1994 sentra cyl. head rebuild, runs rough, loud intake
noob here. yes read sticky even though it's 10 years old. Anyway-
I'll just give you the background. My Sentra had 196k miles and engine was perfect. My sister somehow lost the radiator cap and overheated it multiple times and warped the head and blew the head gasket. The head would have cost too much to be re-machined, so I got a used one at a junkyard, and had that one machined.
I did all of the work myself, but had a mechanic fix the electrics, and get it to start.
He told me the cam timing was probably off and that it was running rough, and I asked him to fix it. I got it back yesterday but it was still running a little rough. I trust the guy who did it because he's my dad's friend and has worked on my car before but there's still an issue.
TLR;
Engine runs a little rough when warm and cold, it seems like it has a bit less power and I think it's running rich. The engine sounds like it's missing, but at random intervals. Also, the intake makes a loud BRAAP sound. If anything I want to get this worked out so people don't think I drive a Civic.
Not after the rebuild, but I will. I was wary of my results when I did a compression test before I rebuilt the head and if I remember correctly, all cylinders except for cylinder 3 were roughly 90 PSI, and 3 was lower than that- of course, those numbers were registered when the engine was cranking with the starter motor.
I'll test it tonight if I get the chance, but I'm definitely not pulling the block apart anytime soon
It sounds like you might need rings. I don't know what the spec is but 90 psi seems low and one cylinder lower than the other 3 shows that the rings are worn. You said you did this before the head job though, was this after the head gasket went? A leak in the head gasket can also give a lower psi when testing. If it was overheated multiple times to the point where the head cracked I would suggest a full rebuild or just replace the motor with a used one, for what a rebuild with machine work would cost you can get a running ga16 cheaper at a scrap yard or on ebay. What did the oil look like when you drained it? Was it full of coolant? Did you drop the oil pan and see if anything was gummed up from the head gasket leak? The only times I've heard an engine that matches your description for the "braap" sound along with the misfire, running rich, and lack of power, it was a dead cylinder.
Also, when you check the compression again, after you test all 4 dry squirt some oil into the cylinder and then test again. If you get higher results when they're wet it usually means you need rings.
I tested compression after the head blew. Also, the oil didn't have any coolant as far as I could tell, and I didn't drop the pan but I don't think that matters. Cylinder 3 had a little coolant in it, so I figured it was the blown head that caused the low compression. The compression spec is around 180 or 200 PSI I believe.
The head didn't crack, so I think the bottom end is ok.
When the head blew, the major symptom was overheating, but right now it's running worse than it did before I rebuilt it (minus the overheating, lol)
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! :)
In other news, I checked the compression and got roughly 130 PSI from each cylinder, 170 when I put oil in them. Also, I cleaned the MAF but that didn't go well, (I.E. I broke it)
I just pulled the engine light codes, which are 12 and 14. Vehicle Speed Sensor and MAF, respectively.
well, shoot.
It's hard to hear the sound you're describing. In the video it just sounds like you opened up the intake. Do you have a tach you could point the camera at instead of the speedo so I could tell what's going on? When you let off and you mentioned a lunge it sounded like you just let off the gas leaving the car in gear and usually this will cause a "lunge" from engine braking but I can't tell if that's what happened or not. When the maf my nx went out it wouldn't rev past 2500 rpm or something like that and misfired.
My MAF just barely went out, and it won't rev past whatever it is, my tach is broken.
I'm just going to assume that the loud intake is a just a quirk, since the cams are from a b14. By lunge, I mean it would lunge more than once, but I guess that symptom doesn't mean much. I need to get a new MAF and test the VSS, and go from there.
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