pantera928

A S4 that will not start without a few squirts of ether and then runs rough for a bit until it warms up. THen it runs great and idles fine.
Tried jumping the XX relay to keep the pumps running before trying to start it but made no difference.
Once it has warmed up, you can drive it anywhere and as hard as you want, then stop it and it starts right back up like it should.
Have not checked fuel pressure but figured that would cause other problems if it was an issue.
This car runs like new once you get it started.

Any ideas?
Thanks

Mrmerlin

when was the MAF rebuilt same for the LH computer,
and when were the dampers and FPR swapped out,
and when was the intake refresh done

pantera928

Not sure of the answer to any of those but why would it run so well once warmed up? Wouldn't some of those cause other issues?

Mrmerlin

is this car supercharged?
remember the more info you can add the better the guesses will be

pantera928

Bone stock. No mods of any kind 1989 automatic

FredR

Sounds as though you need to check the resistance values for the LH channel of your temp2 sensor.

To do this pull the LH plug off the computer and measure the resistance between terminal 13 and either terminal 5 or 17 [both earth]. When cold you should see values around 5k ohms and when hot about 100 or so ohms.

If the value you measure hot or cold is the same and frozen at around 100 ohms or so then the LH will not enrich the fuelling for cold starts.

The Forgotten On

I was going to guess the Temp II sensor as well.

They are a wear part and should be replaced either with every timing belt or 10 years.

545svk

When my Temp 2 failed, the car would start easy with the sensor unplugged. May be an easy check.

Also, smell the vacuum connectors on the fuel pressure and damper valves. When they failed the starting symptoms were similar to the failed Temp 2.

FredR

Pulling the temp2 connector causes the brains to think that the coldest setting is required [infinite resistance] and it will default to such when cranking and if that works a pretty good sign that the temp2 is toast without having to measure anything..

For those of us with ST2 we simply hook up the laptop and see what value of temperature is shown in both the LH and EZK channels - one presumes the OP does not have such facility.

DHS928

What is a "ST2"? will it work on an 87?

Mrmerlin

Please post a few pictures of the engine bay

FredR

ST2=Sharktuner version 2. This requires modifications to the LH and EZK computers that have to be fitted with programmable eeproms. One also needs the interface kit plus a laptop.

pantera928

Thanks for all of the replies. Where is the temp 2 sensor located? I should know that but haven't been doing any
928 work for a while
.I have a ST2 but since this car does not have eeproms in it, I cannot use it on it.

Mrmerlin

temp 2 is on the right side, (passenger side) of the water bridge
see the blue connector,
2 circuits,
test each pin to ground. they should match,
also the connector can have the wires touch due to shedding insulation,
if its in question replace the boot and connector.

khalloudy

Temp Sensor II is the problem.

Had this happen to my S4 when i first bought it. When extremely cold, the sensor would open loop sending the LH into coocoo mode. Hard to diagnose since when warm, the range of resistance was normal!