I am throwing this up to for the most part cover grounding of the FC, T2 and NA. The 3800RPM stumble has been linked to grounding issues another common issue is the tach not working.



There are a few primary grounds, I decided to get a generic grounding kit from one of my vendors, there are many sources, including ebay for cheap grounding. I ended up grounding everything to a block on the negative terminal, either using the factory grounds or your own setup using some 8 guage or better wire, there a few points to pay special attention too.



Tach issues are often linked to a ground on the tranny, this ground uses one of the bolts on the clutch slave cylinder, there is a small square black plastic box that connects to this ground, I grounded this directly to the battery as I mentioned, you may also use the ground on the firewall near the wiper motor, pasenger side.



Next is the block, there are a couple places to do this, most suitable is near the rear of the engine on top, anything fastened firmly should work.



Next is the braided ground coming from the ECU, in my case with my NA this had been broken off, I beileve the NA braided ground exits near the alternator, t2 near the block, this ground is designed to go to the block.



There is also a grounding bracket at the back of the intake, which runs to the ground point on the firewall. All of these are common and should be checked, beefed up or repaired. In my case I also grounded the alternator bracket to the batter and the body to the battery.



I have not done the ECU grounding as of yet, but will add to this post as soon as I do (next weekend I hope.)



I will also get some helpful pics up although most I have seen are hard to tell anything from the pics.

when you regrounded the wires, did you replace the old wires or just hook up the wires where they were grounded and connect that wire somewhere else, like the battery?

I removed the negative battery cable, which was grounded to the transmission, so the ground from the trans to the battery replaced the old battery cable.



In other cases I left the existing grounds, added new ones to the above points.

I had ground wires running all over my engine bay in my '87 TII, but didn't do a damn thing to help my stumble. But when I spliced in extra grounds for the ECU, it eliminated it completely. I used 10g wire and ran it right to the ECU mounting bracket. The only extra ground I have in the engine bay now is one from the neg battery post to a stud on the block where the ac/ps bracket goes.

Yea I will get some info up about grounding the ECU, good grounds never hurt https://www.nopistons.com/forums/pub...IR#>/smile.png

I just did some grounding work myself today. I used 4 guage wire. I haven't done the ECU yet but the stumble was significaltly less when i drove it around. SO soon i'm going to do what zenrxseven did and see what happens. I couldn't really tell a big difference but it is nice to know that my electrical is bulletproof.

is grounding the cause of my radio, horn, interior rear, and stop lights flickering when i try one of them?

maybe, but you'd have to check the grounds for those switches. Just adding new grounds won't neccesarlly fix that.

so the ecu grounds threw the case? if so i think i found one of my problems.. mine is just chillin on the carpet..

could you throw up some pics of these places i need to look for?

So we should just get some 10 gauge or 8 gauge wire to add these extra grounds from radio shack or something? I want to do this but I don't want to screw this up. https://www.nopistons.com/forums/pub...IR#>/dunno.gif

U can get 8 guage wire from pretty much anywhere. Home Depot, West Marine, etc... Its all pretty much the same.

Hey i was curious if this actually fixed the problem for you. Im having issues at 3800 right now too, can you take a look at my thread and let me know if this sounds like the common issue that people are having? One thing i forgot to mention in the thread that i made is that i have this issue driving (engine under load) and sitting (revving the engine whilst stationary). Someone thought it might be a problem with the secondary injectors?



I cant get the engine past 4000rpm at all! This is driving me nuts!



Thanks in advance, here is my thread. https://www.nopistons.com/forums/Engine-Cut-t73947.html

It can fix it, doesn't seem to always fix it, sure fire way is a S-AFC, but it's not near as cheap as grounding.

When people refer to this stumble at 3800rpm does it usually bog for a second and then continue past 3800? The problem im having is that it gets to 3800 and then wont go any further and the revs die off back to idle until i re-apply the gas again. Trying to find the easiest, cheapest fix for this as i have a swap planned out for the near future and dont want to put too much into this motor to get it running.



Thanks guys

at 3800 it is just a stumble or a bog if it has to do with grounds it feels like you hit a brick wall for a second then continues. You really need to give some more info about your car but from the sound of it I think your in limp mode