Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Performance Talk

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 05-24-2009, 10:17 PM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default My car is missing.

Hey guys its not what ya think. My car is here with me. The problem I have is just yesterday my car was running fine and it has been for about 150 miles since I brought her out of the garage back in late April. Well I was crusing down the highway and I noticed that my car seem to be acting sluggish. It has aquired a slight miss and seems like its running on 7 cyl. With the 508 purple cam it seems to idle ok and starts up and shuts down fine. It only misses when you accerlate.Thought I may have a fouled plug. I had just this winter put new plugs in so I pulled all the plugs and they were all fine,even the resistors were white. I double check the gap and all were at .045 right where I had gapped them. My spark plug wires look to be in good shape. I examined every one and two of them have a slight rub mark from my valve cover and one from my throttle linkage on them but I dont see ark jump which I checked at night time in a dark garage These wires have been on the car for 4 1/2 years. I have not checked the "D" cap yet. The cap and rotor was new 2 yrs ago along with the Blaster SS Coil. So my question is, before I start tearing into things, even though wires look good could there be a break down in the wires from all the heat that I cant visually see or feel? I am running 340 c.i. .030 over with MSD 6A, 509 Mopar purple cam, Headers, and I know the wires get a lot of heat. Can the Blaster Coil be causing this problem? Or how about the rotor / cap? Previously it had a tan cap but this one is black. Any difference between the colors? A friend of mine is leaning towards the spark wires being weak. What do you guys think the problem may be? Any feedback would be greatly appreciated.... Thanx
Reply With Quote
  #2  
Old 05-25-2009, 12:36 AM
JVMopar's Avatar
JVMopar JVMopar is offline
Senior Member
 
Join Date: Feb 2000
Location: Mellen, WI
Age: 42
Posts: 2,524
Default

Yes the plug wires can be bad and still look good. Had that problem with my MP wires that I had on my truck. You can measure the resistance of the plug wires but that doesn't always show they are bad. 10,000 ohms per foot is the limit, but I'd compare them to each other.

Can you feel the miss if you load the engine (holding the brake and giving it gas when in gear)? If you can then get an assistant and some insulated pliers and start pulling one wire at a time till you find the cylinder which you have no change. That will be the cylinder that is missing.

I actually got an oscilloscope so I could track down my miss.

You could also have a lean misfire. Your plugs shouldn't be white. They should be a light tan color.

Cap color doesn't mean anything. It's the terminals inside the cap. You want brass ones not the cheap aluminum ones.
Reply With Quote
  #3  
Old 05-25-2009, 02:48 AM
Tarrbabe Tarrbabe is offline
Inactive User
 
Join Date: Jan 2002
Location: Cumberland Plateau
Posts: 1,972
Default I don't have the fancy equipment...........

If you have a miss, you need to pull the wires at the dist. untill you find which cycl. is not fireing properly. At that point you have two things to look at. IF it is getting spark at that cyc, then you look to see if the cam is working the valves to the engine. Good luck.

Warning! if you pull the plugs at the spark plugs, you will get your ass jolted like a boxer in the ring when he is fighting.
Reply With Quote
  #4  
Old 05-25-2009, 04:38 AM
cudabob496 cudabob496 is offline
Inactive User
 
Join Date: May 2007
Location: Richland, WA
Age: 71
Posts: 2,018
Default

Tech Question
don Tackett, Virgie, KY, 1972 dodge charger, 400

I have a 400 dodge motor that has every thing it is new cam, lifters, everything. I have a bad miss and popping from the carb. What could be my problem? I'm about ready to give up on it!

Don, 99% it's a timing problem, valves or ignition.

Since this is all well known, I'll just briefly go over the concepts. First, check the accuracy of the TDC mark using the "positive stop" method. Then be sure the ignition timing is set to around 30-35 deg. BTDC, at 3,000 RPM, with the vacuum advance temporarily disconencted. And be sure the plug wires are connected correctly - in the correct order!

