# No start, no spark



## 1967pontiac400 (Dec 10, 2020)

Hi all,

As of yesterday my 67 GTO was running great, I spent the day dialing in my idle mix screws on the tri-power and all was well. I started her up to go for a test drive and it idled a little low and died. I went for a re-start and the starter cranked and cranked but not so much as a cough from the car. What's odd is I started the car at least 15 times and it started right up within 1-2 seconds each time.

I spent all of last night and today working on the ignition system. I replaced the condenser, points, coil, two new sets of caps and rotors and two sets of plug wires. The plugs were replaced a few weeks ago and the gaps were triple checked and I don't believe to be the problem. In all testing ran a lead from the + battery cable to the coil to ensure the ignition switch was not the issue. During these tests, I ran a timing light on various plug wires to check for spark and saw nothing. When I ran the light on the coil wire however, there is spark every time. Something it going wrong I think in the distributor where spark is getting in from the coil but not making its way out.

I followed the 67 service manual troubleshoot flowchart for this and it said to "check the cap and rotor". I'm absolutely stumped and have no idea why the spark wont make it out of the distributor. The only thing that seems odd is it's sitting a little crooked, perhaps 4 degrees off center and there's some play up and down on the assemblely so is it possible the cap and rotor are just too far apart?

I'm about to upgrade to a pertronix electrical distributor system to eliminate as much of these complication as possible and get a more reliable spark.

Any ideas? Thanks in advance!

-Will


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## 1967pontiac400 (Dec 10, 2020)

Update: The engine was running overly rich for a couple of weeks while I diagnosed a vac leak that ended up being bad throttle seals on the tripower secondaries. Because of this, I checked the plugs tonight and they are super carboned up and are probably not letting spark through. I put the plug wire to the block and saw spark so I'm now thinking it must be mucked up plugs. Will post an update if that cures the problem.


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## 1967pontiac400 (Dec 10, 2020)

Update 2: I put in new plugs today, triple checked the gap and installed. The car had trouble but it did fire, however, it was loping at idle really badly and needed some throttle to stay alive at first. It felt like it had a big cam (it does not) and at one point a plume of what I suspect was exhaust smoke plumed in the engine bay. I have no idea if that means a head blew or if a valve is stuck or what - I suspect it came out of the valve cover breather but I'm not 100% sure. 

I fired it again, no smoke this time and it was able to idle on its own although it was a bit choppy. I dialed in the correct dwell angle and shut down the engine. I went to re-start it and check the initial timing but it would not come back alive. The same problem re-occurred as before,starter spinning, and not so much as a cough from the engine. 

A diagnosis using the timing light indicates good spark from the coil but nothing going to the plugs. 

Back to the drawing board!


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## PontiacJim (Dec 29, 2012)

Hmmm. Pull the plugs again. Almost sounds like a flooding issue seeing the plugs were black and fired up with new plugs, ran rough, and smoke blew out - then died again. You didn't break/stretch a timing chain? Have you checked for this. Original stuff is only good for about 50-60K and have the nylon coated timing gear.

Next I would check all my ground connections from block to frame and block to firewall.

It seems odd that you are getting fire out of the coil wire going into the cap. It is possible the rotor is not making contact well enough with the electrodes on the cap. The cheap thin flat metal rotors suck. You need a good brass rotor from someplace like NAPA, the Echlin brand. Same goes with the cap, you want brass contacts, not the cheap aluminum. 

There is also a black ground wire inside the distributor that attaches to the points plate. We have had members swapping out parts only to find that this wire had broken loose and once repaired, car fired up.

Just a few suggestions.


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## 1967pontiac400 (Dec 10, 2020)

Thanks, Jim this gives me a few things to try. 

The engine was rebuilt and only really idled and driven around the block a handful of times so everything is really fresh.

I have tried running NOS cap and rotors and at the moment have a duralast gold cap and rotor on the car. 

I will check the ground connections next. 

I suspect the same issue with the cap and rotor connection. I don't know if this is normal (I'm newer to carburation), but there's play up and down on the distributor rod that goes down to the cam, it seems almost as if it might be spinning under the cap and not connecting anything?

I have run my spark tests so far using a timing light for the most part, maybe it would make sense to do the spark to ground test and see if it's no spark or weak spark.

