Need help with Mazda EFI.

[Mark Bjork]

Tuck wrote:
> 
> At 04:19 11/7/96 -0600, you wrote:
> 
> >I know this probably sounds simplistic but have you actually checked the
> >spark?.  I was expermenting with a Renault and was inadvertanntly inducing
> >noise on the ECU so that it kept the fuel relay on with the cold start
> >injector. I flooded it good.  I was just about to give up and trash the
> >whole electronics when I finally checked that I had totally fouled the plugs.
> 
> Yeah, I strapped the timing light onto each of the three coils to check for
> spark and didn't get any on any of the coils.  All of the switching
> transistors for firing the injectors are run by T304 on the board (that
> Toshiba Japan IC I asked about), and I checked the transistors last night
> (sort of) and it appears that they are ok.  That pretty much only leaves the
> IC that drives them.
> 
> >My point is to dont take anything for granted (spark. all injectors firing
> >and input signals).  Start back at square one and look for the simple things
> >first.  They are the ones that usually kick your butt.
> 
> I am sure the injectors are firing because I can smell fuel, I also just had
> them blueprinted by Marren a thousand miles ago, so I don't suspect injector
> failure.  FWIW, drive voltage to the injectors is correct also.  All the
> input signals are correct, from the crank angle sensor, the throttle
> position sensor, and the MAF as far as I can tell.
> 
> Justin "Tuck" Cordesman
> SOLID BRASS-> FEAR NOTHING.
> 
> There is a reason the first place trophy looks so much better than second
> and third.
> SECOND AND THIRD SUCK.

As someone before me mentioned, CHECK THE PLUGS.
I recently had to replace a head on a Ford V-6, and the heads I replaced 
them with had been hot-tanked, with the plugs in. Well, this is a fuel 
injected, ecm controlled (both ignition & fuel) engine. After struggling 
to get all the controls back on the engine, and to the point of start-up, 
I found there was NO SPARK AT THE PLUGS- AT ALL! Well, after putting a 
inductive timing light on each of the 6 plug wires, I was convinced that 
I installed the distributor incorrectly. After double checking this, and 
finding nothing wrong, I disconnected the coil wire (remote coil) to the 
cap, and stuck a old used sparkplug in the cap end of the coil wire. 
Walla, SPARK. To make a long story shorter, it turns out that hot tanking 
the Bosch Platinum plugs caused them to short internally, and this would 
prevent any spark at the electrodes, AND, Prevented the timing light from 
firing. I have seen plugs on a two-stroke foul in this same manner when 
flooded from unburned fuel.

Just my $.02,

Mark
snomo at ballcom.com