NO CEL w/ key on and no spark?

[Mike621]

Originally Posted by Hocrest

I've seen fuses that look good, but are blown. Check them all with a meter.

Do you have another ECU you can swap?

Dave,

I am going to check fuse #16 EG IGN AIRBAG and the associated circuit, as I was able to get Erics car to duplicate the symptoms (NO CEL w key on and no start but fueling) with that fuse out.

I tried my ECU in Eric's car and the igniter. Both work fine.

[httrdd]

Did you try what I pmed you back?

[Mike621]

I tested the igniter and ecu on another car. The thing is that the ecu acts as if it isn't getting power. That's where I am going to turn my attention to next.

[Mike621]

Fuse 16 tested good (airbag/eg/ign). I put a test light in it's spot and it lit up but was dim. Not sure what to do next :/ reading the wiring diagram now but having a hard time understanding it.

[Cam]

Are you sure your battery is good? I was chasing electrical issues only to find ot my battery was toast.

[Mike621]

Car cranks fast. Battery was replaced before the test drive when the car had shut down.

[Mike621]

I really appreciate the help and time both Tom and John have spent in helping me diagnose the car. I just left CT, and the car. I'm still stumped, and waiting a day or two to hear back from one other person, but at this point I'm strongly considering selling the car as is, as I don't have the resources, time, or patience to deal with it any longer.

[TomsSVX]

Mike just took a just glance at the schematics... here is what I see and you should check.

The main relay is my key focus right now. Fuse 16 is only the ignition power to the ECM. if it does not have the "control unit power supply" voltage at pins 2 & 13 it will not function regardless.

The main relay takes power from Slow Blow Fuse 2 and sends it to the fuel pump relay and the main relay. So we can assume it is getting to the main relay... but lets not assume anything

Here is a relatively logical set of tests w/ their desired results

1. Check Slow Blow fuse #2. It is a 30A (green) fuse located next to the spare slots in the fuse box under the hood. You can remove the clear top and use a test light to check both sides of the fuse to ensure proper op. I would suggest using a voltmeter to confirm voltage values if possible. This should have +12v all the time.

2. Check Ground supplies to the engine ECM
- B59 pins 21, 11, 22, 14
- B61 pins 7,8
- B62 pins 25, 14, 15, 24

If these all check out follow the test sets

Test Set #1

A. Check for +12v at pins 5&6 at the main relay connector. You can unplug the relay to check this. This is to confirm there is no loss of voltage from SBF-2 to the main relay

B. Check for good ground at pin 1 at the main relay connector. This is to check the ground source for the relay's coil.

C. With the ignition switch ON check for +12v @ pin 2 at the main relay connector. This is to confirm the integrity of the ignition switch circuit to the relay. If this is not @ 12v w/ the switch ON see test 2A

D. Reconnect the relay to the connector

E. Test for +12v at pins 3&4 at the main relay with the ignition switched ON. This is to test the contact integrity internal to the relay to ensure it is passing voltage out.

If all of these check out OK then we can confirm the main relay is working properly.

Test Set #2

A. This test is only to be performed if test 1C failed. Locate the fuel pump relay(next to main relay). Turn the ignition switch ON. Check for +12v at pin 1 of the fuel pump relay connector. If there is +12v at this pin and not at pin 2 of the main relay, check the Diode in line to see if it has failed.
-The Diode can be checked by performing an ohm reading of the circuit. Using a DVOM check resistance between B60 pin 12 at the engine ECM and B62 pin 5 at the engine ECM. Also, with the ignition ON both of these pins should have +12v

Test Set #3

A. Locate connector B59 at the engine ECM. Yellow 22 pin connector

B. Turn the ignition switch ON and check pins 2&13 for +12v.
- if they have +12v then this concludes the power supply fault tracing
- if they do not have +12V and all previous tests passed, check wiring for breaks or high resistance. Continue with test set 3

C. Using a DVOM (digital volt. ohm meter) check resistance for the following cicuits

-Main relay pin 3 and B59 pin 13
-Main relay pin 3 and B59 pin 2

If all tests pass with expected values, we will need to start looking into other causes but I am pretty sure you will find the fault within these tests

Tom

[svxcess]

Originally Posted by Mike621

Just looking for additional opinions.

The Claret was out on its shakedown run with the new engine in, and all of a sudden shut off, and cranks, pumps fuel, but will not start.

When I turn the key to "on" the CEL is NOT illuminated as it should be.

So if the all the usual lights come on but NOT the check engine light, then these seem to be the only possibilities:

1. The CE bulb has burnt out (but I have never seen this happen)

2. Connections inside the the dash panel are no good (again highly unlikely)

4. Connection from dash panel to ECU is no good (again highly unlikely)

5. The CE lightwas out before this and had not previously been noticed or has happened quite by coincidence and has nothing to do with the problem. (not very likely)

6. It seems that the CE The bulb is NOT getting a negative connection to ground through the ECU as it should because the ECU (which tested fine when swapped into another car) or connections are bad, or the ECU ground is bad. This could account for the other things involved.

It seems that these are the only possibilities associated with the fault light not working, which is a most important clue, and are among the very first things to check out.



I have been going over the FSM wiring diagrams as well. If I am reading the diagram correctly, pulling the plug from the ECU and grounding pin d19, which has a red yellow wire going to it, should bring on the CE light. The other end of this wire is the blue multi-pin connector B41, which is under the driver's side dash. This seems very likely IF the problem is No. 6 above.

.

[Mike621]

Quick update: I will be going to the car this weekend to troubleshoot further using methods suggested by Trevor, and then going through the thorough list that Tom has made up for me.

Many thanks to Original Tom, John, Trevor, and Young Tom for the time and effort they have all put into helping me figure this out.

I will post the result after I see the car this weekend.

[SSSVX]

Keep us updated!!

[Green1995SVX]

Originally Posted by Mike621

Quick update: I will be going to the car this weekend to troubleshoot further using methods suggested by Trevor, and then going through the thorough list that Tom has made up for me.

Many thanks to Original Tom, John, Trevor, and Young Tom for the time and effort they have all put into helping me figure this out.

I will post the result after I see the car this weekend.

I'm gonna need a shout-out here for providing much needed moral support.

Just sayin.

[Mike621]

SBF #2 (Green 30A) underhood fuse keeps blowing. From what I can see, the yellow wire looks to be in good shape. I'm looking at the wiring diagram, and the main relay clicks when you turn the car on. Not entirely certain what to do next.

[Mike621]

This sums up where I'm at.

[Green1995SVX]

Does SBF2 still blow when connection 4 is unplugged?