Break in/Back Fire Help

[Prometheus_2]

I assembled a 95 350 w/ a 400 crank (383 stroker), vortec heads, GMPP TBI Vortec Intake and headers. I turned it over today to break it in, it fired right away then died. I turned it over again and it would only run w/ the accelerator 3/4 of the to the floor. After about 2 minutes the TBI spit out a 3 foot FLAME( I had left the air filter off to check spray). I checked the firing order and that was okay, and timing is on. I haven't adjusted the stock GM Fuel Pressure yet. I thought it would break in fine w/o this adjustment. I clamp on the airfilter and ran it a couple more times. It still will only run w/ 3/4 throttle and (exhaust?) fumes roll out of the TBI after I turn it off and unclamp the air cover. I stumped, I don't know what could be wrong. Any one have any ideas or suggestions?

[James B.]

Sounds to me like the plug wires could be mixed up, but that depends on if it's missing badly or not. Look over the ignition system. This would be an easy fix. Unfortunately the darker possiblity is that the timing is a tooth off on the chain. Verify your plug wires and ignition, then check your baseline timing, if you still have problems you may want pull the timing cover. That's a pain as you know.

[Prometheus_2]

thanks, I had some FireWire plug wires on, I pulled those off and put on a generic delco set and double checked the firing order then and it was correct. I'll recheck my base timing, boy, i'm hoping I didn't F-up and get the timing chain off. Quick Additional Question, I assume that 87-95 350's used the same size hydraulic lifters? Anyone know off the top of their heads?

[LOWGREEN1]

It sounds like you know what you are doing, But I have to ask...Did you set your timing off TDC on the number 1 cyclinder?? It almost sounds like your timing is 180* off. BTW how do you adjust the fuel pressure on a 95?? I didn't think you could?

[Prometheus_2]

You can adjust the fuel pressure on the TBI, it just requires a little tinkering. Here's a great link with some useful information http://www.diy-efi.org/gmecm/faq/tbi_fp.html. I (*think*) what I did was install the cam sprocket at the 12 o'clock position instead of the 6 o'clock position. If I recall when I was assembling I got sloppy. This would be the cause of my woes if I did? At this point I better get some second advice and opinions before I drop the pan to check. Thoughts?

Oh, I did set the timing off the #1 cylinder

[LOWGREEN1]

Originally posted by Prometheus_2
You can adjust the fuel pressure on the TBI, it just requires a little tinkering. Here's a great link with some useful information http://www.diy-efi.org/gmecm/faq/tbi_fp.html. I (*think*) what I did was install the cam sprocket at the 12 o'clock position instead of the 6 o'clock position. If I recall when I was assembling I got sloppy. This would be the cause of my woes if I did? At this point I better get some second advice and opinions before I drop the pan to check. Thoughts?

Oh, I did set the timing off the #1 cylinder Cool thanks for the link. I will check it out later, right now the site is down..

[Prometheus_2]

No problem, might try this link instead, http://www.diy-efi.org/gmecm/faq/ it brings you to the same page

[Don454SS]

Originally posted by Prometheus_2
You can adjust the fuel pressure on the TBI, it just requires a little tinkering. Here's a great link with some useful information http://www.diy-efi.org/gmecm/faq/tbi_fp.html. I (*think*) what I did was install the cam sprocket at the 12 o'clock position instead of the 6 o'clock position. If I recall when I was assembling I got sloppy. This would be the cause of my woes if I did? At this point I better get some second advice and opinions before I drop the pan to check. Thoughts?

Oh, I did set the timing off the #1 cylinder
Double check your timing. As I recall dot on cam sprocket at 6 and crank at 12 gets the teeth lined up easily/properly but is not #1 TDC (but rather #6 TDC). I thought cam at 12 and crank at 12 were #1 TDC. Did you line up #1 properly upon reinstall of the distr?

ANyway, if your plug wires are correct, to get that "flame thrower" you've got a timing issue.

[Prometheus_2]

I managed to get the Timing off by 180 (Thanks for the advice LowGreen1) not quite sure how/when I managed it but it's corrected now. Thanks for all the input. I think my project is cursed. The motor sounds/runs awesome but when I threw it into drive nothing engaged. I hope someone can help me out with this as well. It's a 95 tahoe, 4l60e. When I put it into any gear there is no engagement felt and no go at all. When I put it back into park the gears ground(didn't do that again). I'm clueless? I don't think I moved the torque converter so I don't think its the pump? Anyone care to take a stab? This is driving me nutz.

[LOWGREEN1]

Originally posted by Prometheus_2
I managed to get the Timing off by 180, not quite sure how/when I managed it but it's corrected now. Thanks for all the input. I think my project is cursed. The motor sounds/runs awesome but when I threw it into drive nothing engaged. I hope someone can help me out with this as well. It's a 95 tahoe, 4l60e. I have the vortec intake so I bent the old cable bracket to fit onto the vortec intake. The TV cable doesn't appear to be set right to me, the cable has the plastic hook and the adjustable screw but the line doesn't move, when the throttle is moving. Is there suppose to be a clip or something I misplaced? When I put it into any gear there is no engagement felt and no go at all. When I put it back into park the gears ground(didn't do that again). I'm clueless? I don't think I moved the torque converter so I don't think its the pump? Anyone care to take a stab? This is driving me nutz. This is what I was trying to tell you on my first post. You must find TDC by compression on the number 1 cyclinder to set timing. Also your 4l60e doesn't have a TV cable. That's what the "E" stands for Electronic. You should have 2 cables coming off your brackets. One is the throttle cable the other is the cruise control cable.

[retorq]

You hooked up the torque convertor to the fly wheel right?? the flywheel is one the correct way right?? For some reason the last owner put the flywheel on my truck on backwards. :( The TC would have been pulled out of the tranny by 1/4 to 1/2 an inch. also it is selectronic so I would check all the connections on the side of the tranny, especially that black box by the external shifter linkage. Did you remove the tranny?? Maybe the fluid is extremely low??