wvumtnbkr

Good Day!

I can't seem to get spark on my girlfriends 87 GXL. We bought the car as a shell with some of the wiring in the car.

We are using the Coils, AFM, CAS, and all other items from my S4 NA.

I have checked the leading coil and all fuses (including main relay). I have also checked the CAS. I have used all of the above on my running S4 TII. THey all work!

When I have the key to run on the ignition, and I turn the CAS, I get no spark! THis same procedure works on my car with all of the same equipment.

I can't figure out what is going on! I also tried to unplug the AFM (as per some members suggestions). No sparky!

All items are plugged in on the CPU.


Any Ideas??!!??

Also, I have one black wire with white stripes and one white wire with black stripes that are in the engine harness. They go towards the firewall on the passenger side with all of the rest of the engine harness. They are not connected to anything.


Thanks for any help!

HAILERS

The power that makes things work.....goes from the two EGI fuses in the engine bay.........to and through the MAIN RELAY...........to the coils and to the fuel injectors and ECU's small plug.

Plus you need the ENGINE fuse in the interior to be good so it can pull in the Main Relay and the Circuit Opening Relay.

The black/white and White/black are probably the two wires that go to the small plug on the alternator.

If you can hear the fuel pump run with the key ON, and the yellow two socket connector jumpered, then the ENGINE fuse is good.

If you see the tach needle do little tiny jumps when the key is put to START, then you are getting spark at least to the trail coils.

You need a meter to be sure your getting power to the coils and to the small plug on the ECU.

wvumtnbkr

Thanks for the clarification. We do have the fuel pump running. I will check for the 12V on the lead coil.

There is no spark on the trailing coils either.

I have been searching for the diagram of the ECU plugs to no avail (I never find it when I need it!) Which wire on the small ECU plug should have power?

Thanks!

Do N/A's have the circuit opening relay? <-- this is something I have never had to deal with before.

wvumtnbkr

Okay, I checked for voltage on the leading coil. We have 12 V with key in the run (on) position.

All fuses check out with a DMM.

I have also regrounded everything including the coils (a wire was run from the base of the coil to a common grounding distribution block I added.)

Mobius

could you snap a few pics?

I'm curious about the b/w wires runnng up to the passenger side harness. It seems like a bad coil. Car is old.

Coil might return: 12v on the dmm

But really, the coil Might return 0V in reality.

DMMs don't always tell the truth behind an electrical event

wvumtnbkr

I checked all of the following in my running car and had no problems with the relays, CAS, AFM, or coils.

They all check properly with the DMM and WORK in my RUNNING car.

Thanks!

HAILERS

The black/white, white/blue and all the light green/black, light green/red, light green/white and just light green wires should have power with the key ON. Small plug on the ECU.

All the solenoids have one black/white wire and it comes from the EGI COMP fuse. So if you have that then the Main Relay is pulling in. The black/white wire for the alt comes from the ENGINE fuse. The white/black wire for the alt will show voltage and it comes from the METER fuse via the alt relay in the CPU. That's the ONLY white/black wire I know of in a series four car.

Check those wires at the small ECU plug.

IF the voltage is at the ECU on the small plug, the only thing I know of that would prevent spark and injection pluses is if the REF VOLTAGE output of the ECU on pin 2A is NOT 4.5 to 5vdc and is being pulled down by one of the sensors in the engine bay i.e. afm, tps, boost sensor, and the others with a brown/white wire in their plug. See FSM wiring for those sensors.

Both the Lead and Trail coils both failing is a unreal and impossible situation.

Plug off b/t the CAS and the ECU could also cause no spark/no injection pulse. Ring the wires out at the ECU thru the CAS.

YOU say you have a black/white and a white/black wire hanging around on the harness. Do you have any wires going to the small plug on the alternator ...or not. Won't keep a engine from starting if they are not there, but what's the deal?

wvumtnbkr

i got the harness with the engine. The car had NOTHING in the engine bay when we bought it. The harness had those two wires just hanging. The engine and harness was going to go in an FB. There are wires on the alt. However, They may not be connected on the other end.

wvumtnbkr

Does the CPU (by the drivers feet) have anything to do with spark? The logicon (2 of them) and the blower motor don't work either (I thought they are also controlled through the cpu).

HAILERS

CPU, Logicon have nothing at all to do with spark or fuel.

Post #7 needs to be looked into.

wvumtnbkr

Thanks! I was just wondering if it is possible that they are related (some major electrical issue)

What does "ring out the wires at the CPU to the CAS" mean? Do you mean check for continuity?

Also, to clarify, do you think the two wires that are not connected have anything to do with the no spark situation?

