Heres the story, about 4yrs ago i bought this z28 since i had been wanting one for the longest. i drove it for two months and every since nothing but problems. i replace the engine about a yr ago with one from a caprice(got ripped off) and guess what... still more problems. I've had big plans but now just want it to run right. So far i have put the 98-02 front end on it, jet stage 2 chip, 95 vette heads(due to it having cracked heads when i bought engine), cai, exhaust, full guage set, and i was in the process of paint it. If i didn't have so much money in it i would junk it, but i dont want to see what i have done go to waste. Please help me figure out whats wrong with it. Thanks!

THE PROBLEM: It has a miss in it but im not sure where, so my question is how can i find whats causing it to miss? It has brand new plugs and wires. it cranks straight up. Could it be the opti? DO the caprice lt1 have a different firing order than camaro?

 

We need more info. as where/when that miss occurs.Is it off-idle,@30 mph,60 or other?Are there any chk.engine codes?When my egr.went i had code 29,the opti was 36,etc.Btw you can also junk that Jet chip as their stuff is garbage!

 

Have you flashed the codes?

 

Did you get a Caprice 350ci LT1, or a Caprice 265ci L99? If you got the LT1, its virtually identical to the F-Body LT1 except for the iron heads and smaller cam. No difference in firing order.... its the same engine. Even the L99 has the same firing order. Same as the Gen 1 small block Chevy.

There is a cam difference, so you might want a new chip burned to match the specific combo of the LT1 aluminum heads (flow less than the CI heads, but allow more timing advance) and the smaller B-Body cam. The current mismatch should not cause a specific misfire, but its not likely the engine would run as well as it could with the correct tune.

FUEL:
Have you checked the fuel pressure? Have you used a 'noid light to verify the injectors are all firing? Have the injectors ever been cleaned? What size are the injectors?

COMPRESSION:
Have you done a compression check, and a leakdown test?

IGNITION:
Plugs and wires are less than 1/2 of the ignition system. Have you checked for codes from the Opti and IC Module? Have you checked the coil? Have you run it in the dark to look for arcing around the Opti, coil and wires? I believe the Caprice LT1's got the vented Opti. Do you have the vent system hooked up correctly? Have you checked the Opti wire terminals for corrosion? Have you checked the Opti harness for corrosion or damaged pins?

As noted above, check for codes. If you can, run a data log using scanning software like TTS DataMaster.

That should get you started.

 

the miss is there all the time and there is no check engine light on. I am going to check tonight to see if there is any arcing of the wires but there shouldn't since i just put them on today. i checked the compression awhile back when i put the motor in and took the numbers to a mechanic and he said it was good. i checked coil and its good.I dont have the opti vacumn lines hooked but they are pluged so nothing can get in. What is fuel pressure supposed to be?

 

There are codes that don't turn on the "check engine" light. You need to scan it, which you can do with a paper clip.

 

can you tell me how to check the codes? i tryied to check for any arcing last night but it would not crank, but i seen the plug besides the coil had came off so i will try that again tonight.

 

The answers you got were on the money. Fuel pressure on the 93 is done w/ the vaccum line off the regulator and manifold port plugged, according to the G.M. service manual,
Pressure =43 Lbs. @ idle.
A miss at all speeds sounds like a plug or injector, perhaps a valve. A check for a leaking valve would be to use a vaccum gauge at idle. 16-20 inches and steady needle.
Double check your wire routing with your new wires. The wires, as they leave the passenger side of the opti spark, on the 93 are very close to a pulley, make sure the wires are in the wire looms and not rubbing on that pulley. Double check that they are on the proper spark plug.

 

how can i check to make sure the injector wiring is hooked up right. because when i put in the motor i didn't mark where they went but i think they are in the right spot.

 

In a 93, as long as you have the left bank injector wires on the left bank, and the right bank injector wires on the right bank, it doesn't matter which specific cylinders they are attached to. 93 is "batch fire" - all 4 injectors fire simultaneously, once per crank revolution. It wasn't until the 94 model year that they went to full sequential injection.

To flash the codes on a 93 (courtesy of Shoebox):

http://shbox.com/1/dlc2.jpg

When you get the codes, Shoebox also has a code list that is specific to the LT1 engine, and has a column for the 93 models on the right hand side of the page, since they are a bit different than the other years:

http://shbox.com/1/Dtcs.htm