8708 $A8 Does it have VATS?

**RobertISaar** · 12-23-2013

i would find the buzzing relay before doing anything else.... could explain the run characteristics.

**EagleMark** · 12-23-2013

I think the run charictoristics is the kid put the coils on backwards and the spark plug wires numbers to cylinder are correct!

What the heck makes a relay buzz?

**1project2many** · 12-23-2013

AMDD works but may be automagically looking for 1X detection hardware.

Rapid on/off cycling, incorrect voltage, short on the "device" side sometimes causes relay buzzing. Which relay is it? Was this a carby truck or EFI? If EFI, what did you do with fuel pump wiring?

**EagleMark** · 12-23-2013

It ran just as bad on AMDD as it did with ACxx from the 8708 with Roberts Ignore 1x signal, with the 1x signal still connected (to empty hole in the TBI DIS) when I looked at the coils...

Fuel pump relay is wired and acting just like stock. With conversions I use an extra relay turned on by Key On power from whatever was used in the carb truck, in this case power from the ignition coil and it turns on all other EFI related relays. But it is this extra relay that is buzzing? I did have a charger on it at the time.

So first thing is get coils on right and spark plug wires numbered properly. Timing and firing are both off at this point. Then recheck wiring to buzzing relay.

**dave w** · 12-23-2013

I'm wondering if the relay that is buzzing has a resistive coil? The GM relays I've measured with an ohm meter show about 5 ~ 10 ohms.

dave w

**EagleMark** · 12-23-2013

I swapped it with another I had in a pile on bench and same thing... was pretty late and tired when I got to that point. More today after appointments and try to work out these bugs.

**1project2many** · 12-23-2013

Charger can cause buzzing. If voltage is fluctuating or if rectifier isn't producing true DC, maybe with A/C carrier. Much more common with older chargers or high current boost types.

**EagleMark** · 12-25-2013

Originally Posted by 1project2many

AMDD works but may be automagically looking for 1X detection hardware.

Rapid on/off cycling, incorrect voltage, short on the "device" side sometimes causes relay buzzing. Which relay is it? Was this a carby truck or EFI? If EFI, what did you do with fuel pump wiring?

Had the relay wired wrong which caused buzzing. Cause a lot of issues!!!

If I run the AMDD would it need this 1x signal? I'm not even sure wiring the 1x signal into that empty hole is corrcect to get a 1x signal?

Also what would I look up for ALDL file for the AMDD bin? It's trying to fire on it. Dead on stock 8708 ACxx bin that came in the ECM. Even with the 1x ignore bit set from Robert, no fuel.

Still may have a timing issuse as well, need diagnostics for this 2.2L ICM, it was a JY unit. Double checked the crank sensor and it's with maybe 2 degress of where it should be.

**RobertISaar** · 12-25-2013

AMDD comes up as 88 model year, N-body with LD2 engine. A44 or A69 looks correct.

**1project2many** · 12-25-2013

AMDD in 7749 does not need 1X signal. But in your ecm?? I'd expect no but I can't make any promises. Also, use scope or DVOM to watch for voltage on 1X signal line. Some while cranking, none while not cranking is a good sign.

**RobertISaar** · 12-25-2013

now that i'm thinking about it: Mark, do you have a testbench setup for a 7727? if so, i would hook the 8708 up to it and see what happens when 7727 code is run on it. would at least be able to see if injectors and EST are being toggled.

i'd run 8708 code on my 9396, but i have at least one or two important wires going intermittently open and causing random resets, i still need to dig into it and fix that when i transition to a larger enclosure.