86rutmaker

some of you may have read the thread i put up of my jeep not running the fuel pump and not having spark, well that was the ecu, now ive come into a total different situation, once i plug in the alternator it starts to run rough and i cant even touch the gas or itll die, it is the 2.5 5 speed manual, 1986 cherokee, i put a brand new alternator and still does the same thing, im completely lost, ive even ran the wire directly to the battery, tried a different battery also, is there like something else the alternator runs or is connected to, if i UNHOOK the alternator itll run like a top, no issues. please help if you have any idea what the issue might be, it ran great before the ecu went out than this.

cruiser54

Click on the link in my signature and do post #1 before chasing your tail any further.

86rutmaker

welp cleaned off all grounds and sanded them to bare metal, didnt help, i was online reading where a few people had the issue of hooking up the alternator and it would run bad but, unhooked runs like a top, but on different vehicles.

any other suggestions???? im still super lost on this

86rutmaker

also was wondering if its possible to plug in this old of a jeep to a diagnostic machine??

Doc Paul

Have you measured the voltage at the battery, WITH A VOLT METER, when you start the Jeep? Before you start it, it will read somewhere between 10.50 to 12 volts. when you start it and it is running (even roughly) it should read about 13.75 to 14.25 volts. Then watch the meter as you touch the gas pedal. What happens then??? Let me know.
Doc

86rutmaker

when idling it will charge, have not tried to touch the throttle with the meter on it, will try that and let you know

86rutmaker

so i tried what you said the voltage when alternator is hooked up is like 13.8 to 14 something. one time one i hit the gas it dropped to 9 and another i didnt notice. but what i did notice is if i spray carb cleaner in the tb while its running it will rev no problem and clean up the sloppy idle until the carb cleaner burns away than itll run like crap again and die when the gas is pushed

Turbo X_J

Whats the fuel pressure in psi?

SHELBYGT NSM

I dont know much on that engine, but is there any vacuum leaks?

freegdr

Id take alternator back...

86rutmaker

well it did it even with the old alternator, would it be possible for this old of jeep to have something in the ecu that has to deal with charging

cruiser54

Nope.

freegdr

Is regulator internal or external on 86 ?

cruiser54

IIRC, internal to the alternator.

86rutmaker

well what could possibly be the issue, any chance it could affect spark or the fuel pump