Driving with disconnected ISV?

Nedavno Steve Sears pise:


| No, I don't believe that it has a valve, but it should have a vent
| hose that collapses over time.

OK, thanks. I recently replaced that hose.



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Update:

I disconnected ISV electrical connector, and result is that engine idles
OK when warm (50 deg Celsius or more). The higher the engine
temperature, the higher the RPM, but no more than ~900.

When I stop, rpm does not drop low to ~600 rpm and then up to ~900 and
then to normal 750 as it does with ISV connected. It just goes down to
to ~900 or less depending on engine temperature.

Am I right to assume that my problem is ISV?

How do I find out if it is exactly ISV an not some sensor somewhere that
sends wrong signals to ECU? I have oscilloscope and digital multimeter
so I would appreciate if anyone can give me details, or point me to some
url on the net with detailed specification of voltages (or any other way
to determine what is not functioning correctly).

I ordered Haynes manual from haynes.co.uk, but it has not arrived yet.




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I do not see a thread where you described what problem you are trying to correct.

Also, What car is this?

If a T44, you might want to see numerous threads on this at Audiworld:
http://forums.audiworld.com/v8/

The ISV is operated with the ISV controller (in T44s it is in drivers side under
dash in Aux relay panel).

One input that it uses is a temp sender (on T44, I5 it is under the upper
radiotor hose)

Yvan wrote:

> Update:
>
> I disconnected ISV electrical connector, and result is that engine idles
> OK when warm (50 deg Celsius or more). The higher the engine
> temperature, the higher the RPM, but no more than ~900.
>
> When I stop, rpm does not drop low to ~600 rpm and then up to ~900 and
> then to normal 750 as it does with ISV connected. It just goes down to
> to ~900 or less depending on engine temperature.
>
> Am I right to assume that my problem is ISV?
>
> How do I find out if it is exactly ISV an not some sensor somewhere that
> sends wrong signals to ECU? I have oscilloscope and digital multimeter
> so I would appreciate if anyone can give me details, or point me to some
> url on the net with detailed specification of voltages (or any other way
> to determine what is not functioning correctly).
>
> I ordered Haynes manual from haynes.co.uk, but it has not arrived yet.
>
>
>
>

Nedavno Tony pise:

| I do not see a thread where you described what problem you are trying
| to correct.

I have problem that I briefly described in my previous post. When I
stop the car rpm drops to some 500-600 and then sometimes stalls, and
sometimes goes up to 900-1000 and then back to standard 750.

| Also, What car is this?

1989 Audi 100 2.3E (NF 5-Cyl. engine).

| If a T44, you might want to see numerous threads on this at Audiworld:
| http://forums.audiworld.com/v8/

It is not V8.

| The ISV is operated with the ISV controller (in T44s it is in drivers
| side under dash in Aux relay panel).
|
| One input that it uses is a temp sender (on T44, I5 it is under the
| upper radiotor hose)

I found some instructions he

http://www.sjmautotechnik.com/troubl...r.html#mixture

but it seems it is not for my NF 5-Cyl. engine. But I am going to test
it like this anyway.

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Yvan,
The temperaturpm correlation should be about right, as the LPG will turn
to a more diffuse gas with greater heating, and you are using the engine
coolant to heat the LPG, right?
It sounds like the ISV is indeed working, but the feedback from it being
designed for a different purpose than LPG sounds like it may be causing the
problem (by working properly!) - I suggest that you may have to rig in a way
to disable the ISV when you are running LPG, as the engine runs properly
when you're running on gasoline, correct? Thus, when the LPG turns on
(engine at required temperature), then you would have to take the ground
connection away from the ISV. I expect that there may be a relay doing that
already - to shut off the fuel pump.
BTW, the Audiworld type 44 (aka type $$) forum, which covers 100/200/5000/V8
(and, apparently 500 in South Africa and other places) - appears as:
http://forums.audiworld.com/v8/
- it's not just V8's covered in there
And the "Haynes" manual?.......ugggh! When you read "Assembly is the
reverse of removal" you'll realize why the Bentley Manual is worth the extra
$ for those who actually do work on their car.
Steve Sears
1987 Audi 5kTQ - Bentley Manuals (2 volumes) referred to often
1980 Audi 5k - Bentley Manuals (2 copies of 1 volume) close at hand -
Haynes/Chiltons manuals use to keep Bentley Manual pages from blowing aroung
as I work outside - and as Joke Books
1962 and '64 Auto Union DKW Junior deLuxes - pre-Bentley Factory Manuals (in
German and English) in use....along with Babelfish
(SPAM Blocker NOTE: Remove SHOES to reply)

Yvan wrote:

> I have problem that I briefly described in my previous post. When I
> stop the car rpm drops to some 500-600 and then sometimes stalls, and
> sometimes goes up to 900-1000 and then back to standard 750.
>
> | Also, What car is this?
>
> 1989 Audi 100 2.3E (NF 5-Cyl. engine).