HAILERS

It means ohm out the CAS's coils by going to the ECU and pulling the large plug off the ECU. Put the meter on ohms. One meter lead on pin 1P and the other lead on pin 1N. The reading should be the same as when you do the same thing to pins 1T and 1O.

If they ohm out then the wiring b/t the two is good and forget about the CAS being the problem.

Go see if the small plug on the ECU has voltage on the two wires on the far left and all the light green wires have voltage.

Those other two wires should have nothing to do with spark. Not connected to anything are they? And I still know of only one white/black wire and it's for the alternators small plug. Something is screwy if the alt already has a small plug on it with a black/white and white/black wire already. Makes no sense. Unless this car is a Turbo car (unclear to me if it is/isn't). The turbo car gets its alt wiring from the Engine harness unlike the n/a that has the alt wires in the EM harness.

Something is odd here.

SirCygnus

iTrader: (1)

check the airflow meter. unplug it, and crank the car. if its a bad AFM, the car will fireup, run at 3k rpms for like 10 secconds, then die.

the airflow meter cuts spark as well.

HAILERS

You've already tried the major componets in your working car, so it has to be some wiring problem. The harness on the engine is suspect to me because you saythe alt has wires on it but you have two other similar wires just laying about on the harness.

I suggested the ohming out of the cas wires to prove the wires b/t it and the ECU are good. I know you already swapped CAS and spun the cas with the key to ON with no results.

Where are these two wires laying on the engine? The B/W and W/B??

A bad AFM can kill spark by killing the REF Voltage signal on its brown/white wire. But you've already tried disconnecting the afm plug with negative results. Other sensors besides the afm also have the brown/white wire that has the ref voltage. They also can kill the ref voltage signal inside the ECU therefore no spark.

If you had a meter, you could pull the plug off one of those sensors and see if the brown/white wire in the plug has appox 5vdc or not. The boost/pressure sensor is easily accessed and it takes but a moment to disprove that as being the problem.

wvumtnbkr

Sorry for the long delay! I got sent to Germany for a few weeks unexpectedly. I am back and have some test results.

I ohmed out the CAS wires. All were good and had continuity. After checking the continuity, I checked the values. Pin 1N (green), pin 1P (blue), pin 1Q (White), and pin 1T (Red) all showed .57 volts while the key was in the on position.

I confirmed that the two wires "hanging out" in the engine bay are the alternator wires. They are conected to the alt, but hanging loose on teh other end.

Finally, I checked the plug "3" on the ecu with the key in "on" position. SOme of the values were interesting.
Pin 3C is 13.6v.
Pin 3D is 2.5v.
Pin 3E is 13.6v.
Pin 3F is 13.8v.
Pin 3H is 13.8v.
Pin 3I is 2.6 v.
Pin 3J is 2.6 v.

Obviously the battery is fully charged (13.8v on all injectors). I am concerned with the voltage on the Fuel pump resister relay (3D) and both the battery voltage (3J) and the main relay voltage (3I).

Any help is appreciated!

Rob

HAILERS

3I is very important and should show batt voltage. 3J is not required to start the car, and IF memeory serves gets fed from the Room fuse. Not worth looking into.

There is but one connector b/t the Main Relay and the 3I and it's underlined in BLUE in the jpg. It's one of the ORANGE in color plugs in the passengers foot well and that plug carries many more wires. I think about fifteen wires or sixteen wires.

So pull the plug off the MAIN RELAY that has four wires in it. See if the W/L wire coming from the EGI COMP fuse has batt power or not. Should with key ON.

If it does, then leave that four wire plug off the main relay. With a piece of spare wire, jumper b/t the W/L wire and the Black/White wire in that plug. THEN go to the ECU with the key ON and see if the 3I has power or not. IF it does, the main relay MIGHT be bad or at least one set of contacts inside it.

IF you backprove 3I and it has marginal power, then pull that plug off the ECU and see if the plug has power on it now. IF it does, then it's the ECU that's pulling the batt pwr down to ?? 2vdc or whatever you said you have.

Back to 3J. It gets fed from the Room fuse via the BTN fuse in the engine bay. Make sure the BTN is good.

wvumtnbkr

I checked the W/L wire at the main relay. It had battery voltage with the key to on or off. I jumpered it to the Black/white wire. The pin 3I had the same voltage as before (2.5v). I took the plug off the ECU, and the voltage went DOWN to .75 volts.

Next, I disconnected the large blue connector behind the dash for the interior wiring. I was doing this for another reason, and just happened to look at the DMM. THe voltage on pin 3I went down from 2.5 v to 1.5 volts.

I am wondering if there is a wire crossed between the chassis harness, and the engine harness.