One other piece of info I can share is that the power to the coil when the ignition is on run is only about 6 volts. Is that too low? I've jumped the coil to rule out the ignition switch as the issue.


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## AZTempest (Jun 11, 2019)

I had symptoms like this awhile ago that I chased similar to what your doing and it turned out to be bad points. Got a quality brand new fresh set and all was good.


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## Lemans guy (Oct 14, 2014)

Make sure that your distributor is bolted snug to the block and also that your tab on top of the rotor is up enough to make full and strong contact with the cap, you can bend it gently with your finger, very gently and not much do not break it. If it is a new cap and rotor in the box there may be a paper guide that shows you where that rotor button must sit so it make contact. You put that piece of paper on the rotor and you can see if your contact is at the correct height.

The resistance for the points in run is more like 9volts than six, six ix is pretty low. Make sure your battery is at full charge and retest that circuit.

as for play in the distributor shaft , it sounds like you may have too much. It should not feel sloppy it should be tight 10 to 15 thousandths.

pull the dist nd check the play with a feeler gauge, A lot of them are very sloppy, when they get up to 75 or 80 thousandths they cause idle and timing issues easy.

It is an easy fix with a pack of Moroso distributor shims, about $10 , you pull the distributor, mark the dist shaft to gear so you can replace it in the same orientation, knock out the roll pin out of the gear remove the gear and add some shims, keep the thin ones in the middle check with a feeler gauges eat cose to 10 or 15 it is not a crank bearing, does not have to be exactly 10 or 15, even up to 30 or 40 they run fine, but is real sloppy they don’t.

So some more things to check, but you are moving along stay it!


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## 1967pontiac400 (Dec 10, 2020)

Thanks for all the replies!

One other thing that occurred to me that I ought to mention to the group here is that the new following parts that I installed are NOS, but have been sitting in a box for about 40 years, not sure if they have a shelf life. Those items are:

Cap - since removed and replaced with a duralast gold
Rotor - since removed and replaced with a duralast gold
Points - AC Delco
Condenser - AC Delco
Plugs - AC Delco

On my to-do list from all of your feedback will be:

Replacing duralast cap and rotor with NOS AC Delco that are brand new, just old unless the consensus here is that the shelf life expired on these
Using paper to gap test cap and rotor to ensure good contact
Checking shaft of distributor for an approximated play, I suspect there is too much to AZTempests point, if so maybe a "new" unit from Ames is the best bet
Check circuit to determine why the coil is only reading 6V rather than 9V with the ignition key on the "run" setting
Put on new wires (I have a fresh box of blue streak 8.5mm wires from standard ignition
Check all ground connections
Check black ground wire inside the distributor that attaches to the points plate
Spark test new plug wires to ground and watch for spark - the timing light did not read and blink any light during cranking on wire 1, so maybe it is just a weak spark as opposed to no spark. 


I also ordered a plug tester and remote starter to make testing all of this stuff on my own a ton easier. 

I'll get this all going tomorrow, thanks again to everyone for the help and support!

Happy new year!!


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## 1967pontiac400 (Dec 10, 2020)

Hi again all, I wanted to post a quick update. I was working on going through this checklist today and noticed that the plug tips are visibly wet with gas, could this all just be an overlooked flooding issue?

I have not attempted to re-start yet but I discovered my GTO did not have a block to frame ground, so I ground down to bare metal and installed one and cleaned some paint under the others, also replacing an old strap that may have been original. 

I still have much more to do, but I wanted to see if anyone thought the gas covered plugs may be the problem here? Might that cause cranking and no coughing ot start from the motor?


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## Old Man Taylor (May 9, 2011)

Yes.


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## PontiacJim (Dec 29, 2012)

Old Man Taylor said:


> Yes.


X2 - Flooding will do it. Several have come here and learned that one.

6 Volts to the coil in the run position can be OK. But, you want 12 Volts in the start position when you hit the key. You should see 2 wires. One will be the cloth covered resistor wire which drops the 12 volts down in the run position. Make sure your battery is up to par as well. Low battery voltage/charge can fool you into thinking electrical issues.

