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View Full Version : Brand new 383 lt wont run on 4 cylinders??



Svante
09-19-2010, 01:59 PM
Hi. As a new member on this forum i thought i would start with a serious problem i ended up with on my -92 Vett. Heres the mods i made: 4-bolt 383 stroker with a scat 9000 4340 crank, compstar 6" H-beam rods w, Arp-2000 upgrade. The pistons is the SRP Professional ( 394 grams ). Heads is AFR 195cc eliminator ( 301cfm @ .650 ) 55ccīs, intake from Edelbrock.

Camshaft specs are 278/286-248/254-.621/.607-108LSA solid roller. Isky racing lifters.

Engine management- Autronic Sm4

Ignition: Msd 6al w, single coil
12:1 compression ratio

I fueled it up with E85 and started it to idle a couple of days ago with a set of pretty small accel injectors ( just to be sure i didīnt overrichen it ).

I sprayed a mist of water on the headers to be sure it ran on all, but it didīnt. Looks like the rear cylinders was not running right.

Cylinder 1,3,2,4 looks allright and reacts when i pull the injector connector, but either one of the cylinder 5,6,7,8 reacts when doing the same test? It rather sounds like itīs running better when i pull one of theese connectors.
I have a 4-tooth trigger with a camsync.
I have compression on all cylinders and spark, even tested the timing light on all plugs when its running and no problems.

Even if there was a minimum possibility i tried to change the injectors from my other Vette today ( bosch 1680cc ) but the results are the same. I'm out of ideas, does anyone recognize a problem like this? If you just listen to it you cant hear that it only runs on 4. It sounds nice and has a very fine throttle response. Its cracking me up.

Damn car.
Thanks
/Johan

spina74
09-22-2010, 06:46 PM
check your msd if you bought it used there are 2 wires i believe behind that little black circular cap that you have to cut if your running a 4 or 6 cyl, they either control the tach signal or the entire spark system.