Strange issue with 1997 D21

[brad2358]

Hey everyone,

I've been reading all over the web for months now, all the different forums, sites, I've even taken the truck to a mechanic but the issue still hasn't been solved. I'll go into some detail.

About a year ago, the truck started to have rough idle, hesitation, etc. It was time for new plugs, wires, distributor cap & rotor, and I replaced them all. That instantly fixed the rough idle issue, but another issue remains.

After running for a while, I'd say in the ball park of 30 minutes, the truck gives a #4 cylinder or just general misfire code. Right around the time this happens, the horsepower starts to drop a bit, It almost seems that the longer I drive it at this point, the weaker it gets. I've noticed this is worse in warmer weather.

Also, another strange issue is that once this starts to happen, I hear what sounds like relay clicking coming from the right side of the engine bay. It just so happens to be that's where the EGI and Fuel pump and some other relays are.

The truck is at 170000 miles.
Here's what I've done so far:

-Replaced battery
-Replaced alternator (just happened to die recently)
-Replaced positive battery terminal, it was very corroded.
-Excercised/cleaned all fusible links by the battery
-Cleaned, sanded down grounding cables to ensure good ground
-Cleaned/excercised EGR and BPT
-Replaced a lot but not all of the vacuum lines.

The main thing to keep in mind is that this issue appears to "linger". For example, if the issue is happening, and I turn off the truck for an hour, it will come back right as I start it up and drive again. However, if it sits for a few days, the issue is gone and it runs like a new truck until a half hour or so of driving, then it comes back.

I just can't figure out what's wrong with it. Any ideas would be greatly appreciated.

Thanks in advance.

[Desert Rat]

did you keep your old wires? Try putting your old #4 wire back on and see if it persists. Rules out the easy stuff that maybe you just got a bad new wire.

I had a similar issue on my Frontier a while back. Swapped wires back over and the problem went away.

[brad2358]

I'll do you one better. I have a whole new set that hasn't even been used. I'll put it on and let you know what happens.

[JarredH]

That's a thought.

So, it's there when engine is warmed up plenty good. It it's general misfire, or number four, it's pretty safe to just focus on the ignition side of things for now. Like said, wires are where to start, there's always the chance of a DOA part. I'd check the rotor and cap while you're there, might as well. Also new plugs if they aren't already.

You're clicking you hear, along with power loss, could be voltage leak. When it happens next, shut off the lights, make the room nice and dark anyhow you can, and look for arcing in there somewhere. Water in a spray bottle help find it sometimes, but be careful. Youtube it for info, Eric the Car Guy has a good video on it.

[brad2358]

I'll change the plugs tomorrow. I looked tonight in the dark, and didn't notice any arcing or anything like that but here's another thing that I forgot to mention:

The relay clicking only happens when the vehicle is moving. So when I come to a stop, it stops, and starts back when I start moving again. Very wierd. It makes it almost impossible to troubleshoot. When I flip on and off the ignition switch (not cranking the engine), I can hear the exact same sound coming from the same place. I think it's coming from the relay box on the passenger side of the engine bay. I guess the question is, what's causing it?

Once I change the plug wires tomorrow I'll let yall know and we can see what happens. Once again, this problem appears to be worse when the car is warm/has been running for a while. I wonder what would happen with warming up that might trigger it.

[JarredH]

There's supposed to be a relay click for the fuel pump and that stuff, but I'm pretty sure that relay is in the fusebox inside the cab. At least that's how it is with my 91, but a lot can change in eight years. Don't know about clicking when only moving. Is it in tune with road speed? There may also be a loose or shorting wire for the fuel pump input wire, which would cause it to click a lot from moving the truck, and it vibrating around. That'd also make the engine not run right, I'd think.

Start by following that fuel pump wire. I'd have a buddy sit outside the truck and find where the relay is clicking at, and which one it is. Wouldn't hurt to look at a wiring diagram to help you.



For a general and number four cylinder misfire, it could be some ignition stuff. I don't know what sort of things for that would be other there that click.

[brad2358]

Ok, thanks for the replies so far. I've replaced the plug wires, and still the problem is occuring. The rate of the clicking sound doesn't depend on engine RPM, but it does get faster as the truck warms up. The click is rapid, but random, almost like the sound of a computer hard drive.

I'm going to do some research on relays. I wonder if the EGI or Fuel Pump relay is going bad, and perhaps causing this.

Once again, the clicking and the loss of horsepower and misfire codes all co-incide.

Thanks so far,
-Brad

[JarredH]

I would think it wouldn't be the fuel pump relay if it's giving good pressure. That'd make all the cylinder's read misfire, I'd think. Might be the EGI, but again, I'd think it'll do all four cylinders. With what you've told us, I would start to suspect individual injectors at this point.

When you finish all your research, I would probably just swap out the EGI relay to see what happens, they're cheap enough to just buy one and if it doesn't fix the problem, keep on the shelf for later. If that doesn't do it, then I'd start testing injectors, and all their wiring. Also make sure you're actually getting good fuel pressure, maybe the pump is overheating and not pumping good?


If you happen to be 'roundabouts NorCal, I'm not opposed coming over with some of my tools to lend a hand.



I've also head of some engine problems being fixed by swaping the ECU out for a known good one. Expensive, but if all else fails...