NOS condesor could go bad from humidity/oxidization. Make sure the points contact faces are not oxidized from sitting either. You will read all kinds of do's and don'ts on what to use to clean them. I used to use a piece of really fine sandpaper, but apparently today that is a big no-no - who knew? Others say use a fine emery cloth, points file, piece of cardboard, the striker strip on a pack of matches, donkey urine, a solvent, and Cambell's chicken noodle soup. So you are on your own on this one, but I always used a fine sandpaper like the wet/dry type and just folded it in half, inserted between the points, squeezed the points together lightly, and pulled the paper through - didn't try to sand them down to a nub or anything.


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## 1967pontiac400 (Dec 10, 2020)

So I took the center carb apart and I can't really figure out why it might have flooded, however there are few factors that come to mind that may contribute - perhaps the experts here can weigh in:

1. The idle mix screws were set to 2.5 turns out which I realize caused a rich running scenerio
2. The power piston was stiff, I replaced it with a new one
3. The float was set a little low, maybe 5/32 or so, however, it's running one of those fancy brass ones with nylon on it as opposed to the cone type

I can't find anything that may have changed to cause a flooding scenerio, although who knows, I'm learning that it's not uncommon for tripowers to flood.


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## 1967pontiac400 (Dec 10, 2020)

Is it possible that the choke can be closed too much and cause the engine vac to pull fuel over the bowl if it's set too stiff?


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## Old Man Taylor (May 9, 2011)

If you measure your float the way I do, then it is WAY too high. It would be puking fuel. The spec is 23/32", so yours would never shut off (close the needle and seat). Remember that the float is measured upside down, so a lower number means a higher float level.


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## Old Man Taylor (May 9, 2011)

Also, the float level is measured at the seam in the middle of the float.


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## 1967pontiac400 (Dec 10, 2020)

Sorry, I was not clear. The float was off by about 5/32, sitting at about 18/32. After I made the adjustment today I brought it to 22/32. And it's sitting not 100% level (which I hear is normal) but the 22/32 is right on the middle of the float.


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## Old Man Taylor (May 9, 2011)

I always give it an extra 32” to try to preclude the fuel level getting too high.


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## 1967pontiac400 (Dec 10, 2020)

That sounds like a good idea, nothing wrong with a little safety buffer. 

Is it always common that the brass floats seam is at an angle when measuring the air horn upside down to dial in the float setting?


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## Old Man Taylor (May 9, 2011)

Yes.


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## 1967pontiac400 (Dec 10, 2020)

She's alive!!!

It turned out to be a flooding issue, from what I can tell a few things potentially occurred:

1. Choke was set too tight (potentially pulling gas over the bowl)
2. Valve assembly did loosen itself a bit
3. The float level and drop was off
4. It was running too rich, idle mix screws were about 1 full turn further out than they are now. Currently they're right near the initial setting and that's where the vacuum seemed happiest at about 15in.

I poulled off plug 1 just to be sure and it was dry! I think we're good now, on to getting her dialed in as best as possible and enjoying some blacktop.

Thanks again for everyone's input and ideas here, it has been extremely helpful!

-Will


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## tomwadsworth (Sep 30, 2018)

I had a similar problem. I have a 468 and am running a 65 tripower. Before the tripower I had a Quadrajet and would have problems keeping the bowl full. I put a high flow Edelbrock fuel pump on it and it helped but didn’t cure it. I put the tripower back on it and immediately had flooding problems. I spoke to my tripower guy about it and he said that they only need a few pounds of pressure to run them. So I put my old fuel pump on and all was good. What I am getting at is, you may have a needle and seat problem or a little to much fuel pressure.


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## BLK69JUDGE (Jun 10, 2010)

it might be time for an oil and filter change ...
after all that flooding ...


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## 1967pontiac400 (Dec 10, 2020)

That's not a bad idea, I better check the oil and make sure it's still looking clean!


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## 1967pontiac400 (Dec 10, 2020)

Bad news....the flooding came back today.

I had the car sitting for a couple weeks while I replaced the suspension. When I started her up today to drive up onto some ramps the idle got weird, like I am running a high lift cam, fluctuating between 600 and 1000, chug, chug, chug. 

I did not think much of it and finished up on the ramps. When I started it again to move it back down the pipes spat out a cloud of white smoke and it stunk like gas. I had a feeling I knew that this was another flooding issue, pulled the #1 plug and there it was, a soaked plug that smells like gas. 

I took all 3 carbs apart and I could not find anything wrong. All floats are set right, no needle seats are loose and nothing else seemed off. 

