Question : Spark but no detonation at all..

[Texasguy]

Just assembled my car from doing a valve job, it has an engine with a distributor 3100 3.1L.

Problem is that I have fuel going, spark is there, starter is revolving the whole thing... but there is no detonation at all. Not in a wrong order, not even a weak one.

At one point I was cranking a lot and pushing gas pedal at the same time, I think I heard 2 puppy explosions (really weak) but they kinda put a little fire to the top of the intake where fuel is spayed, I am not even sure it was a detonation, more over-saturation of gas. I might have over-flooded the engine then...

What should I check for? I am a little at loss... The car acts as if spark plugs are not installed. I was hoping at least at some rough idling until timing is set correctly..

I think I put the distributor on correctly, at cyl #1 at TDC, I put the distrib in and called the plug #1 where it was pointing at. My thoughts that even if distrib is put incorrectly, it still should fire some even out of order, not that it is a good thing but I am looking for any signs of life at this point.. Yet the spark is there, I took a few boots off spark plugs and while cranking it did produce good strong electric pings to the wrench.

Could a distributor be placed such that it would make an engine "inert" ?

BTW, I have a new fuel pump that was replaced like a month before I did the engine. So, the pump and filter are all new, relatively. Spark plugs and the wireset are also bought before the engine started to give me noises (lifters). Distrib cap is also almost new.

So, what should I do?

[Texasguy]

PS: Couldn't sleep, was thinking, could it be timing chain? Though it did seem that cam was moving when I was doing pushrods and was turning the engine manually.

[95Grand-Am]

I would recheck the timing, you might have the timeing off or 180 degrees off. Find the compression stroke on the 1# cylinder and reinstall the distributor.

[Superdave]

ok, we need more info on your engine/application.

you say it's a 3100 which is a gen3 engine that does not use a distributor.

Is it a 3.1 Iron head engine as found in a Camaro/S10?

[60dgrzbelow0]

GM V6 Distributor Installation Procedures...

I would recheck the timing, you might have the timing off or 180 degrees off. Find the compression stroke on the 1# cylinder and reinstall the distributor.

Texasguy...

I agree with 95Grand-Am. Here is a helpful procedure list to check your actions against:

Three things are called for for this timing setting to be done correctly...and all must occur at the same time:

(1) The block side insertion end of the distributor must mate up with the Hex Drive Shaft of the Oil Pump.

(2) The Distributor Helical Drive Gear Teeth must mate up perfectly with the matching gear teeth on the back of the camshaft.

(3) The Distributor Rotor must be positioned to the firing position of the #1 Cylinder WHEN THE DISTRIBUTOR IS FINALLY SEATED COMPLETELY INTO THE BLOCK.

To guarantee that you are on the compression stroke of the firing cycle for Cylinder #1, begin rotating the crankshaft until you see the timing mark or notch on the harmonic balancer lined up with the "0" mark on the timing tab mounted on the engine block. To confirm that you are on the compression stroke in the cycle, you should get some help from someone who can hold their finger across the spark plug hole to feel the air compressing and expelling as you rotate the crank, approaching TDC.

Next, to identify when the Dist. Rotor is pointing directly at the #1 Spark Plug Tower in the Dist Cap. You can do this by installing the Dist. Cap for just a minute and after tracing the plug wire to the #1 Cylinder, mark the base on the outside of the cap with white paint at the location where the Cylinder #1 Spark Plug terminal is located. Now...this is the helpful part... Take off the Dist Cap and then rotate the Dist Shaft until the Rotor is positioned 30 degrees in front of the white mark you just made when viewed from above.

While holding everything in place, slip a new Dist Shaft gasket over the end of the Dist Shaft. Then lower everything into the hole in the block very slowly until you make initial contact. This happens in a step-like fashion, with the Dist Shaft contacting the Hex Shaft or late model shaft design of the Oil Pump Drive and the helical gear teeth on the camshaft mating almost simultaneously as you slowly lower the Distributor further down inside the engine. Watch, as the rotor will turn clockwise, assuring the gears are meshing on the way in. But even with all this attention to detail...the base of the distributor may STILL not be flush with the back of the engine/manifold.

