Gas misting out of header. #7 cyl. Changed plug, what other possibilities of problem?
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I was worried about white smoke at first, because the car used to ne able to smoke out a Walmart parking lot within 10 minutes. But it's clear as day now. I had it running for 15 minutes or so tampering with fuel pressure, and looking for leaks, adjusting TB, ect.
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You could always be lazy and do what I do- Disconnect the old one, then run a new one ![Tongue](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_tongue.gif)
I've done that more times than I'd like to admit... My last beater was a flood car, I replaced at least of a third of the wiring in the damned thing while I had it. I just bought a roll of wire loom at El Vatozone and ran all the new wires through that, through the firewall to the PCM..
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I've done that more times than I'd like to admit... My last beater was a flood car, I replaced at least of a third of the wiring in the damned thing while I had it. I just bought a roll of wire loom at El Vatozone and ran all the new wires through that, through the firewall to the PCM..
Thanks for all the tips and tricks guys! Making time for me to tip a few back in the evenings! Much appreciated!
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Shbox, help! I traced the ground wire of the #7 cyl pigtail to the PCM, it was fine. I then took it out of the PCM to determine if the wire was grounded and I missed it or the PCM was actually sending a constant feed. Put my lil light bulb tester on the + side of Battery and touched the wire, no light. Put it on the pcm, I got light. So the PCM is sending a constant feed. Why?!!! Lol maybe I should mention it is the #6 prong on the connector that is labeled "RED".
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just got off the phone with PCMforless and there wasnt much they could help with. ive been studying the wiring pin ups but i dont get very far with that before i start going cross eyed... he mentioned that i may have an injector bank that has gone out, but if that were the case then wouldnt more then one injector not be working?
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Shbox, help! I traced the ground wire of the #7 cyl pigtail to the PCM, it was fine. I then took it out of the PCM to determine if the wire was grounded and I missed it or the PCM was actually sending a constant feed. Put my lil light bulb tester on the + side of Battery and touched the wire, no light. Put it on the pcm, I got light. So the PCM is sending a constant feed. Why?!!! Lol maybe I should mention it is the #6 prong on the connector that is labeled "RED".
I looked at two injector plugs on my car and I get ~12k ohms to ground on the PCM control wire (and of course, power on the pink wire). I'm not going to try it, but that shouldn't be enough to light a test lamp. You might compare that one to another, just to see (though, I don't recommend using the lamp). At this point, I think maybe you have a bad injector driver in the PCM.
What I find weird is the PCM wire legend says the injector control wires should have battery on them, but that just can't be right. The schematic shows them going to ground.
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Do yourself a favor and don't use a test light on anything on the PCM. Damage to the electronics could result from too much current.
I looked at two injector plugs on my car and I get ~12k ohms to ground on the PCM control wire (and of course, power on the pink wire). I'm not going to try it, but that shouldn't be enough to light a test lamp. You might compare that one to another, just to see (though, I don't recommend using the lamp). At this point, I think maybe you have a bad injector driver in the PCM.
What I find weird is the PCM wire legend says the injector control wires should have battery on them, but that just can't be right. The schematic shows them going to ground.
I looked at two injector plugs on my car and I get ~12k ohms to ground on the PCM control wire (and of course, power on the pink wire). I'm not going to try it, but that shouldn't be enough to light a test lamp. You might compare that one to another, just to see (though, I don't recommend using the lamp). At this point, I think maybe you have a bad injector driver in the PCM.
What I find weird is the PCM wire legend says the injector control wires should have battery on them, but that just can't be right. The schematic shows them going to ground.
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Just had another thought that makes me think that My problem may lie outside of the PCM... When I sent my PCM to PCMforless for the tune, I cleaned it up... And the one I got back was kinda dirty. Couple cobwebs, a bit of a leaf or two, and a little dirt. I don't think it was my PCM I sent in. I do believe I had the same problem before I rebuilt the motor and got the tune tho. No way of prooving that... Is there anywhere else to look beyond the ground wire I've already checked? Maybe somewhere up the line further? Or does that not exsist? To get another PCM it'll cost me almost $200 with the tune. And that'll **** me off to find the problem still exists...
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Find someone local and temporarily swap PCM's to see if the problem goes away with another ECU
How far are you from Santa Fe/ Columbia/ Spring Hill/ Franklin area? My car's at my moms, I'd be more that willing to let you go over there and tinker. Hell, they've got just about every tool known to man.