If this doesn't fix it, it's a valve timing problem. If the cam is near-stock, you can use the service manual procedure to check it. But, since this is really the only other likely possibility, just pull apart the front of the engine and check to see that the timing marks on the cam and crank sprockets are correctly lined up. Aslo, be sure that the locating pin has not broken off the camshaft....remember, it's only bolt torque that keeps the sprocket correctly positioned to the cam. If the bolt isn't torqued to specs, the sprocket will snap the pin in a second and destroy the cam / crank timing relationship.

Rick (Mopar Action)
Reply With Quote
  #5  
Old 05-25-2009, 06:40 AM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Well before I get into tearing this and that apart I think that I am gonna replace my cap and if that isnt the problem gonna try the spark plug wire elimination theory next. Removing one plug wire at a time. I honestly dont think that anything has snapped as the engine doesnt spit and sputter. I once had a BB mopar and it jumped timing and it did nothing but spit , sputter and back fire and had very little power. I have about 90% power right now. Thanx guys for the feedback. I will keep all informed when I find out the problem.
Reply With Quote
  #6  
Old 05-25-2009, 10:31 AM
peg leg peg leg is offline
Inactive User
 
Join Date: Jan 2005
Location: Star, Idaho
Age: 88
Posts: 2,669
Default Cap color

Does in fact make a difference. The tan colored cap from Mooar is made from Alkyd material, which has higher resistence to arcing. I would suspect in your case that you have a bad wire. Put some Taylor 8mm wires on it and you might solve the puzzle.
Reply With Quote
  #7  
Old 05-25-2009, 11:29 AM
JVMopar's Avatar
JVMopar JVMopar is offline
Senior Member
 
Join Date: Feb 2000
Location: Mellen, WI
Age: 42
Posts: 2,524
Default

Another way of spark elimination is instead of pulling the wire take a test light ground the dumb end and then insert the probe between the boot and wire. I've seen people pierce the wire itself but I wouldn't do it. It work good and doesn't harm the test light and works just like taking the wire off but without as much of a chance of getting zapped
Reply With Quote
  #8  
Old 05-25-2009, 11:47 AM
DJM DJM is offline
Inactive User
 
Join Date: Sep 2008
Location: VC, ND
Posts: 258
Default

I have never seen a plug on a cylinder that is missing that is not a different color than the rest. In your testing around make sure that you didn't cross 5 & 7 plug wires. Very easily done and the symptoms you describe fit to a T. Barely perceptable miss at idle being right next to each other on the engine and fire in direct sequence but will be definitely there under load.
Reply With Quote
  #9  
Old 05-25-2009, 12:24 PM
aarracer aarracer is offline
Inactive User
 
Join Date: Mar 2007
Location: British Columbia
Posts: 891
Default

First 0.045 may be a bit much on the plugs. I would try 0.040 and see if the miss goes away. The concept is to open them up 0.005 at a time until you get a miss and then close them down 0.005
Also, high output coils (particularly msd's) have a tendency to overheat and breakdown from low speed (constant driving under 3000 rpm) operation. MSD coil two years old hmmm?

The combination of these ie, the plugs too wide (possibly just for a failing coil)and the coil breaking down causing the miss may be your issue.
Reply With Quote
  #10  
Old 05-25-2009, 01:18 PM
passing you passing you is offline
Banned
 
Join Date: Dec 2008
Location: ca
Posts: 731
Default

Quote:
Originally Posted by aarracer View Post
First 0.045 may be a bit much on the plugs. I would try 0.040 and see if the miss goes away. The concept is to open them up 0.005 at a time until you get a miss and then close them down 0.005
Also, high output coils (particularly msd's) have a tendency to overheat and breakdown from low speed (constant driving under 3000 rpm) operation. MSD coil two years old hmmm?

