I do hear minor exhaust sound in the passenger side, but I have made sure the exhaust manifold and flange are tight (while it was cool but running... No small feat).

Codes are now p1300, p0208, p0308, p0304, p0154, p0300, p0304, p0135, and p0155. The connections to the front o2s are clean and snapped together. Recall that the #8 injector has been swapped and I have checked the wires to it with a test light and the contacts on the injector with an ohm meter. Of course I have swapped the coils and put new wires and bosch +4 platinum in. I did a compression test. I have replaced the HG. Squishing and gently moving the main harness (along the firewall) randomly while it is running does not seem to make a difference.

I am stumped. The codes have changed so much, and always right after some operation on the top end, I really wonder if it is wiring. Further, All of the problems I have had must have affected the cats. Maybe I have low compression on 8 and 4. I don't know anything about crank sensors but I do know what the look like and haven't done anything crank sensor wise. Can anyone else come up with anything?

The drivers seat affect of the codes above is rough idle, hard start, and raising the rpms is followed by a short hesitation. The rpms go up a but then the engine bogs and of I let off the accelerator a bit the rpms continue to rise. So, if I was driving down the street, I would start, feel it slowing down, let off the gas a bit, and it would continue to accelerate very slowly. If the ses flashes, I let off the gas entirely or switch into neutral, then after a couple of seconds the ses stops flashing but stays on.

Why would the new oxygen sensors and heaters show no activity when I know they are there and plugged up (snapped together? When I reset the codes and let it idle, the first things that come up are cylinder 8 misfire and o2/heater codes (sometimes for the front ones, sometimes for all of them).

 

I had a problem with misfires under acceleration as well. Mine was solved by replacing the coil packs. Also you should run the engine in the dark to verify that you cannot see any electrical arcs that might come from a plug boot not being fully seated or the plug wire has not melted from touching the block.

 

Thanks Matt. I swapped the coils for another set I have and didn't see a change. It is possible that I have two bad sets, but maybe unlikely. The spark plug wires are only a couple of days old (driving time) and I even constructed an elaborate Web of zip ties to keep them from touching each other or the block, as an experiment. But I am going to get on the engine and make sure the Web of zip ties is still doing its job. Appreciate your contribution!

 

In the datastream all of the o2s show point 440 volts but none of those values are changing.

I checked fuse number 2. It is good.

How can I check for a grounding problem? I know the strap and the ground at the alternator and at the front passenger corner of the block are good. There is a hoop in the harness by the driver side coil connection that is hanging free. I am not sure whether that is just to secure the harness or it is a ground, but I suspect the former.

 

Fuelsys1 and 2 stay open even after 30 minutes of idling. Pressing the skinny pedal gives a small rpm rise then retards, then I let off a little and it continues up. All o2s showing codes.

I've been reading that there is a common circuit between all of the o2s. Maybe that circuit is broken somewhere.

I still hear the rattling that is strongest at the driver side cat, but it gets less as the engine warms up.

Leaving alone the rattle for the moment, is this how an engine behaves while it is waiting for the oxygen sensors to warm up?

 

Sorry to hear you are still having issues. I can't remember, Have you done a fuel pressure test yet?

 

I haven't done a fuel pressure test yet though I did locate the spot to do the test (back of the intake).

I cleaned the o2 sensor contacts then put dielectric grease on them and they still did not register present (same o2 codes and heater codes for all 4), so I grabbed my old o2 sensors that did not have a heater problem and they suddenly had all of the same issues. I'm reasonably confident that my wiring harness is the culprit.

I do have my old wiring harness and I am going to swap them out tomorrow.

My guess is that I have not been nearly careful enough with my wires in the multiple operations I have done. For instance, I was getting a code for my number 8 injector. Tired, I just reached my hand around the back of the intake and jiggled the wires, and it came to life. All 4 o2s being out (only a week after install) really doesn't strike me as possible. The HG leak and misfires probably cooked and clogged my catalytic converters, and as I have flailed about the wiring has taken some abuse. The final straw was when my entire driver side bank of cylinders went out. I piddled with the wires a bit but didn't swap anything other than the coil (which really couldn't have been the cause, but I had the extra and wanted it back in the truck), and they started working.

So, either there is a very poor ground somewhere or a broken wire. Some fault somewhere. I think this is why most threads on these problems start with "my head gasket was replaced". I certainly hope so because after replacing the harness I am going to be out of ideas (except maybe to check the fuel pressure, though I'm not getting a code for it).

It is frustrating but I also like figuring how things work. I am certainly getting a master's level course in that.

Best,

Charlie V

 

Yeah, I always try to baby the harness. I've heard horror stories like yours before.

Congrats on figuring it out!

 

I really hope the harness fixes your problems. Keep us posted.

 

I will know late tonight. The funny thing is that I already have yet another well running engine and could just swap them. But I will. Not. Be. Defeated. Not yet anyway.

At least I revel in the fact that I can remove an intake in 22 minutes with an 8mm socket with 10 inch and 3 inch extensions, 6mm socket, screwdriver, some cardboard to set it on, and needle nose pliers. Done that several times. That's worth something..

I will certainly post the results.

I think once I started getting random codes that went away when I just jiggled wires I should have paid more attention to the persistent o2 problem. Once I cleaned the contacts and swapped others and still had no signal from them I really should have stopped and thought about why that would happen. Instead, I considered the o2s the least of my worries and got over focused on chasing everything else down. Live and learn. At least my engine has a lot of new stuff on it. Keeping fingers crossed.