How far are you from Santa Fe/ Columbia/ Spring Hill/ Franklin area? My car's at my moms, I'd be more that willing to let you go over there and tinker. Hell, they've got just about every tool known to man.
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It's possible the #7 fuel injector is sticking open allowing fuel through constantly. If I were you, I would remove that injector and see if you can blow air through it without power/ground applied. If so, then you have a faulty injector.
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No. Already pulled the fuel rails and done some swapping around with injectors and pigtails. Injector only flows when connected with ign on. And whatever injector I hook up to the #7 cyl pigtail is which one sprays. All the injectors will have a +12v feed constantly. It's the ground that breaks the circuit. So I traced the ground all the way back to PCM, it was fine, unplugged it from PCM and tested it to find it was ungrounded. (as it should be) Then test PCM prong it connects to to find it WAS grounded. Stopped there because I didn't further understand the wiring pin ups. But if I'm correct no other factor going into the PCM can effect that. It must be an internal issue with the PCM, (injector bank went out) and I have to just bite the bullet and fork out $200 to PCMforless for a new PCM with my tune, when I just gave them $200 to put on my Tune a week ago. All over a F*€%!#G ground wire...
Last edited by Numba20; 04-12-2013 at 08:36 AM.
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ok heres how that driver circuit works.........
its a sinking circuit...
12V is applied to one side of the injector at ALL times when the key is in RUN or START position........
the PCM switches ground on and off to pulse the injector, when it wants to open the injector the driver in the pcm outputs a ground on the pin and the injector opens, when the pcm doesn't want the injector open the input is floating from the pcm there is no voltage output and no continuity to ground, it is a transistor drive that is not saturated at that point........DO NOT UNDER ANY CIRCUMSTANCES HOOK UP A TEST LIGHT TO A PCM OUTPUT......this can cause instant damage to the driver circuit in the PCM.......if you have 0-1 ohm continuity to ground at all times from the driver output of the PCM the driver in the pcm is junk, find a new pcm.........this sounds like its your issue
its a sinking circuit...
12V is applied to one side of the injector at ALL times when the key is in RUN or START position........
the PCM switches ground on and off to pulse the injector, when it wants to open the injector the driver in the pcm outputs a ground on the pin and the injector opens, when the pcm doesn't want the injector open the input is floating from the pcm there is no voltage output and no continuity to ground, it is a transistor drive that is not saturated at that point........DO NOT UNDER ANY CIRCUMSTANCES HOOK UP A TEST LIGHT TO A PCM OUTPUT......this can cause instant damage to the driver circuit in the PCM.......if you have 0-1 ohm continuity to ground at all times from the driver output of the PCM the driver in the pcm is junk, find a new pcm.........this sounds like its your issue
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ok heres how that driver circuit works.........
its a sinking circuit...
12V is applied to one side of the injector at ALL times when the key is in RUN or START position........
the PCM switches ground on and off to pulse the injector, when it wants to open the injector the driver in the pcm outputs a ground on the pin and the injector opens, when the pcm doesn't want the injector open the input is floating from the pcm there is no voltage output and no continuity to ground, it is a transistor drive that is not saturated at that point........DO NOT UNDER ANY CIRCUMSTANCES HOOK UP A TEST LIGHT TO A PCM OUTPUT......this can cause instant damage to the driver circuit in the PCM.......if you have 0-1 ohm continuity to ground at all times from the driver output of the PCM the driver in the pcm is junk, find a new pcm.........this sounds like its your issue
its a sinking circuit...
12V is applied to one side of the injector at ALL times when the key is in RUN or START position........
the PCM switches ground on and off to pulse the injector, when it wants to open the injector the driver in the pcm outputs a ground on the pin and the injector opens, when the pcm doesn't want the injector open the input is floating from the pcm there is no voltage output and no continuity to ground, it is a transistor drive that is not saturated at that point........DO NOT UNDER ANY CIRCUMSTANCES HOOK UP A TEST LIGHT TO A PCM OUTPUT......this can cause instant damage to the driver circuit in the PCM.......if you have 0-1 ohm continuity to ground at all times from the driver output of the PCM the driver in the pcm is junk, find a new pcm.........this sounds like its your issue
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Very elaborate and descriptive way of what I attempted to state. Lol but yes, all of that is correct. I just want to make sure that there is zero possibility it is anything else before I buy a new PCM, assuming its not injector or ground wire, but the ground is fed non stop on the one injector. Nothing to look at before the PCM? No other possibility?
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i got to send a shout out to Keith at PCMforless. he is hooking me up with a good PCM and tuning it for $140 ! since i never even got to take the car on the road with my PCM.
