Absolutly no spark

[SHOWGN]

Hello all,
I am well into a sho project i recently started involving an 89 SHO drivetrain, and a 93 merc Sable body. The problem is i am getting it to crank perfectly but i am not getting any spark at all. I have fuel pressure and my dis and crank and cam posotion sensors are pluged in. I ran the engine before the swap and it ran fine so I am missing a plug in somewhere, or two. I am trying to find all the identical plugs between the sho engine and the sho chassis wiring as i just pulled everything from the parts car. Anybody out there know why there is no spark at all. Any and all help will be much appreciated.
Thanks,
MAtt

 

[rubydist]

Matt, there is a good chance you are missing a ground or two. There needs to be a very good ground from the intake manifold to the chassis for the dis to work. Its easy to overlook that or not have it tight.

 

[projectSHO89]

Quick ground check: LOWER DIS mounting screws to battery negative post. Has to be perfect.

Also, check the batt power to the DIS module with ignition switch in RUN/START.

 

[SHOWGN]

Ok so where is this ground strap normally. I know i missed it but I can't find it. If i get another ground strap i should just be able to ground the intake and that will work right? Also There is only one DIS right? So just the lower mounting screws on the one on the intake, corrtect? Also I have connected all the fusiable links to the power dist. box. This should provide the approiate power for them? The correct voltage should be 6 volts to the dis and thats across the outter terminals i believe?
Thanks guys,
Matt
Thanks Fred, I am contemplating the trade still just trying to get this going

 

[SHObill]

forget that silly stock complicated crossover tube ground path & just run a wire from the strut tower to the two lower DIS mounting screws. That takes the DIS ground out of the equation!

 

[rubydist]

SHObill's idea is easy to accomplish. The stock way runs a ground strap from the passenger side rear intake support bracket to the chassis right by the hood strut.

 

[SHOWGN]

Ok, I grounded the lower dis screws to the strut mount and i sanded the paint off strut support to make sure the ground was correct. I think my problem is that the key inside the car turns nothing on with the wiring harness as it is completly seprate minus the fusiable links comming from the power dist box. Where does the dis pick up its power from. Would it be possible to hard wire this threw a switch located inside the car and make an actual ignition switch? I am pretty sure there is no power getting to the dis but i am unsure where it gets power from.
Thanks all,
MAtt

 

[NovaSS]

Go to barnes and nobel and order " How to tune and modify Ford fuel injection" by Ben Watson.

The ECU get voltage in from two points, a yellow wire that is tied to ignition run / start and red wires that get 12 volts from the battery ( by way of a power relay)


The ECU supplies voltage to the DIS. The DIS controls the grounding half of the coil using 3 wires from the coil to the DIS . The grounding of each of these wires will fire a set of plugs. The DIS get it timing infofrom the crank and cam sensors.

 

[rubydist]

Ok, I grounded the lower dis screws to the strut mount and i sanded the paint off strut support to make sure the ground was correct. I think my problem is that the key inside the car turns nothing on with the wiring harness as it is completly seprate minus the fusiable links comming from the power dist box. Where does the dis pick up its power from. Would it be possible to hard wire this threw a switch located inside the car and make an actual ignition switch? I am pretty sure there is no power getting to the dis but i am unsure where it gets power from.
Thanks all,
MAtt

So you will need to do some more wiring - the pcm has to tell the dis to fire the plugs, and the pcm tells the injectors when and how much to spray - so you will need to include the pcm in your wiring....

 

[SHOWGN]

:thankyou: I will see if i can get that book, as it will probably be very useful in the future. I have the yellow and red fusiable links connected to the power dist. box on the wagon because that is hot with the ignition on. Which means the pcm is getting power, correct? I did however find a square red four prong recieving plug that is not pluged in with a solid wire going into it (6 volt switched from the ignition generally?) Should this be plugged into the power relay or is the power relay on the inside of the vehical?
Sorry if I seem dense guys,
Thanks for everything,
Matt

 

[projectSHO89]

Nothing under the hood should be 6 volts!

BTW, does your CEL come on at normal brightness when the key is turned to RUN? If not, you have a power distribution problem, not an ignition problem.

Got to the Electronics sub-forum. There is a stickied thread there regarding the IRCM/CCRM. In there is a comprehensive post regarding the inputs and outputs of the module. Several of those are critical prerequisites for the operation of the PCM and the DIS modules.

 

[1bad98SHO]

Check for a faulty ground at the Constant Control Relay Module (CCRM) pin 15 (BK/LG wire) or faulty power feeds on the YL wires to the Constant Control Relay Module (CCRM) pins 8 and 12.

Potential Causes:
Constant Control Relay Module (CCRM) Ground

Tech Tips:
To check for faulty power feeds and grounds, use the voltage drop method. Leave the Constant Control Relay Module (CCRM) connected, and connect a DVOM between battery negative and Constant Control Relay Module (CCRM) pin 15. If the ground is good, the DVOM will indicate less than 0.2 volts with the ignition key in the RUN position. Connect the DVOM in the same manner between battery positive and pin 8, then 12 and again voltage should indicate less than 0.2 volts with the ignition key in the RUN position.

 

[SHOWGN]

Ok so if theres no ground from pin 15 where is the ground located. Im pretty sure i missed a couple grounds and thats why im not getting spark. The ccrm is which module because Im pretty sure I took everything but its possible i missed the ccrm.
Sorry guys I seem like a total noob and I kinda am with the electronics so all of your help is greatly appreciated. I will check that ground asap.
Matt