TTA with no start issue

72firebird

Active Member
Joined
May 18, 2004
So I just finished doing a full rebuild on my TTA, but now I'm having issues getting it to start. I have both fuel an spark, but it tends to "chug" while attempting to start. The car has a new short block just built by Cruz Performance running the stock ECM with an SD2 chip, Powerlogger, and low Z injectors drivers with brand new Holley 160 lbs injectors

Steps that I've done:
  • Verified spark using one of the old Caspers CCCI/Coil testers with the metal plate that sits on the coilpack
  • Replaced crank sensor as it was touching balancer, verified 10V and ground to sensor
  • Verified 10V and ground to Cam sensor
  • Set cam sensor using the Caspers plug in light while shortblock was out of car and re-verified tonight at 25 deg ATDC
  • Used caspers cam sensor light to plug in and verify it was registering while cranking
  • Have fuel as the plugs have some fuel on them
  • Checked continuity on all fuses using a multimeter and verified power to pins M and P on the ignition module.
  • Tried another coilpack and ignition module which seemed to crank a lot smoother, but no spark and didn't show any spark using the Caspers Tester either.
I'm currently planning to order a TR6 with high tech coil from Bob because I told myself if I ever end up needing to replace my original ignition module or coil pack that I would upgrade and not deal with the headache.

Any other suggestions of things that I should check?

Here's a powerlogger log while attempting to crank NoStart5-4-2020A.dat
 
Turn the cam sensor a little at a time until it starts.
^^^^ no dont do this !!!!!! but verify that its at 25ATDC on the #1 compresion stroke
are the injectors new/ recently tested ?
cant read the log ..are you getting RPM reading if not check crank sensor output
dry out the plugs and try again
 
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^^^^ no dont do this !!!!!! but verify that its at 25ATDC on the #1 compresion stroke
are the injectors new/ recently tested ?
cant read the log ..are you getting RPM reading if not check crank sensor output
dry out the plugs and try again

I did the cam sensor install using the caspers light while it was still on the engine stand. Yesterday, I verified the setting by determining the #1 compression stroke by removing the spark plug, holding my finger on the hole and feeling for when it generated pressure through the stroke, then aligned the timing mark to 25 ATDC and the cam sensors was still right on using the light.

Injectors are brand new out of the package last week.
Not getting RPM on the log, which is why I replaced the crank sensor as it was touching the reluctor wheel and then I set the gap and rotated a full rotation to make sure it maintained gap through all 3 fins. I read that you won't see RPM on the ECU until it starts, and if the crank sensor wasn't reading I wouldn't have spark right?
I pulled the plugs, dried them out and cleaned them off with a lighter
 
^^^^ no dont do this !!!!!! but verify that its at 25ATDC on the #1 compresion stroke
are the injectors new/ recently tested ?
cant read the log ..are you getting RPM reading if not check crank sensor output
dry out the plugs and try again

What’s the problem with trying this?
 
What’s the problem with trying this?
if its been checked at 25atdc a little wont make any difference , if you keep turning (a little at a time) eventually you will end up on the next fire cycle and you can do damage firing a cylinder when its not at tdc

to the OP you need RPM and it will log during crank if its there , you can also check injector pulse with a noid light
 
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to double check the cam sensor ,,,set balancerto 25 ATDC and take cap off .. it should look like this
cam sensor align , set crank  to 25ATDC.JPG
 
I have both fuel an spark, but it tends to "chug" while attempting to start.
.......
I pulled the plugs, dried them out and cleaned them off with a lighter
Verified plug wire locations?
 
besides the basic motor stuff , you need the throttle set properly TPS and the throttle blade , was the throttlebody new or running previously on an engine, if new the blade may need to be opened with the screw
also make sure coolant sensor is reading properly , if its reading -36 it will add a ton of fuel to try to start in cold
 
to double check the cam sensor ,,,set balancerto 25 ATDC and take cap off .. it should look like thisView attachment 354028
I'll go out and double check this in a little bit, but yes it was oriented with the housing dot towards passenger fender and window towards drivers fender and I had used the little sticker that comes with the Caspers light to set the timing mark to 25 ATDC.

Verified plug wire locations?
Yes, I even have the little cheater plate from Mark Hueffman that has all the cylinders engraved on it.

besides the basic motor stuff , you need the throttle set properly TPS and the throttle blade , was the throttlebody new or running previously on an engine, if new the blade may need to be opened with the screw
also make sure coolant sensor is reading properly , if its reading -36 it will add a ton of fuel to try to start in cold
It is a new TB and I haven't adjusted the screw. I tried giving a little throttle while cranking as well. TPS is set at 0.44V with throttle closed. Coolant temp is reading 82.8 degF.

can you add your PL log as an attachment

Added as an attachment this time.
 

Attachments

  • NoStart5-4-2020A.dat
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The cam sensor ONLY sets the fuel timing, not the spark timing. During cranking, the injectors are all firing at once, in batch mode. It switches to sequential after the start. If you get the car started, then unplug the cam sensor, it'll default to batch mode, all injectors will "puddle" fuel before being sucked into the head and the car will run pretty rough. However, if unplugging the cam sensor causes the engine to die, your fueling curve is off, particularly with big injectors. You're too rich.

IF the cam sensor is 180 degrees off or less, the car will still run, albeit without the advantage of precise fuel delivery to the cylinders. It may backfire and pop, run rough, but it should still run.

Also, the orientation of the window with respect to the timing mark is meaningless...the important thing is that the interrupter is relative to the cam sensor pickup slot, regardless of where the sensor drive happens to be. So you can twist the cap anywhere, as long as the interrupter is in its proper view with respect to the window on the interrupter.
 
also need to ask ..is there 93 or e85 in the tank , with 160 injectors id assume you are running e85 tune and should have e85 in tank but i see your ethanol is 7.8% on PL so looks like you have pump gas
 
25ATDC on the compression stroke??
Yes
also need to ask ..is there 93 or e85 in the tank , with 160 injectors id assume you are running e85 tune and should have e85 in tank but i see your ethanol is 7.8% on PL so looks like you have pump gas
Have 93 in the tank right now to get it started and running, but plan to run E85.

So when turning in the direction of the engine cranking (CW if looking at the front of the motor), the Caspers light comes on here
70892350746870592556.jpg


and off here (25ATDC)
82338640748164017537.jpg


Here's a video of attempting to crank, it has normally been doing the "chug" and I had only heard the pop once previously. I'm going to pick up some noid lights here in a little bit.
 
also if the tune is for e85 trying to run it on 93 will flood it out as youll be way too rich unless that SD setup can adjust for it (flex)
 
i checked his SD2 tune from pl file and shows param 13 is correct for gas (128) , sd instucts also ask for Fuel pressure to be dropped to 38 base for larger than 80 injectors ..im not really sure how well 160s will work on 93 on a 3.8 motor
 
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