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Hi Officer, how ya doin'?
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438 Posts
Discussion Starter · #1 ·
The motor runs like absolute ****. It won't rev past 4500rpm. It spits out black smoke and won't idle. If you all remember I dyno'd
the intake manifold and something let loose past 6800rpm. I had just assumed that the ringlands cracked as usual.
Last night, I finally got around to checking everything over with a compression check. The motor was 155/154/155/155 psi across the board. I thought about the head gasket, but if something was wrong it would show up in two adjacent cylinders. Next, I pulled every spark plug and checked them. They all looked black which indicated a rich mixture. There wasn't any oil on the plugs at all. The other motors that I hurt previously had oil dripping off the plug, which were the ringlands.
So, my next venture was to pull off the valve cover. I expected/hoped to see a rocker arm displaced off the shims. Everything looked fine. I saw no scoring on any of the cams at all. I checked the oil and saw no coolant in the oil pan.
The only things that I can think of is either a burnt valve or to see if one of the cylinders isn't firing. That may explain the smoke coming out of the tail. It could be raw gas not burned. How do I determine if the valve is the culprit?
Any hints or tips you all can provide will be greatly appreciated.
Down, but not out.
 

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El Chingon
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892 Posts
Cylinder leakage test. That should give you an excellent idea of what the problem is.

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David De Anda
Turbo Sentra SE
HTA Drag Squad
 

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Registered
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858 Posts
get the leak down test done and check what signal the ecu gives you .maybe maf or other sensor

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91 SE-R,10:1 comp.pistons,balanced &blueprint rebuild.comp.4angle valve job,extrude honed heads/intake manifold,No emissions.crap,RC TB/MAF,nismo cams,UR pulleys,stillen4-1 ceram.header, ACT HDS/S clutch,PR CAI with POPchgr,2 1/2"OD test pipe,mandrel 2 1/4"ID superturbo ex., ZEX flywheel & JW 50 shot nos with 60 shot jet. and much more goodies!
 

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Premium Member
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1,619 Posts
<font face="Verdana, Arial" size="2">Originally posted by jacen99SE:
I think you should check your MAF connections and voltages.</font>
That's what I would check. Had spewing black smoke after an autocross run a couple years ago. Car then wouldn't start, and I thought the worse. Turned out, I forgot to put that little metal clip on the plug to the MAF. The plug had jostled loose (still looked connected but wasn't snug).

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'93 SE-R, for sale soon
'91 SE-R, future racecar
'00 Lightning, future SE-R puller
 

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Hi Officer, how ya doin'?
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438 Posts
Discussion Starter · #7 ·
The ECU didn't give me any codes. However; it still could be a loose connection. I will find out today. Any other suggestions?
 
G

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<font face="Verdana, Arial" size="2">Originally posted by Big Boost:
The ECU didn't give me any codes. However; it still could be a loose connection. I will find out today. Any other suggestions?</font>

So I take it you didn't like mine.


Black smoke would scare the crap out of me. You're not driving it anymore are you?

Chris


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Blaming guns for murders is like blaming spoons for fat people.
 

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484 Posts
"If you all remember I dyno'd
the intake manifold and something let loose past 6800rpm"

it almost sounds like something is sticking/blocking the intake and the computer is trying to make up for the lack of O2 by adding more gas. is there some way check to make sure all of the intake valves are working properly or to make sure that there isn't something in your intake track? Definitely let us know, im kinda curious myself..

Alex
 

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vincit omnia veritas
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1,085 Posts
Not being able to rev, good compression, black plugs.... HELLLA rich?
Not to be an ass but you did not mention checking it so I might as well ask.
Timing? cap/rotor? what igniton are you using to boost to that PSI? Could the ignition have shorted internal or maybe externaly?
Cam timing? do you have adjustable cam gears? did one slip and fawk the cam timing all up?
HTH, let us know, best of luck
later
david lau
 

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Hi Officer, how ya doin'?
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438 Posts
Discussion Starter · #11 ·
Here's a list of what I've checked so far:

1) Compression good
2) Injector impedence good (11.9 ohms)
3) MAF reads 12+ volts
4) Timing good (15 degrees)
5) All electrical connections good
6) Checked vacuum lines for cracks/leaks

Will check
1) Fuel pressure regulator
2) MSD 6AL spark & Blaster 3 coil
3) Distributor/cap/rotor
4) Individual cylinder spark
5) Leak down test
6) O2 sensor
7) ECU codes?
8) Exorcism rites

White smoke = coolant
Blue smoke = oil
Black smoke = rich fuel mixture
Green smoke = I'm high and on crack because I can't find something so trivial and evident with my SE-R!

[This message has been edited by Big Boost (edited 10-18-2001).]
 

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3,473 Posts
A Big Boost as the name suggest you are turbo'd? And most likely you don't have a CAT or do you? Well anyways my NA SR20DE one day would not REV past 4500 rpm well it would but it would take a long time, well anyways I noticed the intake note got super loud sounded really good but had absolutly no power to match anyways I thought maybe a intake/exhaust valve cracked and that was the reason for the aggressive intake note anyways turns out when I took the CAT off to check it was completly (almost more like 80% clogged) melted together. I ran water through it to check to see how bad it was and maybee 20% of the water would come out the other side. I know this post is old but anyways did you figure out the problem?
 

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fabricator
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841 Posts
rob, i assume you meant that the MAF is being supplied with 12+ volts, but if not, you should check the signal voltage with the car running and see what you are getting. MAF voltage fluctuations can wreak havoc, even with the connector plugged in. I experienced similar crap when the car would start sputtering and not rev/idle, spit unburnt fuel etc.. but only when it was raining hard. Turns out filter was getting a little wet, and small water droplets would get sucked into the intake tract. Occasionally, one droplet would hit the HOT wire in the MAF, instantly cooling it off completely, thus signaling 100% airflow, even with the throttle closed. I finally tracked this down while sitting on the side of the road, missing the morning practice for a roadrace, furious at the gremlins in my car and watching my Multichecker. Every so often the MAF % would spike to 100% and Injector pulsewidth would accordingly do the same. I pulled off the filter and it ran fine. Anyways... sorry for the tangent. My point is: monitor the MAF signal and make sure you are getting reasonable numbers.

andris
 

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Hey I know that this thread is REALLY old but my car is doing the same thing. Did anyone ever figure this out?
 
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