Try my no-start question : quiz style
 

i dont know if there's an answer, but sounds like it. fill in the blank below. Yes this is all about my no-start:

You put new spark plugs in your no-start late NA 944 that gets a steady ~2.5 bar of fuel pressure. Turn the key, get spark from all plugs, starter goes, but another no-start. Try a few times. You look at the spark plug tips : one is blackened, the others like new. This means _________(no word limit)_____.

... My guess is three failed injectors and one good one in a cylinder with oil leaking, but I think that's wishful - it's probably more than that.

I will play by the rules:


This means since I cannot detect fuel in the three clean plugs_the shop messed up the injector seals job. Maybe they didn't connect the harness properly, or possibly wires broke in the harness_____.

This means it is time to pony up for a set of noid lights... They will tell you if the injector is getting a pulse from the ECU....

OK, noid light - there's all these acronyms out there like "Bosch PFI" - so what is the late NA 944 Bosch L-Jetronic / Motronic? EV1 like I found/said the other day?

... and about noid lights - can't I just put a 12 volt LED in there?

It is a little more complicated than using a simple test light since the electrical pulse is too short to see without a NOID light (some magic I don"t fully undersatnd). However it only checks the ECM and not the injector.

https://www.youtube.com/watch?v=5MmR-wXddVw

To test the injector you would need to check the resistance of it or test fire it by tapping a test lead against the battery terminal.

https://www.youtube.com/watch?v=hZrRVWe2Km4

For your situation you might want to start with the 2nd video if you already have a dvm.

Vielleicht. buy a set of noid lights. They're ev1 style used on everything. Sounds like you are not getting pulse. go over the basics. tach bounce, speed reference. Confirm spark. ect ect