New Install and No Spark

[Mattb]

Hi guys,
looking for some diagnosis advice. Im in the process of installing an S6 in my Tuscan. At present I simply cannot get a spark.

The car runs a Bosch "Double Fire Coil 3 x 2" http://www.bosch-motorsport.com/media/c ... 019pdf.pdf

Between the coil and the ECU I am running an Ignition amplifier in line. http://www.eurocarparts.com/ecp/c/Audi_ ... 1b3&000503

I am using 3 outputs from the amp and have continuity between the amplifier output and the coil. I have 12v at the coli, and have verified the correct ignition pin outs are being used on the syvecs unit to the amp.

I have disconnected the amp and verified that the S6 unit is working by running the Ignition output bas state tests. All three ignition outputs (pins 26,27,28) being used have approximately 4.5 volts.

I cannot though for the life of me obtain a spark performing a "ignition output pulse request" or simply turning the car over.

I have tried two amps now and the coil was working fine with the MBE unit prior to the sevens install.

The only thing Ive noticed idd is that the amp gets very hot even with the ignition switched on. Ive checked the ground pin and that also has good continuity.

Anyone else experienced anything similar. Im a bit puzzled where to go from here really. Im not un familiar with engine management swaps and building looms, but I'm slightly stumped at the moment.

Any advice is greatly appreciated

Thanks

Matt

[stevieturbo]

Are you turning on the output testing first ?

And you should see the voltage go between 5v and zero, or thereabouts when the output switches off/on

unplug the coil and amp first to test the ecu outputs actually work and at least that should eliminate that aspect.

[Mattb]

Hi Steve,
yes switched out put testing on, and did the output base tests for ignition. From the ignition pins I am using I get something like 4.8 volts on the multimeter, which I'm presuming is about right.

Measured the voltage at the amp input plug with the amp removed.

This is whats puzzling me. The box appears to be generating the correct output voltage but when pulsing I'm not getting a spark.

Also wondering why the amp is getting hot with out any voltage or current flowing into it.

Cheers

Matt

[stevieturbo]

Weird...I replied earlier ? Doesnt seem to be here.

Forum seems screwed up at the minute.

Can you confirm. You are seeing the output change between 0v and 5v as you change the off/on state ?

You just mention 4.8v only, not that the outputs are actually turning off and on.

If the amp was seeing a solid "high" voltage ie your 4.8v, then it would be charging the coil all the time. It must drop to 0v to turn off.

And are you sure the amp is wired correctly ? I know on some amps, any un-used channels need the input grounded. ( and sometimes output too )

[Mattb]

Yep. When output base testing the voltage is zero when disabled, and 4.77 volts when the pin being tested is enabled.

The wiring set up I'm using has been pretty tried and tested on other S6 tvr installs so haven't done anything too radical with the wiring.

The amp is wired using 3 out of 4 of the input and output terminals. With the ground pin on the output side of the amp being wired to the loom ground (on the engine). I've verified all of the wires and the ground wire from the amp has good continuity with the engine.

The unused pin has been left unconnected on both the in and out side.

This article shows the amp I'm using, the pin outs and a wiring diagram showing how it is wired in the Audi set up. http://www.audiworld.com/tech/elec181.shtml

Im still really confused how the amp can be getting hot with no voltage going to it. Surely that means there is a short. It gets seriously hot.

[stevieturbo]

Well the test at least proves the ecu appears to be functioning ok.

Was the ign amp new ? Any chance it could be faulty ?

When it is attached and wired in, does the output state of it change when you switch the input off/on ?

Would it be easier to move to a coil near plug setup with 6 small coils ? and use coils with built in amps ?

LS type coils can be had fairly cheap

[Mattb]

I haven't run the output base tests with the amp connected to avoid damaging it.

I've tried two brand new amps now. I could use an amplified coil pack like a vr6 coil pack, which would have the same mounting points, but that is effectively what's being replicated here and has been used on a number of other tvr installs.

The coil on plug would need some re-engineering of the cam cover as a plate screws down to seal the plugs/ht leads. If that makes sense.

[stevieturbo]

LS would be coil near plug, with a short lead, so any lead arrangements near the plug won't change. You would just need to mount the coils somewhere convenient. But yes what you should have should be working too.

[Mattb]

I'll have to get back out with the multi meter, but at the moment I'm a little stumped.

Wanted to get to super car Sunday this weekend but that doesn't look like it's going to happen. I can't put it back to the mbe set up as I've machined the throttle bodies for the idle valve feed, and the mbe doesn't run with an idle valve hmmmm

[stevieturbo]

If it's just a case of plugging the MBE in, then just plug the holes for the idle valve.

air idle valve isnt essential anyway