Doesn't run good between 1000-2000rpm
05-23-2006, 09:52 PM
#1
Doesn't run good between 1000-2000rpm
Like the title says, my engine seems to be having problem running well between 1000 and 2000 rpm. It idles fine and past 2k rpm it runs great. Before 2k, I'm barely touching the throttle and it coughs and stumbles slightly. It doesn't really stop me from riding my car but I don't like it.
I played with the idle mixture screws (lean and richer) but that didn't change anything. I feel that I'm too lean or too rich around that rpm but I just don't know how to ajust it.
Another possible culprit is a bad cable going to my cap. I didn't have any problems with that before but this last weekend, my tach started jumping for no reason and it wasn't only the gage as the engine was stumbling at the same time. I played with said cable (the one bringing power to the coil in the cap), made sure the connector was well seated and the problem went away. Could it be related to the above problem?
Thx for any advice!
I played with the idle mixture screws (lean and richer) but that didn't change anything. I feel that I'm too lean or too rich around that rpm but I just don't know how to ajust it.
Another possible culprit is a bad cable going to my cap. I didn't have any problems with that before but this last weekend, my tach started jumping for no reason and it wasn't only the gage as the engine was stumbling at the same time. I played with said cable (the one bringing power to the coil in the cap), made sure the connector was well seated and the problem went away. Could it be related to the above problem?
Thx for any advice!
05-24-2006, 08:47 AM
#2
Melting Slicks
I dont know what year you have. But in my -91 vette i did got the exact same probleme. I changed everything in the ignition ( cap, pick-up, cabels etc ) . But nothing worked. For me it whas 2 bad injectors. the spray pattern where poor on low rpms, but abow 2200rpm the probleme whent away. Got 8 new injectors and the probleme whent away.
Regards
Regards
05-24-2006, 02:32 PM
#3
unfortunatly it can't be that because I have a carbed engine. Here are the specifics:
1978
rebuilt 350, holley 650 double pumper, new spark plug wires, almost new sparkplugs, edelbrock performer RPM.
I had an off idle stumble before so I changed the edelbrock torker intake for a performer RPM and that went away but it made me notice this caughing at low RPM. The holley carb was added after rebuilding the engine 2 years ago.
I'm really only looking for ideas, pointers or past experiences like devilfish's to give me something to work with... cause I think I ran out of ideas. (besides changing that power cable going to the coil)
It could even be the cam... I kept the same cam that came with the car when I bought it 5 years ago. Its a flat tappet and thats the only thing I know about it... I know it ran alright (no coughing) with the Q-jet that was on the engine before but there's no way I'm going back to that carb... I definitly gained power with the new carb.
Worst case, I'll get a O2 sensor and see what comes out of the exhaust in that RPM range. That will definitly tell me the truth. If the mix is fine then the fire ain't getting there.
1978
rebuilt 350, holley 650 double pumper, new spark plug wires, almost new sparkplugs, edelbrock performer RPM.
I had an off idle stumble before so I changed the edelbrock torker intake for a performer RPM and that went away but it made me notice this caughing at low RPM. The holley carb was added after rebuilding the engine 2 years ago.
I'm really only looking for ideas, pointers or past experiences like devilfish's to give me something to work with... cause I think I ran out of ideas. (besides changing that power cable going to the coil)
It could even be the cam... I kept the same cam that came with the car when I bought it 5 years ago. Its a flat tappet and thats the only thing I know about it... I know it ran alright (no coughing) with the Q-jet that was on the engine before but there's no way I'm going back to that carb... I definitly gained power with the new carb.
Worst case, I'll get a O2 sensor and see what comes out of the exhaust in that RPM range. That will definitly tell me the truth. If the mix is fine then the fire ain't getting there.
