[s-cars] S-CAR Bucking under WOT - SOLVED!

[Ivan Demkovitch]

List,

Attached on a bottom my original problem.

Huge thanks to Chris Chambers who agreed to test my coil pack and MAF.
When I got parts back I knew that I have bad coil pack.

Then it was time to decide if I want to do 1.8T conversion or I need to buy 
1 new coil.
I decided to go with new coil and got it + 4 new coil connectors for ~$130

Tried to troubleshoot bad coil by unplugging injectors and driving around, 
but engine wouldn't build enough boost and car vibrates so badly that you 
can't tell if it's 4 or 3 cylinders working :)

Then I tried spark tester test again and it worked. The trick is to be 
patient. First time I was testing while doing vodka shots with my friend and 
presence of "spark" was good enough for me.

This time I counted 10 sparks on each coil. This is very important because 
you can see how often they go and get a feel. Then I increased gap and one 
coil missed 3 out of 10 sparks. It was on cylinder 4.

30 minutes later I was about to get tickets on highway. Lots of boost and 
car drives like never before.

Ivan
93' S4


Folks,

Same problem keep bugging me. Any time under WOT car would surge violently
when boost starting to build up. Sometimes it would be just 1-2 surges and
then it accelerate just fine and other time it will surge without letting me
go fast :)

If I accelerate slowly - car gets up to speed just fine.

It used to be intermittant problem but within last month it started to
become regular.

What I had done (thanks to advices here):
1. Replaced spark plugs
2. Replaced air and fuel filters.
3. Tested coils using "spark tester" test. All coils tested out fine with
similar gap. Maybe 1 turn difference.

Yesterday I had to buy compressor (good excuse for wife and starting point
to collect air tools :)
Tested intake for leaks today.
1. Connected 3' PVC plug to hose from MAF to pressurise all intake.
2. Got huge leak from oil cap
3. Read archives
4. Plug hose to valve cover
5. Pressurise again.
6. Got very big intake(MAF->Turbo) hose. Yes, it was inflated and ready to
blow.
7. No sign of obvius leaks. Can't really test because was scared of that
hose to blow up. 10 psi didn't show anything. 15-20psi quick check didn't
show anything.

If it's coils - I'd rather go with 1.8 coils setup.

Anyway - don't want to spend money to replace different parts. I'm sure
there is better way.

Any pointers on what do I need

Thanks for advice!

Ivan
93' S4