Ryan1992M

Hey guys, I'm new to this forum and this is my first post. I've had a couple F-bodys before (84 Trans am 305, 99 Trans Am LS1, then went over to a 4.6 Mustang) but never an Lt1. From my time over on the LS1 boards, I've heard the optispark is a big problem on the LT1 motors.

I'm in the process of buying another car, just sold my Jeep and I want to get back into the F-bodys. I looked at a 1994 Z28 yesterday. It was in good shape, and when I drove it, it ran/shifted very well it seemed, but the owner told me sometimes it has trouble starting. When I started it, it fired right up. Tried a few times after that, and while it started up, sometimes it took a couple seconds of cranking to turn over. One of them times sounded like a slow crank. He said it always starts, just sometimes takes some time.

The battery looked newer, the owner said he replaced the starter recently, could this be an optispark problem? He seemed to think it was, but he didnt know where to start with it. The alternator didnt look new, but I wonder if that would cause these symptoms. Basically, my question is what do you guys think? What are the symptoms of a bad opti, and does sound like it could be one? He also mentioned he spoke to someone on the phone who seemed to guess it had something to do with the ECM.


Thanks for any help

Injuneer

A few possibilities:

If the Opti was contributing to a slow start, it would probably set a code for the signals from the optical cam position sensor in the Opti. Scan it and look for DTC 16 and DTC 36.

Slow start/slow cranking can be due to low system voltage. What was the volt gauge reading while you cranked it?

Slow start can also be related to the fuel pressure failing to hold after the pump primes and shuts down. Rapid pressure loss can be due to a faulty check valve in the fuel pump, leaking fuel pressure regulator, leaking injector(s), or a leak anywhere in the lines, including the flex connector in the tank. To check this, cycle the key between run and off several times, before trying to start it. If it starts quicker, you have identified a fuel pressure problem.

If the injectors are leaking, could be flooding the cylinders, making the start more difficult. To check, put the accel pedal on the floor before you turn the key, then try and start it with the pedal on the floor until it starts. That puts the PCM in "clear flood" mode.

There are also more people reporting problems with the ignition switch. As they age, they seem to over heat and melt the body of the switch, the contacts or the connectors.