Speedtoys

Crank position sensor plug

bayrrej

I believe I have tracked the new no start issue to an injector harness short?
It would seem (from the wiring schema, anyway) that resistance between the two contacts on a given injector plug should be more than 1 ohm -- that a fair 'surmisal'?

jb

bayrrej

Looks like the excitement has finally withered a bit on this exciting thread!
At any rate, just in case someone actually follows this thread in an attempt to learn something, I found the problem for turning over but not starting: two injectors were shorted. Once repaired, the car started right up.
And then on the up side, it no longer stalls at 2000 RPM! On the down side, the car now idles at 2200 RPM. So, it would appear we have some "disingenuous" air coming in from somewhere -- time to press the old smoker into service again!!

" Ah, the foolishness!"

JBGold07

Nice find of the shorts! Which injectors were they?

bayrrej

1 & 3...

davek9

I've seen a bad LH hold the ISV open, but as you are mixing parts from two different engine types that use different controls (ISV, S3 , S4) correct?
You may have damaged the S3's LH by using the S4 ISV, if that is what you did, the Driver Transistors and the method used is not compatible between them.

bayrrej

All the electronics that I've checked are S3 as is the new ISV, the new injectors, the existing LH, etc. I have no idea how or why the PPO decided to assemble this mutant! According to the PO, it's been "chipped" -- whatever that actually means...

bayrrej

So why did I step into this steaming bucket of $h17...?
Clearly, I'm a degenerate masochist and love a befuddling challenge!

davek9

when in doubt check it out, open up the two ECU's (LH and EZF) and have a look see, then you will know for sure

Ducman82

saw you post again about this. ever check the computer?

bayrrej

No, but I'm about to as I've run out of other ideas.
Very possible that I mucked the computer with all the other juggling going on...

Ducman82

i have a friend with an S3 that is having this exact same issue. sent him the links to this. i know he has replaced the ISV a number of times as well.

bayrrej

This largely for information as I haven't seen ANYTHING about this particular behavior... (BTW, it idled perfectly before I pulled the intake to refurbish..)

Pulled the intake again and tested the ICV and it failed spectacularly. Replaced w/ S3 ICV, checked and replaced suspicious hoses/connectors. Replaced the TPS since I was there. Tested the Flappy.
Initial smoke test turned up broken hose which is now replaced.
Current smoke test shows no smoke after 10 minutes.
When it starts, it revs to about 3000, drops to about 600 and then settles in at exactly 2400 and stays there.

For the record, ALL components are S3 EXCEPT the intake which is S4. There is a flappy actuator but I haven't figured out where that signal is coming from...

I've replaced: (all S3 components)
ICV
TPS
MAF (rebuilt)
Injectors -- Bosch 4 hole Gen III
Fuel Regs and Damper
relevant gaskets, hoses and connectors

GlenL

Sounds like you've covered a lot of ground trying to solve this.

I'll suggest you're at the Repair Reassessment Juncture or RRJ. I just coined that as there has to be a term for the point in a repair where something that's been fixed really isn't fixed. Since it's the most complicated part, and hard to test, I'm going to suggest the MAF isn't measuring the airflow correctly.

hwyengr

Have you checked the computer yet? If you can't find a loaner to test with, there's a vendor that can put an LH on a test rig and check it out. Rich Andrade, maybe?

If there's no false air, then the components aren't being controlled properly. Everyone says the S3 computers don't fail, but that's not true.