Based on the puddling in the intake manifold, it looks like the center carb is the main perpetrator. I've rebuilt the carb twice now, most recently with the fancy "daytona" seat/needle style. 

I'm at a loss here, I can't figure out why the flooding keeps returning. The only think I have left on my mind is the fuel pump which I believe is rated at 6.5 PSI as that's what the 67s 400 required. Maybe the next best step would be to add a valve to cut the pressure down to 3.5 psi?


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## PontiacJim (Dec 29, 2012)

1967pontiac400 said:


> Bad news....the flooding came back today.
> 
> I had the car sitting for a couple weeks while I replaced the suspension. When I started her up today to drive up onto some ramps the idle got weird, like I am running a high lift cam, fluctuating between 600 and 1000, chug, chug, chug.
> 
> ...


If it is flooding that much, then a pressure regulator may be helpful. Some of these aftermarket replacement pumps are too high. The factory was 5 - 6.5 pounds @ 1,000 RPM's for non-AC cars, and 3 - 5.5 pounds @ 1,000 RPM's with AC. The AC had a return line which would lower the fuel line pressure going into the carb. So, I would think you want 4 - 5 pounds fuel pressure without AC and see how that works for you.

I think I would also want the needle and seat with the smallest hole as it may act as a regulator and the float may work better to close off the smaller diameter hole as opposed to a larger needle & seat diameter that allows a greater flow/volume of gas into the bowl and would take more pressure from the float to hold fuel pressures in check and close down the needle & seat.

If it still floods, you must have a carb issue - a crack or maybe some warpage not sealing a gasket? You may want to pull it apart and take it to a machine shop where they could magnaflux the main parts for cracks that you may not see.


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## 1967pontiac400 (Dec 10, 2020)

Thanks Jim. I ordered a pressure regulator and I'm checking the plugs every day for any moisture.

It's not right, but maybe she just needs to start every couple of days to burn everything out and stay clean until I can get this flooding fixed. 

If this does not do it maybe it's time for a re-built center carb from vintage speed, they're about the only shop I've seen that selld authentic 65 tripower center carbs.


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## 1967pontiac400 (Dec 10, 2020)

Come to think of it, the last time I shut down the car before this weekend (about 2 weeks prior) the plugs were dry after I shut her down. So this must be a slow seepage thing while the car is off, meaning is has to be something valve or carb related, yeah?


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## PontiacJim (Dec 29, 2012)

1967pontiac400 said:


> Come to think of it, the last time I shut down the car before this weekend (about 2 weeks prior) the plugs were dry after I shut her down. So this must be a slow seepage thing while the car is off, meaning is has to be something valve or carb related, yeah?


When you shut the engine down, it heats up because coolant/fan is not operating to do just that - cool. So engine temps will rise which is normal. The gas is no longer flowing either. What could be happening is that the heat from the engine is causing the fuel to either boil in the line or in the float bowl itself. In either case, that boiling of the fuel means pressure and the pressure has got to go somewhere. So it is possible the fuel in the line is over-pressurizing the needle/seat and pushing additional fuel into the float bowl which is now being flooded and it is spilling into the intake. Same goes for the carb itself, the fuel could be boiling out into the intake. If enough, the gas might find its way past an open valve and the plug on that cylinder gets wet.

Now this is just a guess on my part, but it is plausible. If you have the fuel filter used on the tri-power that is up near the carb, and has the additional nipple for the 1/4" return line, I would think that any boiling/expansion of the gas, and the pressure, in the fuel line would be diverted out through the 1/4" return line and back to the tank. Now if there were an issue with the 1/4" return line or the gas tank, such as a plugged vent, then the pressure might not be relieved and you would be back to that pressure over powering the needle/seat, and then flooding the carb.

The fuel pressure regulator is still needed in my opinion as this will ensure you don't have too much fuel pressure and may prevent any pressure/gas from the heated gas line from pushing fuel past the needle/seat. And, you can play around with it at different pressure settings. If you find you don't need it, you can always remove it, but it wouldn't hurt to know you have a steady inlet pressure.


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## 1967pontiac400 (Dec 10, 2020)

Thanks, Jim/.

