After an encounter with a civic that wanted to race me on the highway, I turned into the nearest Mobil gas station. Filled up the tank, grabbed my receipt, and got in my 92 Camaro. Thinking I’d be happily on my way back to college, I turn the Ignition key. Cranks once, cranks twice, cranks. 20 times? If you haven’t guessed what is being described yet, you have never experienced a "no start." Right away, I jump to the conclusion I do not have spark. Looked at all the connectors such as distributor, coil, msd, etc. They were all plugged in and secured. Still, my car wouldn't start.

Being stuck at a gas station is not by any means a shop or garage. You have to make good of your resources. I proceeded to call my friend up and told him to grab a noid light and some tools. He didn't have a spark tester, so we threw a 1/4" extension into the spark plug wire end and leave a small gap to notice spark. And yes, his friend sitting in the car 20 feet away saw the spark. You got to love them msd ignition systems. Next, we hooked up the noid light and noticed no light at all...

Right away we start checking grounds, listening for the fuel pump and following the light blue and light green wires back to the computer. For those that do not know, the computer sends out a ground signal to each bank of injectors. One wire for each bank. A 12V key on run wire feeds the positive or hot side of the injector. With that being said, I pulled down the computer and was getting 12V key on crank from both ground wires to a known good ground. This wasn't good. We were going nowhere and I was starting to think I had a faulty transistor in the computer.

Then something suddenly hit me after 2hrs of endless diagnosing. I thought about what kind of "things" would turn off the injectors. Clear flood mode popped into my head first. For those not as experienced, clear flood mode is programmed into the PROM as a safety and diagnostic aid. It uses the TPS (throttle position sensor) to determine weather or not to allow the injectors to pulse while cranking. Basically, a crank fuel multiplier is used at each percentage of TPS (0% being no throttle, 100% being full). At 87.5% and higher TPS, this multiplier is set to "zero." This zero will cut off your injectors after 87.5% of TPS. The benefits? -To help prevent flooding and performing starter related tests or other diagnosing involving fuel shut off.

Getting back to the story, I decided to unplug the TPS located on the passenger side of the Throttle Body. First turn over of the engine and she starts rumbling again. Although this threw a code, I was able to get back to my college without having to call a tow truck. When I took a closer look at the TPS, the lever got stuck against the throttle body. Two hours to find a problem with a TPS. Just wrote this post to guide others in their diagnosing. I overlooked something I shouldn't have. I bet I know the first thing I'll check next time I see a no start where the injectors aren’t pulsing. Good luck to all of you with similar problems.

 

having the same problem, I will check tomorrow and hope it helps me. If not i might end up takint it to a shop, but more-than-likely not

thanks

 

why were you flooring it in a gas station to get the tps stuck in a wot position?

 

Wow...I'm going through this right now on a new build. Even if it doesn't fix my problem thanks for taking time posting it!

 

Hey, I'm not even experiencing a prob. like that, but thanks for the info.... I love reading these things just for the extra info..