The combination of these ie, the plugs too wide (possibly just for a failing coil)and the coil breaking down causing the miss may be your issue.
amazing, I've had mine since 2001, my plug gap is .045 and I've run the coil with/on everything from the orange box,chrome box, msd 6A with a slant six, 318, 340 but hey.....
Reply With Quote
  #11  
Old 05-25-2009, 01:20 PM
passing you passing you is offline
Banned
 
Join Date: Dec 2008
Location: ca
Posts: 731
Thumbs up

Quote:
Originally Posted by peg leg View Post
Does in fact make a difference. The tan colored cap from Mooar is made from Alkyd material, which has higher resistence to arcing. I would suspect in your case that you have a bad wire. Put some Taylor 8mm wires on it and you might solve the puzzle.
Taylors [cut to fit]are great wires that really last and don't break the bank.
Reply With Quote
  #12  
Old 05-25-2009, 01:23 PM
passing you passing you is offline
Banned
 
Join Date: Dec 2008
Location: ca
Posts: 731
Default

And by the way....

If you have headers, especially, with it running rub the plastic handle of a screwdriver on each header pipe at the head, if it slides like butter on a skillet it's firing, if it sticks/drags it's dead.
Reply With Quote
  #13  
Old 05-25-2009, 03:22 PM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Quote:
Originally Posted by DJM View Post
I have never seen a plug on a cylinder that is missing that is not a different color than the rest. In your testing around make sure that you didn't cross 5 & 7 plug wires. Very easily done and the symptoms you describe fit to a T. Barely perceptable miss at idle being right next to each other on the engine and fire in direct sequence but will be definitely there under load.
It is safe to say that I do not have #5 & #7 crossed. The car was running very good so good that the first time I stood into her I almost pooped my britches ...lol... and this was after I had already put new plugs in with a gap of .045. That was back in April so it has been on the road for about 150 miles and it has ran super up until now. Anyways I checked my cap and it was fine, ballast is fine so that leaves wires and since peg leg said there is a difference in Caps, I am going to take the black one off and put the tan one back on. I have already started changing spark plug wires and it is a pain in the A$$ trying to slide the wire into the cap boot. I even used the lubricant that came with the wire to make em slide on easier.... nothing doing. 1 1/2 hrs to do 2 plug wires and my fingers are absolutely sore. Any ideas on how to make this JOB easier?
Reply With Quote
  #14  
Old 05-25-2009, 03:33 PM
peg leg peg leg is offline
Inactive User
 
Join Date: Jan 2005
Location: Star, Idaho
Age: 88
Posts: 2,669
Default Maybe

It's always a pain putting boots on. My trick is to put a strong length of string through the boot, tie it onto the wire in two places, lube with Armorall, and pull it through.
Taylors are strong enough to handle it.
Reply With Quote
  #15  
Old 05-25-2009, 03:40 PM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Quote:
Originally Posted by peg leg View Post
It's always a pain putting boots on. My trick is to put a strong length of string through the boot, tie it onto the wire in two places, lube with Armorall, and pull it through.
Taylors are strong enough to handle it.
I have Accel peg leg and the instructions are to put the terminal on the wire first then feed it thru the boot. I tried w/o the terminal on the wire and that was no fun either. A string? Hmmm trying to figure how I could keep it from coming off of the wire....Hmmmm I have a thought, gonna run out and give it a try... Thanx peg
Reply With Quote
  #16  
Old 05-25-2009, 04:17 PM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Well just got thru swapping out the black D-cap back to the Accel Tan cap and the engine does seem to run a bit smoother. Sitting at an idle in park and reving it up there is no noticeable miss,the "R"'s really climb, only when in gear starting out and going down the road there is a miss. I am now definetly leaning towards the plug wires, like a lot of people have said. I dont know if this has anything to do with it or not but in the past I have always cleaned the plug wires with a rag and a little kerosene, takes the grim and so forth right off. Now I am wondering if kerosene has penetrated the wires and this is what could be giving me problems. I will find out once I get them assembled.
Reply With Quote
  #17  
Old 05-25-2009, 08:43 PM
DJM DJM is offline
Inactive User
 
Join Date: Sep 2008
Location: VC, ND
Posts: 258
Default

Are you real sure that you don't have a vacuum leak??? All open carb ports capped and all open intake ports capped???
Reply With Quote
  #18  
Old 05-25-2009, 09:14 PM
aarracer aarracer is offline
Inactive User
 
Join Date: Mar 2007
Location: British Columbia
Posts: 891
Default

Yes pu

There is ALWAYS ONE story that is used to discredit good/useable information. Try to find something positive to add, might be a bit more challenging?

