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FFCobra Fanatic
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Norm mentioned the intake gasket, not a head gasket. Depending on what intake gaskets were used, you could be getting a little leakage from the water passage in the intake into the intake port. But you said it seems more like fuel so I am hoping the plugs will fix it. Check the distributor cap and rotor real good too, sometimes they crack or get corroded after some run time. Again you can swap an injector from one cylinder to another to see if the problem travels to that cylinder. Good Luck and keep us posted.

Mike
 

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A day or two ago you said this;
"Swapped injector wire 7 and 8"
Exactly what do you mean here? Just pulled the wires off the injectors and installed them on the other injector? That won't work since the injectors shoot gas at different times. It's been a long time since I worked on one of these, so I am trying to understand if you mean you swapped the entire wire, but don't the injector wires go into the harness and run all the way to the ecu?
In early 302 port fuel injected engines, Ford used batch fired fuel injection. My understanding is, all the injectors on one side of the engine pulsed and then the other side. Injector timing would not be so critical the cylinder miss or hit would not be detectable. IMO
 

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Discussion Starter #23
Really appreciate all the suggestions!

I got the new Autolite plugs and put a new one in cyl 8. Still same issue. I can hold my hand on the exhaust exit of #8 without it getting warm when running.

At the beginning I thought this was an interesting challenge to figure this out - now it getting a bit weird :wink2:
 

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Discussion Starter #24
In early 302 port fuel injected engines, Ford used batch fired fuel injection. My understanding is, all the injectors on one side of the engine pulsed and then the other side. Injector timing would not be so critical the cylinder miss or hit would not be detectable. IMO
Yes, I believe this is correct as well.
 

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Discussion Starter #25
Norm mentioned the intake gasket, not a head gasket. Depending on what intake gaskets were used, you could be getting a little leakage from the water passage in the intake into the intake port. But you said it seems more like fuel so I am hoping the plugs will fix it. Check the distributor cap and rotor real good too, sometimes they crack or get corroded after some run time. Again you can swap an injector from one cylinder to another to see if the problem travels to that cylinder. Good Luck and keep us posted.

Mike
I do have an RPM II intake that I wanted to put on as a winter upgrade - perhaps I should get that done now and get some new Felpro gaskets to eliminate that option.

I also have my old distributor and TFI module that I replaced as a preventive measure - could also try to swap that one in to see if that makes a difference.

(did try the injector swap as well as)
 

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Also, replace or swap the #8 spark plug wire too. They can go bad and cause no spark.
 

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In early 302 port fuel injected engines, Ford used batch fired fuel injection. My understanding is, all the injectors on one side of the engine pulsed and then the other side. Injector timing would not be so critical the cylinder miss or hit would not be detectable. IMO
OK, thanks for straightening me out. Now that you write it I do remember hearing about that system.
 

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FFCobra Craftsman
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If you do the intake be sure to get the steel core FelPros. Info I have saved;

The new gasket numbers for the Windsor blocks are;
1250 S-3 (port size 1.20" x 2.00")
1262 S-3 (port size 1.28" x 2.10")
1253 S-2 & 1253 S-3 (SVO/Yates head w/port size 1.35" x1.95)
 

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If you can truly hold your hand on #8 exhaust tube and it is not hot, it sounds like the exhaust valve is not opening. Even with a dead miss, typically the header on that cylinder will still get hot enough to burn you pretty quickly even though it will be a hundred degrees or more cooler than the rest. It won't show on a compression check because the cylinder is still sealing. You may have a bad rocker arm, pushrod, etc.

sorry - missed that you had already checked under the valve covers
 

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You have fuel and compression to the cylinder. That you’ve already verified. You also have spark but you said it looked weak. Thus, the problem has got to be ignition related. You’ve changed wires and plugs to no avail. That tells me the problem is high resistance between the plug and the distributor rotor. That leaves the post on the number 8 cylinder inside the distributor cap. Pull the cap and check out the number 8 post. Hopefully it’s cracked or rusted out.
 

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If you can truly hold your hand on #8 exhaust tube and it is not hot, it sounds like the exhaust valve is not opening...
Nope. If the exhaust valve was not opening he would have it blowing back through the intake.

Jeff
 

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Just Thinking...