The BTN fuse has full battery power across it.

wvumtnbkr

I also checked the plug that you described. It is plugged in and in good condition. However, I am thinking of taking the electrical tape off of the wiring to and from this plug and check for any issues.

HAILERS

Something is seriously scrogged on the wiring. There is but one connector b/t the MAIN FUSE's black/white wire and the ECU.

That connector is called FEM-02 in the jpg I attached earlier. IT is ORANGE in color and located in the passengers foot well up and to the far right. It has thirteen pins/sockets in it.

I mention the thirteen sockets/pins because there is another ORANGE in color plug in the same area, but I think it has fifteen pins/sockets.

So. Find the FEM-02 and unplug it from the EM harness. Put the key to ON and see if the BLACK/WHITE wire has batt voltage or not. Should if the main relay is plugged in or jumpered as I described before. There are three black/white wires in that plug. Make sure they all have batt voltage. IF one does not, describe which one it is.

wvumtnbkr

None of the wires show anything over .75 volts. This is the same voltage that I had when I unplugged the connector from the ECU.

However, I wanted to make sure I was checking the correct side of the plug: I checked the side of the plug that had the 2 B/W wires and the one B/L wire.

Is this as simple as running a new wire from the main relay over to this plug?

wvumtnbkr

I did some further testing. None of the black wires from the FEM 02 plug show continuity from the B/W wire from the main relay.

However, they all show battery voltage when using the main relay as the positive and the black wires on the FEM 02 plug as negative.

What I did was this: I attached a paperclip to jumper the main relay between the wires you suggested earlier (W/L and B/W). From that paperclip I connected a long wire that I ran to the passenger side foot well. I then used this wire to check for continuity between the 3 wires on the FEM 02 connector and the B/W wire that comes from the main relay.

None of the B/W wires showed continuity, but when I changed the meter to read DC voltage, they all showed 14+ volts. I had the positive lead on the wire from the main relay, and the negative lead from the meter to the connector wires.

I think I have a wire going to ground.

Any other thoughts or suggestions?

HAILERS

BLACK wires with a WHITE stripe are power wires.

In GENERAL, BLACK WIRES are grounds wires....... but on a series five not always so. You have a series four so the pure black wires are ground wires.

Never check continuity with power on the wires or key ON. A general rule.

If you have the relay jumpered like you say, then just put the meters negative lead to ground and the positive lead to the black/white wires in the connector with the meter on dc volts. Should show batt voltage. IF so, good.

Which of the black/white wires in the FEM-02 have batt voltage on them when you check it out? Actually two of them should and the third one not (that one gets batt power only when the key is HELD to Start).

FEM-02 has to sides to it. That would be the FRONT side of the plug(s). IF you look into the WIRE side of the plug, you would have a Light green/Black wire and a Brown/Yellow wire on the left end of the plug.

The other half of the plug, when you look into the WIRE side of the plug, will have a light green/Black wire and a Brown/Yellow wire on the RIGHT side of the plug. That half of the plug is from the harnesss on the engine who's name is the EM harness. You won't find power on that side of the harness if it's disconnected from the Front half of the plug.

Anyway, two of the black/white should have batt power on them if you put the meter to a ground like the ECU bracket and put the meters positive lead on the black/white wires contact in the plug.


EDIT: I see now. You should NOT be checking the plug with just two black/white wires. That is the EM half of the plug and it goes to the harness on the engine and cannot have any power.
The power is on the FRONT side of the plug with three black/white wires. IT goes to the main relay.

wvumtnbkr

Okay, I understand now. I will re-check the plug.

Ayes

iTrader: (1)

hows the wiring between the CAS and ECU? i had weird fuel and spark issues up until i ran 4 new wires from the CAS to the ECU and that fixed the problem

wvumtnbkr

here we go...

From Left to right (looking at the wire side of the plug), my plug colors are slightly different.
The top row is:

Y/B B/W L/R open B/W B/Y BR/R

Bottom row is:
BR/Y B/W B/R BR Open B/Y G/B

basically, I am missing the 5th wire on the bottom (from Left to right on the front harness side). It is missing from both sides of the connector(s) (EM and Front harness both).

Also, you may notice that the wire colors are different than what is described in the excerpt from the FSM that was posted.

There is also a B/R wire cut on the EM harness side of the plug. It is the 3rd wire from the left while looking at the wire side of the plug.

That being said, the B/W wires (2nd from the left, top and bottom, and wire side of plug) both show battery voltage. THe B/R wire (should be B/W according to FSM) that is the 3rd wire in on the bottom of the wire side of the plug shows no voltage.

Any ideas?

Need me to clarify?

Thanks!

Rob