1993 LT1 Idle surging
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On The Tree
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I think itd be a good idea to get that second o2 sensor installed. Right now your engine has no idea what each bank is doing (assuming that 1 o2 is talking to both banks of the pcm). You could be lean on one bank and rich on the other. This can be expensive if not repaired. But you have no idea of it is or not without that 2nd o2.
What mods does the engine have?
What mods does the engine have?
I need to see what the computer is telling me. When I unhook the battery, it'll clear and run fine until fully warmed up.
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From: Maricopa, AZ
The problem has started again. Runs fine until all the way warmed up, then crazy rpms at idle. Can I pull out my ecm to have it scanned somewhere maybe someone online??? This all probably sounds super dumb to yall, but can I wire both O2 sensor wires to 1 and get away with it until I can afford exhaust work?
I need to see what the computer is telling me. When I unhook the battery, it'll clear and run fine until fully warmed up.
I need to see what the computer is telling me. When I unhook the battery, it'll clear and run fine until fully warmed up.
Basically, get that other O2 wired up and get an OBD port wired up too. After you install the OBD 1 port, you'll be a $60 ALDL cable and some free software away from datalogging, and tuning too.....
Are you running a MAF?
Thread Starter
On The Tree
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You CAN run both O2 signals from 1 O2, but you shouldn't. When you reset the pcm you're clearing its stored data. That stored data is data it collect a for long term fuel trims. It gets that from the O2s. If you have 1 O2 running both banks of the PCM, the PCM is receiving false data. It'll trim according to that false data, and you end up with bad fuel trims. Add in aftermarket intake and exhaust (location of the O2 in distance from the heads is important for some fuel trimming) and you end up with poor calibrations and false data from sensors feeding the PCM information that directly effects how the engine works.
Basically, get that other O2 wired up and get an OBD port wired up too. After you install the OBD 1 port, you'll be a $60 ALDL cable and some free software away from datalogging, and tuning too.....
Are you running a MAF?
Basically, get that other O2 wired up and get an OBD port wired up too. After you install the OBD 1 port, you'll be a $60 ALDL cable and some free software away from datalogging, and tuning too.....
Are you running a MAF?
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I Also replaced the injectors during the above 24lb. Could I have gotten wrong injectors? Very possible. I ordered them off amazon, year make, and model where correct. After initial test after, it ran great for a couple weeks.
Last edited by Alaskanbadfish; Jan 29, 2016 at 12:12 PM.
Thread Starter
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Just did new opti/water pump (with new sensor) a couple months ago.
I Also replaced the injectors during the above 24lb. Could I have gotten wrong injectors? Very possible. I ordered them off amazon, year make, and model where correct. After initial test after, it ran great for a couple weeks.
I Also replaced the injectors during the above 24lb. Could I have gotten wrong injectors? Very possible. I ordered them off amazon, year make, and model where correct. After initial test after, it ran great for a couple weeks.
I've replaced every sensor that deals with fuel delivery. This thing ran great the way it was (one O2) for over 3 years. After my new injectors, opti, water pump, water temp sensor on pump, plugs, plug wires, ignition moduel, coils, is when the trouble started. Would have thought this major tune up would benefit the engine, not make problems.
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From: Maricopa, AZ
Just put in new O2, still same issue, feeling defeated. Wouldn't even know where to begin to install a data port. Is there anyone online I could send my computer to that could scan it and tell me what's wrong?
I've replaced every sensor that deals with fuel delivery. This thing ran great the way it was (one O2) for over 3 years. After my new injectors, opti, water pump, water temp sensor on pump, plugs, plug wires, ignition moduel, coils, is when the trouble started. Would have thought this major tune up would benefit the engine, not make problems.
I've replaced every sensor that deals with fuel delivery. This thing ran great the way it was (one O2) for over 3 years. After my new injectors, opti, water pump, water temp sensor on pump, plugs, plug wires, ignition moduel, coils, is when the trouble started. Would have thought this major tune up would benefit the engine, not make problems.
Thread Starter
On The Tree
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On The Tree
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Bottom line with this thread is I need to get this pcm scanned and see what's wrong. Only thing is, I've been to numerous websites and looked at numerous wire harnesses for 93 lt1's and I don't see a data port or plug on the harnesses. So my question is what steps do I need to do to wire this in? Where can I get one? Where does an original on get wired into an lt1 equipt vehicle? Why isn't it incorporated onto a standard wire harness? What can I do to get this?
Teching In
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Bottom line with this thread is I need to get this pcm scanned and see what's wrong. Only thing is, I've been to numerous websites and looked at numerous wire harnesses for 93 lt1's and I don't see a data port or plug on the harnesses. So my question is what steps do I need to do to wire this in? Where can I get one? Where does an original on get wired into an lt1 equipt vehicle? Why isn't it incorporated onto a standard wire harness? What can I do to get this?
