alright 1990 Turbo
I cannot for the life of me seem to get my car to start
There is no spark there is no injectors clicking the fuel pump runs when I spin a CAS by hand with the key to on. but nothing else I have changed the fuses three times... I do not know what else it could be.
What causes the ECU to not power anything?
1A and 1B have 12V with key to on.
I have no idea... please help me out.

 

Ok i just ran a 14 gage wire from the ground connected to the housings to the one that is loomed with the TPS connector, then straight to the - batt terminal.
and the one by the actual ECU is also connected.
when I spin the car by hand I get the fuel pump running but no injectors clicking or any spark, tach does not bounce either.

 

Sounds like something out of an 80's sci-fi cartoon...

For future reference, you don't just randomly replace fuses; you check them (visually and with a meter) to see if they're blown. Replacing perfectly good fuses will get you nowhere. Replacing them more than once is just daft...

If you're sure the 30A EGI fuse is okay, check to see that you have 12V at the black/yellow wire at the coil packs. This circuit feeds the injectors too, so if the coils have power, so do the injectors.

 

I like sci-fi!!!


I have actually done that, with every fuse that has to do with this circuit. None have yet to be blown.

The injectors have 12volts, so do the coils, both leading and trailing.

As you can see I am running out of ideas... this mystery has got to be solved soon.

 

anybody with any thoughts theories or suggestions?

 

Your in trouble. Since you have 12v at the injectors and at the black/yellow wire at the white, two wire Lead coil connector, this could mean the so called REF voltage has gone south in the ECU.

So find out if this is so. It's easy. Turn the key ON. Go to the Boost sensor and pull its plug off. Put the meters neg lead on a KNOWN good gnd. The probe the brown/white wire in the boost sensors plug. It should have approx 5vdc. No 5vdc? Bad ECU most likely.

IF it's not there, try pulling the afm's connector the go back and check that brown/white wire once more and see if it's gone up to approx 5vdc.

IF you see just 2vdc..................it's still a bad ECU.

IF the ref voltage is bad there's some concern just why it went bad. IF someone has at one point in time grounded the brown/white wire on any of the sensors (afm, tps, boost sensor etc), that act could have fried the ECU imho. So you have to wonder "is the brown/white still grounded somewhere????".

IF the brown/white wire has approx 5vdc..................heck, I've no idea why the car won't start. I've see practically brand new sparkplugs go deader than hell before for ?????? reason and replacing them made the car start right up. I'd certainly only buy two new LEAD plugs if you try this tack. Trails are a waste of money in this situation.

By the way, the LEAD coil NEEDS to be bolted to the chassis like from the factory. Even just one of the four bolts will do the job. Don't add gnd wires. Not required. But if the coil assy is not mounted to the chassis it's ignitor will have no gnd so it won't spark. Like I said, even just one of the four bolts will do the job so don't get goofy on this and add extra wires.

And of course, does the tach move the slightest when you crank the engine over? IF it does, then you have spark, at least at the trails. Trails only make for a difficult start sometimes.

 

There is 5vdc at the brown/white wire on both the pressure sensor and the afm.


The Plugs are brand new and dry, not an iotta of fuel on them.


Yes it is bolted down properly, and just to make sure it was being grounded I temporarily grounded it with a wire and made no difference.
The Tach does not bounce at all this just confirms that I have no spark wich my timming light also indicates.
Any other ideas?

 

You''ve gone to the ECU and rang the four wires that go to the CAS????? I forget what each *coil* in the CAS should ohm out to but it's in the FSM.

And also check each wire coming from the CAS to the ECU to see if any of them are being shorted to gnd. Shouldn't be shorted to gnd.

Engine should have spark if the cas wiring is good............the cas wires are good to the ECU..............you have the 5vdc ref voltage.................ignitor is bolted to the fender.

Try another LEAD coil/ignitor from another car OR take your LEAD coil/ignitor off and put it on ?????'s car to see if it works.

Each coil ignitor, lead or trail, has a single black bullet connector near them. IT should not be connected to anything much less a gnd. Check it out. That would kill the ignition if grounded.

I saw a car where the fellow said he had no spark. He was using a timing light and sure enougn it did not flash. Well we took a plug off and held it near the strut tower bolts and he turned the engine over. It sparked. PUt plug wire back on...........killed the fuel pump....sprayed starter fluid for two seconds in the intake.....engine started.

Tell you what, hold a sparkplug wire in your hand and touch the fender while someone turns the engine over. See if you get a tingle. Hope you don't have a pacemaker if you do that. some humor, some not humor.

I'm stumped. No spark and you have the stuff for spark. Bad ignitor .....but both???

 

I have tried running independant wire to the pins on the ecu from the cas bypassing the stock wiring for the car to ensure that isn't the case.. no difference

Yes they do ohm out and they are not shorting out... infact when I spin a cas hooked into the harness by hand the fuel pump starts running. so the ecu is seing the signal


Yes

Tried both another lead and trailing coild and did not make a difference.

Nope they are not grounded or even have the chance to ground.

my timing light is not inductive, it is direct.

I have tried this and it does indeed not have any spark.


Couldn't be a bad ignitior I tried two spairs that worked with the haltech... I have no idea, what is going on. But please keep the suggestions comming.

 

I am going to arrange to have my ecu tested is another working s5 car to ensure that is/or is not the problem.... but in the mean time do you guy's have any suggestions?