Sprark plug leads touching?

[GTO52]

My Toyota pick up with 3RZ-FE engine developed an intermittent misfire(mostly under load) on Friday.I had a fuel pump failure 18 months ago, so I was worried the new pump might be on its way out?
A few weeks ago I had a dead cell in the battery and when jump starting it, it would start and then stall immediatley but then it was fine on the second start, but it has been fine since I installed the new battery?

Any way yesterday I changed the fuel filter as a precaution(7000km on the old filter) but it didn't seem that dirty.
Then I checked the spark plugs and the leads(resistance okay)but I found No 1 and 2 leads touching right at the coils?
So I moved the plastic twirly things so that they don't touch any more.No 1 and 2 are on seperate colis.
The pick up runs perfectly now?

 

[eljefino]

There... you fixed it!

You can get inductive effects where one wire is near another, particularly parallel. The factory clips and wire routing really do keep interference down both between other plug wires and the rest of the car's electrics.

Though I suspect your plug wire insulation is starting to break down and you should invest in some new ones. For a test, spritz some water on your wires while it's running.

 

[GTO52]

Its back!
I just pulled the truck into my garage and it started missing again.I left it running for a few minutes or so and then it cleared up?
I will have to take it in to the mechaics tomorrow.

 

[crw]

Before you visit a mechanic, change those wires.

 

[ARCOgraphite]

How old are the plugs?

 

[beast3300]

Check for bad wires or cap. In a dark place (I'm talking super dark) start the truck up and spray fine water mist on the cap and wires. If you see arcing then replace those parts.

That's where I would start.

 

[GTO52]

Originally Posted By: ARCOgraphite
How old are the plugs?


Plugs have done 17000km, I will change them when they have done 20000km.They looked fine when I checked them yesterday.

I will try the water mist thing later tonight.
I have a new set of wires, when I checked the ohms readings yesterday the exisiting leads were pretty much the same as the new ones.

Does this sound more like an ignition problem than fuel?
This last misfire wasn't under load.
The engine was running similar to a time before when I washed the engine and had a misfire from water in one of the plug tubes?

 

[GTO52]

I changed the leads, started it up ,after it was idling for a minute the engine stumbled slightly but regained itself.
I went for a short test drive and it was fine?
So I think the best thing is to take it in tomorrow to the mechanics.

 

[Quest]

feels like misfire while under load? check your fuel rail pressure against the factory spec.

While your mech is at it, replace fuel filter whenever possible.

don't dwell on spark plugs (unless you are using something simply [censored]).

Also: I have a strong suspicion that besides fuel pump, your fuel quality there in S. Africa maybe in questionable state. So don't rule out the possibility of fuel spray pattern problems from your injectors (incl. cold start injector) before you proceed to spark plug cables.

Q.

 

[mechtech2]

If fooling with the wires made it OK, then you have narrowed it down.
New wires seem like a good thing to do.

Maybe new plugs [which take less voltage to fire and are easier on the system]. Possibly a crack in the coil.

 

[GTO52]

The mechanics found some condenstion in the small multi plugs that connect to the coils otherwise everything else was okay, they did change the plugs as well.
Seems a bit strange, I last washed the engine about 6 weeks ago, could the water have gotten in and only caused the intermitent misfire now?

Also I see they fitted Champion RC9YC but that isn't the exact match to the NGK BKR5EY?
I checked some cross reference charts it seems to be equivilent to 6 on the NGK scale in otherwards colder than the std plug.
I think I will leave them in and change back to the NGK BKR5EY when I service the truck in 3000km.

 

[beast3300]

That's a pretty cold spark plug (Champion RC9YC). You will know soon if it's too cold. Gas mileage will drop like a brick.

 

[mechtech2]

AHA! Washing the engine, you say?
I rarely recommend this.
Once shorts/leaks start, the part stay broken!

 

[morris]

on the older dodge v-8 small blocks and big blocks, the no 5, and no 7 cylinders are next to each other at the spark plugs AND on the distributor cap. it was easy to let the wires run next to each. but some times it would induce voltage into the wrong wire. so we always routed the wires at 90 degrees to each other. new subject: on most chrysler engines with a dist. cap they have a vent. in high moister places its best to fill the vent with jb-weld, ie. you DONT need the vent, and the cap will last LOTS longer.

 

[GTO52]

Originally Posted By: mechtech2
AHA! Washing the engine, you say?
I rarely recommend this.
Once shorts/leaks start, the part stay broken!


How do you keep it clean then?

My truck is 4x4 and is driven on a fair amount of dirt roads, so the engine gets pretty dirty!

 

[GTO52]

Update:

I had the vehicle back at the mechanics while it was misfing this time.
They said it was No 2 cylinder, they ended up swopping No's 1 and 2 injectors, it ran alright for a while and then started misfiring on No 1.
So it looks like a faulty/dirty injector!

 

[GTO52]

I had the injectors cleaned today, the guys that did the cleaning said the flow rate was below spec for all the injectors when they tested them before cleaning.
But otherwise they reckoned the injectors were okay and that they didnt think they were the cause of the misfire?
Mechanics refitted injectors and test drove it and said itwas okay.They also did a diagnositic test and no codes came up.
So now I will have to see if the misfire comes back?