4 cylinder V8 ?!
 

OK here's the deal, changed one blown head gasket. New ignition wires, new sparkplugs. 1,2,8,6 cylinders aren't firing. When the wires are removed from the dist cap, we have spark from the terminals. When we put the wires back on, there is no spark. We take the spark plug out and leave the wire on the plug, and it fires when out of the cylinder... Car will not run off of all 8, just four. We are going off of the correct firing order and everything. Fuel pressure is set to 32lbs, timing @ 12 degrees advanced. Stock everything except fuel pressure reg (BBK), pulleys, and exhaust. Before yall ask how do I know that the spark plug isn't firing when it is in the cylinder, we were grounding each one out by putting a test light on the negative battery terminal and stabbing the top of each dist terminal through the boot. Theoreticall, the idle will go down and there will be a noticable difference when the plug is grounded out. 1,2,8,6 did not do crap. Please help

:confused: no one has any ideas?! Push it in the river?

Which car is it Shawn?

The white GT, I swear it is getting to be more trouble than it's worth. We just finished the head gasket and now this, ever heard of it? What could it be?

Do yourself a favor and stop ruining your plug wires. Using the same general idea, instead cut 8 1.5" pieces of vacuum hose, and insert them inbetween the distributor cap posts and the plug wire ends. Then touch the test light tip to the vacuum hose. This works much better, and won't damage your wires. Please verify your findings this way, and post the results.

Take care,
-Chris

OK, I will do it this evening and let you know. But isn't the way I was doing it accurate? I mean do you think I will get different results from this? The car has no power and when we checked the terminals through the wires we got nothing, but without we got spark... I dunno, I will post the new results tonight, I am desperate.

May sound strange
 

I know this goes against all logic,but couple of questions first.

How many miles on the car? Reason I asked that does it still have the stock cam? Reason I asked that is this,some times when you put an engine back together,you could have installed everything on the exhaust stroke,in other words your car is firing 360 degrees off.

What I mean by that simple.......you think it is on the intake stroke,it could be on the exhaust stroke,sometimes this happens and lot of people never realize it.

Second if this is the original cam and the car is high mileage it could be this and this is really strange....you might have a cam that has rounded out,and cause the sporadic firing,lot of things can be wrong that is definitely a strange situation you have there.

But I am willing to bet it is 360 off,I think you are firing on the wrong stroke.

Re: May sound strange
 

In otherwords, the distributor is 180 off. Possible, but I don't think so. It is interesting though, that the cylinders that are dead are the ones that are the same in both firing orders, and are cycled together (1&6 and 2&8). Still, I suspect that is a coincidence.

Have you verified the valve adjustment for those cylinders?

If you have done the test I suggested, and still have the same results, run a compression test, and post the results.

Take care,
-Chris

OK, sorry it took so long to post back. Wiht the vacuum lines between the dist terminals and the wires, there was spark all the way around. We also had a toll that went between the wire and the plug with a light in it to show spark, again all were firing, but here is the wierd thing still....when we put the test light through the vacuum lines to ground out the spark and listen for the drop in idle there was no drop at all in 1,2,6,& 8, but we saw the spark. We pulled the plugs and they were wet with fuel, ran the compression test and had at least 140 on all. the heads that are on have had a valve job with new springs and retainers. The cam wasn't flat because we turned it over with the valva covers off and we have the same amount of movement on all. Still at a lose. We brought a scanner home but it wouldn't pick up any codes, I don't know if this has something to do with the car used to being an auto and I swapped it to a stick utilizing the same computer, I was told you could do this with no problems, and it ran fine before with that computer so i know that isn't it. Please help. Also I was told the dist being 180 off won't let the car run at all?.. Thanks:confused:

Okay, first of all, to kill a cylinder while doing it my way with the vacuum hose, you don't need to pierce the vacuum hose. Just make sure the alligator clip is grounded, and test the bulb by touching the positive battery terminal. If it lights, then start the engine, and just touch the test light probe tip to each vacuum hose (inbetween the cap and the wire(s)). That should kill that cylinder. Pull the test light away, and that cylinder should start firing again. You can test all 8 cylinders in less than a minute, without shutting the engine off.

Please try it that way, and confirm for me the results.

Take care,
-Chris

Yeah, I'm sorry Chris I should have been more clear, that is exactly what i did. When I did it to the other cylinders, the idle dropped showing the cylinder stopped firing, but when i did it to 1,2,8,& 6 nothing happened. I pulled the plugs to see them and they were wet with fuel like they aren't firing. I can take the plug out while the wire is still on it, start the engine and it fires then. Seems like it doesn't want to fire while it is in the cylinder?! I was reading the other post about the guy having problems with the revving and driving, that is what I had, no power under load, so that is when I checked for spark on all the cylinders and found this problem. the wires and new and so are the plugs, don't remember if I mentioned that. thanks again

Okay, where I'm getting confused is you said when you did it my way, you had spark all the way around. Every cylinder was firing?

Then you said 1,2,6 & 8 didn't change when grounded out, meaning they weren't firing?

