the car is a 1986 camaro 305 tpi to 350 tpi ( the 350 was bought from oreilys and is what would go in an 87 camaro)
ive had my car back for awhile now got it after the swap and had roughly 200 miles on it, it now has right at 1000 miles and now it has a very bad rough idle and it misfires, it has been scanned by a mechanic and has shown codes for a bad electronic spark control module, it has since been replaced and it still is the exact same, im trying to get help and figure out what it could be. and on a side not if this helps as far as i know the knock sensor from the old motor(305) was put back in the new motor(350). it also has a hypertech chip, i was wondering maybe if that has gone bad. my friend who is working on it is having a friend bring his stock chip over and we will try that but i dont think it will help anything. if any of you guys have any ideas of what is going on all help is appreciated

 

I'm still learning so I don't have much input, but I do know that you need a 350 knock sensor, not the 305.
I don't know if it will affect your idle, but you will want to change that before too long.

 

still no luck, it was scanned again and everything seemed to run fine while hooked to the scanner the only thing weird was that it read the EGR valve was running in test mode???? could this be the problem?? i really need help havent had my car for 2 weeks and trying everything i can think of

 

Did you ever change the memcal out ?

https://www.thirdgen.org/forums/tpi/...-computer.html

 

How about the basics?
Plug wires not burned thru or arcing on manifolds or headers?
Pickup coil good?
Cap/rotor good?
Fuel PSI
Ohm injs
Dirty/sticking/open EGR will cause problems
Vac leak?
Clean Maf sensor wire if you Have K&N filters
A factory service manual will help you out a lot.
Yes, you need a knock sensor from a 350 car and also a 350 chip or program, ditch that hypercrap thing.

A side note,
I would bet money your rebuilt motor has TBI heads on it.

 

You should put the actual trouble codes, not what the mechanic told you what the problem was. Start at the lowest numerical code and work your way up.

Have you had the ignition control module inside the distributor tested? A distributor that is off a few teeth will make it run poor and/or if you got a couple spark plug wires crossed. I would start with the ignition and then have a look at the MAF sensor and connector.

A stock memcal would be better than that Hypercrap chip. You have any friends you can borrow one from? The TPI ecms are all the same from 86 to 89, with different memcal configurations.

You put a centerbolt engine in a perimeter bolt intake setup?

 

i havent changed the memcal out cause this started happening and didnt want to spend money on the chip not knowing what was causing this. ill call the guy that is working on my car tomorrow and run this stuff by him and make sure he has checked it all. i read around the internet (not knowing much about motors) that some say a bad injector can make an engine have a rough idle or misfire. wondering if that could be it cause the car still has the old injectors from the 305 in it(also need to buy southbay 22lb injectors)

 

Yup, thats y I asked about OHMing the injs ;-)

 

ive also read around that the wiring harness and intake is different on a 86 and 87, if i were to put the 87-89 memcal 350 chip what would happen to the cold start injector?? as ive been told that the 86 was the only one to have that and that the wiring harness is different. but i could be wrong im just going by what ive told

 

The csi is on a timer switch separate from the ecm it was use on 85-88 tpi maf. 1989 tune is the best IMO but it has vats enabled. You can use any 350 automatic memcal from 86 $32 mask to 87-88 $32B mask or the 89 $6E mask. The 1989 tune does not make use of the csi and contains a lean highway cruise feature.