Is there another full moon this week?
Reply With Quote
  #19  
Old 05-25-2009, 10:20 PM
passing you passing you is offline
Banned
 
Join Date: Dec 2008
Location: ca
Posts: 731
rolleyes

Quote:
Originally Posted by aarracer View Post
Yes pu

There is ALWAYS ONE story that is used to discredit good/useable information. Try to find something positive to add, might be a bit more challenging?

Is there another full moon this week?
I don't get it?

Why are U offended and implying what I said is wrong?

Saying .045 gap will trash a coil is bogus, like just fishing with no hook.

Oh and thanks for the lame insult, P U, ha ha your funniest ..

thanks friend.
Reply With Quote
  #20  
Old 05-25-2009, 10:23 PM
passing you passing you is offline
Banned
 
Join Date: Dec 2008
Location: ca
Posts: 731
Default

Do you get a pop through the carb at all?

what carb? what timing? with vac advance? it could be lean surge.
Reply With Quote
  #21  
Old 05-25-2009, 10:46 PM
passing you passing you is offline
Banned
 
Join Date: Dec 2008
Location: ca
Posts: 731
Default

If not the wires...
Reply With Quote
  #22  
Old 05-25-2009, 10:56 PM
JVMopar's Avatar
JVMopar JVMopar is offline
Senior Member
 
Join Date: Feb 2000
Location: Mellen, WI
Age: 42
Posts: 2,524
Default

I really don't think that there is a benifit from running a wider plug gap, unless your running and excessively lean mixture. Plug gaps in the '60's and early '70's were 0.035" it wasn't untill the late '70's that the plug gaps were increased to help light the leaner and leaner mixtures. I run mine at 0.035".

My Blaster coil is 9 years old. The Mopar Performance wires are also 9 years old but 1 has failed and I'm sure the others aren't far behind.
Reply With Quote
  #23  
Old 05-26-2009, 12:16 AM
cudabob496 cudabob496 is offline
Inactive User
 
Join Date: May 2007
Location: Richland, WA
Age: 71
Posts: 2,018
Default

Quote:
Originally Posted by JVMopar View Post
I really don't think that there is a benifit from running a wider plug gap, unless your running and excessively lean mixture. Plug gaps in the '60's and early '70's were 0.035" it wasn't untill the late '70's that the plug gaps were increased to help light the leaner and leaner mixtures. I run mine at 0.035".

My Blaster coil is 9 years old. The Mopar Performance wires are also 9 years old but 1 has failed and I'm sure the others aren't far behind.
I have an MSD6A box, and MSD 8mm wires. MSD wires are about 10 ohm per foot length I think. And the MSD box makes a large spark. I run .060 gap. That will make more power than .035 gap. I also cut back the tip of the negative electrode about 1/16 of an inch to expose more spark flame kernal. Maybe good for another 10+ hp.
Reply With Quote
  #24  
Old 05-26-2009, 06:43 PM
JVMopar's Avatar
JVMopar JVMopar is offline
Senior Member
 