Getting it all the way in right involves gently rotating the base of the distributor and the rotor itself back and forth... very slightly until it finally drops into place. If it does, make a quick check that the position of the rotor electrode tip aligns with the white mark you made on the Dist Cap... to within about 15 degrees. If it does, you can adjust the timing afterward by rotating the body/base of the Distributor to get the sparks to fire on schedule. But if it is too far off the right firing position when the #1 Piston is at TDC, take a deep breath, relax... then swear loudly and pull the "Effing" Distributor out completely and start all over again until you manage to get it right.

Once this nightmare is over, install your Distributor hold down clamp and bolt and tighten it just enough to allow you the chance to rotate it on its axis without too much force...but not free-wheeling or loose to the point where engine vibrations and torque on the shaft from the cam helical gear can dislodge it from inside the engine. When it comes time to start the engine, swing the Distributor from one side to the other slowly and once you have its range of adjustment arc identified, return the Distributor body to a mid-point as your starting place before firing up the engine. This way, you will have a feel for the amount of advance-retard you can do by knowing how far you have to move in either direction. If the engine fires up while trying to start it...Don't forget to tighten the hold down clamp snugly to finish the job.

Good luck with the rest of the repairs!

--==Bob==--

[SappySE107]

Have you done a compression test?

[Texasguy]

Wow, this is some detailed description, I will attempt Monday to do that step-by-step. I so hope that it is incorrectly put in distributor that is causing all this as my signif-other is taking it hard that I have to use her car.

I have not attempted a compression test yet, the battery is out of juice from all that cranking, Autozone should recharge it while I am at work. However, I doubt that all 6 cyl have a bad compression at once, even with unevenly distributed compression the engine would at least try to get to idle speeds, be it successfully or not. In my case I don't get any boom at all. Before I did the valve job, the engine always was starting up great even when it ran noisy at the end. I cannot imagine I could have affected compression since then..

I have found it the hard way that manuals make it sound easy by skipping some real advice.

[Texasguy]

A question:

Rotor is kind of an axis rotating inside, the distributor body is holding it. Rotor should be positioned to (when distrib is lowered all the way down) where #1 on cap is. Question, does it matter how the distrib body is positioned in respect to the engine or the rotor (when it is all pushed down)?

[60dgrzbelow0]

A question: Question, does it matter how the distributor body is positioned in respect to the engine or the rotor (when it is all pushed down)?

The short answer is: Yes.

But the reason why follows in a much more detailed and hopefully illuminating explanation.

(Please forgive me these two (too) lengthy back-to-back-posts)

The Distributor Rotor Shaft is kind of on an independent axis, rotating in only one direction while encased inside of the Distributor Housing (Body). To perfect a "starting point" for the cycle of firing spark impulses to each spark plug in proper timing, the Rotor (Shaft) has an armature fitted with a Brass Tip mounted on the outer edge at a right angle to the axis of rotation. This tip is capable of carrying an electrical charge delivered by the high voltage coil packs via a single central electrode fitted in the center top of the Distributor Cap and a spring loaded carbon 'Button' that stays in contact with the center point of the rotor and routes electricity down a wire connected to the rotating Brass Tip of the Rotor.

The High Voltage Electric Charge is very much needed to make a spark jump across the gap area between the spark plug tip in conditions of nearly ten times atmospheric pressure at sea level. This charge comes from the coil (s) and is considered always "ON". This electric charge is only released in a closed circuit when the Brass Tip of the Rotor comes into very close proximity with any of the Six (6) (sometimes eight for V-8 engines) Brass Electrical Contacts fitted inside your Distributor Cap leading to the Six Spark Plug Wires.

The whole idea here is that when "Setting the Timing", it is necessary to initially prepare this entire sequence by starting on Wire Position #1 to make it ready to fire an electric pulse down the wire to the spark plug in the #1 Cylinder at just the right moment. If this is done correctly and if all the other Spark Plug Wires have been fitted properly inside of the Distributor cap in accordance with the proper firing order in your engine manual, then they will follow suit and do their jobs perfectly.

This is also why it is important for you to ensure that the piston is on its way up to the top of the cylinder on the Compression Stroke at a time when both the intake and exhaust valves are completely closed up tight to allow the ingested fuel and air to be squeezed in anticipation of being set on fire when the spark plug fires and ignites the mixture. Because gasoline vapors burn rather slowly as opposed to immediately detonating or exploding to create their high energy during confined combustion, it is preferential to have the spark plug firing just a "little bit" before the piston reaches "the end of its rope" or at Top Dead Center (TDC).