So I don't have the "correct" fuel set-up since it's a 65 tripower, on a 69 block in a 67 body. Because of this I'm running one of those clear glass filters i a customer set-up, after the car shuts down I can see the fuel filter is full for a while. Is the pressure supposed to be relieved through the pump since that's where the return line is?

Agreed, the regulator is going on there for sure since I know the pump is firing at 6.5PSI which is too high for the 65 tripower. 

I fired her up this afternoon, checked the plugs before and after and all looks good. We'll see!


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## PontiacJim (Dec 29, 2012)

1967pontiac400 said:


> Thanks, Jim/.
> 
> So I don't have the "correct" fuel set-up since it's a 65 tripower, on a 69 block in a 67 body. Because of this I'm running one of those clear glass filters i a customer set-up, after the car shuts down I can see the fuel filter is full for a while. Is the pressure supposed to be relieved through the pump since that's where the return line is?
> 
> ...



Those see through fuel filters can be misleading. I have a plastic replacement one on my '73 Fury and while watching it, it would fill so I could see the gas, then there was no gas. But it still ran fine. WTF? I thought maybe my fuel pump was going bad. Nope. Did a web search and this is normal - it is just a "vapor pocket" but fuel is still flowing. Heat from the engine can cause the gas to vaporize and create the pocket. As the needle and seat opens/closes to fill up the fuel bowl in the carbs, you can watch the change in fuel amount in the filter.

With the later pumps, the fuel return circulates the fuel to keep down vapor lock and would act as a pressure relief down at the pump and it would not reach the line going up to the carbs. The filters on the earlier AC cars used a different fuel filter as compared to a non-AC car and has been covered on here before. It mounts on a bracket up at the front of the carb on a tri-power. Instead of the return line coming off the fuel pump lke you have now, the return line comes off the filter housing. So it keeps fuel circulating and keeps vapor lock down, and also acts to lower fuel pressure as the return line acts like a leak, so pressure is lowered.

Inline Tube has them and you can look at this to see what I mean.









1964 -66 Pontiac GTO Tri-Power with AC 1967 Pontiac GTO Ram Air Rochester AC GF-98 Fuel Filter


1964 -66 Pontiac GTO Tri-Power with AC 1967 Pontiac GTO Ram Air Rochester AC GF-98 Fuel Filter




www.inlinetube.com


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## Lemans guy (Oct 14, 2014)

Just use the return line once....not on both the pump and the filter....pick one and use it as the return, plug the other.


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## Lemans guy (Oct 14, 2014)

As PJ was pointing out and from your description of symptoms it sounds like you are experiencing “Heat Soak”, we all have it. “ Vapor lock” is different and PJ clearly outlined that as well.

vapor lock happens when you are driving, the suction from the fuel pump creates a vacumn to suck the fuel, but it also lowers the boiling point. And today’s modern gasoline formulas have much lower boiling points than in the 60’s. Although they had similar problems then, now it is worse. The fix for vapor lock is a fuel return line to the tank. The pump never dead heads and the flowing fuel keeps it from boiling and “Vaporizing” in the line.

Heat soak happens after shut off, the engine compartment heats up and the fuel in the bowls reaches boiling temp, with 10% ethanol winter blend it is low. Pure gas a bit higher, but they both will boil.

you can check this by after shut down leave it overnight and then go and open the carb bowl big nut on the side to see where the float is. If you have a see through sight glass even easier. But check it, if it is real low, the gas boiled off overnight after shutdown mostly into the intake. Now you have a dry or almost float bowl and a flooded intake. Makes for hard starts.....this is when folks say if I shut it off it starts right up....but after an hour or a few days it is hard to start.

The fix for heat soak are many, phenolic spacers under the carb, heat shields, fuel line wrap, fans, electric filler pumps etc.


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## integrity6987 (May 10, 2017)

1967pontiac400 said:


> So I took the center carb apart and I...........


If you do that again see if you can do it carefully (remove only the air horn) to see if there is still fuel in the bowl.

Q-Jets have brass or lead plugs under the fuel bowl that are prone to leaking, which will flood the intake. Not sure if the tri-powers are Rochester design.


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## 1967pontiac400 (Dec 10, 2020)

They are all Rochester's. I think what happened was too much fuel pressure and re-occuring flooding.

I've since installed a pressure regulator set aat 4psi and the problem seems to have gone away. I also understand that vapor lock can cause this as well.


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