I had a situation the other day in which I lost partial power intermittently and had a strong gas smell in my '94 NAS 90. I did some research which lead me to believe it was ignition related so I started going through the ignition tests in the workshop manual. I ended up seeing a pretty strong spark between the coil lead and the rotor arm, so I replaced it with a red rotor arm I had bought probably about a year ago, being all proud of myself that I figured out what the issue was AND had the part on hand to fix. So fast forward to yesterday, and the truck completely died right as I was pulling into a parking space. It started right back up though and I was able to get home. I repeated the coil to rotor arm test and saw the spark again so I'm hoping I just got a bad rotor arm. I have another couple of red ones on order but in the meantime is there anything else I should check that would cause the rotor arm to ground out? Thanks all!
Red Rotor
- Thread starter EBS
- Start date
I only ask because I had a similar situation on a '95 NAS Defender. In my case, the fuel line had a very small leak in it at one of the clips along the top of the frame kind of under the passenger seat area. When I repaired the fuel line, the problem went away. May not be related, but I figured I would share.
evilfij
Well-known member
Yes.
New red rotor, same issue. It runs but feels like it’s down on power and almost like it’s misfiring. No check engine light on. I replaced the cap too while I was in there. Will turn my attention to the amplifier but I’m still wondering about potential other causes of the rotor arm grounding out.
MountainD
Technical Excellence Contributor
it Could be no spark, weak spark, over fuel, fuel timing…bunch of things. If it’s consistent, you may have a stuck injector, your fuel pressure regulator may be unplugged or a leak in its vacuum line, it could be amp module, rotor, cap…. Just don’t become myopic looking at symptoms and start looking for the cause. For instance, you say strong smell of gas. For me, that means a fuel leak or a cylinder isn’t firing. I’d start by looking at my plugs and seeing if one is wet. It could be as simple as a damaged sheath on an spark plug cable.
My point is, and correct me if I’m wrong, but I’m not sure you have really figured out what is wrong past the loss of power/gas smell—and sort of are taking stabs at replacing stuff till it goes away— something I have done way too many times. Now, Im more likely to pull plugs (a GREAT DIAGNOSTIC TOOL, btw) and see if you can see what is going on— is it a cylinder, a bank of cylinders, or the entire engine. And go from there. It’s been my experience with gas smell that there are indicators on why and typically one can back track to a solution.
just good for thought.
My point is, and correct me if I’m wrong, but I’m not sure you have really figured out what is wrong past the loss of power/gas smell—and sort of are taking stabs at replacing stuff till it goes away— something I have done way too many times. Now, Im more likely to pull plugs (a GREAT DIAGNOSTIC TOOL, btw) and see if you can see what is going on— is it a cylinder, a bank of cylinders, or the entire engine. And go from there. It’s been my experience with gas smell that there are indicators on why and typically one can back track to a solution.
just good for thought.
Frobisher
Well-known member
Try looking at your wires in the dark with the engine running. If, like me, you’ve pulled on them several times while investigating, you may find them damaged. The lightning show you may see will be evidence of bad wires. I was having similar issues after a bad distributor, and the damaged wires were the culprit. New wires, no problem.
I was skeptical until I looked, and the light show was remarkable. It’s free and easy to test.
I was skeptical until I looked, and the light show was remarkable. It’s free and easy to test.
I checked the odd side wires and pulled that side's plugs. The wires all tested between 4.6k and 5.05k ohms/foot with my multimeter, which I think is fine. They looked fine too. That all said, for reference, the new set of Kingsborn wires I plan to install when (if?) this is all resolved are all around 400/ft. Plugs are dry, but very sooty to my untrained eye. Tough for me to photograph well but picture of #5 plug below. I do a lot of short trips so I guess the soot is not surprising. I think I should change the plugs regardless of how this all shakes out but open to suggestions.
I tested the resistance of the chicklet too, which was at 7.2k. I think that's high but no idea how sensitive it is.
This is my first attempt at trying to diagnose an engine issue so I really appreciate any and all direction. In the meantime I am going to pull the even side and go from there.
I tested the resistance of the chicklet too, which was at 7.2k. I think that's high but no idea how sensitive it is.
This is my first attempt at trying to diagnose an engine issue so I really appreciate any and all direction. In the meantime I am going to pull the even side and go from there.
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D901560
Well-known member
I've found new plugs make a huge difference with starting and idling and is the first place I start troubleshooting ignition issues. Its relatively cheap and easy since you already have the old ones out. Just use the regular Champion plugs (no platinum plugs) and make sure they are gapped correctly. Attached are the specs from the owners manual.
D901560
Well-known member
I don't know what the issue is with platinum plugs but at best they seem to offer zero benefit. I've tried them before and found copper plugs work best and to check / change them more often. I also stopped changing out the rotor and cap as often for preventative maintenance due to poor quality OEM replacements. When I have a good working set I just keep them in until there is a problem. These are just my observations from 18 years of ownership so others may have a different opinion.
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Very small electrodes that foul easily.
Going back to ignition issues - nearly every ignition part in 14CUX is garbage nowadays. I am at the point of keeping known-good old parts - because new replacements (from no-name junk from Amazon to genuine LR) are failing frequently right out of the box.
Got it. That's helpful. Will replace the plugs, hook everything back up and see where we stand. Thanks all.
So I replaced the plugs and wires and while I'm not declaring 100% victory just yet, it hasn't died since. I also cleaned the IACV and the flame trap (which was disgusting). Haven't driven all that much which is why I'm not quite convinced yet. I did test a few things (ignition amplifier, coolant temp and fuel sensors and wires) but nothing stuck out as obviously faulty.
I just received a new rovergauge cable so I can try to take a look more in depth. Is there any easy way to access the port behind the A/C, or if not an easy way to drop the A/C?
I just received a new rovergauge cable so I can try to take a look more in depth. Is there any easy way to access the port behind the A/C, or if not an easy way to drop the A/C?