well just bought a 88 TII that has been sitting around for awhile....things i need to get sorted out...its not firing on the leading or trailing side, ENGINE fuse is good and when i turn the key to ON the main relay clicks. i have 12 volts at one of the wires on the two prong plug at the coils. when i jumper the yellow fuel pump test plug on the pass side strut tower the fuel pump does NOT come on but when i turn the car over the fuel pump works. Also neither headlight works...they move up and down but neither light comes on....What could cause all of this? would a bad airflow meter cause this? i havnt checked for spark when the afm is unpluged yet....

thanx

 

When you jumper the yellow plug are you turning the key to "on" to check if the fuel pump is working?

 

yes key is in the on position

 

Thats a bit strange because jumpering the yellow check connector puts a ground to the brown wire found in the circuit opening relay which should cause the blue wire in the relay to send power to your pump. Might I ask how you verified the pump was working with the key held to start?

 

https://www.rx7club.com/2nd-generation-specific-1986-1992-17/86-tii-swap-wont-start-but-really-wants-887302/page7/

 

had the fuel line off the rails and ran into a bucket outside of the drivers door...so i crank the car over fuel starts pouring out...

 

ya ive seen that thread thats why i thought it was weird....maybe the wire off the check connector is broken in the harness somewhere?

 

Actually, the car needs to be running for the brown wire to receive a ground so that was my bad. My previous post was incorrect so disregard the circuit opening relay jumper insight.

 

Do you happen to have a spare CAS hanging around?

EDIT: Some people would disconnect the AFM and attempt to start the car.

Also, opening the flap on the AFM will place a ground signal on the brown wire and cause the pump to work with the key to on.

The fuel pump check connector has two wires and besides the brown wire the other is a constant ground so that constant ground might not be grounding properly as a cause for the jumpering trick at the yellow plug not working as designed. Either that or as you surmized that there is a break in the harness wiring involving the brown wire.

 

does the yellow check connector have anything to do with the coils not firing?thats my main problem because thats all i need for the car to start because the fuel pump works when i crank it...also would it make a difference in grounds if the ecu isnt bolted down in the pass. side floor? its jst sitting on the carpet right now....

 

There shouldn't be any relationship between the check connector and the coils unless the ground wires of the ECU are not properly grounded. The circuit opening relay has two coils in it used for closing the relay and allowing the blue wire to pass voltage to the fuel pump. One coil is for starting and the other coil is used for when the car is running. The coil which you have working is the one to start the car but not to keep it running. The relay requires that the brown wire receive a ground and that only occurs when the car is running.

EDIT: If you could get the coils to fire and the brown wire wasn't providing a ground when the car is started it would die out quickly. You could jumper the black constant ground in the circuit relay to the brown wire but this would only prove the brown wire is not receiving its proper ground from the AFM. The brown wire from the AFM is channeled to the circuit opening relay via the fem-02 connector located by the ecu kick panel. As the wire comes from the AFM it is part of the emissions harness and the brown wire at the circuit opening relay is part of the front harness so they connect at fem-02

The check connector black wire is a ground and is connected to one of the grounds that comes from the ecu. You need to check the condition of these grounds. The ECU does not need to be bolted down to create a ground but the ground wires which come from it definitely need to be grounded.

Also, pin 2A on your ECU needs to indicate approximately 5 volts or the ECU will not fire the coils!

 

edited out. Just a repeat of the above post.

Try this. Go to that yellow two socket connector. Find the BLACK wire. Get a piece of wire bare at both ends. Put one end to a known gnd point like the bracket for the boost/pressure sensor. Then put the other end into the yellow connector where the BLACK wire is. With everything connected up. spin the engine and watch the tach needle. Did the tach needle make small bumps up/down? I'm guessing if you gnd that black wire it will also gnd the ECU internal circuits and the ECU will now make spark.......proving the ECU gnds need to be fixed on top of the engine.

And or just put the new wire into the yellow connector where the BROWN wire is. Does the pump run with key to ON now???????? Should. If it does and didn't without that new wire inserted into the socket, then the ECU gnds are disconnected at the engine imho.

Anyway........cars broke

We're saying........it's not that we're trying to make the pump run with the yellow connector jumpered.......we're proving whether or not the ECU grounds are......grounded or not. Pump matters not at this point. ECU needs it's internals to be grounded in order to pulse a signal to the coils and injectors. Make sense? Say yes.

 

Go look in the passenegers foot well. Look up and to the far right for two ORANGE in color plugs. Are they both connected up or not?

 

one of the orange plugs above the ecu was unplugged...the leading coil fires only when the afm is unpluged now but still nothing from the trailing coil...it has 12v at both the positive and negative prongs of the trailing coils also has 12v when i put the positive lead on the outside of the igniter caseing.....i also took sandpaper and cleaned up the all the grounds and replaced the one from the transmission to the firewall because it was fried...

 

The coils ground out via being bolted to the fender and the trailing coil only receives a ground from the ECU through the wire coming from pin 1X. The trailing coil receives 2 B/Y wires and both should contain 12 volts.

 

hmmm well they both have 12v going to them....if i just had the coils sitting on there bracket and not bolted down to the fender would that make a difference? also the fuel pump comes on when the test connector is jumpered now that i cleaned the grounds up....

 

The coil assy internal electronics get their gnd from the base of the coil assy's making contact with the chassis. Gotta have at least one fastener holding the coil assy's to the chassis or...........no spark. It's not so much the coils themselves but the ignitors in the assy that need to be grounded.

 

I believe there are two coils in the trailing coil thus requiring two voltage wires. And good news on the fuel pump but we want more!

 

hmmm well i can try to pull the bracket that holds the trailing coil assembly out and sand the contact points and bolt it all down and try it that way because the car sat without a hood with no engine for like a year so all the little brackets and stuff are rusted pretty good...

 

well ive tried all the above, the car runs decent but nothing from the trailing coil....i replaced the coil with two different ones i had around and still the same,,,,

 

With the plug connected, Pin 1M (L/R) should have below 2 volts either with key to on or car idling. Pin 1U (BR/Y) should have 4.4 volts with key on and 2.2 volts with car running. Pin 1X (L/Y) has 0 volts with key on and close to 1 volt while idling. All three of these wires run from the ECU to the trailing coil.

 

ok ill give these a look tomorrow..also one thing i noticed is with the car running the tach seems to vibrate on 0 a little when i rev it and moves a little sometimes....

 

still havnt got a chance to look at the ecu pins....but one thing ive noticed now is that with the key on the fuel pump runs all the time now its like i have the yellow test connector jumpered...what could cause this??

 

anything? what would make the fuel pump run all the time when the key is on?