Thread Starter
On The Tree
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So you don´t have the obd1 port at all in your car? I just traced the right wire from the pcm and hooked that directly to the "usb to aldl" cable. I bought the cable from obd diagnostics but you can make the cable yourself. It cost 60$. The wire was tan colored if i remember right. shbox.com has all the color codes for the pcm so you can check there.
Teching In
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yes just one wire. I have the usb cable and all you need is the one wire and second is ground, you can hook the ground any where i think. I hooked it to the same ground as my pcm is hooked.
Thread Starter
On The Tree
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I just ordered the needed obd1 plug (aldl) to wire up and read the pcm, once I get it installed and read I'll need additional help I'm sure. Thanks for the guidance so far everyone.
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From: Kernersville, NC
Sounds like it's having trouble when it's going into closed loop. Although with only one O2, it may not be going into closed loop.
A scan log will defiantly be needed to find the trouble without throwing a ton of money at it. Did you wire up the Service Engine Soon(SES) lamp? With only one O2, I expect it will be on.
As HRC mentioned, you need to get both O2's installed(one in the left exhaust manifold(bank 1), one in the right(bank 2)) just after where all the exhaust ports for each bank collectively come together.
Also, keep in mind that new parts does not mean good parts. I've pulled parts new out of the box that don't work. It's the exception rather than the norm, but it can drive you bonkers trying to troubleshoot, because you think the parts are good when they are not.
Can you elaborate on the MSD ignition you installed(not the opti)?
A scan log will defiantly be needed to find the trouble without throwing a ton of money at it. Did you wire up the Service Engine Soon(SES) lamp? With only one O2, I expect it will be on.
As HRC mentioned, you need to get both O2's installed(one in the left exhaust manifold(bank 1), one in the right(bank 2)) just after where all the exhaust ports for each bank collectively come together.
Also, keep in mind that new parts does not mean good parts. I've pulled parts new out of the box that don't work. It's the exception rather than the norm, but it can drive you bonkers trying to troubleshoot, because you think the parts are good when they are not.
Can you elaborate on the MSD ignition you installed(not the opti)?
Thread Starter
On The Tree
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Sounds like it's having trouble when it's going into closed loop. Although with only one O2, it may not be going into closed loop.
A scan log will defiantly be needed to find the trouble without throwing a ton of money at it. Did you wire up the Service Engine Soon(SES) lamp? With only one O2, I expect it will be on.
As HRC mentioned, you need to get both O2's installed(one in the left exhaust manifold(bank 1), one in the right(bank 2)) just after where all the exhaust ports for each bank collectively come together.
Also, keep in mind that new parts does not mean good parts. I've pulled parts new out of the box that don't work. It's the exception rather than the norm, but it can drive you bonkers trying to troubleshoot, because you think the parts are good when they are not.
Can you elaborate on the MSD ignition you installed(not the opti)?
A scan log will defiantly be needed to find the trouble without throwing a ton of money at it. Did you wire up the Service Engine Soon(SES) lamp? With only one O2, I expect it will be on.
As HRC mentioned, you need to get both O2's installed(one in the left exhaust manifold(bank 1), one in the right(bank 2)) just after where all the exhaust ports for each bank collectively come together.
Also, keep in mind that new parts does not mean good parts. I've pulled parts new out of the box that don't work. It's the exception rather than the norm, but it can drive you bonkers trying to troubleshoot, because you think the parts are good when they are not.
Can you elaborate on the MSD ignition you installed(not the opti)?
Thread Starter
On The Tree
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[QUOTE=Alaskanbadfish;19131832]MSD 8226 blaster ignition coil. If not having 2- o2s was the problem, how did it not have an issue for over 3 years running this way? I understand I need to get another in there, I'll have to see if someone can weld a bung in there.[/QUOT
Also, no SES light installed. Probably will once I get that data port put in.
Also, no SES light installed. Probably will once I get that data port put in.
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From: Maricopa, AZ
You changed fuel injectors, if they don't match injector voltage offsets it'll mess with your fueling.
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From: Maricopa, AZ
Also, they are very likely to have a different voltage offset. That can give you long term fuel trim issues and sometimes immediate driveability issues (like throttle tip in response). So, you'll need a tune with those injectors. And if you need a tune anyway, replace those injectors (sell em to some Ricer on Craigslist) and get some quality injectors. Reconditioned/refurbished ones on ebay from GM or Ford usually do the trick.
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From: Maricopa, AZ
When you did this coil, did you also install a vented opti?