Initial Startup - backfires (tweecer)

[DonMaximo]

This crate engine has already been fired/dynoed, so all internal components are in working order.

- I've checked my TPS 0.98=closed 4.57=WOT
- Initial timing is set to 10 BTDC

- Using tweecer, I adjusted cranking PW down by 19/30# injectors (0.63333)

- Fuel pressure appears to be around 39.
Hard to really tell when I'm starting.
After I attempt to start the gauge is reading 39.

- With throttle body (TB) closed - some small pops from tail pipe.
- With throttle body WOT - the pop become more aggressive/loud - at one point it did seem that the engine
was going to start -

Ideas ? Suggestions ?

 

[liljoe07]

What have you messed with mechanically since it was Dyno'd?

 

[2000xp8]

I'd start by taking the tweecer off completely.
Then get the car running correctly, and if you want to mess with it with the tweecer after it runs right go ahead.

 

[DonMaximo]

Long block assy came in the crate. Never pulled a valve, timing, or oil pan cover.

I added induction & ignition.

Induction: MAC CAI, MAF calibrated for 30# injectors, Professional Products TB. Replaced the TPS, but as noted above, checked/set calibration (0.95 --> 4.57), GT40 Upper & Lower

Ignition: MSD TFI distributor, MSD coil.

Set initial timing to 10 BTDC. Called T&L engines to ensure I'm using correct timing marker.

*****************************************
I set tweecer switch to off and then unplugged tweecer completely... got pretty much the same behavior....although the engine began to run on it's own with WOT. Hardly a success, but very small progress toward the right direction. Once I let go off WOT...it died

It's difficult to tell, but I may be firing out intake and exhaust.

I checked injectors for misalignment, but that looks OK.

*****************************************

Again... I appreciate the feedback...each suggestion has me checking more things

 

[liljoe07]

Surely find out what timing marks you need to use. Thats more than likely your problem. Im assuming you have 3 sets of marks on the balancer.

ITs a lot of work, but you pull the distributor and set in on another set of marks and try it, if it doesnt work, just try the last set and see. Or just wait and try it once you figure out the correct marks.....Im impatient so I wouldnt be waiting on someone else, but thats me.........

 

[jrichker]

Putting the distributor back in is fairly simple. Pull #1 sparkplug, put your finger in the sparkplug hole,
crank the engine until you feel compression. Then line up the TDC mark on the balancer with the pointer
on the engine block.

The distributor starts out with the #1 plug wire lined up at about 12:00 with you facing it. Align the rotor
to about 11:00, since it will turn clockwise as it slides into place.

Align the distributor rotor up with the #1 position marked on the cap, slide the distributor down into the block,
(you may have to wiggle the rotor slightly to get the gear to engage) and then note where the rotor is pointing.
If it still lines up with #1 position on the cap, install the clamp and bolt. If not, pull it out and turn 1 tooth forwards
or backwards and try again. Put the #1 spark plug back in and tighten it down, put the clamp on the distributor,
but don't tighten it too much, as you will have to move the distributor to set the timing. Note that if it doesn't
align perfectly with #1 position, you can turn the distributor until it does. The only problem is that if you are too
far one way or the other, you can't turn the distributor enough to get the 10-14 degree optimum timing range.

10 degrees BTC is towards the drivers side marks.

Simplified diagram of what it looks like. Not all the marks are shown for ease of viewing.

ATC ' ' ' ' ' ' ' ' ' '!' ' ' ' ' ' ' ' ' ' BTC
---------------- > Direction of Rotation as viewed standing in front of the engine.

The ' is 2 degrees.
The ! is TDC
The ' is 10 degrees BTC
Set the timing 5 marks BTC. Or if you prefer, 5 marks towards the driver's side.

At this point hook up all the wires, get out the timing light and start the engine. Set the timing where your car
runs best. Don't forget to disconnect the SPOUT jumper connector when you set the timing, and plug it back
in when you finish.

The HO firing order is 1-3-7-2-6-5-4-8.
Non HO firing order is 1-5-4-2-6-3-7-8

 

[DonMaximo]

Problem solved... and I'm almost too embarrassed to fess up. I knew the issue was in my face... just couldn't see it.

Many thanks for pulling me out of the weeds boyz.

It lit right up... next step is to set idle, timing, fuel pressure, etc.

 

[liljoe07]

Firing Order

Go ahead an fess up