Troubleshooting Help

blandq

Founding Member
Jun 10, 2002
146
0
16
Houston Texas
It's been a while...kids job etc. Here goes the tale. 5 years ago I had a small accessories fire that took out windows door locks nos controller but did no other damage. The car was not drivable in that state at the time as I believed the damage was far worse. A day to a week new job, moved built a house...stang sat covered with 2000 miles on ...everything until 1 month ago.

Cleaned it up, removed bad wiring and focused on the engine. Got the wiring figured out, clean the engine bay up, pulled all plugs, oiled the cylinders, hand turned the engine. Filled my pre oiler with 2 quarts and pushed that through the motor. Connected new optima, and turned the key.

Started right up. Ran for a minute or so then turned it off for review. No leaks all looks as it should. Went to start again....nada, no spark. Trouble shot, MSD 6al is the culprit. Bought new ...had to do new wiring as my old one was pre connector.

Got done, tested for spark, nice! Turned the key...started right up!...sounded cold normal. Ran about 30 seconds, coughed and died abruptly.

Since then it will only start with throttle, will not run without throttle. Behaves similar to a rev limiter in sound with additional throttle and bogged down. I believe all cylinders fire. Note I have not touched nor altered any timing components. I run the big MSD billet distributor, 13 degrees initial advance 35 total mechanical all in by 3000 mag pickup.

I believe the "cough" which sound more like a weeze. Air pushed back through the intake without a spark??...I was in the cab at the time. Anyway is the big clue. As well I believe the engine is running hot but difficult to tell. 8m .04 over on the original '64 block. ..she heats quick.

I've also thought of head gaskets, lm 11.8:1. But don't have a reason. ..age? Sitting? Also thought it sounds really really rich. I did pull the carb ...very clean inside and put it back together prior to first start....just what I do before I start carb'd engines.

What are the 1, 2, 3 things to check?
Please help me think through the symptoms to at least understand what the motor is doing....

Thanks!
 
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Next I'd pull the plugs and see if they are fowled (black) if it is running rich they may be all carboned up.
Next I would verify you are getting plenty of fuel. After sitting that long you could have blockage and only be getting minimul fuel. Pull the fuel line of and see what you are actually pumping. You also could have water in the fuel? Is it all fresh fuel?
 
Morning tos, Many Thanks! Appreciate being welcomed home!

Agreed. The behavior and sound are not quite right but similar to jumped timing; (1) abrupt...or so it seemed, I was bringing the engine up, no more than 60-90 seconds running. Meaning, the issue could have been there from the start but don't believe so. My son (17) was there on the initial start and we did hit about 3/3500 rpm via slow throttle from idle up and back down and my ear recall smiled! It sounded like my baby was alive. (2) gotta keep throttle open or no run, So, I'm keeping the one clue...was good, abrupt change during run, now not good. Last night I removed the Start/Retard controller from the Ignition and used the Mag Pick-up directly of the 6AL with ZERO change in behavior! Since the 6AL is not programmable, is brand new, let's assume for now the Spark from the 6AL is 100% aligned to the Mag Pickup and not molesting the timing. To your point that does put the spotlight on Fuel Air Ratio.

I scoped the tank prior to start as well it too has only a thousand miles on it. It was clean as a whistle. Lines are all stainless and I DID NOT clean them out! I did open the carb Edlebrock 1405 jetted Fat in the secondaries and inspected, it too was very clean. BUT clearly....If the car wont idle at all without cracking the throttle, the idle circuit on the carb is not functioning correctly (still assuming timing is good). Secondly, if it was just the idle circuit I should be able to overcome that Air:Fuel issue with throttle but no, advancing the throttle yields the 'rev limiter' - starvation sound and RPMs are limited to ~2K. NOTE: I have not exercised the throttle past ~ 10-15% @ that point since it's not clear what is going on. Last clue on lean would be I believe she's running pretty hot.

Tonight:
1. Pull the fuel line of the carb, check for volume. If good.
2. Pull the Carb and look for a common (Idle, part, full throttle) fuel restriction.....clean it out soup to nuts.

I'll have to review the carb circuits on the 1405. I'd like to have a target area to look for Vs. just cleaning it again. Have any thoughts?
 
Even if you get good flow I believe Edelbrock uses a glass bead filter under the banjo fitting on the carb? (could be wrong) I would take it out and clean it. An issue I once had drove me nuts. I went thru two or three pumps before I figured it out. My car kept stalling while on the road. I had two inline glass bodied filters, one at the tank and one before the carb. I could see nice clean fuel in both but kept having fuel starvation fuel issues. After a few minutes the car would start and run for a bit then do it again. It mimicked vapor lock. My filter at the engine was clogging but I couldn't see anything in the filter. The stuff was like fine grain sand and was about the same color. It clung to the filter screen and couldn't be seen from a couple feet away. No sediment in the filter bowl itself. One day I pulled that filter and looked real close then I could see it. Don't know what it was but it wasn't rust. Maybe some sort of tank coating from the PO?
 
Morning! Have made some progress but symptoms continue to confuse.
Inspected and tested all fuel items to carb. 6psi on the nose, plenty volume.

I backed out both idle circuit screws 4 turns from my normal two. Ran better. STILL have to Crack the throttle to keep it running. But seemed a smoother transition to main circuit. As well the engine does not heat up near as much. Backed them out another turn and got a backfire in carb with flame.
Suggesting too advanced...

I open the distributor and made sure the weights were not stuck and nothing looking odd, etc. in the mag pickup. all good
Re-re-checked my firing order. Good
turned in the carb idle screws 1.5 turns each
FINALLY decided to back the timing off. Rotated CCW about 5-10 degrees by sight.
Hard starting...didn't want to start, then got a small backfire out the tail????

QUESTIONs:
How does a carb backfire effect the 1405 carb?
I believe the original point of change was a carb backfire (the weeze) that actually popped of the driver side vacuum port rubber cover.
I Run a split plane manifold.

WHAT would the symptoms be if 1 of the idle circuits was (?) Non-functional, Zero fuel but the other side was fine?
By opening up the idle circuit I would be running FAT on 4 cylinders and Lean on the other four...4 trying to run well, 4 acting very very different.
 
Yes if is a true split plane you would be running a bit heavy on one side with your screws out as far as they are and lean on the other (at idle) but you should be able to verify that easy enough by feeling the exhaust on each side.
Check again for additional vacuum leaks? Cracked carb baseplate?