Engine started to "puff"

[totle]

I have just barely driven my car after engine rebuild.
Yesterday I went for a small drive to measure AFR. The engine stated to jump, got fire from the exhaust and died.
I found that the wire between distributor and coil, was loose since I there was a spark to ground spark wires on distributor
I hooked up the wire and the car started but was running poorly.

Today I have tried to figure out what is wrong.
Ignition is correct, but when misfires, it jumps between Z1 (TDC) and 10 degrees.

I measured the pick-up in distributor since I was not sure if this was destroyed to to spark from coil on spark plug wires.
It was measured to 650 ohm, so I guess this is all working.

I removed all the plugs and 5 of them was dry (little to black, but running too rich)
The spark plug on cylinder 1 was wet
I checked and verified that there was spark on this spark plug.


Tomorrow I will do a compression test on cyl #1


Please help with suggestions, running out of ideas now

Next I'm thinking loose rocker arm, exhaust side??

Not a good video, but might give you a clue. The "puff" you hear is air coming back and out intake manifild

[WERK I]

Are you sure you don't have the distributor 180* out or spark plug leads incorrect?

[totle]

I went over the spark wires and the orders are correct.
When installing the distributor I installed with cyl 1 in TDC, so should be good.
Also the car was running well 2 days ago

[WERK I]

For fun, you might try swapping out the fuel pump relays with two known good ones. The black ones will work for the test. I had a red relay go bad that controlled the front pump and my engine sounded similar to yours..... almost like I had a major engine fault. As soon as I tried accelerating the engine, it died. Relay solved the problem.

[totle]

But there was only 1 spark plug that was wet.
This would not happen if fuel pump was bad

[WERK I]

But the other 5 were sooty. It was just an idea. It is a lot easier swapping in a couple of relays than removing a valve cover.
I just can't see an engine running fine one day and then started up a couple of days later, the exhaust rocker is loose.
IMO, of course.

[totle]

But there was only 1 spark plug that was wet.
This would not happen if fuel pump was bad I guess

[totle]

Going to Germany the 23'rd to Nurburgring.
Need to have my car ready soon to drive and test it out before i go

[torresmd]

You probably already did this but check all fuses especially in the engine bay.

[911st]

To do the spark plugs you took off the intercooler.

I would look for somthing that is making for an intake air leak and check the intercooler O ring did not get pinched.

If that dose not do it then put the CIS gauge on it and check the system and warm control pressures.

[WERK I]

Let's start with the basics and do some very easy tests.

Unplug the green connector on top of the fuel distributor shown in the photo. DO NOT PRESS ON THE METERING PLATE as this could hydro-lock your engine with fuel........very bad.
Turn the ignition key to "On" and listen for the fuel pumps in the front of the car and at the left rear wheel well. After you've confirmed the fuel pumps are running, turn the ignition switch to "off" and reconnect the plug on the fuel distributor.

You mentioned that you got a fire out the exhaust pipe which makes me suspect the engine is being put in an over rich condition.

[totle]

YES, found the fault today.

Turned out that the plug I had made to block the whole where the AAV had been, had blown out.
I was so focused on checking ignition, that I forgot looking for air leaks. It was when a friend came over he saw a fire ball coming from the hose
I now have used a better plug and glued and sealed the whole.

Here is a picture showing what I mean


I am still running too rich.
Is it only the CO adjuster to adjust to make it more lean?

What would a typical idle AFR be at?

[RarlyL8]

Fireball? That's a new one.
I block that port with a large pipe plug and worm clamp.
Idle is 13.5:1 AFR / 3% CO. Yes mixture adjust screw does this function.
I notice that the oil breather hose hard line is not secured to the intake bolt but rather sitting on top. Engine is really clean! Nice!

[totle]

Brian, picture was taken of the engine before it was put back in. It is secured:-)

[mooney265]

Originally Posted by totle

Brian, picture was taken of the engine before it was put back in. It is secured:-)

I was wondering how you got that "angle" on the picture... The camera would have had to been inside the rear fender...

[mooney265]

Originally Posted by totle

YES, found the fault today.

Turned out that the plug I had made to block the whole where the AAV had been, had blown out.
I was so focused on checking ignition, that I forgot looking for air leaks. It was when a friend came over he saw a fire ball coming from the hose
I now have used a better plug and glued and sealed the whole.

Here is a picture showing what I mean


I am still running too rich.
Is it only the CO adjuster to adjust to make it more lean?

What would a typical idle AFR be at?

If you don't have a way to verify your idle AFR settings, my mechanic always said you can push the adjustment screw in while the engine is idling. If the idle goes down initially [the split second you depress the screw], then you're too rich at idle. If the idle goes up initially, you're too lean.

Now, this is only for idle mixture adjustments...

[RarlyL8]

Yes it's on a stand as the throttle cable is not connected. The heads up on the tube was to get that fixed before the engine goes in. Ask me how I know, ha!

[911st]

As it was getting spark and fuel I thought it sounded like a leak in the intake tract but never would have guessed that one.

[WERK I]

What get's me is the plugs were sooty and wet, the engine ran(barely) in the video posted above, with that big air leak in the intake tract. It really shouldn't of started at all or started and immediately stopped.
Something still isn't right with this engine.

[totle]

It might have been ignition issue as well.
I removed distributor cap and checked. Re-ired the spark wires.
Adjusted AFR today from 9 to 13,5 at idle.
Engine is running fine at idle and boost. Will log AFR now.
One strange thing I noticed today was that when accelerating in a turn, left or right, it seems like engine is loosing ignition or fuel, and stuttering and ends with a bang in the exhaust.
When accelerating straightforward all is well