Bulldog92

iTrader: (1)

This is a story that involves a LOT of flames and plumes of smoke, so I'll understand if you can't handle it (ha)

I have had several threads on TGO lately explaining all the different problems I have had since I swapped from a 305/T5 combo to a Vortec 350 HO/T56 combo with a 454 TBI. However, I have been neglecting to tell what I go through to get the engine started each time because I didn't think much of it. However, I learned there was more going on this weekend. Let me explain what it takes to crank my "mighty" engine...

I crank...and crank...and crank...might get a little indication it's going to start...then crank some more...spray some carb cleaner in the bores...acts like it's going to start, but doesn't...crank some more...a 2-foot flame shoots out of the throttle body...crank some more...another flame shoots out...crank some more...

...and it eventually starts after MUCH pumping of the gas pedal. The initial start also involves TONS of black smoke being cast out of my tailpipes. It cuts back to a much smaller amount of black smoke after that. I originally thought this difficulty in cranking was OK because (a) the engine was totally cold due to the car sitting for several weeks each time I work on it and (b) I could kill the engine and it would fire up immediately with no problem at all once the engine was warm. It still concerned me, though...it just seemed like it wasn't getting enough cranking fuel or the timing was off, even though we had already set the timing dead-nuts with a timing light. As for the smoke, I'm pretty sure it is due to running rich with the larger 454 injectors...which is a separate problem in itself because I can't get WinALDL to work with my 1228746 ECM to get data and make BPC/VE table adjustments.

Anyway, this weekend I was actually able to work on it for two days in a row, and I had the exact same problem both days for the initial cranking of the car. I mean, it took like 10 minutes of desperate cranking to get the engine to light (and LOTS of flames shooting out the throttle body). I checked my trouble codes right after start-up and found a Code 54, which indicates low fuel pump voltage. I disconnected the battery to reset the codes, fired up the engine again (which of course it did immediately now that it was warm) and there were no trouble codes at all. It is as if I am getting low voltage to the fuel pump only when the engine is cold or something.

Does anyone know what is going on here? Why do I have absolutely no problem cranking it once the engine is warm? And is my engine getting severely damaged each time I go through this horrid initial cranking procedure?

Fredless

I had a HARD time getting my 350 H.O. started the first few times. It was running WAY to rich and at the time I was using 65pph injectors, plus JET AFPR turned all the way down. Had the flames etc...It also wasn't timed right and it still isn't, but its the best we could setting it old school.

Keep playing with the timing. Put your SB TBI back on with 305 or 350 injectors MAX with the GM VAFPR or STOCK FPR...If you want it to run, ditch the 454 TBI. I had a TERRIBLE time with mine and couldn't get it to work. And thats after running the new engine for a few months.

If you want to get it to run just so you can drive it, SB TBI back on with 305 injectors with stock FPR. I know some members will say it will run lean, which is ONLY under WOT. I ran my car with the stock FPR and 305 injectors for a few months like this and no problems. Then I bought the VAFPR and I could feel it pulling better on higher rpms. Finally got some 55pph +GM VAFPR seems to be the sweet spot with the 350 Stage 1 generic chip from tbichips.com

Once you get it running right, mechanically wise, start doing tuning and upgrading. I think your fuel pump is ok because its running rich. Your injectors are spraying WAY to much on start up because its cold.

Also, did you set the timing at 12 advanced (I think)? Look in the booklet that came with your crate motor.

AJ_92RS

Pumping the throttle and using carb cleaner shouldn't help.

Pumping a TBI is just exercise for your foot. There's no accel. pump to respond to your pumping.

If it's running rich at start-up (which the black smoke indicates), the carb cleaner is making it run MORE rich. I'd suggest you stop using it.

The easy fix for a stock TBI that's "flooded" is to HOLD the accel. pedal to the floor and crank it. This sends a signal to the ECM that the engine doesn't need fuel. It will reduce the PW dramatically, if not cease squirting. That's what you should try.

I'm gonna suspect you have a fuel leak into the engine, be it an injector, or somewhere near the TB. Place a piece of cardboard, or a small paper cup under the injectors and leave it overnight. Check for fuel stains (the fuel will probably have evaporated) in the morning.

