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Old 12-26-2014, 02:43 PM   #1
Statek
 
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Gas leaking from exhaust manifold and a wet spark plug

I have a 1990 240sx with a SR20DET swap that has been running rich since I got it around a month and a half ago, but more recently I saw it giving off more white smoke out of the exhaust with no change in fluid levels. When I brought it home after it started smoking, I started it and saw gas spurting out of the exhaust in the cylinder closest to the firewall (4). I took out the injector rail and turned the key to see gas spraying everywhere from the 4th injector and replaced them all today. I did the same test without any leaking from the new (used) injectors but the gas is still spraying out of the exhaust manifold (right where the gasket is) and the spark plug is still dripping with gas when I take it out. I'm fairly certain a new gasket would fix the issue with the gas spraying everywhere, but I don't know what I should do to get the cylinder firing properly. The only other bit of information I can think to add that when I was doing the first oil change, the oil filter shot out and I drove for maybe a quarter of a mile in a neighborhood total with oil shooting out. I accidentally overfilled the oil a quart above and drove it like that for a day or so afterwards, then emptied it out to see the new oil pretty much black. Any ideas?
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Old 12-26-2014, 08:49 PM   #2
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injector O-ring or the injector ground signal (from the ecu) is grounded (shorted out)
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Old 01-02-2015, 01:50 PM   #3
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I'm waiting on a time when I'm both free and it's not raining outside to check how the injectors spray after pulling the fuel rail, but without doing that, if its shorted, would a new injector harness most likely fix the problem, maybe along with an extension? It has an after market intake manifold that puts a lot of strain on the harness.

Last edited by Statek; 01-03-2015 at 07:33 PM.. Reason: new information
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Old 01-04-2015, 03:31 PM   #4
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Okay, I'm thinking I found the problem, sometimes when I pull the fuel rail out and turn the key, gas sprays out of that one injector, and sometimes it doesn't, leading me to think that its a cable that's sometimes being shorted and sometimes not, like you said, so I'm probably going to end up extending the harness by a few inches and fixing the short if I can find it.
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Old 01-04-2015, 06:09 PM   #5
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If you cant find the short, you can run a new wire. Find the wire at the ECU using a pinout and run your own temporary solution to the rail. at least this way you can drive the car, and further diagnose the issue. If the injector continues to open intermittently by itself, you have narrowed it down to the computer.
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Old 01-10-2015, 05:01 PM   #6
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The car has also had a current draw on it without the key in the ignition recently, and using a voltmeter today, I found out where the draw was, the stuck-open injector. So now would the next step be to cut into the harness and try to find where the short is or just go ahead and run another wire to the injector? Since the injector harness is hardwired directly into the rest of the harness, I'm thinking I'll just run new wires to it for now at least.
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Old 02-02-2015, 07:41 PM   #7
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Okay, so it's not a short in the harness, it's in the ECU, or at least so I think, correct me if I'm wrong. With the battery hooked up, I check the voltage between the positive and negative lead on injector 4 and there's battery voltage on it, the others have nothing. I took the injector drive input 4 (where the ecu grounds it and completes the circuit when the injector needs to go off) pin out and checked voltage directly between the ecu on that pin and the injector on the "power" pin and got battery voltage, meaning the ECU is completing the injector circuit which keeps the injector stuck open at all times. So, what I'm asking is essentially if this can be fixed with a tune and keep the same ECU (since the problem seemed to come and go earlier but now seems to be rather permanent) or would I need a new ECU or what? And if getting a new ECU for my s13 redtop, would a s13 blacktop ECU work as well, since they're a lot cheaper and from what I've read, they shoould work interchangeably.
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Old 02-02-2015, 09:54 PM   #8
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If you have a 62 ecu, then you can also use the E5 (blacktop chuki) ecu.

You can find both for around $100-$130 here on zilvia.
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Old 02-10-2015, 05:42 PM   #9
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Got a replacement ECU and it seems to have completely fixed the problem
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