This sort of "head start spark" allows for the combustible, compressing mixture of gasoline and air vapors to burn as completely and efficiently as possible to create the maximum expansion or "push" on the piston head at just the right time to get the most force possible to push the piston down inside the cylinder and complete its Power Stroke.

You can see that if you are 180 degrees out on the insertion of the Distributor, then "sparking" the spark plug in Cylinder #1 would be wasted at a time when the piston is rising, the exhaust valve in Cylinder #1 is opening and the upward motion of the piston is serving to expel all the burned waste gases it needs to vacate from the cylinder. With nothing flammable left inside inside Cylinder #1 to burn ...your spark plug will indeed fire ...but it will have absolutely no "Pop" effect as you called it happening at all.

As for the Distributor Housing encasing the Rotor Shaft, this is where the more subtle adjustments in timing can be made once the Distributor Housing is at home inside the block. The housing around the Rotor (shaft) is capable of a very LIMITED range of rotational motion, but just enough to change whether the Brass Tip on the Rotor (shaft) arrives in time with each electrical contact for each Brass Spark Plug Wire Contact inside the Distributor Cap...to be either a little before (timing advanced) ...or a little after (timing retarded) the piston in the #1 Cylinder is reaching Top Dead Center on its Compression Stroke. Too much rotation of the Distributor Housing (Base) either way...and you either get a kind of "Pre-Ignition" effect that actually inhibits the motion of the piston...or a lack of power because the "Firing" of the Spark Plug comes too late to burn the fuel/air mixture completely.

To accomplish this, one simply has to rotate the Dist Housing (Base) either to the left or to the right to make the Six Brass Electrical Contacts inside of the Distributor Cap be either closer to or farther away from the Rotor Tip as it spins independently inside the Distributor Housing. If the Dist Housing is moved in a direction slightly opposite of the direction of the Rotor Spin, then the spark firing happens sooner and is called "Advancing Timing". Likewise, if the Dist Housing is moved slightly in the same direction as that of Rotor Spin, then the spark firing happens later and is called "Retarding Timing". And so...you can see that "Setting the Timing" all comes off of making sure to follow the instructions previously detailed above to make everything work correctly on the #1 Cylinder.

[robertisaar]

^at least you put the short answer first...

[60dgrzbelow0]

^at least you put the short answer first...

From his responses to my posts, the OP...Texas Guy, seems to have really appreciated the more detailed and informative answers given about a very complex mechanical problem. But if it happens that he indicates otherwise when he returns to tell us all of his progress (hopefully), then I'll delete the longer explanation(s) to spare his sensibilities in general ...and since you seem very concerned about their length ...yours, in particular.

[robertisaar]

...and yours, in particular.

????

[Texasguy]

I have suffered an utter and a complete failure to start the engine today. I have repositioned the distributor not less than 6 times. Watched fuel to give a nice firm spray. Wires to give off a good solid spark. Watching at the fuel lines I had an idea to torch the van then hang myself on the rope I fed into the cylinders. You think just the car has problems? You are so wrong! Then I had the image of crashing the damn van at 120 mph (the max my speed scale shows) but I was spared by the fact that the damn thing won't turn over...

Tomorrow I will go to the Gander Mountain to price a desert Eagle in .42, I think I have enough savings left to blow that 60 degrees V6 to its bits and take a few windows out with a gun handle.

This is a first DIY project I have failed in my life. Tomorrow when I will wake up sober I will probably humiliate myself to the worst degree by asking for a paid help on Craigslist. If it won't cost much I might have enough for a professional psychological help, hopefully with an ability to prescribe drugs. God knows, I need all the help.

[robertisaar]

texasguy: shit happens, and electrical problems are about the worst you can get since they take forever to figure out...

[CNCguy]

What should I check for? I am a little at loss... The car acts as if spark plugs are not installed. I was hoping at least at some rough idling until timing is set correctly..

Texasguy... I assume by this statement you are saying that the engine is cranking very easy like there is no resistance. If so, it sounds like there is no compression. Distributor orientation will not change your compression. As Ben said, a good place to start is to check your compression. If you have a lack of compression, perhaps the valves are not adjusted properly.

You need fuel, compression and ignition to run an engine. You said that you have fuel. Check to insure that you have compression before beating your head against wall on the timing issue.