So, when you did it my way, was it running on 4 or 8 cylinders?

do you have a number i could call you at? Anyway if not, here is the deal, they had spark at the dist but not in the cylinder. If we leave the wire off of the dist but close to the terminal we can watch it jump to the wire from the dist, which would mean fire, but turn it off and pull the plug and it is soaking like it wasn't firing. When we ground it out the idle didn't go down any..

So in other words, it's the same as it was before.

It sounds to me like you have a problem with the injectors in cyls 1, 2, 6 & 8. It sounds like those cylinders are getting flooded out. Do you have a fuel pressure gauge? if you do, hook it up, and get the pressure up, then shut the key off, and watch the gauge. Does it drop at all? How much, in how long?

Yes, we put the pressure guage on it and set it to 35psi, when the key is turned on it jumps to 35, but goes away very quickly, we have to turn the key on again for it to read where the pressure is at. We had thought it might be the injectors before and tried to put the test light on them to see them (pulse) if you will. the ones we tried stayed solid light the whole time when we started the vehicle. So it running out quickly, does that mean stuck injectors? I do have another set of 19lbs laying around, I also have another stock Mass Air, some have told me it may be that.......

Ahhhhh. Now we're getting somewhere. When you shut the key off, the pressure dropped quickly? I suspect you have 4 injectors that are either stuck open, or are severely leaking. This would explain why those plugs never fire, and why the plugs are always so wet. Try installing the other set of injectors that you have, and see what happens.

Take care,
-Chris

I think I will worship you if that is it, I have tried everything and have been working on this for 4 and a half weeks. I will do the swap tomorrow and let you know.:)

After you swap the injectors, but before you try to start it, check the pressure, and see if it still drops like it does now, or if it holds steady. Then try and start it, and see what happens.

Let me know.

Take care,
-Chris

Did the swap still firing on four cylinders. The pressure slowly drops once it hits 30psi then really holds around 10 or so. It seemed to idle better once the MAP sensor was unpluged, but now I am back to shooting in the dark with this thing. Anymore ideas? Anyone?

Question, could it be the pickup in the dist? I was told that when they go bad, the car won't start at all, any chance it partly went bad? Also, firing order, we have tried several different firing orders besides the correct one in the book, but nothing is working. On my notch the firing order is different than any book and I was thinking it was to the cam for better performance, could this be an odd firing order it is looking for? The car idles good, just no power and there is still no firing on 1,2,6.8. Is it coincidence that 1 and 8 are directly across from the other two that aren't firing 2 and 6?

Sorry, I've been busy for a while. I still think it's an injector problem, but it may be in the wiring.

What year is your cam for? That will determine your firing order.

Take care,
-Chris

Well, the cam is stock. Is there a way to test the wiring of the injectors, should I see a pulse in the test light? Any self tests I can do? I had a code reader but it wouldn't pull any codes at all. It was a real expensive one from the Mech shop and all it told us was to look up the ford manual for help. The car idles fine, just doesn't have the full 8 yet.

The firing order is 1-3-7-2-6-5-4-8.

You're confusing me again. You say it idles fine. If it's only running on 4 cylinders, it shouldn't be idling "fine".

Do you have access to a noid light?

Take care,
-Chris

I know, but it does, it idles pretty smooth, once you rev it up it pops and backfires too. Yes I can get a noid light, the Mechanic I am working with is my uncle in law if you will and he can get just about any tool I need. I figured since 2 cylinders weren't firing on both sides that it made sense it wasn't vibrating or looking off balance. He swears it is electrical and that we will never figure it out. Yeah you could never tell there was something wrong from idle, but man alive when you try to drive it or rev it it goes to crap. I have a perfectly low 12 second N/A 88 coupe that my uncle wants me to start swapping parts between the two now. Isn't there anything else before resolving to swapping?

Before you swap anything, check each injector harness connector with a noid light, and tell me what happens.

Take care,
-Chris

I read your other post about the regulator being bad, do you think mine is bad with the problems I am having? Could it be overloading the injectors? I mean it does change when adjusted but the BBK FPR's are known to go bad i was told. I will test them with the noid light tomorrow though and let you know. Thanks

Well, got the noid light, but never got the time to test it this weekend. But made a decision to go ahead and pull the motor,yep, I am going to put the motor out of my Coupe and put it into the GT. The only problems is I bet the GT has an electrical problem rather than a motor problem. I will swap computers and wiring harnesses if I need to but, I figure why put all of this money into this stock engine when I could put the money into the 460 that is sitting in the garage. I am going to put a post in about it taking suggestions about putting into a fox body. All the help you gave is very appreciative and i hope I will be able to narrow the problem down with two stang side by side and let you know what it was for future reference. Thanks again.

I still think it's an injector problem, but I agree that it's probably electrical. That's why I wanted you to check with the noid light. I have a hunch that the drivers in the ECM for 1, 2, 6, & 8 may be bad, leaving the injectors open at all times, rather than pulsing them. If the noid light didn't pulse for those injectors, but just stayed lit, then that's what was (is) happening.

Anyway, good luck with your new project.

:cool:

Take care,
~Chris

ECM? Computer?

Yes. Sorry about that.

:)

Take care,
~Chris