View Full Version : All plugs arcing on 1987 Ford Ranger
I recently bought a 1987 Ford Ranger w/the 2.9 liter. The truck would have trouble picking up speed going up hill and acted like it was missing during acceleration on level roads. It was dark when I looked at it and noticed all plug wires were arcing at the boot/plugs. The coil wire was arcing in a couple of spots and an arc was found between the primary and secondary coil windings. I bought it anyway because I felt that a set of wires and plugs would solve this as it always has in the past.
I have replaced the plugs, wires, coil, distributor, rotor cap, o2 sensor, and MAP sensor. The coil and coil wire are no longer arcing but the arc at the plugs on all 6 remain. A ford dealer checked the injectors, cylinders etc and can't figure out what is causing it. It starts fine but the idle does race and then it almost quits and then 5-10 minutes later it races again.
04-12-2005, 09:38 PM
I think you and chemistbert's truck must be relaited,LOL.
04-13-2005, 04:13 AM
Is that truck modern enough to have an MAP sensor?
The racing/quitting scenario sounds exactly like
a defective MAP sensor.
This would have no connection to arcing high
voltage, of course, but you could have more
than one problem at work here.
04-13-2005, 06:38 AM
Not trying to brush you off.......... Have you tried Yahoo Groups and search for Ford Ranger? They have a group for everything. I did that for my toyota when it was acting up.
04-13-2005, 09:25 AM
>replaced the ............, and MAP sensor
>Is that truck modern enough to have an MAP sensor?
How many doctorates do you have???? :D
A couple more guesses that can be checked for the rough idle are the throttle position sensor and the idle speed control motor.
04-13-2005, 08:31 PM
>> Is that truck modern enough to have
>> a MAP sensor?
> How many doctorates do you have????
In car repair, none.
But the 1984 2 Liter Ford Ranger >>DID<< have a
MAP sensor, and so did the 1986 2.9L V6 Extenda-Cab.
I remember having a recall force replacement
under warranty, I just could not remember what
exact years of the trucks were. [They weren't
mine, they were a buddy's. He needed me to drive
one of the two over to the dealership for the fix,
so he could get both done in one day. He told me
all about the recall. Funny how the mind recalls
> ...throttle position sensor and the idle
> speed control motor.
Regardless, sounds like one of the electronic
components. Starts up runs OK for a bit, and
then goes insane. The sensor (or processor)
gives valid readings until it heats up (due to
either electrical current flow or engine heat)
and then gets wacky due to heat-stress failure.
jim (I'm only a QUANTUM mechanic!)
04-13-2005, 09:37 PM
>But the 1984 2 Liter Ford Ranger >>DID<< have a
MAP sensor, and so did the 1986 2.9L V6 Extenda-Cab.
Jim, well of course it HAD one. Sive mentioned in his post that he CHANGED it. Why did you ask if it had one? I don't have any doctorates, and even I can figure out if he changed it, then it must have one.
You don't have to yell. Who do you think you are anyway--George Imire?
Well I have cleaned all the grounds, replaced the battery ground cable, replaced the 10 gage wire from the battery ground to the chassis that holds the radiator, and moved the strap coming off of the exhaust to the chassis as it was attached to the plastic well well. However, the problem remains.... I fired it up and all 6 continue to arc. I then checked continuity across the heads to the firewall, plugs to the firewall, block to the firewall, exhaust to the firewall, and heads to the block. It all seems to be grounded well.
I have thought about running additional straps from the valve cover(s) hold down screws to the firewall as I have seen in older model chevys. The spark plug wires I am using are the Car Quest Gold premium set. I have thought about trying an MSD set. Should I go to this extreme on the grounds first? Also, could this possibly be caused by the PCM?
I tried a different set of plug wires. Now I only have 3 wires arcing and less frequently. I plan to go w/an MSD set to see if that will cure all of them.
04-16-2005, 04:50 PM
> Sive mentioned in his post that he CHANGED it.
I'm sorry, I missed that.
> You don't have to yell.
I didn't yell, I was just typing. smile.gif
> Who do you think you are anyway--George Imire?
Watch it - George is a good buddy o' mine.
Don't use his name like that. Yeah, he is a
bit of a fascist, but you still gotta love his
single-minded dedication to turning newbees into
beekeepers who at least know some basics.
04-17-2005, 02:14 PM
I'm from 100 years ago. There used to be a resister in the dc feed to the coil that was jumped by the ignition switch so that it (the coil) got the full 12 volts to start a cold engine and when the key was released 7-10 volts fed the coil while the engine was running. (Don't ask me how old this data is) If a similar circuit exits in this electronic age and was flawed that could account for a coil getting too much voltage and putting out too hot a spark. If that resister still exists someone could have removed it or jumped it. You could have the wrong coil. Sometimes parts change within the model year. If the same deal is handle by a 'puter ......it still gets handled. It ties in with the heat thing too because this was a heat dependent item, I think. Is it possible to get the specs and discover if you have too much high voltage? What's the DC at the coil when running and when starting? what should it be?
Just rambling but it may stimulate something.
04-17-2005, 05:28 PM
I had a fuel injected VW Quantum which repeatedly raced, then sputtered, instead of idling nicely. It turned out there was a gaping hole in the vacuum manifold. Closing that fixed it.
The fuel injection brain had been trying to compensate when the vacuum leak altered the fuel-air mixture.
04-17-2005, 07:02 PM
Does it have cruise control?
Yes, it does has cruise control.
04-20-2005, 06:54 PM
I had a ford ranger that did the same thing and I replaced almost the sane things but this did not fix the problem. Then I talked to an old ford mechanic and he replaced the distrubitor cap with the recomended ford part and this fixed the problem.
If I still have the problem after I install the MSD plug wires I'll try a distributer cap from Ford. The one I bought and installed was the cheaper of the two that Napa carried. The cap that came on it was pretty well pitted up.
04-25-2005, 07:42 PM
Carbon tracks down the side of the plugs will make them arc to the head . It will look like a balck dust on the plug porcelin .
The race then idle rough sounds like a vaccum leak . Listen for a hiss sound around the throttle body or the intake manifold . There are many things run by vaccum on the rangers as well that could have a leak .You can pin point it by using a can of WD 40 . It will seal the hole for a short time returning it to a regular idle . But be careful as it is flamable don't squirt it onto a hot manifold .
I have now put a 2nd set of new plugs in with 2 still arcing. I also have the low resistance set of MSD wires on it. I have noticed that when I change the plugs, the threads are saturated with black oil. Even after only 1-2 hours of off and on run time during trouble shooting.
Not sure, but as for the carbon tracks, isn't that caused by the arcing in the first place?
The MSD wires and a couple new plugs w/dielectric grease on the plug threads cured the arcing. The chugging was because the #1 cylinder wasn't getting any power to the injector. The wrong wire was connected to it. The only remaining problem is that it idles high. I have only worked on carburated outfits, so I am not sure what controls the idle on one of these injected engines.
05-20-2005, 05:30 AM
Have you reset your ECU yet? Disconnect the negative terminal on the battery. Go make some lunch and then reconnect the battery and try it. A website called the ranger station has idle reset instructions too. Don't just turn the linkage stop, you will jack up the idle sensor that way.
05-23-2005, 06:33 PM
I saw a chevy do the things with speeding up on it's own all due to a not correctly wired up cruise control.