I have an '87 VW Golf GTi with CIS-e (= KE-Jetronic) fuel injection. I
too had a problem with idle speed earlier this year. I first suspected
the ISV and replaced it (the replacement cost me $4, so replacing it was
cheap troubleshooting). No change. I then found out the the idle
position switch (the switch that closes when you release the gas pedal)
was broken. The fuel injection system would never know to get into idle
mode, and thus the idle speed was off. A new switch (they are sold only
in a set with the wide open throttle switch for my car) was over US$100
from the dealer so I went to a local junkyard. What I found was that a
large number of both Audis and VWs at the junkyard had broken idle
position switches, so it seems to be a common problem for VAG vehicles
of that vintage. I eventually found a working one from a slightly newer
car with Digifant, not CIS-e. The switch is the same for the two, but
the wiring is different. The switches are located on the throttle body,
on mine there is one switch in plain view on top, which is the WOT, or
wide open throttle switch, and another underneath the throttle body.
This is the idle switch. Your car may be different.

I don't know what type of fuel injection you have on your car, but I
believe you said you do not have an oxygen sensor. That would be
consistent with CIS (= K-jetronic), and I believe (but am not sure) that
CIS uses the same switches as CIS-e. The simplest test of the switch is
to open the hood and move the throttle by hand between closed and barely
open. If the switch is working, you should hear the clicks at is turns
on and off. The broken switches I have seen have had the plunger fall
out, so that the switch would not operate at all. Another test is to
disconnect the switch and short the two wires that goes to it. If
shorting the wires make the idle go back to normal, you can be pretty
sure there is a problem with the switch.

Nedavno Steve Sears pise:

| The temperaturpm correlation should be about right, as the LPG will
| turn to a more diffuse gas with greater heating, and you are using the
| engine coolant to heat the LPG, right?

I think that engine coolant is used only to keep vaporizer from freezing
and it perhaps heets lpg spmewhat, but I think that does not make any
difference.

| It sounds like the ISV is indeed working, but the feedback from it
| being designed for a different purpose than LPG sounds like it may be
| causing the problem (by working properly!) - I suggest that you may
| have to rig in a way to disable the ISV when you are running LPG, as
| the engine runs properly when you're running on gasoline, correct?

No. It is the same, gasoline or lpg, I did some more testing. Perhaps a
problem is not so big on gasoline as it is on lpg, but it is there.

| Thus, when the LPG turns on(engine at required temperature), then you
| would have to take the ground connection away from the ISV. I expect
| that there may be a relay doing that already - to shut off the fuel
| pump.

I can install a switch to disconnect ISV, but as I just wrote I have the
same problem with gasoline too.

| BTW, the Audiworld type 44 (aka type $$) forum, which covers
| 100/200/5000/V8(and, apparently 500 in South Africa and other places)
| - appears as: http://forums.audiworld.com/v8/
| - it's not just V8's covered in there

I will check thaere, thanks.

| And the "Haynes" manual?.......ugggh! When you read "Assembly is the
| reverse of removal" you'll realize why the Bentley Manual is worth the
| extra$ for those who actually do work on their car.

It seems like I will have to get the Bentley Manual, I just received
Haynes manual for '77 Puch Maxi that I own, and I am completely
disappointed. It looks like "complete idiots guide" to disassemble and
assemble moped's engine. I did that without the manual.



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Nedavno Randolph pise:

| > | Also, What car is this?
| >
| > 1989 Audi 100 2.3E (NF 5-Cyl. engine).
|
| I have an '87 VW Golf GTi with CIS-e (= KE-Jetronic) fuel injection. I
| too had a problem with idle speed earlier this year. I first suspected
| the ISV and replaced it (the replacement cost me $4, so replacing it
| was cheap troubleshooting).

ISV for my car is $220 (BOSCH 0 280 140 512) Audi part 034 133 455B is
probably more $$.

| No change. I then found out the the idle
| position switch (the switch that closes when you release the gas
| pedal) was broken.

One on my car works OK. I checked.

| I don't know what type of fuel injection you have on your car, but I
| believe you said you do not have an oxygen sensor.

I have O2 sensor.


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Yvan wrote:
> Nedavno Tony pise:
>
> I have problem that I briefly described in my previous post. When I
> stop the car rpm drops to some 500-600 and then sometimes stalls, and
> sometimes goes up to 900-1000 and then back to standard 750.
>
> | Also, What car is this?
>
> 1989 Audi 100 2.3E (NF 5-Cyl. engine).
>
> | If a T44, you might want to see numerous threads on this at Audiworld:
> | http://forums.audiworld.com/v8/
>
> It is not V8.

The forum link that I gave is for all Type 44s ('82 to '91) and most of the
discussion is for the five cylinder engines.

> | The ISV is operated with the ISV controller (in T44s it is in drivers
> | side under dash in Aux relay panel).
> |
> | One input that it uses is a temp sender (on T44, I5 it is under the
> | upper radiotor hose)
>
> I found some instructions he
>
> http://www.sjmautotechnik.com/troubl...r.html#mixture

Very good source for information. SMJ site is nearly the 'bible' for T44 series.

> but it seems it is not for my NF 5-Cyl. engine. But I am going to test
> it like this anyway.
>
That would be a good start.

Good luck.

Tony
'91 100q 5spd
ISV BTDT

Oh, that's right and the thought is that on LPG the ISV might be functioning
just opposite from gas due to the location of the LPG infection.

Tony

Steve Sears wrote:

> Tony,
> Yvan has a Type $$, but he's running an LPG convertion on his car. You'd
> have to look at the a.a.a archives to see the troubleshooting that went on a
> couple of months ago.