Hello all,

I'm in a little bit of a bind here and I have no idea what is causing my problem.
I had a new engine built for my Trans Am, installed it, and didn't have too many bugs except for a timing issue, which i got straightened out. The only code i was getting was 43. I figured, since I had a new knock sensor laying around, I'd install it when I went to change the oil. I installed the new sensor, changed the oil, and now the engine won't start. (It's turning over, and acts *almost* like the coil has gone bad, with it picking up for a split second then not starting.)
If I mash the gas, the car would start up for a second or two, run very very roughly, then throw Code 43. This is after I cleared all the codes. I just can't see a knock sensor causing a no start issue. Is there anything that I may have done that would lead to the problem? I have the timing set at 10 degrees BTDC (set with the wire unplugged). But I have really no idea what is going on here. Any input that anyone could offer would be appreciated.


System specs:
L98, running 730 ECM, Stock injectors, stock ignition, distributor, etc.
Engine itself: Eagle forged crank and rods, SRP forged pistons, COMP cam, 220/229 duration @ .050" lift, .525/.525" valve lift.
Brodix Aluminum heads, 180CC runner, 2.02/1.60 valves.
Harland Sharp 1.5 ratio roller rockers.

 

Try unplugging the sensor.

 

I tried that, made no difference. Thank you for replying!

 

How about bypassing the EST?

 

I might just be a coincidence. Have you checked your fuel pressure or tried some starting fluid? The fuel pump might have failed.

 

Me Too!

exact same problem let me know what you find out. No one here was able to help me.

I bought a new coil and ecm they fixed nothing, my engine has less than two hours on it. I just ordered a new engine to see if that would help.

by any chance to you have accel injectors? I think they are my problem.

Jeff

 

Sorry I haven't replied sooner, but with work schedule, etc. going on It's been tough for me to get to work on this thing.

Well, thanks for the replies all! It was appreciated, and I have a novel for you.

First off, to Vader: Yes I unplugged the Tan/Black wire and it did not make a difference.

Following a manual I got from a friend, I ran through a battery of tests and flow charts, every item passing the tests, fuel injectors pulsing properly, fuel pressure at 45 psi and fluctuating appropriately as the engine would crank. The ignition circuits all passed their tests as well, but I did replace the ignition coil since I had one. Two days ago, I finally got a lead: I pulled each individual plug and checked its spark as the engine cranked. What I found was the passenger side plugs were producing a bright white spark, but the driver plugs were producing a dull orange spark. Odd enough isn't it?

I also found 2 bad plugs that were arcing off to the side instead of at the electrode on the driver side. I bought a complete new set along with ignition wires, the cap and rotor. When I opened up the cap, I noticed the rotor was seated, but came off rather easily, and the underside contact didn't look to be in the best condition. The reluctor ring also had "flecks" of green corrosion on it as well. I hit that with some contact cleaner, seated the new rotor and installed everything.

Another oddity I noticed: I decided to check the resistance level of the new ignition coil wire vs. the old one. The new one registered at 4 ohms, the old one at 216 ohms. I had originally planned to reuse the old coil wire simply for the fact that the new one is shorter (by about 1.5 inches) and would require a relocation of the ignition coil.

After seeing those numbers, I relocated the coil. Seems like quite a difference in resistance values, but enough to cause a no start issue? Apparently so, as the car fired up instantly when I turned the key. I was kind of surprised that this here caused the car to run one minute and not the next after changing the knock sensor and the oil.

The ECM is still throwing Code 43, which tests are currently leading me to a break in the wire, but not 100% sure yet .

 

what is code 43 i think i had that not to long ago...

 

43 is an ESC fault, defective knock sensor, or low ignition voltage. i got mine figured out, just had a broken wire in the knock sensor circuit

 

nice sometimes it just that easy. i stress when my camaro goes south and tend to over think things.