oldgoat

Second that, a hairline crack in the old brittle tubing causes all kinds of trouble.

Take a look at the ID of the CA bushing dimension vs. the OD of the bolt, is there a steel sleeve inside the bushing? If the clearance is too great you will get a clunk as the control arms move.

I can promise that the tester at O'Reillys is not accurate. Over the years I have grown to not trust "testers". Real life is the best test.

Oh yeah, that was one of the first steps. At that point I could get it to start once in a while after prolonged cranking. That made me think CPS signal was weak. Installed new CPS, discovered existing was fairly new. Same story. With a used ICU/coil it lights up on the first crank.

I solved the riddle, drum roll please............... ICU, swapped from running Cherokee, lit right off first hit. I also discovered that the scanner I was promised would work, won't. Now on to the next.

Yesterday I removed the entire Renix wiring harness and laid it out on the bench. I stripped off all of the convo tubing and tape. I discovered that someone had previously done the same thing since all of the gang connections were wrapped in duct tape. I did validate each wire for continuity and cleaned all of the connectors and re taped and wrapped the whole thing then reinstalled. Still no fire. I went back and validated all of the fusible links at the starter relay. There is 12V getting to the ECU with the switch on and in the crank position. Tried to start again. Still cranks, no fire. It appears that it is either the ICU or the ECM. Interesting , the ECM has been replaced with a Cardone reman unit. I am checking with the guys I work with for a known good ICU. It is confusing that after the problem manifest I have been able to get it to start sometimes and not others.

Cruiser, I don't find the C101 that everyone refers to. Should I ?

Pretty much all applicable. I did remove the ECU and took it apart. I see one chip that has what might be a white burn bubble on it. I am going to see if I can test it tomorrow. I also found an abraded wire in the bundle from the ECU going out the bulkhead. Obviously lots more testing before I go any further.

We have a diagnostic code reader that will interface with the Renix. Are the readings reliable?

I forgot to mention that I have never seen a "Check Engine" light come on, ever. Also discovered that the FP relay has been bypassed in the harness for some reason. It is direct wired to an Ignition on terminal at the fuse panel. The 2 orange wires to the pump are ganged together with the 12v hot signal. right next to the resistor. Do you think this could have created a back feed to the ECU causing a problem? I have yet to determine why the FP relay was by passed. I wonder if the ground signal from the ECU to the relay is dead? More wiring to validate.

So it just keeps gettin better. Yesterday morning tried to start - dead. Came home last evening to pull the ICU to have it tested - Started right up. This morning - Started right up. Took the ICU to have it tested. Tests good. Brought it home hooked it up - dead. How can I test the ECU - I wonder if it is shorted internal on the ignition output side. The injectors don't fire which tells me that either I don't have a tach signal from the ICU or the CPS signal doesn't process in the ECU.

CPS is varying from .42 to almost .6 after I readjusted. I get absolutely nothing for coil output. The Yellow to coil + shows battery voltage. I did put a test light from the yellow to the green/white which I believe is coil signal from the ECU. I don't see a flash in the test light while cranking.

Is there a way to test the ICU? Truck started just fine this morning, I went about 1.5 miles and it shut off just like you turned off the switch. Won't restart, no fire at the coil. I have fuel. Pretty much the way things progressed last week. Any other ideas?

I probably have a 1/8 npt x 1/8 or 3/16 nipple in my brass collection. If time allows tomorrow I will perform the mod. Tomorrows big plan is really to work on finally re-doing the audio system in my GTO.

I will check that this weekend. Are the rubber blocks that the MAP tube plugs into at the TB available. The one I have is less than great.