Intermittent loss of power, E16 barely runs!

toygeek · Nov 2nd, 2003, 01:25 AM

B11 Sentra, Federal Emissions model. Chokeless carb

About 2 months ago it started missing at times while I was driving. Now, its so bad that its difficult to drive at all. I'm afraid its going to break down altogether. It IS intermittent, though, and sometimes it runs great.

Thinking "I'll start with the basics" I bought a fuel filter and installed that. No change. I got a new cap/rotor and installed those today. No change. I haven't looked at the plugs yet, and the wires tested good about 6 months ago, so I don't THINK its those. Although I suppose they could have gone bad, one or two of them.

I thought maybe the timing belt slipped a tooth, but its not constant so it rules that out. I do have leaking front seals, though.

Is there anything on this car that is possibly known to cause this? I am almost SURE its an ignition issue, although it could be fuel starvation too. Is it easy to pop the top off the carb to check the needle valve and seat? I've never taken it apart. Also there has always been a rather strong fuel smell coming from the engine compartment that I've never figured out, but that never seemed to make a difference. I just figured the charcoal canister was shot.

Sorry for the epic novel here, I just want to be as descriptive as possible. Thanks!

Gforce · Nov 2nd, 2003, 07:50 AM

check all these and replace it order so that you know what's the culprit. Do the easiest first.

losing power mostly an electrical problem.

check first your ignition timing!

1. Distributor CAP [approx. $9.00 @ autozone]
2. Distributor Rotor [ approx. $12.00 @ Nissan dealer]
3. Sparkplug Wires [they ussually glow in the dark if the cables are worn out or I may say leaking.
4. Sparkplugs [ Ngk regulars are cheap $2.00 each at Nissan Dealers]
5. Ignition coil

other area that may cause problem:

check and... replace if necessary

air cleaner filter
fuel filter

check your CARBURETOR clean if necessary [do not dissamble]
check for air/fuel leak at carburetor
check your emission components....

hope these helps

Lazarus_023 · Nov 3rd, 2003, 01:55 PM

Quote:

Originally posted by toygeek
B11 Sentra, Federal Emissions model. Chokeless carb

About 2 months ago it started missing at times while I was driving. Now, its so bad that its difficult to drive at all. I'm afraid its going to break down altogether. It IS intermittent, though, and sometimes it runs great.

Thinking "I'll start with the basics" I bought a fuel filter and installed that. No change. I got a new cap/rotor and installed those today. No change. I haven't looked at the plugs yet, and the wires tested good about 6 months ago, so I don't THINK its those. Although I suppose they could have gone bad, one or two of them.

I thought maybe the timing belt slipped a tooth, but its not constant so it rules that out. I do have leaking front seals, though.

Is there anything on this car that is possibly known to cause this? I am almost SURE its an ignition issue, although it could be fuel starvation too. Is it easy to pop the top off the carb to check the needle valve and seat? I've never taken it apart. Also there has always been a rather strong fuel smell coming from the engine compartment that I've never figured out, but that never seemed to make a difference. I just figured the charcoal canister was shot.

Sorry for the epic novel here, I just want to be as descriptive as possible. Thanks!

could you be a little more specific about what it's doing?

toygeek · Nov 3rd, 2003, 02:05 PM

Well, I'll be driving along and it is running normal, has plenty of power etc. Everything is fine except the low idle (different issue). Anyhow it'll lose power completely, if I put the clutch in, it'll usually die, sometimes just idle barely. It still runs, because if I put the clutch in I can rev the motor still, but there is just no power to it. It often bucks and you really have to pump the gas alot to keep it going. The reason I think its electrical is because its intermittent. Sometimes it'll run great for a few minutes, then have problems again. It also generally happens when the car is warm, not cold.

Lazarus_023 · Nov 3rd, 2003, 06:28 PM

Quote:

Originally posted by toygeek
Well, I'll be driving along and it is running normal, has plenty of power etc. Everything is fine except the low idle (different issue). Anyhow it'll lose power completely, if I put the clutch in, it'll usually die, sometimes just idle barely. It still runs, because if I put the clutch in I can rev the motor still, but there is just no power to it. It often bucks and you really have to pump the gas alot to keep it going. The reason I think its electrical is because its intermittent. Sometimes it'll run great for a few minutes, then have problems again. It also generally happens when the car is warm, not cold.

