ttiwkram

Hi, All.

I could use a little help in troubleshooting a problem. Thanks in advance, and I’ll keep this as short as possible.

Background: 1996 Sentra GXE, 5-speed with 1.6L GA engine, about 195,000 miles. Usual gas mileage is 34 to 36 mpg overall.

The last time I drove the car to work, I noticed an unusual skip or hesitation for maybe ¼ of a second while cranking. Other than that, the car started normally and I soon forgot about the “glitch.”

On Thanksgiving I started the car and moved it 30 feet or so to make room in our driveway for guests to park. The following evening my wife told me the car wouldn’t start.

There were no OBD trouble codes.

The car would crank like crazy (great battery!), but there was no hint of firing. I tried some starting fluid; no change.

Nevertheless. at that point I still suspected a fuel delivery problem. (I could hear the fuel pump come on and turn off like it should, but I’ve had other vehicles with bad fuel pumps act the same way.) I replaced the fuel pump with a known good unit from my son’s ’99 Sentra (sorry, Gregg). No change.

A timing light reading the #1 cylinder showed consistent spark. I didn’t get a good read on the exact timing; it could have been right on or considerably off. The insides of the distributor and the cap were clean and dry – no oil or dust. The cam position sensor wheel looked perfect.

All fuses were good. All wires looked good, and all connections seemed intact. I located the ECCS (or ECM or PCM) relay, and it tested good. Just to be sure, I bypassed it. No change.

Spark plugs 1 and 4 were fairly wet with gasoline, so fuel delivery was looking less and less like the culprit.

I did a compression test, with these results:

#1 - 80 psi
#2 - 50 psi
#3 - 63 psi
#4 - 75 psi

I figure that HAS to be a change; I can’t believe a car with readings like that could get 36 mpg on the previous tankful. So now -- because of the compression and possible spark timing issues -- I suspect a jumped timing chain (I know neither chain is broken because I can look through the oil filler hole and see the intake cam rotate).

I’ve had about enough for one day. Tomorrow I plan to take a look at the timing chains and sprockets to see if they’re aligned as they should be.

Does anyone have experience with this set of symptoms? I’d just like to make sure I’m not barking up the wrong tree.

Thanks --

Mark W. in MI

rogoman

With compression readings that low, I would suspect that the chain may have jumped several teeth and possibly several valves got bent ever so slightly. This of course would account for the no-start condition. To determine the cause of the low compression, you'll need to do a leak-down test on each cylinder to pin-point whether it's the valves or the rings.

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KA-T for life, yo!

jdg

And we all know a billion things could've caused that. I'd forget about it too.

All other things considered, I think you just got drilled by the same old thing that seems to happen to a lot of GA16DE owners......Move the car 30ft (or 10 or 100 or whatever, just a really quick short run) and the thing doesn't want to start up next time around.
(EDIT#2:And make sure the wife knows not to touch the gas pedal while starting it up too! Had to re-teach that lesson to my other half a number of times!)

Before you go tearing into the engine, pull the plugs, pull the fuel pump fuse, crank it over until you are absolutely sure there isn't any fuel pressure left in there, buy some new plugs (real NGK replacements, not the usual Autozone suspects, and don't just dry out the old ones and put them back in. Likely won't work). Slap those new plugs in there, put the fuses back in, crank it over, wait for the fuel pressure, and see what happens (don't touch that gas pedal!!!).

Sounds really stupid, but, it's happened a number of times. For some stupid reason, the engine gets flooded out or something along those lines, plugs get wet fouled, engine doesn't start the next day (or later on that same day).

That kinda confirms what I'm thinking...about the gas fouled plugs that is...

Sure, those numbers are low, but, they also depend on a number of things. What were the compression numbers the last time you checked it? A lot of people don't know 'cause they don't check unless they've got a problem. Just sayin...
You've got an old engine. Was the gas pedal held full wide open while you cranked it? Was the battery completely charged for each cylinder check?

Chain jumped one link? Entirely possible. Has the upper timing chain tensioner been changed in those 195,000 miles? If not, even more possible.

Problem with that one link jump theory is that you gotta take off the whole timing chain cover to be absolutely sure. Serious PITA!!!

If it does turn out to be that you've stumbled upon that stupid "delayed flooded out engine after a short drive" scenarios, then all it's gonna cost you is a set of plugs and some time.
If not, well, you've got a new set of plugs to put in there after you do some major engine work.

Moral of the story (and no, it's not in any of the owners manuals or anything), Don't take these cars for a quicky one/two minute drive.
Good luck...

EDIT: As far as bent valves and compression goes... I did jump a chain (long story, the saga is posted elsewhere, has to do with getting interrupted by the other half and untightened lower chain guide hold down bolts falling out and getting wrapped up in the crank sprocket) and bent the exhaust valves in one cylinder, barely bent them, like you couldn't slip a piece of paper thru the gap but you could see light thru it, and got zero compression in that cylinder. So, with at least some compression in all your cylinder, I'd say there aren't any bent valves....yet....