If it's not that, I'd suspect the ICM. Mine did that for about 2 months. It would only do it after the car sat overnight, or for a string of days. I could see the damn injectors spraying, but it wouldn't start. Once I got it started, it was fine the rest of the day.

That could also explain your rich problem. The injectors just dump fuel until the ignition module either lights the fuel, or tells the ECM to stop squirting fuel.

Bulldog92

iTrader: (1)

Fredless----I think I may just have to take your advice, my friend. I wonder if I could just swap out the injector assembly as opposed to the entire throttle body...I'd like to avoid having to wire the old IAC connector back in to the harness if I can. That may not work, though, since the 2" bores may mess up the A/F ratio. If putting the old 305 TBI back on will get my car back on the road, I'm ALL for it. As for the timing, we set it at 10 degrees BTDC, exactly according to the GM specs.

AJ_92RS, you're exactly right...the carb cleaner would just make a rich situation richer. The only reason I used it was because it did not appear that the injectors were spraying much, if any, fuel into the bores. The carb cleaner actually seemed to help the car start, even though it doesn't make sense. As for pumping the pedal, I did not originally think it would help at all...I initially just tried holding down the pedal as I cranked it, but got absolutely nothing after lots of cranking attempts. Pumping the pedal actually resulted in the engine attempting to light up...ultimately, the engine barely lights and pumping the pedal is what actually makes it come to life. I know it doesn't make sense, but it's true.

As for the fuel leak...do you mean the injector may actually be dripping fuel into the engine when it's not running, resulting in a totally flooded engine? That's interesting...I'll place something underneath the injectors and see if I can find any evidence of the such. Also, you mentioned that you suspected the ICM...don't have a clue as to what that stands for. Is that a different issue than the dripping injector?

AJ_92RS

Yes the injector can leak while the engine is not running. It's rare, but it happens.

I'm sorry. The ICM is the Ignition Control Module. Pull it out and take it to the local parts store and have them test it.

If ANYTHING doesn't look right, buy a new one. The lazy *** that tested mine said "It's fine."

Then I asked "Why was that one red light on the tester flickering?

"It just does that."

I said "Well give me a new one anyway."

Car's been fine ever since.

Just remember to use that grease stuff if you do change yours. It should come with a new one if that's what your problem turns out to be.

Bulldog92

iTrader: (1)

Thanks for the translation...I've got a 3-page list of all the abbreviations I read on TGO, but you stumped me on that one. Joining TGO discussions almost requires learning a new language, especially over on the DIY PROM board

I'll definitely get my ICM (check me out) tested...looks like a new one only costs about $30. As for the possibility of a leaking injector...what would be a fix for that? Would I just have to install new injectors, or is there some kind of internal seal that could be replaced?

AJ_92RS

I've been lucky enough to never have a leaky injector, so honestly I don't know how to fix that problem.

Sucks to be me, right???

Brent

iTrader: (1)

I'd swap the 305 injectors into the 454 TB and put the stock prom in, and see how it starts. That should remove the rich condition. Do not go to WOT setup like that.

Bulldog92

iTrader: (1)

Thanks, Brent...I'll give that a shot after I eliminate the leaky injector and bad ICM possiblities. I really appreciate all of the input...good to have some support when all you want to do is yank your hair out

dimented24x7

iTrader: (2)

I did this dozens of times over the last few winters. Not all the ecms seem to cut the fuel by holding the pedal to the floor, not to mention that itll shoot flames out teh tbi. Just unplug the injectors and crank the engine for 5 seconds. Itll dry the plugs and clear out all the fuel w/o the mess. When its clear. Hook up the injectors and try again. The immidiate flooding is a sure sign that your mega rich. Get the smaller injectors that are closer to your stock ones pph wise. Some very cold start problems are inevitable, like fuel puddling for me, but if your giving it that much fuel, you wont have a snowballs chance in hell of having a normal cold start since all teh gas thats on the floor of the intake immidiatly rushes into the cylinders as soon as the engine fires and it gags and immidiatly stalls. Also make sure your starter is in good shape. A slow turning engine wont start as easy as one that rotates at the normal speed.

jasonbennett

try backing off your initial advance and see if that helps too. that is a classic symptom of too much ignition advance. it shouldn't take much maybe a couple of degrees.