you will want to check vacuum lines. ESPESCIALLY on the chokeless carb, they should be the first thing you check. look for cracked, broken, or weathered lines, and replace them *one at a time*. pay particular attention to the ones leading to and from the array of coolant temperature vacuum switches in your intake manifold and cylinder head (they control the idle at cold/hot temperatures...)

you may also want to check the temperature switches and wires. input from these switches is given to the ECU to control the fuel mixture solenoid.

it also sounds like you may have a bad fuel cut-off solenoid. if you have a multi-meter, call up a nissan dealership sevice dept, and ask them if they can look up the resistance of the fuel cutoff solenoid for your car (you'll need to provide info on your car...). you should also make sure there is power (use a multi-meter or test light) to the solenoid when your keyswitch is in the "on" position (you may have to let the car die and check it on the side of the road if the problem is intermittent).

if you need a walk-through, please post.

toygeek · Nov 3rd, 2003, 06:56 PM

Okay will do! I'll pull the stuff today and take a look-see. Some vacuum hoses do look old so I'll likely just replace a bunch of them at once to see if that's it.

Also, would a bad coil do this?

EDIT: I really appreciate this help. My wife has to drive this car too, and it actually hurts her. I'm trying to get this fixed so its smooth again. I am good with older cars, like my 1969 Land Cruiser. This stuff baffles me though, until I learn more about it.

Gforce · Nov 4th, 2003, 06:59 AM

BAD IGNITION COIL! these coils are prone to intermittent operation. They are good when they are still cold and when they reached operating temp. they go intermittent.

Ignition Coil is like a transformer enhanced by external power transistors. They greatly produced heat because of the cycle colapse of electrical current. If one of the coil's inside wire strands is loose it will disrupt coils magnetic field causing voltage fluctuations sometimes normal voltage output and sometimes low. Low ignition voltage output is not good.

anyhow check all easiest and cheapest parts first then replace it. Ignition coils are not cheap

toygeek · Nov 4th, 2003, 10:31 AM

PROGRESS:
Well, I found that some previous owner had plugged a vacuum line with a spark plug

I just LOOKED at it and it fell out. Car barely ran on the way home from the auto parts store where I was buying vacuum line.

I found another spark plug (haha) to plug it with for now, and guess what? RUNS GOOD! But it still has the power loss thing intermittently, so I am guessing the coil is bad.

This might sound like and odd question but I do have a spare coil, but its not from a Nissan. It looks the same, has the same connections, and as far as I know, all coils are equal for the most part. Is there any reason to NOT try it?

toygeek · Nov 4th, 2003, 04:22 PM

Okay I just spent my lunch hour working on the car. I have a good employer that doesn't mind

I replaced a number of vacuum hoses that looked like they needed it. There is also a sensor in the air cleaner, it looks like a temp sensor and is on the passenger side. It had a wire broken off on it. I managed to scrape enough of the potting compound away to get some wire to solder to. I soldered the wire back on and used hot glue to provide some protection and strain relief. Hopefully it won't break again.

I also found that the big fat vacuum hose that had been plugged by a spark plug actually had somewhere to go, and I plugged it in. Some lazy PO just didn't make the time to LOOK. Good grief.

I still think the coil is bad, and I see no reason not to replace it with the one from my spare parts (its the spare for my Land Cruiser). Its got a + - on it too, and it came from some chrysler car, as I recall.

Anyway unless someone tells me otherwise I am replacing it tonight, and hopefully all goes well

Now I gotta fix the broken motor mounds. Pick'n'pull, maybe?

Gforce · Nov 5th, 2003, 06:46 AM

ignition coils might look the same, same connectors etc but different electrical orientation in the inside. Try only ignition coils designed for Nissan with your model, I'd rather not try diferent coils it burn out your Ignition Power Transistor!

toygeek · Nov 6th, 2003, 12:17 PM

I'll be replacing it with a Nissan coil this weekend. Gotta get out to the pick-n-pull and get one, as well as motor mounts and a couple of other odds-n-ends.

Jericho · Apr 8th, 2004, 01:32 PM

toygeek what happen then after you replaced the ignition coil with a new one?

toygeek · Apr 8th, 2004, 01:37 PM

Quote:

Originally Posted by Jericho

toygeek what happen then after you replaced the ignition coil with a new one?

Never got to find out. Was supposed to have the carb rebuilt, but the guy who I made a deal with to do it backed out, or rather, never delivered. Shortly after replacing the clutch, the transmission died a horrible death because it had so many miles, or lack of lubrication. Not sure which. Either way, the car ended up at pick'n'pull with 280K miles on the odometer.

May it Rust In Pieces.