Nope. If the exhaust valve was not opening he would have it blowing back through the intake.

Jeff
If the exhaust valve is not opening, and the intake is, then there would be a charge of air/fuel on the intake stroke, and a solid compression reading. If the mixture is ignited, and can't escape through the exhaust valve, the first time it happened there might be some blow back when the intake opens again, but with the cylinder full it can't draw another charge of air/fuel and would not fire again, resulting in a cold header tube.

Just snow balling the thought, that is what I see as a possibility.

Regards, Rick.
 

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Discussion Starter #34
Thanks again for all the suggestions!

I have not had too much time this week to tinker, but I did try the following:

  • Leak down test. Put pressure on #8 and it seems intake and exhaust valves are tight. Only hissing was out of valve cover. Tried to do the same on #1 and it seemed to be about the same.
  • Swapped the distributor and TFI module with another used one I have had on the car before. No change in how it runs.
I guess I will have to pull the intake now to see if there is some sort of blockage - could do the same for the exhaust I guess. It will also allow me to get my endoscope camera in there to take a look.
 

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This is so intriguing with so many possibilities. Perhaps someone should be running a book on it ?. I would have put money on an over fueling injector causing the cylinder to be flooded, but I believe that has been discounted now.

Hopefully the endoscope will bring an answer.

Best of luck, Nigel in South Oz
 

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I was half jokingly thinking "shop rag stuffed in #8 intake runner" -

It still sounds like ignition to me though, did you double check wire routing and ensure that there is no crossfire/spark leakage? (run car in pitch darkness, look for sparkles)? Are you sure that #8 is the ONLY failing cylinder and that you haven't cross-wired it with another cylinder (firing order, are you sure it's correct for your engine/cam?)?


What EFI system specifically is installed, and can you post a link to the SCT chip specs? (I have a Quarterhorse, and there are LOTS of ways to mess it up)



Intriguing puzzle, please keep us posted!
 

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How long has the car been running in this same configuration, before changing anything? How did the symptoms first appear?
 

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Discussion Starter #38
I was half jokingly thinking "shop rag stuffed in #8 intake runner" -

It still sounds like ignition to me though, did you double check wire routing and ensure that there is no crossfire/spark leakage? (run car in pitch darkness, look for sparkles)? Are you sure that #8 is the ONLY failing cylinder and that you haven't cross-wired it with another cylinder (firing order, are you sure it's correct for your engine/cam?)?


What EFI system specifically is installed, and can you post a link to the SCT chip specs? (I have a Quarterhorse, and there are LOTS of ways to mess it up)



Intriguing puzzle, please keep us posted!

I am now running with a different distributor cap and wires just to check if that was the cause. I will try to put the original set back on and check it. I am fairly sure that the wires did not get crossed while I was racing down the track though :wink2:

I will try to double check the temperature on each of the exhaust exit pipes. The temperature was a bit varied, but #8 always sticks out as not raising until the heat bleeds over from the head.

I like your idea about the chip - yesterday I called the tuner who installed it and dialed it in on the dyno to see if they have and any similar experiences with this chip on a Windsor engine (Revolution in Baltimore). They said that they had never experienced that (other than one that came in with a cam lobe that was self destroying and therefore not firing on one cylinder). He also mentioned that the chip/ECU does not control ignition on individual cylinders.
One idea though is that there is a selector wire where I can change maps. There is a map that says go back to stock tune. Perhaps I should try that.
 

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Discussion Starter #39
How long has the car been running in this same configuration, before changing anything? How did the symptoms first appear?
I have run this configuration since I put the AFR heads on two years ago. The car has also been on the track a couple of times, plus a long drive down to the tail of the dragon this summer. So lots of miles on it both cruising as well as getting beat on on the track. The only change I have made recently is to add electric power steering (one of the Saturn Vue units).

The car ran good the first 20 minute session of the day on the track. On the second session I had only done a couple of laps - although this session I turned the heat up a but, but always shifted before 6k rpm. There are a couple of turns where you run it up to 5-6k rpm in third before getting on the brake. When I got on the gas after the second quick bursts I could feel that I did not get the same throttle response, the sound had changed and there was a slight vibration. I did not notice any bang/rattle when it happened.
 
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