and is measured to draw about six Amps. Starting of car while using the
> > shunt produces a result that is NO different than using relay.
>Conclusion:
> > Relay is likely not the problem.
> >
> > TESTING OF FUEL PUMP OUTPUT:
> > The fuel pump was disconnected at the entry to the filter (filter is
>new-was
> > changed as a first step in trying to solve this problem) and carefully
> > directed into a container in which I could measure flow. Fuel pump was
> > energized for about 2-3 seconds...during this time it pumped about 60ml
(2
> > fluid ounces). Note that I don't have the equipment to accurately and
> > safely test flow, or to test it under pressure. But this test gives me
>some
> > confidence that its pumping and more than likely the pump is not the
> > problem.
> >
> > TESTING OF CURRENT FLOW THROUGH DIFFERENTIAL PRESSURE REGULATOR:
> > Today I was not successful in getting the car started. Thus the current
> > flow would be about 100mA once the ignition was engaged, remain at that
> > during cranking, and once the key was released (released because it
seemed
> > like it was starting) the current essentially followed the rpm...i.e.
> > descended from 100mA to zero just as the rpm descended from 1000 to
zero.
> > Time between releasing key and zero rpm was almost always under 1.5
>seconds.
>***** "Thus"?? "would be"??
>Did you measure the current or not?
>Current should be at 100ma with igniton "on", but engine not cranking. Is
>it?
>
>
> >
> > TESTING OF POTENTIOMETER DURING STARTUP:
> > Previously I'd tested the potentiometer resistance with the bonnet open.
> > I'd found that The resistance between the bottom and the middle contact
is
> > about 2 kOhms at rest and rises to a max of about 13kOhms near full open
> > falling slightly to 11kOhms at full open. Today I decided to measure
this
> > resistance during an attempted start just to ensure that the plunger is
> > actually moving. The resistance moved from about 2 kOhms up to about 4
or
>5
> > kOhms. when it appeared that the engine was about to start and then as
it
> > sputtered the resistance fell back to 2kOhms.
> >
> > TESTING THE EFFECT OF UNPLUGGING OXYGEN SENSOR:
> > O2 sensor disconnected (heater and sensor plugs). Result...no change in
>any
> > observed behavior.
> >
> > Two of your suggestions...the inline spark plug tester and the starter
>fluid
> > will have to wait until I can get a ride to a car parts store. The
>spark's
> > been verified but you're right, it could be intermittent. I'll try to
get
> > both as soon as practical...note however, with regard to the starter
>fluid,
> > its really too cold to barbecue up here right now :-)
>***** Ok, we need to check these two items in order to eliminate spark as
>the problem and fix the fuel system as the problem.
>
>After you do the above > spark plug tester, starter fluid:
>Verify again that you have no vacuum leaks. You said two lines had leaks .
>pinch them off to make sure the intake has no leaks. Since this is the #1
>problem with hard starting, really make sure this is not the problem.
>
>Redo the ground connections at the back end of the intake manifold. Take it
>apart, sand the lugs, reinstall.
>
>Do you have the Bentley manual?
>
>Does the Cold start valve fire? You said it tested ok when you did the
>diagnostic tests.
>If its not too much trouble, take out the cold start valve, and see if it
>squirts when you crank the engine. If the engine fires up with starter
>fluid, this will be the area to check next.
>
>Take out the plugs also and check them. See if they are fouled or wet. If
>they are wet(fuel) I would get a new set. Clean and dry out the old ones in
>the oven.
>
>
> >
> > Marc
> >
> >
> >
> > ----- Original Message -----
> > From: "SJ" <syljay at optonline.net>
> > To: "Marc Boucher" <mboucher70 at hotmail.com>
> > Sent: Wednesday, January 28, 2004 11:38 AM
> > Subject: Re: SJ Audi 100 Won't Start (Vacuum Leak?)
> >
> >
> > Theoretically, the car should run without the fuel injection ECU. The
>system
> > will run in a mechanical mode.
> > Basically, all the ECU does is vary the Diff Press Reg current to fine
>tune
> > it for emissions.
> > The other ECU outputs are minor, ISV, vapor canister, cold start valve,
>etc.
> > Many of the inputs to the ECU can be "faked" . . ie, resistor in place
of
> > temp sensor, jumper for idle switch, etc
> >
> > Are you keeping a log of your tests?
> >
> > Things that you arent doing and should be doing.
> > 1. Get that $7 in line spark plug tester . .and leave it on. Just in
case
> > you have an intermittant ignition problem.
> >
> > 2. Hook up the ammeter for the Diff Press Reg. I use a cheap analog
meter
>
> > radio shack. You can calibrate the analog against the DMM. Always
monitor
> > this current . . . you should have a list of current values and
>conditions.
> > I sent you an email with these values.
> > Both my cars have insulated male and female spade lugs crimped on one of
>the
> > regulator wires. And I made up lug type test leads to interconnect to
the
> > wiring and my meter. Now its very simple to hook up a meter.
> >
> > 3. Get starter fluid and rig up rubber hose so you can inject the fluid.
>Its
> > a lot easier to troubleshoot if you can get the engine to run. The
starter
> > fluid will bypass cold start valve and lean mix from pressure regulator.
>
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