Join Date: Feb 2000
Location: Mellen, WI
Age: 42
Posts: 2,524
Default

Cudabob-

I'd like to see the Dyno results on that.
Reply With Quote
  #25  
Old 05-28-2009, 06:47 AM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Quote:
Originally Posted by cudabob496 View Post
I have an MSD6A box, and MSD 8mm wires. MSD wires are about 10 ohm per foot length I think. And the MSD box makes a large spark. I run .060 gap. That will make more power than .035 gap. I also cut back the tip of the negative electrode about 1/16 of an inch to expose more spark flame kernal. Maybe good for another 10+ hp.
What C.I. motor are you running Bob? Is it Hi-performance? I have MSD6A along with SS balster Coil and my spark plug gap is .045 I noticed when I took out the old plugs this winter plug#5 gap was close to .050 while the rest were in the vicinity of .045 in which I had gapped 2 yrs ago. I have a slight miss under load when accelerating and while at idle its fine.The left bank(drivers side) while holding my hand over the exhaust doesnt seem to be as powerful as the right bank.I have checked all of the obvious, replaced all wires, checked plug gap on all plugs which are still gaped at .045 where I gapped them back in April of this year, replaced D-cap with a Tan accel cap. Timing is ok. Now I think that I am gonna remove plug #5 and gap a little wider to see if this cures the problem. A friend of mine told me that he knows of people that gap their plugs at different gaps due to one bank or cylinder running hotter than the others... Worth a try..
Reply With Quote
  #26  
Old 05-28-2009, 11:36 AM
aarracer aarracer is offline
Inactive User
 
Join Date: Mar 2007
Location: British Columbia
Posts: 891
Default

Leige

Then go the other way for a try.
Reply With Quote
  #27  
Old 05-28-2009, 12:13 PM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Quote:
Originally Posted by aarracer View Post
Leige

Then go the other way for a try.
Yes aarracer I plan to do that also...
Reply With Quote
  #28  
Old 06-06-2009, 02:56 PM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Update: Well guys time to put your brains to work. This is a strange problem. The small misfire is still present. After further engine check, I have found that cylinders, 7 & 8 are both running cool with #8 plug being some what damp. We used an infered thermometer checking the heat on the headers right as they exit the head and cyl 8 temp around 300 with cylinder#7 being around 350 while all the others are runnning anywheres from 550 degrees and higher. Done a compression check and have 145# in both 7 & 8. Did a check on a couple of others and they are in the same range. Check the spark and it's ok. So now were thinking that the distributor, which is stock w/o points, may be bad so I bought a Pro-Billet MSD distributor and does seem to run a little bit better but not the way it has in the past. Timing where it seems to run the best is about 10 degrees advanced. All electrical components have been replace except for the coil and we swaped it out with another one, same results. We do not have any idea where to look next. Think I am gonna tear the valve cover off and see whats going on with the valve train. Anyone have any further thoughts or ideas? Sure would appreciate it.
Reply With Quote
  #29  
Old 06-06-2009, 03:11 PM
DJM DJM is offline
Inactive User
 
Join Date: Sep 2008
Location: VC, ND
Posts: 258
Default

It sounds to me like a vacuum leak effecting only those 2 cylinders. What intake are you using, is there a power brake vacuum fitting at the rear of the manifold?
Reply With Quote
  #30  
Old 06-06-2009, 03:16 PM
Leige's Avatar
Leige Leige is offline
Inactive User
 
Join Date: Nov 2004
Location: Meadville, Pa
Age: 68
Posts: 165
Default

Quote:
Originally Posted by DJM View Post
It sounds to me like a vacuum leak effecting only those 2 cylinders. What intake are you using, is there a power brake vacuum fitting at the rear of the manifold?
DJM it has an Air gap intake and no power brakes.Only vaccum lines are on the front of the carb and they are blocked off... No other vaccum on the car.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
VIN tag missing Red 49 Vintage MOPAR chat 2 04-18-2007 07:56 PM
what am I missing? crewcab83 Ram Truck Chat 2 05-15-2002 06:24 PM
missing something rockyrunner99 Front Wheel Drive Chat 0 03-20-2002 12:53 PM
Missing dsteamboat Slant Six Chat 0 02-25-2002 12:10 PM
Need missing vin tag tommy goddard Restoring your MoPar (Tricks & techniques) 6 12-18-2001 09:51 AM




All times are GMT -4. The time now is 08:23 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .