97 Crank, No Ignition (1 Viewer)

[uscmas412]

@FlyingDevil42 and I finished up his valve cover gasket repair. On the initial crank, she fired right up but ran rough for ~20-30 seconds and we turned it off. Subsequent starts have been unsuccessful and we also do not have a check engine light (MIL) with the key in the "ON" position. It's unknown whether the MIL worked on the first crank.

During the first start, a Prestone cooling flush kit was installed next to the heater control valve and sprayed water in the engine bay. The amount of water/pressure was equivalent to spraying the engine with a garden hose.

We accomplished the following troubleshooting steps, roughly in order:

1. Checked distributor cap to wire connections
2. Tightened grounds at battery and beside heater control valve
3. Confirmed Plug #1 had ignition by grounding it on the block at crank
4. Swapped EFI fuse and fuel pump relay with known working parts
5. Checked all fuses, all showing good
6. Replaced fusible links with new OEM part; removed aftermarket electrical connections for lockers/compressor
7. Swapped ECMs, still no MIL
8. Checked resistance at MAF, read 2.0; attempted to check voltage but we obviously don't have airflow
9. Inspected EGR harness below heater control valve. It obviously got wet from the leaking flush kit, but appears to be in ok condition. We let the vehicle dry for 7 hours to no avail.

We did not check fuel pressure at the regulator for two reasons:

1. During one of the cranking attempts a large spark occurred IVO of the distributor cap. From my POV looking at the cap from the DS, it occurred at the 3-4 o clock position.
2. We believe this to be an electrical issue due to the absence of a MIL

What does the brain trust think we should do next?

 

[BILT4ME]

The key needs to be in the RUN position to show if the CEL light works, not just in the ignition.

 

[uscmas412]

The key needs to be in the RUN position to show if the CEL light works, not just in the ignition.

Checks, I should have worded it correctly. I'll clarify the original post.

 

[inkpot]

You should get the CEL on with the key in and turned to RUN. If not then you have no power to the ECM.

 

[uscmas412]

You should get the CEL on with the key in and turned to RUN. If not then you have no power to the ECM.

I believe this is the issue, when the code reader is hooked up it doesn't power on either. Any obvious things to check that we may have disconnected while fixing the valve cover gasket?

 

[george_tlc]

Did you visually inspect fuses or pull them and measure with a meter (resistance check)?

You swapped/replaced a lot of stuff in your fault finding, I'd be checking every connector you touched.

I'd go back and check the fusible links again (and of course ALL the fuses, in dash and in engine bay). Big sparks are not a good thing...

cheers,
george.

 

[Tools R Us]

If all of the fuses are good, when the key is cycled off to run, does the EFI relay click each time? Need to get out the meter or test light, most often the problem is on the red/yellow circuit. With the key to run, is there power at the B+ in the diagnostic connector? If not, start chasing it back towards the EFI relay. A common connection fail is the red/yellow single wire connector near the distributor.

Is the main wire harness contacting the EGR pipe? It should be tied in place to the peg near the valve cover.

 

[uscmas412]

If all of the fuses are good, when the key is cycled off to run, does the EFI relay click each time? Need to get out the meter or test light, most often the problem is on the red/yellow circuit. With the key to run, is there power at the B+ in the diagnostic connector? If not, start chasing it back towards the EFI relay. A common connection fail is the red/yellow single wire connector near the distributor.

Is the main wire harness contacting the EGR pipe? It should be tied in place to the peg near the valve cover.

Harness is not touching the EGR, I'll check the diagnostic connector and red/yellow wire near the distributor.

 

[Tools R Us]

Harness is not touching the EGR, I'll check the diagnostic connector and red/yellow wire near the distributor.

I got that backwards, after the EFI relay it's the yellow/red circuit.

 

[uscmas412]

Am I doing this correctly? I assume I should be reading 12 volts?

 

[Tools R Us]

With the key to run, it should read close to battery voltage.

 

[uscmas412]

Key was in the run position when the voltmeter was hooked up to the diagnostic port. Looks like I'm narrowing down problems anyway.

 

[morganism]

is it still turning over?

run a ground wire from the coil/ignitor case to ground. See if the alternator output wire is heating up.

 

[uscmas412]

is it still turning over?

run a ground wire from the coil/ignitor case to ground. See if the alternator output wire is heating up.

Yes, still turning over.

Are the two steps you recommended related or separate? If I connect a ground wire from the ignitor case to a ground point, the alternator output wire should heat up?

 

[Tools R Us]

Yes, still turning over.

Are the two steps you recommended related or separate? If I connect a ground wire from the ignitor case to a ground point, the alternator output wire should heat up?

The ignitor is inside/screwed to the distributor that is bolted to the block. Don't see how you would get a ground wire in there or how any of this would help to get power to the ECU?

 

[george_tlc]

The ignitor is bolted to the body via a bracket and is near the driver's side fender - near the engine bay fuse block. Inside the distributor are the pickup coils that the ECU uses to determine timing to fire the ignitor that fires the coil that puts HV into the rotor on the distributor. The ignitor ONLY gets ground via the bracket/body (bit stupid, but it is what it is).

As per tools-r-us, first step is to determine why you have no B+ at the diagnostic connector. Don't get sidetracked chasing windmills

cheers,
george.

 

[uscmas412]

With the key to run, is there power at the B+ in the diagnostic connector? If not, start chasing it back towards the EFI relay. A common connection fail is the red/yellow single wire connector near the distributor.

To clarify, is the red/yellow wire a component of the EFI system? I located a single yellow/red striped wire harness aft of the distributor and visually it looks okay. Should I connect the voltmeter to it and test for 12v power?

 

[Tools R Us]

Oops, yep, was referring to the pickup, but still irrelevant to this problem.

Do you have power at the EFI fuse, both sides?

If no, the problem is between there and the battery, fusible link main, white wire connection have power?

If yes, is the EFI relay clicking when the key is cycled to run? Pull the relay, is there battery-ish voltage at term #2 in the relay socket? If all of this is yes, disconnect the single yellow/red connector near the distributor, voltage there?

 

[Tools R Us]

To clarify, is the red/yellow wire a component of the EFI system? I located a single yellow/red striped wire harness aft of the distributor and visually it looks okay. Should I connect the voltmeter to it and test for 12v power?

Red/yellow is the power circuit to the EFI relay, after the relay it changes to yellow/red. It supplies power to most of the EFI stuff, ultimately the ECU, if the power is interrupted not going to run.

 

[uscmas412]

Tested the EFI relay and it looks like there may be a lack of 12v power on one half. Pics of the testing:

Wiring diagram for reference/posterity.