bdubz94

I have an 87 fc purchased with blown motor. I bought another 13B from a friend but the motor is from an 88. I have fuel pressure to both primary and secondary fuel rails. One problem I'm having is t2 of my trailing coil will not spark. Changed whole pack and still no spark at t2. The motor has compression and I have tried unflooding it multiple times with no luck. Any insight will help

satch

iTrader: (1)

Switch the plug wires on the trailing and see if T2 fires and T1 doesn't. Also, are you checking for spark visually or not.

bdubz94

Already tried that still no spark at t2 and visually. I had the old motor running in this car before I did the swap so I assume the fuel and ignition systems are fine. I'd assume the car could fire even without spark at t2 but misfire yet it only cranks. Even with both the haynes and Chilton repair guides I cannot figure this out

satch

iTrader: (1)

The car should start and run just using the lead coil so maybe you have other problems as well. The coil/igniter gets its ground from being bolted to the fender. Maybe cleaning the grounding surface between the fender and mounting bracket will bring the coil back to life.

bdubz94

Been there done that hoping the same thing. Is there any possibility that using the 87 wire harness on this 88 could cause issues? I have the low impedance injectors in since it is an 87 harness.
I just checked resistance at the leading terminal, and both at the trailing so those check out. I've checked the main relay and all fuses. Along with I just restabed the CAS and checked resistance which checks out. Any procedure on checking the cpu?

bdubz94

Been there done that hoping the same thing. Is there any possibility that using the 87 wire harness on this 88 could cause issues? I have the low impedance injectors in since it is an 87 harness.
I just checked resistance at the leading terminal, and both at the trailing so those check out. I've checked the main relay and all fuses. Along with I just restabed the CAS and checked resistance which checks out. Any procedure on checking the cpu?

satch

iTrader: (1)

Is it possible that T2 of the trailing coil didn't fire in the previous car?

And did you use the resistor box for the injectors (needed for low impedance injectors).

bdubz94

Resistance box? I'm not familiar with this, typical location? All I did was pull the old motor, reused the low impedance injectors (off old motor), kept the 87 wiring harness and cpu. I had the water thermosensor conector and oil level sensor conector blow up on install due to being crushed :P thanks for bearing with me, this car is driving me crazy

bdubz94

And yes very possible old motor had coolant seal failure and ran like crap

satch

iTrader: (1)

If the water thermosensor connector was used then it's imperative that it be fixed because it helps decide how much fuel is used based on the engine temp (more fuel is used on a cold start than a warm start).

If the motor is new and everything else is old then the box would still be there if the car was pre 87.5. The box's location is against the passenger fender near the air box.

You could always unplug the coils and pull a spark plug from both rotor housings and w/key to start there should be a mist of fuel come out of each plug hole.

bdubz94

Oh yes. I checked that earlier, resistance checked out according to haynes. And only problem is that I don't know which wire goes to what side of conector so it's correct when plugged into the sensor

bdubz94

Also my tach bounces as the motor cranks, seems weird, I feel like most tach don't respond until the motor turns over.

satch

iTrader: (1)

The tach bounce indicates the trailing coil is firing for it controls the tach.

The Green/White wire at pin 2I of the ECU is for the thermosensor and it should read 2 to 3 volts w/key to on and engine cold.

bdubz94

Gonna test that in a few. Just curious is there any way to check primary fuel injectors spray pattern or volume?

satch

iTrader: (1)

Outside of the info in post #10 you would have to remove the primary rail and tie the injectors to the rail and spin the CAS w/key to on and watch them spray.

bdubz94

Alright, thanks just trying to rule out leaky injectors so I'm not chasing my tail. Anyone happen to know which connectors for the ecu harness are required upon start? I've looked everything over 10 times and still no luck. I get the occasional puff of exhaust smoke but other than that just cranks all day.