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okay i got my new PCM put in tonight, and started the car. it was the injector bank, as i no longer have any fuel leaking out of my headers as the last time i started the car. but when i started the car tonight, i had pretty regular rhythmic back fire. i got under the car to better inspect. im getting blue flame out of both headers when backfire occurs. so that tells me its not just the plug fouled on the cylinder that was getting gassed out. i havent checked but i think plug is okay.
I CHANGED NOTHING FROM THE LAST TIME I STARTED THE CAR, EXCEPT OF CORSE THE NEW COMPUTER. car was NOT backfiring previously. it does now, and thru the whole RPM range.
i considered the possibility of it being the opti, but why would it not backfire a week ago, and now on the next start up, it does, and consistantly.
i should also mention that when i first got the car, you had to crank, and crank, and play with the throttle, and it would finally fire up. after my tune, i had the injector bank go out (i didnt know at that point) but it would fire sooner and more easily with a steady slight step on the gas. tonight, i just turned the key, and snap of a finger, it started sooo fast. i started it twice tonight, same result.
im just looking for someone to reassure me that it is indeed my PCM, i think PCMforless had forgot about me, and i called 3 days in a row, after much confusion, i got them to tune a new core, and overnight it to me. i spoke to keith on the phone at 2 pm, and he had it in the mail at 3:35.... so i am thinking that maybe they were rushed and missed something.
also, i changed the oil today, put in:
5 qts of 5w-30 casteroil GTX
a 12oz bottle of zmax
1/4 of a qt of lucas synthetic stabilizer
with a little 5w-30 left in the single qt i mixed it in
5 3/4 qts in all.
my dash says low oil, and it may just be the sender, but my oil pressure gauge is reading 70ish at idle! WTF??!! i dont remember it being anywhere close to that?
I CHANGED NOTHING FROM THE LAST TIME I STARTED THE CAR, EXCEPT OF CORSE THE NEW COMPUTER. car was NOT backfiring previously. it does now, and thru the whole RPM range.
i considered the possibility of it being the opti, but why would it not backfire a week ago, and now on the next start up, it does, and consistantly.
i should also mention that when i first got the car, you had to crank, and crank, and play with the throttle, and it would finally fire up. after my tune, i had the injector bank go out (i didnt know at that point) but it would fire sooner and more easily with a steady slight step on the gas. tonight, i just turned the key, and snap of a finger, it started sooo fast. i started it twice tonight, same result.
im just looking for someone to reassure me that it is indeed my PCM, i think PCMforless had forgot about me, and i called 3 days in a row, after much confusion, i got them to tune a new core, and overnight it to me. i spoke to keith on the phone at 2 pm, and he had it in the mail at 3:35.... so i am thinking that maybe they were rushed and missed something.
also, i changed the oil today, put in:
5 qts of 5w-30 casteroil GTX
a 12oz bottle of zmax
1/4 of a qt of lucas synthetic stabilizer
with a little 5w-30 left in the single qt i mixed it in
5 3/4 qts in all.
my dash says low oil, and it may just be the sender, but my oil pressure gauge is reading 70ish at idle! WTF??!! i dont remember it being anywhere close to that?
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stays about the same. i started car with old PCM a few minutes ago, and the oil pressure was 45-50. so its not the gauge or the sending unit i dont think. maybe some of the synthetic stabilizer was concentrated around the sending unit?
havent tried it again with the new computer though.
havent tried it again with the new computer though.
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i started with the old PCM today to see if it still had the backfire, and it did, so now im thinking its the opti.... going to do some more research and hopefully get a code reading that might point me in the right direction.
could coil cause backfire? im thinking that the opti is giving weak orange spark instead of blue. would a fouled plug or two cause it? since its backfiring out of both headers and the idle isnt extremely bogg-ish and stays up im leaning against it, but not going to rule it out yet. trying to look at everything under spark.
i just thought, i had the car tuned for 93 octane, and it has 87 in it with a bottle of seafoam mixed in with a couple gallons. would something as simple as the be causing my problem?
could coil cause backfire? im thinking that the opti is giving weak orange spark instead of blue. would a fouled plug or two cause it? since its backfiring out of both headers and the idle isnt extremely bogg-ish and stays up im leaning against it, but not going to rule it out yet. trying to look at everything under spark.
i just thought, i had the car tuned for 93 octane, and it has 87 in it with a bottle of seafoam mixed in with a couple gallons. would something as simple as the be causing my problem?