I had a hotcam, crane 1.6 rr, and new springs locks and retainers put in my 94z28. After install I cranked the car up and It idle real bad; rpm going up and down 300 rpms. yes i have stock tune, but I was at the shop about to get on the dyno when i cranked it up. Well on the first start it died after about a min. And this continued even after the initial tune was programmed in. Once the car got warm, 180ish, it would idle and not die, but the ideal was still worrible, the same as before up and down 300 rpms. Well the mechanic was like lets take if for a drive. Well it spark knock like crazy. He asked what kinda gas i had in it and i told him 93. Well my tank was low, so we went and filled up with some more 93 just to make sure that i didnt have so bad gas. Well after wards is was still spark knocking. So the mechanic decides that the opti was probably installed wrong. well he tore down the car and it was the opti. Reinstall correctly, and this time it want crank. Well retorn down the car, and install a new opti, and it idle the same as before, up and down 300 rpms. So torn down car again to make sure cam was degreed correctly, and it was. This time he put a new timing chain on, said the other one was loose.

So now i need help, dont know what is the matter. Computer says that all vacuum is good, and every thing is fine. But the car still will not run. The mechanic is going to check the values tonight to make sure that they were adjusted correctly.

Does anyone have any ideas?

thanks pride

 

plug wires mixed up. u have probably already thought of that, but just in case.

 

If it cranks hard and knocks, my guess would be he is still installing the opti incorrectly. Been There Done That when they installed mine. And you should have no starting or idle problems because of the stock tune, but you will make more power when you get it retuned.

 

I would look for a better mechanic.

 

Could be the rockers not installed properly.

 

Maybe your rockers are too tight??? Could also be a vacuum leak. I think that both of those would cause it to act something like that.

 

I'm with Joe. Get a mechanic that knows what he's doing.

 

The mechanic/shop is very reputable. I dont want to mention any names now, but there suppose to be damn good. But they just keep telling me that they dont know what the problem is. There suppose to be checking the rr's today. They told me that they put a new timeing chain on because the other was lose. Well, i did not want them to do this, because i heard that new timing chains can make the front bearing spin. I dont know what to do. I was suppose to get the car back friday, and well it doesnt look like im going to get it back until mid week. I just wish they could tell me something besides I dont know.

I did some research and I came up with a couple of reasons y the thing want work. Cam installed wrong, opti but they put on a brand new one and still same problem, and lastly the ignition is not strong enough for the cam and the stock one needs replacing.

If any one thinks of any thing else, it would be mighty helpful.

thanks for your responses Pride

 

I would think the RRs are to tight or the opti is on wrong. Even though its a good shop how much LT1 experience do they have? How tight are the rockers? With the stock tune on my hotcam kit my car would start and run ok, but did idle a little bit erratic, and when coming to a stop would want to cut out on me. Had the PCM tunned and it was 100% better.

Aaron

 

The shop specializes in lt1 and ls1
they have several corvettes and trans in their shop right now. Alot of people on this forum have used them, and alot of people recommended them. But they still dont know what the problem is.

Yes the first time they installed the cam, the opti was installed wrong, but common on after they redid it four, five times they should have that part fixed. I hoping it is the rr just on to tight.

Thanks for the help, does any one else have any other thoughts.

Thanks pride

 

Cam degreed? Just line up the marks. I'd venture to say the Valves are to tight right off hand. Also, if the coil was removed was dielectric grease put on its backing plate? Thats all I can think of other than some crossed wires..

 

I just finished installing a 'hot cam' in my 93Z .new timing chain and gears while it was apart. it started up and ran on first attempt. It ran rough. I had MADZ send me a piggy back chip to solve the problem. It didnt solve the rough, rich running, most noticible at idle with short term fuel 96 t0 108 range ,very rich! vaccum 15.5" and steady. Fuel pressure at 42 lbs. I played with the fuel pressure adjusting 40 lb up to 46 lb but no difference in rich condition. I payed MADZ for the piggy pack chip in advance! He wont even call me back to discuss the problem! Has any one else experienced a similar problem?