Ford Mustang Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
I got new plugs for my 1985 mustang 5.0 and changed them out. now that i have the car makes a popping sound kinda when i go to accelerate and backfires like crazy when i half throttle or more. when it starts making the popping noise it starts to lag. its not a constant lag only when it makes the noise and thats only when i start to get on it, than it backfires. it was running way better with the old plugs. i got motor craft plats and changed the wires and the coil is pretty new as far as i know. rebuilt the carb a few weeks ago also. i gapped the plugs and everything. idk whats wrong its really irratating.

could it be that the carb needs to be tuned to these better plugs? i also installed glass packs on yesterday but i dont think that would do anything because like i said it was driving good untill i changed the plus
 

·
Registered
Joined
·
128 Posts
were the spark plugs platinum or standard?
 

·
Registered
Joined
·
590 Posts
Sounds to me like your wires might have been put back wrong. Or a plug wire isn't clipped in all the way
 

·
Registered
Joined
·
13,138 Posts
Sounds to me like your wires might have been put back wrong. Or a plug wire isn't clipped in all the way
+1 I will have to concur with this observation. Check and recheck the order.
 

·
Banned
Joined
·
1,207 Posts
+2 - fire order wrong or one of the wires not on tight.
 

·
Registered
Joined
·
228 Posts
Just happened to me the other night. Ended up getting the wires mixed up and my firing order was out of sack. Just check your wires and make sure they're ran right
 

·
Registered
Joined
·
128 Posts
my mustang specialist said that the platinum plugs can cause interference and other issues. He said they run best on standard plugs.
 

·
Registered
Joined
·
292 Posts
Limit changes/ upgrades to one or two between test drives. That way you know what you did.
 

·
Registered
Joined
·
1,353 Posts
The copper plugs tend to work better in the 5.0, but not to the point where platinum plugs will cause backfires and whatnot...

Possible bad wire or bad plug maybe? Never hurts to pull the plugs out and check them for any damage, especially if you are going to be taking the wires off and going over the firing order and whatnot.

1-3-7-2-6-5-4-8
 

·
Registered
Joined
·
13,138 Posts
So what is the prognosis?
 

·
Registered
Joined
·
330 Posts
The copper plugs tend to work better in the 5.0, but not to the point where platinum plugs will cause backfires and whatnot...

Possible bad wire or bad plug maybe? Never hurts to pull the plugs out and check them for any damage, especially if you are going to be taking the wires off and going over the firing order and whatnot.

1-3-7-2-6-5-4-8
I have used the Bosch platnum single tipped plugs and the +4 plugs and I had no problems with them.
 

·
Registered
Joined
·
1,262 Posts
I went back to copper plugs on the last change out. As for you problem, I once had to replace my wires because I pulled the boot off and the metal connector tore from the wire and stayed connected to the spark plug. I say check the wires and make sure they are all in good shape.


Sent from AutoGuide.com Free App
 

·
Registered
Joined
·
590 Posts
Just did my tune up this weekend, used the Autolite 2545s (for the 86) and man she is purring like a fat baby tiger! You can't beat that performance for $1.50 per each! Haha, they were on sale. $10 and 30 min once a year is not a lot to ask for...

Also set my timing to stock 10* btdc....previous owner had it about 12*. Also got rid of that annoying whistle from the TB. Also you guys are great for having all this great info :bigthumbsup:bigthumbsup
 

·
Registered
Joined
·
18 Posts
Discussion Starter #16
I took care of it. I had a faulty plug that wax cracked. found it when I was checking my plugs. pulled the wire ofg and half the plug came with it. thanks everyone
 
1 - 16 of 16 Posts
Top