I need some help. I have installed a replacement engine in a car for someone else. The car is an 86 I believe it to be the base RX-7 with the luxery package. It has an auto, A/C and manual steering. There are no bins as well. Now for the major problem(s): The car will not start. I cannot get fire from the coils. Please help me to find the culprit.

 

I don't understand. People asking the dumbest ******* questions get 50+ responses. I guess nobody knows how to fix an RX-7 huh?

 

I will document the problem so that this can be in the system. I searched and came up with nothing useful.


I currently have 12.46 volts (static) I try to start car and no spark.

I have replaced the spark plug wires. I try and no spark.

New leading plugs and still no spark.

Checked resistance of leading coil: 0.7 ohms. The consensus is, the coil is good.

Well, the first problem in diagnosing the problem.
"Testing the ignitor assemblies requires special equipment and is therefore beyond the scope of the home mechanic. Take the vehicle to a dealer service department or other qualified repair shop to have the ignitors checked."

Testing the CAS: G1 and G2: 168.2 ohms, within specs
Ne1 and Ne2: 168.8 ohms, within specs

 

A little more detail would be helpful.

 

check for codes?

 

Car has never started since engine install. No codes would have been stored in the ECU.

 

Did you replace the coils or use the existing one from the old car?
You may want to check all the electrical hook-ups at the Distributor and at the coils.

 

I have performed the tests for the actual ignition components, so it's obvious the problem is in the wiring. I will begin by cleaning CAS connector and leading coil connection. and then update.

And to clarify, I have tried leading coil assy from my spare parts bin. My spare stuff is all S5 though but it is the same coil.

Cleaned the previosly mentioned connections with contact cleaner and jewelers files.

 

The engine does not have to have actually run for a code to show up. That's a known.

You have not stated whether or not there is batt voltage at the black/yellow wires at the lead coil plug.

You have not said whether or not you have spark or not, fuel or not, whether the tach needle bumps as you try to start the engine, whether or not the engine fuse is good or the EGI COMP/EGI INJ fuses .

 

HAILERS, thanks for the help, although I think you need could stand to learn to read the thread.
As far as fuel, it is irrelavent at this time.

Concerning the tach, I get no bounces.

EGI/COMP fuse tests good. I also get 12 volts on the left leg to ground on the underhood fusee block.

 

no voltage at the leading coil connector. Tested continuity from connecter at coil to connecter at ECU and it tests good. ECU bad????

 

Right now it seems that either the ECU is defective or not getting power. Any suggestions?

 

The black/yellow wire at the two socket, white plug at the lead coil should have 12v.

The 12v comes from one of the EGI fuses and passes thru the Main Relay to the coil. The engine fuse pulls in the Main Relay to feed the coiil assy.

So the EGI fuses have to be good. The engine fuse has to be good and all the connectors have to be connected.

The ECU is not the problem if you don't have 12v on the black/yellow wire.

 

Alright, I get 11.49 volts from the Black/Yellow wire to ground. So, I misunderstood the schematic. Why am I not getting spark?

I was testing Green/Yellow to ground and getting nothing.

I still get no bounces or spark and am now confused. What about the main relay?

 

The Main Relay is good because you got batt voltage at the black/yellow wire at the coil. I wouldn't be messing around with the G/Y trigger wire.

The Engine fuse is good also if you got batt voltage at the coil.

The only thing I can think of right away that could cause this problem, is...............the ground wires for the ECU and it's internal components, is actually located on top of the REAR ROTOR HOUSING. It is two wires in a *ring* terminal bolted to a boss on the REAR ROTOR HOUSING.

You really don't have to dismantel the engine to figure out if it is bolted down or not. Go to the small ECU plug and with a meter, see if the two pure black wires on that plug are grounded or not. If they read less than say 1 ohm, that should be good enough to start that engine.

The ECU is probably getting pwr since the coil is. But you might check that small plug on the ECU and see if it's getting batt voltage also. I believe one wire is black/white on the far end and it should be batt voltage. I've no diagrams with me. The online fsm, fuel section has a section called Control Unit and describes each wires input/output.

 

One way to check the health of the ECU is to pull the plug off the pressure sensor on the right front strut tower. See if the brown/white wire on that plug has approx 4-5 vdc or not. It shouild. If it is say 2 volts or less..........bad.

 

Thanks Hailers. I was getting ready to disassemble the intakes to verify the grounds. I had suspected that it might be a possibility earlier. I will look again in the morning. As far as the ECU thing, the kid has one that is missing the covers, I wondered if one of the two he gave me are fried (if not both). I appreciate your help and understand that some of these electrical problems can be difficult, especially when it's someone else's car and you aren't sure what was done to it before. For example, I am also going to remove a horrible car alarm install. All the wires seem to tap into the CPU with those Scotchloc connectors. Plus a couple of the alarm control units were empty. The owner suspects to hide drugs in the broken car alarm. I was going to suspect the shitty alarm wiring but the owner confirmed that the car ran before, just on one rotor.

 

Still at a loss. 34.8 ohms, so I ran new wires to ground and still no fire.

 

check the 4-5vdc on the brown/white wire at the pressure sensor on the right front strut tower. Just pull the plug off to check it. Plugs on the bottom of the sensor.