high idle, miss...

[Jarek5_7]

hi. I bought an c4 conv with zr1 engine, trans, interior etc. someone wrecked a Z and swapped all that into C4. as matter of fact I even know in what shop it was done.

ot first I replaced spark plugs and oil, oil filter, fuel filter. one plug was cracked, plug from cyl#6 was carbonated.

engine idles at 2k after a while it drops to 1.5k

it drives reasonably only when just little of throttle is pressed. when I press more throttle it misses.

I measured komh on coils:
1/6 - 18.7
2/3 - 19.2
4/7 - 16.7
5/8 - 16.5

so I`ll change them. also I`lll replace injectors. All secondaries have around 13.5-13.7 ohm, and primaries the same exept #6 and # 8 , those have 05.6 ohm. and they could be leaking also....

fuel pressure is on primary pump around 45psi with ignition on. with engine on its almost 50 psi. couldnt figure out where is the fuse for secondary pump, because I dont have zr1 service manual yet.

vacuum pump after ignition on pumps and after a while its shuts off, and then it comes on for around 1-2 sec in periods of 5 sec. is it normal or its a vacuum leak somewhere?

Can vacuum leak on secondary vacuum relay be the cause of high idle?

sorry for my english.

I`ll post some pictures of the car soon if anyone is interested and I`ll hope I`ll get this baby runnig as it should be.

thanks

[tccrab]

Jarek:

It sounds like you do have a vacuum leak causing your high idle.
When you replace your injectors be sure to check all vacuum fittings under the plenum. Also be sure to check your PCV pipe, it's another common source of vacuum leaks.
Your coils don't seem too bad, the variance you are seeing can be explained by the difference in resistance due to the length of the spark plug wires. Spark plug wire #1 is much longer than spark plug wire #8.

I'd love to see some pictures of your car, I seem to recall seeing a few when you first joined the registry.

TomC