[brad2358]

Update:

I removed EGI relay. Truck runs, but still the same clicking occurs. Then I put EGI back and removed fuel pump relay. As i guessed, it ran for a second until fuel pressure ran out.

Then I swapped the fuel pump relay with the A/C relay, but the same clicking occurs. I'm thinking the problem doesn't lie in the relays, rather something that is causing the noise, which, may not even be caused by the relays. I'm going to now inspect the fuel injectors.

Can fuel injectors click loud enough to hear through the firewall while the motor is running?

[brad2358]

Also, once again, the clicking is random, I would guess the inector click would be in sync with the RPM of the motor. I could be wrong though.

[JarredH]

Is it throwing any engine codes?

[brad2358]

Yes, P0304 (cylinder #4 misfire)

[JarredH]

So, That's all that's in there, eh? Was hoping the computer would be a bit more helpful, but I guess we can take what we can get. Clear all codes, leave the reader hooked up, and run the truck until the check engine light comes on again. Scan the code, and see what it is. Maybe the computer will throw a new one?

Have you looked under the Distro cap and made sure it's making contact? When the engine starts doing it's thing again, slap a spark checker on the wires and see if they all have spark. If you don't have one, I guess you could pull off the number four wire from the distro and slap one of the good ones you took off with a plug on the end, ground it to the head, and check that it's sparking. Make sure it's a good wire, use two or three if you're not getting spark for redundancy testing. If it's getting spark, put it back on and see what happens. If you do have spark, reconnect it, and it still doesn't smooth out, then it must be a fuel issue. Read up on injector testing, or grab new ones. Look at everything you think connects to it.

I'd try and have a buddy stand outside the engine bay and try to pinpoint the sound, too. That's give you a better idea if it actually is the relays.

Could be harness wires, but I don't see how they'd fix themselves after a day or two of sitting.

[brad2358]

Well after a busy couple of weeks, I've payed close attention to the truck. Living in the southeast, we've had some periods of heavy rain, and strange enough, the problem goes away when it's very wet and rainy.

I was thinking there may be a fuel pump issue. During the last few weeks, my brother borrowed the truck to move some things, and he filled it up all the way both times. (I usually run below 1/2 tank just out of habit). Anyway, the problem is not as bad when the tank is full. (Although it still happens with full tank).

My next step is to pinpoint the exact sound thats happening. I'm thinking it may not be the relay, but rather the small pump that is sitting close to the relays. What is this pump? Return fuel pump?

[brad2358]

Another thing I was wondering. I may start looking into replacing the engine, due to high miles and oil burning. Will any year KA24E work, or do I need a 1997? (My truck is a 1997).

[whomadewho]

A starting point would be a compression check. I would also check the engine vacuum,and injectors. When you pull the plugs and discover a plug is wet as long as the plug wire and the injector checks out you can go with a hotter plug. As far as moisture under the distributor cap, Krylon makes a aerosol can called ignition sealer. Spray the inside of the cap and the plug wires,makes the ignition system totally water proof. At 170K the engine is just getting broke in. I have 193k on mine,the engine use to use oil,I replaced the cover gasket and started using Lucas oil treatment and Royal purple 10W 30 oil. When I change oil I use ONE quart of Lucas and the rest Royal Purple. You could also try some fuel injector cleaner,worth a try. It's hard to arm chair diagnose it,I would focus on the injectors verses the fuel pump.

[whomadewho]

One other check. There's a pipe that runs from the exhaust manifold,and goes behind the head and the fire wall, if the pipe is corroded or has a hole in it, this could explain the noise or click when the engine reaches operating temperature.

[brad2358]

I'll double check that, and keep updating as I go along. It takes a while though with my work schedule.

[brad2358]

Update:

I replaced the spark plugs, which looked really bad, even though they're only about 9 months old. Now the truck appears to be running fine. I feel kind of dumb for not doing this earlier, I just thought that they were too new to need replacing. Looks like my leaking oil is fouling plugs. White charred deposits and oil on them.

I'm going to keep a close eye on everything and see what happens.

[whomadewho]

Next time you replace the plugs ask for a hotter spark plug. A hotter plug will slow the plug fouling.

[Q451990]

Sorry to join the party late. If you don't have the factory service manual on hand, it's available at www.nissanservicemanual.com

I'm pretty sure the valve you're talking about is the "swirl control valve" or something like that...

Heath

[brad2358]

Thanks for all the replies so far. At the moment it's running great, minus the oil usage. One clue is that when I start the truck in the morning, or after it sits for a while, I see a cloud of blue smoke come out the exhaust. However, it doesn't smoke after that or when it's running.

Would you guess this to be a valve seal or piston ring?

[whomadewho]

Could be rings,valve seals or valve guides. Could also be oil break down due to short trips. Or an injector issue allowing to much fuel to enter the combustion chamber. The wrong oil weight could also cause oil use. I would go with hotter plugs and Lucas oil treatment. The bottom line oil is cheap compared to an engine overhaul.

[JarredH]

If it puffs blue after sitting, I would personally suspect valve seals, simply because those are overhead for gravity to pull what oil is clinging on them down, and rings are underhead, so those wouldn't drip oil in. At any rate, those are easier to replace, and a hell of a lot cheaper. Definitely go for the oil treatment first. I think it was Slick50 I used in my CR-V to refresh some old and dry seals when I put a junkyard head on it, stuff worked great. I've never tried the Lucas stuff, but I head good things about it from some of my mechanically inclined friends.