Hi, This is my first post on this board but I've done a bit of searching and reading prior to this post. I have a 96 ranger 2.3l. I bought it just recently and it took about 20 minutes to go from 0 to 60mph. It backfired through the intake when revving it up. I did some diagnosis. MAF and TPS tested fine. Checked the coils and intake side coil had one terminal not firing. No codes pulled from OBDII which in itself is a bit weird given the damaged coil.
So I replaced both coils and wires just to be preventive. I also replaced the 4 exhaust side plugs with platinum plugs. I left the intake side plugs with the original standard plugs. I checked timing belt and adjusted tension and compression (175 across all 4 cylinders). Once the coils were replaced, it ran better but here's the thing. I hooked up a timing light to each wire on each coil terminal and watched the firing pattern for each wire. On the intake side coil each of the 4 wires fires (timing light flickers) in a consistent even pattern. On the exhaust coil, the light flickers unevenly and intermittently for all of the wires. This doesn't seem right to me but I am new to Rangers. I'm a Volvo/BMW guy.
Two things I noticed. I had a really hard time getting the exhaust side coil connector back on (the one's that's firing intermittently). I had to pull the connector pins out and tried to reset them in the plug so they were making good contact with the coil pins. Finally it went on correctly without forcing it but... maybe that connector is just not making good contact with the coil. I don't know how to test this other than replacing the connector which is $40!!! Also I did not try swapping the coils just in case I got a bad coil. I should do this but the wires don't like to be taken off the coil terminals too many times as the ends tend to bend and then not seat properly in the coil.
Anyway, I'm posting just because I want to know if anyone can confirm or deny if the exhaust coil should show intermittent flickering on the timing light when the intake coil doesn't.
Thanks

 

Welcome to the forum


No, exhaust side coil should fire like intake side when engine is running.

One heads up, only the exhaust side coil and spark plugs should be working for start up, intake side starts when RPMs are above 400, so after start up.

Ford uses Waste Spark system
This means 2 cylinders spark from one coil
Each coil pack has only 2 coils inside
On a 4cyl engine #1 and #4 pistons are at TDC(top dead center) at the same time, then 180degs later #2 and #3 are at TDC

Spark plug wires on coil pack reflect that
1 and 4 are on the same coil, one will be 1 and 4 the other 4 and 1, doesn't matter they both spark at the same time
2 and 3 are on the other coil, so 2 and 3 or 3 and 2


computer sparks 1 and 4 when they are at TDC, one will be on compression stroke, the other on exhaust stroke
The compression stroke spark adds power to engine
The exhaust stroke spark is Wasted, hence the name of the system

Waste spark was first spark system ever used on gasoline engines, and still used on most single cylinder engines
Just simpler to use and reliable

There is no "alternating" of spark, both spark plugs in each cylinder should spark at the same time, every time
So both spark plugs in 1 and 4 will spark at the same time at every TDC

Coil wiring is pretty simple
Center wire, red, is 12volt, key on
Each outside wire is the Ground for the coil on that side of the coil pack

And it works like any ignition coil
Computer Grounds it to build up charge in Primary then unGrounds it to send out spark on Secondary side
Only difference is that spark plug wires are in Series, so one spark plug sparks "normal" center to tip and the other sparks in "reverse" tip to center.
Which is why you should only use regular copper or Double Platinum spark plugs, single platinum would be a waste of money since it would wear out like regular copper in some cylinders


Same two coil packs were used on Ford V8s, you should be able to find connectors at wrecking yards, and coil packs

 

Hi RonD,
I've read many of your posts. It's so nice to hear from someone that is so knowledgeable in this arena. Among them I've read your waste spark, coil function and initial start on exhaust side only posts and am very familiar with everything you wrote (waste spark system, etc.). Also familiar with how coils work and wiring (12V constant center wire, other 2 pulsing from PCM to collapse field).
Just to clarify, truck seems to idle fine, though it takes an eternity to accelerate from 0-60 which is probably fodder for another thread...or not? There is no detectable missing or rough idle but the timing light seems to be telling a different story when it shows the intermittent flicker on the wires from the exhaust coil. I'm pursuing this because I'm thinking this is causing the lack of power on acceleration. Muffler shop said it only has 2 lbs of back pressure. Well there I go anyway digressing to the acceleration problem :)
As I mentioned in post, both coils are new, wires are new and the four plugs on the exhaust side are new platinum but I fear they are single platinum as they were the next step up in price from the copper ones. Would you suggest putting copper ones back in the exhaust side to match the ones on the intake side? I doubt they could be causing the intermittent firing do you? Although maybe having 2 different types of plugs for exhaust and intake side could be affecting the firing somehow. Your thoughts?
Thanks for confirming that both coils should show identical behavior with timing light hooked up to each wire in turn. I suspected this but wanted to confirm. So the connector could be the issue or a bad coil even though it is new. I'll swap coils this weekend and see if I can get up to a wrecking yard for a connector.

 

After doing a bit more testing, discovered the intermittent spark on exhaust coil was the same on the intake coil. Wire #1 on both coils was solid and consistent. I think the timing light was just throwing some weird pulses. The truck is running fine and I think I was trying to find a problem that wasn't there :) The slight lack of power is probably just the way these trucks run from what I hear.