ignition/electrical problem

cas23

Registered User
hope to get some advice to look at.. but i have a 90 sc with a misfire to simply explain it.. ive tried the coil, dis module, running it without the chip, ive unplugged the cam sensor before. only thing i didnt was was the crank, ive replaced the alt with a new napa one... its charging good. BUT.. when i turn an accessory on, for an instance, i hit the wipers when i last ran it, it missed, when i have the headlights on it carries on like no other.. and when i turn my headlights on my temp gauge goes up? ignition switch was already replaced also, it was splitting apart... i also had indigo gauges in this car and im 99.9% sure i got it all out, and i also have hids on this car that im starting to hate.. starting to feel like a rice burner cause they all have them. what could cause this.. who had a similar problem.. i want to sort this problem out before i put my mpx and all the other parts on.

thanks for any input in advance

Zach
 
its always doing it... but it seems to get a tad worse up rpm.. its very noticable when you hold it at an rpm.
 
Missfires are almost always caused by a bad spark plug (fouled, cracked insulator ect) or a bad/ loose fitting plug wire.

David
 
well last august when i put my new motor in it got new 103s and taylor wires... it done this here and there befoe also.. once in a blue moon.. now it always is doing it. im just trying to get ideas what to look at..

it backfires after i let off, and when it really cuts the ignition then finaly comes back.. itll back fire prety wild.. flames and all that. really see it being plugs or wires with it doing it before i put the new motor in.. it did it worse when it warmed up last time i drove it.
 
if i had bad plugs and wires it shouldve done it always.. it did this way before.. itll cut out (miss) when i put an electrical load on it, like the wipers, i turned them on and it cut out... well then it got very bad when i was driving home from a friends. im not saying you guys are wrong with the plugs and wires.... but if it was, wouldnt it have always done it? i mean it done this even before with the old motor. i dont understand why my temp gauge goes up when i hit the headlights either.
 
have you checked battery voltage with all the accessories on? I would start there if you are worried about a volotage drop. I have seen cars run on pretty low voltage though with misfire at high RPMs. If you are back firing, then you have a cylinder firing when its not supposed to. I would check for mixed up plug wires, bad plug wires, bad plugs etc. It is a good habit to not cross plug wires and try to keep them separated to prevent cross firing. Check your compression, you timing chain may have jumped time. Sounds like a pretty bad misfire to be voltage.

Mark
 
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this is how my car acted when plugs were bad. i replaced them (103s) and it still did it but not as bad. I too have taylor wires and when i pulled them off, noticed the boot had a hole burnt throough it. After fixing that, it never did it again.
 
well 1st you need to ground it better, no and ifs or buts about it you have a faulty ground, add to it, the better the ground the better the power flow

my next thought is the external tfi module (DIS module) or the coil

as stated be sure the plug wires are not close to each other, i too had a misfire after putting a new engine in my black 90 5spd last week, it was due to a crossfire between cyls 5 & 6, i had the wires 'close' to each other, not even touching, moving the wires further apart cleared up my misfire and it was terrible, bad enough that i couldn't take off with anything more than 10% throttle
 
my car always seemed to miss on autolite platinum like app 103
the only fix seemed to be autolite copper or motorcraft platinum
it drove me nuts for about 6 months

ralph
 
my car always seemed to miss on autolite platinum like app 103
the only fix seemed to be autolite copper or motorcraft platinum
it drove me nuts for about 6 months

ralph

My nephew - who I found out is service manager at a nearby Ford dealer! - says that Autolite platinum are junk - he won't put them in a car anymore.

That's in the FWIW department.

RwP
 
well 1st you need to ground it better, no and ifs or buts about it you have a faulty ground, add to it, the better the ground the better the power flow

my next thought is the external tfi module (DIS module) or the coil

as stated be sure the plug wires are not close to each other, i too had a misfire after putting a new engine in my black 90 5spd last week, it was due to a crossfire between cyls 5 & 6, i had the wires 'close' to each other, not even touching, moving the wires further apart cleared up my misfire and it was terrible, bad enough that i couldn't take off with anything more than 10% throttle

with the ground issues, hearing from you and dave (basically you guys said the same stuff) thats exactly what im going to do. now with the wires.... what size? and im going to get wire looms for my car also. thanks for all the help and advice! and its getting new plugs when i do the blower.
 
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