I REALLY need a mechanic to help me!

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TeamPSI
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I REALLY need a mechanic to help me!

Postby TeamPSI » Sat Aug 31, 2002 6:12 pm

Ok.......

I drive a 1995 Nissan Altima 2.4L 4cyl.
I was going down the freeway the other day and I noticed that the car was lacking power. Didnt think too much of it at the time. I went on for maybe 2 miles or so when the air conditioning began to blow hot air. Just after that I had to stop for traffic and the car went dead. Steam came rolling out from the hood....OH NO!
I got out to check it, and as soon as I opened the hood I freaked. The upper part of the radiator was all cracked and leaking, and steam and water were shooting all over the place. I tried to remove the oil filler cap just to inspect everything and it was so hot it blistered me. Once I got it off there was smoke coming from the filler hole. I think the engine was so hot it boiled the oil inside. Anyway...I already know I need a new radiator, thermostat, and probably a water pump, but heres the thing...

I tried to start the car after it had plenty of time to cool off, but all it does is spin now. It wont even try to crank. I checked the oil to see if there was any indication of a blown head gasket, but the oil looks fine....pretty thin like was broken down from all the heat, but no water. I checked the plugs and distributor. They are all functioning correctly. Havent checked the compression with a guage yet, but I believe there is plenty of compression there. I checked just by removing the plug and holding my hand over the hole. The car has a timing chain, and the cams are spinning just fine as well. I dont think the timing is off.

Heres what I find to be very weird...
We took out the fuel rail on the car to see if the injectors were working correctly. They all squirt the gas just fine, but they all fire at the same exact time. This isnt suppose to happen is it? Doesn anybody know why in theyre doing that?

Also.....Even though the injectors all fire at the same time it seems like the engine would still try to crank a little.
Im totally confused by this. I have compression (at least enough to make the car sputter a little), I have fual ( even though it all shoots at the same time), and I have spark (and plenty of it). I cannot figure out what in the world is going on.

Somebody please help me!
Word on the streets is that I should be worth about 100 grand. :greedy:
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sandt38
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Postby sandt38 » Sat Aug 31, 2002 6:33 pm

Whenever a newer car overheats the computer shuts down the AC compressor to reduce load, and warn the driver who is not paying attention to the dash light.

The injectors fire at the same time when cranking for cold start enrichment. It is just like a choke. Even if the car were to run, it would fire so fast as to make it impossible to tell which one is firing. Think about it, 700 RPM is almost 12 rotations per second. Can you see that fast?

I will suggest 2 things. First, pull out the plugs, and replace them. I would dare guess you flooded the holes cranking it so much to get it to start. This will foul the plugs and wash the cylinders. Squirt a little oil down each hole before you replace the plugs, about a tablespoon apiece. Disable the FIs and do your compression test now (with the oil in the holes). Hopefully it is ok. If not, you have heated the engine so hot, you burned the rings, or cooked the temper out of them. They are springy and designed to press against the walls of the cylinders. If you overheat them they can loose their tension and no longer hug the walls, creating low compression or an oil burner. If it all checks out OK, reinstall the plugs, reenable the injectors, and enter the car. Mat the acellerator and crank for a few seconds (this is clear flood, it closes the injectors and allows excess fuel to exit the cylinders, it also allows the oil we used to coat the rings). Now, try cranking as normal.

If that doesn't lead to anything, post again. I'm glad to help out...
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nismo
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Postby nismo » Sat Aug 31, 2002 6:34 pm

worst case scenario, you have a good excuse to get an rb20ve (turbo? :D)

eric
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TeamPSI
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Postby TeamPSI » Sat Aug 31, 2002 6:43 pm

These injectors though.....
Its not like theyre constantly squirting...Its like once or twice a second that they do it.
Word on the streets is that I should be worth about 100 grand. :greedy:
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sandt38
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Postby sandt38 » Sat Aug 31, 2002 6:54 pm

Originally posted by PimpDaddy
These injectors though.....
Its not like theyre constantly squirting...Its like once or twice a second that they do it.


When you are cranking an engine with a starter it is FAR slower than 700RPM. One thing as a diagnostic tech I have learned (and sometimes it is hard to put into practice) is just get over something you see that is questionable, if another source says it is right. Smoetimes I will have a gut feeling, and be unable to get it out of my head. I will continue to chase something even though I know it is not the culprit. This results in wasted time and lost revenue. Do yourself a favor and forget the way the injectors fire. They are firing, that's what matters now. We don't have a fuel problem, if it sputters sometimes, we don't have a spark problem. That leaves mechanical or timing. Timing is not really in my suspect list because of a couple things...
1) it was overheated, that can cause rings to collapse, but I have yet to see it cause a timing jump.
2) Besides, that engine doesn't have a history of timing chain problems.
3) a hard start situation typically leads to the customer cranking the hell out of there car, RE: flooding the engine.

These 3 things make me do the math and give you the initial advice I did. If you were a customer who told me the same thing, I would formulate that strategy in my mind to follow myself.
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sandt38
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Postby sandt38 » Sat Aug 31, 2002 6:56 pm

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TeamPSI
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Postby TeamPSI » Sat Aug 31, 2002 7:11 pm

I really dont think the plugs are fouled because they spark a pretty good bit, but I'm gonna replace them as you said, and do the compression test.

I will check it before and after I add the oil...correct?

Thanks so much just for helping me even this much...Ive been stumped on it.
Word on the streets is that I should be worth about 100 grand. :greedy:
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TeamPSI
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Postby TeamPSI » Sat Aug 31, 2002 7:12 pm

Oh yeah.....The temperature light never came on and the guage was reading normal. ???????
Word on the streets is that I should be worth about 100 grand. :greedy:
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sandt38
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Postby sandt38 » Sat Aug 31, 2002 7:21 pm

Originally posted by PimpDaddy
I really dont think the plugs are fouled because they spark a pretty good bit, but I'm gonna replace them as you said, and do the compression test.

I will check it before and after I add the oil...correct?

Thanks so much just for helping me even this much...Ive been stumped on it.


When they are sitting out in the open there isn't much resistance. When you add the temperature and pressure in a combustion chamber the spark has a hard time jumping the gap, so it follows the deposite left by the fuel on the plug ceramic. That becomes far easier than jumping through compressed, superheated air.

Correct before and after.

Any time.
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sandt38
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Postby sandt38 » Sat Aug 31, 2002 7:27 pm

Originally posted by PimpDaddy
Oh yeah.....The temperature light never came on and the guage was reading normal. ???????


If it was leaking coolant, the water level got below the temperature sensor for the dash. When this happens, the air in the pocket does not allow the gauge, and or light, see the coolant temperature. The sensor for the computer is located low in the head, so this "should not" happen to it as well. That is why the computer shut the AC down. By reducing engine load it was trying to reduce the buildup of heat also. Make sense?

By the way, you may also want to change your oil. High heats can cause reduced viscosity, or make the oil into less of a wedge.

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