Grounding Points, let's run down the list Options

[VavAlephVav]

I've been checking all the grounds for the motor and cleaning up the contact points for them. I found the one from the negative terminal of the battery to the transmission, and the other end of it runs up to the front of the nose by the battery. there is another that runs from the bracket on the head and ties together with another from the transmission and they both connect together on the left shock tower. when I took the bolt loose from the shock tower the head twisted off and left the bolt still inside so I cleaned up a spot on the bracket that holds the wirelimb going to the igniter up. I used sandpaper and cleaned off the paint from the bracket and removed the paint and primer from the shocktower at that point.
then I went looking for the mysterious ground that I've heard is supposed to be from the intake manifold to the firewall, and did not find it. So I crafted one out of some #8 thhn and some crimped ring terminals. I fastened it to one of the empty 10mm holes on the lower part of the intake manifold, but I couldn't find where it should attach to the firewall so I cleaned up a bolt on the igniter bracket and ran it to there and used sandpaper to remove the paint from the bracket and the firewall at that point and landed the manifold ground there. I also saw the point where the ecu grounds come out of the wirelimb and connect to the manifold up by the injectors. and there's one more ground from the other side of the head near the alternator to the right shock tower.

are there any more that I'm missing? or is there some problem with the way I landed the one's I had to change? im still having trouble with spark, it sometimes cranks but wont start and gives me code 12, and if it fires up it will stay running if I keep the throttle open but will die and give code 14.
I tried rebuilding the distributor with some salvage yard parts and got it to work for a little bit then it stopped again. I have ordered a brand new dizzy, coil cap and all, and I have a used ecu on the way just incase. I replaced the connectors to the dizzy and proved the integrity of the circuit by using an ohmmeter from the plug at the ecu to test the circuits for G+,G-,N+,N-, IGT, IGF. if it is in the wiring maybe I need to unlock the pins at the ecu and push the terminal prongs back out a bit to be sure they grab the pins nice and tight.
however I don't think I would have Several of those connections go bad all at once on a plug at the ecu where it is not subject to damage or heat (I hardly ever even have a passenger who could be kicking it with their feet)
Im just trying to be sure ive covered all the grounds and harness points so that when my distributor shows up Monday I can slip it in and go, worse case it needs the ecu. as far as T'shooting the circuit for code 12 by the BGB I'm at the point where it says 'replace ecu' but that is assuming the distributor is good. the pickup coils and airgaps test right but I got the housing from picknpull. and the ignition coil test good by the ohmmeter but it is still possible the insulation on the secondary breaks down at high voltage.

[Bitter]

When in doubt add your own known good grounds. I've done that to solve problems, my old 7A-FE CloneRolla had a bad stumble when the radiator fans kicked on, I added an additional ground between the battery negative and cylinder head and it seemed to alleviate the issue greatly.

[VavAlephVav]

that's pretty much what I've been doing. at least I took each connection apart and cleaned it with a wirebrush and sandpaper. I fitted the ground on the left strut tower to a new empty hole after cleaning the spot real well and my manifold ground to an empty bolt hole between where the igniter bracket and strut brace mount.
I wonder about the igniter though. some say it is grounded through its case to the bracket it is mounted on. but I've seen the pics on rockauto of new ones that use little plastic washers on the mounting screws which would insulate it. its just weird that before I had it trying to fire up and then cutting off. And after I went through and made sure there was good contact to ground with the igniter case and bracket, Then it wont even try to fire up.
except occasionally It will fire up and run. I had it going for a good 15 min the other night then it just stopped again.
and my cap n rotor are only 6 months old and I went to test the plug wires for resistance including the cap and I found buildup on the contact point where the rotor touches so I cleaned that up.

This post has been edited by VavAlephVav: Aug 16, 2014 - 4:30 PM

[Special_Edy]

The intake manifold ground runs to the ecu. It goes through the wiring harness, it does not attach to the firewall. On the 5sfe it bolts onto the manifold next to the VSV, Vacuum Switching Valve.

[VavAlephVav]

right, ive seen where the wires from the ecu grounds come out of the wirelimb and attach to the manifold.
but I thought there was supposed to be a separate ground wire from the manifold to the firewall? ive seen several posts that talk about that one being forgotten a lot.
is that not right?

This post has been edited by VavAlephVav: Aug 16, 2014 - 9:29 PM

[Bitter]

Add one, it can't hurt anything! The engine is supposed to be grounded to the chassis somewhere (or to the - battery post).