355 5.2 No Start Issue

After 9 months of resealing/restoring the engine/engine bay, replacing the clutch, etc., I have a no start issue. Here's some important background. I was having intermittent, slight misfires when hot, and a CEL related to low voltage on an O2 sensor. It turns out that a previous owner had messed with ECU wiring harness and connectors. Initially I only discovered the bad O2 connector crimps, but was still having issues and reviewed the service records, finding that a PO had attempted to install the gold connector kit. I then pulled off the boots on the ECU harness and found 50% or more of the crimps were done so poorly, the wire pulled out of the connector easily by hand. I then looked at the main connector to the ECU, and it was done just as poorly, but the PO had used "liquid electrical tape" to try to prevent any shorts from occurring as he had left bare wire exposed at the end of the connectors. I couldn't remove the wiring from the ECU connector, and so I ordered a new harness, as this thing was such a mess at this point, it wasn't worth dealing with. Image Unavailable, Please Login
With everything reinstalled again, the car will not fire, but will crank. It will not give an indication that it will or start quickly then suddenly and die. Here's what I have done so far in trouble shooting after reading no start issues. When key is in position 2, proper lights appear, CEL, brake, slow, down, etc. Immobilizer turns the LED off upon hitting the button, but upon cranking it is solid red.

1. Fuel pump seems to be okay, I measured the draw upon crank and there is a short amp spike which appears to be consistent with the pump priming. There appears to be pressure at the fuel filter in checking the relief valve, although I have not checked the actual pressure.

2. I measured 12v at the injector connectors, but using a noid light, it does not blink when cranking.

3. Swapped crank sensor just in case with a new one I already had. No difference.

4. I double-checked the ECU wiring diagram with the connectors on the new harness for continuity, and there does not seem to be a problem; I get continuity.

5. Checked ECU ground to battery, chassis ground to battery. Seems ok.

6. Camshaft sensor and knock sensors are brand new.

Am I missing something? This seems like an ECU issue rather than a fuel issue, but I defer to the experts here.

Todd

 

Mine is 98 manual, just to be clear, similar to yours with a starter relay. My car will not crank unless immobilized like yours.

I will check the fuel pump current again.

Re the brown wires - This is interesting, which wires were swapped over? What needs to be reset in the immobilizer ECU?

You might have received the same harness without any colored connectors, like I did. I replaced all those all-black (and unsealed) connectors with either brand new colored connectors or, if not available, such as the blue 3-prong connector, I used the connector from the old harness and swapped out the seal from the new one so that it would be easier to identify in the future. I believe the blue connector was the only one I could not find a replacement for.

I did check the wiring on the blue cam sensor, crank sensor, knock sensors, idle sensor, injectors and coils, just to be sure and I get continuity. Have you updated your chart recently? I have version 35.

Any other thoughts here?

Thanks very much for your help!

Todd

 

I went back and looked at your chart and saw that pins 8/9 on connector 41090 are in fact swapped on the new harness like you said. Wild. Swapped them, and it fired right up. Amazing sir, you rock!

Todd

 

Ran it to temp to allow the fans to kick in, ran perfectly, no issues at all. No CEL. I am hopeful this new harness solves all of the gremlins this car had. Ian's answer saved me hours and hours - thank you again!