86RX7FC

Ill start by saying I am familiar with these cars and sucessfully rebuilt a 13b before, But im still just an ameture at these cars. Anywho I have an 86 N/A S4 and if anyone is interested the last 6 didgets of the vin are 100279.

So about this issue that I have. I was driving around town the other day and it was running good but all of a sudden it fell on its face and sounded like it was running on one rotor. I have about 900 miles on my rebuilt 13b. Immediately I though a seal went bad so I did a compression test and its still about the same from the last time I checked it about a week ago. Both the front and rear rotor had 3 even bounces and the front rotor had 90psi as well as the rear. A little low but im still breaking the engine in. So I thought the plugs might have fouled out so I cleaned them up and they looked like new and put them back in. I cranked up the car and it was still running rough. I let the car get to operating temp and turned the car off. I pulled the plugs out for inspection and all the plugs looked about the same as when I put them in Except for the Leading (lower) plug on the rear rotor looked black. I thought the the plug might just be junk so I swaped all 4 plugs with some spares that I had on hand. It sounded like it was running good but when it got up to operating temp it fell on its face again. I pulled the plugs and the same thing happened. All the plugs looked the same when I put them in except for the leading plug on the rear rotor. Im using stock NGK plugs.

I don't think the coil pack is bad since both leading plugs use the same coil but I checked them out with a meeter and all of the coil packs are good and the plug wires went to the correct plugs. I also checked the fuel injector resistor pack and that was good too. can't really check the timing cause it wont idle with it running the way it is. It might be the temp sensor by the thermostat but i havent checked it but it has been replaced before about a couple years ago and has about 30 - 40k miles on it. I think it might be tempurature related but im not sure. just wondering if anyone else had the same problem. havent been doing much poking around yet just trying to get some info first. I did do some looking around on here and found a guy who had a similar problem but it was a trailing plug that went black. To my knowledge the cause of this problem might be wiring of the fuel injectors, coil pack, temp sensor, or the mas air flow sensor. like i said before i haven't done much digging around yet besides what i described above.

The fuel injector wires were cut to solider on different injector plugs but I guess the Injectors were too much for what i wanted to do so I swapped the injectors back to stock along with the plugs. there might be a posibility that the soldier work could have not been sufficient enough but I havent checked them yet but Probably a good Idea to double check my work.
sorry for writing so much and I thank those who spent their time reading my post.

86RX7FC

problem solved... the culprit was bad fuel injectors.