96 Formula Won't Start Unless Pedal is Held to the Floor

**Seawolf18** · 05-27-2019, 04:45 PM

I had a no start problem with it that ended up being a bad ICM. Replaced the ICM and it started right up. I drove it around for about a 1/2 hour and parked it in the driveway. When I went to start it to put it in the garage, it wouldn't start. I finally got it to start by flooring the gas pedal. After it starts, if I don't feather the gas it will die. I have checked my Fuel Pressure regulator and pressure, they are good. I have white hot spark on #1 plug wire while cranking. I also have injector pulse while cranking. I tested everything while cranking it without touching the gas. There are also no codes in the computer. Any Ideas?

***Fastbird*** · 05-27-2019, 06:03 PM

Does it eventually stay running on it's own if you keep pedaling it? Possible it's ECT or IAC related. I'd look at the IAC first.

**Seawolf18** · 05-27-2019, 09:41 PM

Yes, it will eventually run on it own. I tried starting it today, and got it to run, but it was miss-firing really bad and gassy smelling. If slowly roll into it, its really bad to about 2000-2500 rpm then it smooths out some. You can still tell its missing, just not as bad. The SES light came on and it had a P1351 Ignition Control Module Circuit High Voltage and P0336 crank sensor range/performance, but no misfire codes. The ICM and coil were replaced with Delphi parts, and wiring was tested during diagnostics of the no start issue. I looked at the plug wires, they are pretty new looking MSD wires. None of them were burnt off. I pulled the spark plugs out of it. They were damp with fuel and black. I checked the gap, and it was .050 on all of them. I'm thinking this might be an opti issue. It was replaced by the previous owner, but I don't know what they put in it for an opti.

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**Stormyweather** · 05-27-2019, 10:13 PM

Sounds like IAC

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**Cathead** · 05-28-2019, 07:27 AM

If it's giving you a 0336 code, I would start checking the crankshaft position sensor. I believe it aids in the timing and fuel department or at least it's supposed to. I have a 97 Z28 and my CPS was broken in half.

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**Seawolf18** · 05-28-2019, 11:34 AM

From what I have been reading, The CPS in the OBDII cars only helps to detect miss-fires. The CPS was replaced with an ACDelco one, and the CPS wiring was checked. If thats the case, that could explain why i'm not getting any miss-fire codes The CPS code came back after replacing. Since all of the plugs are out, I'm going to compression check the cylinders to make sure I don't have a dead one and get a new set of plugs for it. I will also pull the IAC out and make sure its not all the way out, shutting off the passage. I'm trying to diagnose the problem, instead of just throwing parts at it until something finally solves it.

**Cathead** · 05-28-2019, 11:42 AM

Definitely don't want to start throwing sensors and opti's at it. The IAC could also be a culprit but I'm not sure if it creates a trouble code. Those plugs look really rich which is also related to the ECT but I know that gave me a code when mine was bad.

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**Seawolf18** · 05-28-2019, 12:15 PM

The ECT is with in a few degrees of the air temp on the scan tool, and the engine is cold.

**Stormyweather** · 05-28-2019, 12:17 PM

Does the IAC show vlotage change? I know a bad one won't change. Seen them stuck open just Abit.

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**Z28pr0jekt** · 05-28-2019, 12:33 PM

Originally Posted by Stormyweather

Does the IAC show vlotage change? I know a bad one won't change. Seen them stuck open just Abit.

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Even on this note, I had a datalog show voltage change on an IAC that was stuck open. I thought the IAC was good until I finally took apart the car. This was causing fuel to load up and a hard time idling. I actually drilled the IAC hole larger before actually checking the IAC like a dummy.