__________________
99% of the questions that are "STRANGE" have a dirt simple answer...usually answered by a dirt simple search.

NISSAN GOOGLE

Is it just me, or does the majority overlook the obvious?

Somebody ate a whole bag of dumbass for breakfast.

Why do people continue to run a vehicle when a warning light comes on or starts flashing? Isn't that a clue that something is wrong and you probably should NOT drive it?
Is this whole car driving thing really freekin' brain surgery?

Here's something new for the crowd/clowns...
"A little bit of Google goes a long way!"

Ever notice the one post wonders for info on turbo'ing a GA16 are never heard from again after they figure out the cost???

And if you can read this, you don't need glasses! :)

And yes, I am diggin' it...

Centurion

Exactly correct about the propensity of these cars to flood out when moved a short distance. I these instances, I usually wait and it will start. In extreme cases, I pull the fuel pump fuse. Never had to replace the plugs, though.

I wonder if he is getting low compression reading because the fuel washed off the oil from the cylinders which would affect the sealing property of the oil.

__________________
1993 Sentra XE auto (original owner)
2005 NISMO Frontier

ttiwkram

The Judge is a GENIUS!

I already had a new upper timing chain, so I pulled off the valve cover and the end cover. The upper tensioner was shot (replaced it), and the old upper chain had only one different-colored indexing link instead of the expected three. I found that I couldn't remove the old chain -- even after loosening the idler sprocket -- without removing the timing chain cover. No thanks at this point (been there, done that on other Sentras). So, I counted rollers and made my own indexing links, put the cam gears back on, turned the engine over twice by hand without tools to check for interference, and put the rest of the parts back on.

Still cranked great with no fire.

Then, after several days of snow and ice, and working at my day job until it was dark outside, my year-end vacation started today and I knew it was time to give it another shot.

The first plan of attack for today was to try out the new spark plugs as recommended by the Judge. The new ones were one heat range different from the old ones (new 5 vs. old 6, if I remember correctly), but my son's '99 Sentra has 5's in it and my manual says 5's are the norm. So I gapped the new plugs to .035 per the manual (the old ones had been at about .060) and put them in.

Still cranked great...and started...and ran great! Woohoo!

THANKS to the guys who responded and pulled me out of this one!

I must admit I'm still confused about it. My previous experience with bad plugs in multi-cylinder engines is that the engine gradually runs worse and worse, like it needs a tune-up (which, of course, it does). I've never seen spark plugs suddenly turn off an entire engine like a switch. And I would have thought that any flooding condition would have been cleared by the compression check. Oh, well...

Before I drive it I'll need to replace the spark plug tube seals (on order), as three of the four cracked when I reinstalled the valve cover. But I'm one happy dude for now.

Thanks again!

Mark W. in MI

jdg

Nope...I just happen to have the same dumb luck as the rest of us once in awhile

The new tensioner should last at least 100K miles without worrying about it (all other things considered).

You can, but it requires a really good dremel, a vacuum, 3 strokes of good luck and holding your tongue just right for hours on end. Like you say...No thanks!

I would've turned it until my arms and hands got tired, but, it worked for you...good enough.

Just a small chuckle here

Might matter, might not, but keep your ears on the engine. When it warms up, it might want to ping a bit. Just a thought to keep in the back of your head. If it does, might have to go back to the 6's.

Like they had about 100,000 miles on them? Been there. But those old 100,000 mile plugs ran great except for the slightest smallest stumble once in a great while.

Ya gotta like those "cheap, little or no work" fixes eh?

Probably 'cause none of those other multi-cylinder engines had a computer to compensate for the unburned fuel.
And as far as the plugs go, near as I can tell (and I may be completely 100% wrong about it too), all that extra gas the ECU feeds it for a little bit gets down in between the porcelain center and the metal shell of the plug itself, and somehow shorts the plug, or at least it fires up in there rather than at the tip. Hell, I dunno. It's my story and I'm sticking to it.

Take that extra $$$ you didn't spend on the fix and buy yourself a case of preferred beverages...'cause they are well deserved.

__________________
99% of the questions that are "STRANGE" have a dirt simple answer...usually answered by a dirt simple search.

NISSAN GOOGLE

Is it just me, or does the majority overlook the obvious?

Somebody ate a whole bag of dumbass for breakfast.

Why do people continue to run a vehicle when a warning light comes on or starts flashing? Isn't that a clue that something is wrong and you probably should NOT drive it?
Is this whole car driving thing really freekin' brain surgery?

Here's something new for the crowd/clowns...
"A little bit of Google goes a long way!"

Ever notice the one post wonders for info on turbo'ing a GA16 are never heard from again after they figure out the cost???

And if you can read this, you don't need glasses! :)

And yes, I am diggin' it...