ok my friends 85 gsl se or somthing like that misses like crazy at 3000 rpm's and up. its a 12a with a street port, stock carb and stock header. the rest of the engine is also stock.



what we have done already for troubleshooting was to replace the cap, rotor, plugs, wires, coils, we screwed around with the carb but didnt get anywhere.

also, the tach jumps around constantly. im not sure if thats related or not. we also triple checked the plug wires to be sure they are in the right position. and when i removed a plug wire 1 at a time the engine noticably changed rpm's, to that leads me to conclude that the ignition is working properly. (is i remove the front or rear bank of wires the rpm's drop alot more than if i just remove 1 wire at a time)



what will happen is that you floor the engine in neutral and it instantly revs to 3000 rpm's and misses like crazy and doesnt rev and higher for about 15 seconds, then finally it will rev up to the redline, but it misses badly while it goes up.



so, i thought perhaps the main jets were clogged (it seems like a classic symptom) but when the air filter is off and the engine is floored and stuck at 3000 rpm's, i can SEE 2 healthy doses of fuel being constantly drawn into the intake manifold, by looking down the carb throat. it seems to be dumping fuel quite nicely.

it mis fires somtimes making a popping sound out the exhaust when this happens. its never out the carb. the engine never smokes oddly. the engine used to run great, but it progressivly got worse and worse untill now when its so bad he cant hardly drive the thing.

have you guys any ideas whats going on? im still suspecting carb related problem, or maybe intake manifold leak, but as best i could tell everything seemed to be working decent though.



the engine is supposedly about 10K miles old. and also supposedly rebuilt with 3mm apex seals. i dont know if this is true or not, its just what the previous owner said so who knows if he was BS or not. it does have a harsh engaging racing clutch, so it has atleast had the engine taken out. its also not the original engine.

 

It sounds like there is a problem with the igniter(little black box on the side of the dist) or the pickup assembly on the inside controlling the trailing ignition that would cause poor running and the tach to go crazy(it gets its signal from the trailing coil) if you have access to anothe dist try swapping them out because the parts are high and usually non returnable if you guess the wrong one

hope this helps some

 

I was thinking the same thing.....