sh!! did I just kill my LT1?
#21
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And on second thought since this is somewhat to deal with ignition/timing, have you checked the grounds on the driver side head right behind the coil? check all engine grounds since this is a simple, but commonly missed resolution. Ensure they have a nice clean shiny surface to mate to,,,
-justin
-justin
#22
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yea i agree with above post, and also i hate to say it but i had all these same symptoms when my opti was going out, and i got mine replaced and vwha la it works amazing now.
#23
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Yeah, the grounds on the head look good and also the ones on the pass. side of the block, however I am headed out right now to check the ground and reference wire for continuity, sure hope it is not the bad word that starts with O. It isn't throwing any of those Opti codes though.
#24
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OK, no continuity between black PCM plug #6 and TPS. I now have a 5v reference to the TPS and the signal wire has continuity ...woohoo! As soon as my feet and hands thaw
I will replace that pin and wire, I sure hope that is the prob.
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#25
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SOB! Code P0123 gone (replaced pin #6 wire)! Code "p1661 manufacturer control, auxiliary outputs, auxiliary input" was thrown back in my face. It sounded like it tried to idle down, but didn't go all the way. Maybe it was trying to leave loop and go into open loop, but got a bad reading from the o2 sensors? My manual doesn't have code p1661. Any body have the definition of that code?
#26
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Found it 1661-Mil control circuit, basically sounds like just the ses light circuit, which isn't hooked up anyway. I don't see how that would cause a problem. I did see something that said it may get tripped if the idle is over 600 rpm or if the ignition voltage is between 6 and 16 volts (isn't it always), maybe it said above or below. I DON'T KNOW, BUT i CAN ALREADY TELL IT IS IDLING ABOVE 600RPM, THAT IS MY PROBLEM, WTF. Sorry, but it is like a blind guy telling me he is blind..I can already tell. What I want to know is why he is blind.
So it is still idling high, is running smooth, not throwing the TPS codes, not idling down, not starting when warm, has 20hg vacuum, revs good, charging at 14.6v, has 40-43.5 psi fuel pressure when running and upon start up, 60psi oil pressure, new coil, new ICM with spacer mod, new TPS, new black #6 pin out wire. Why?Why?Why?![Bang Head](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_banghead.gif)
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So it is still idling high, is running smooth, not throwing the TPS codes, not idling down, not starting when warm, has 20hg vacuum, revs good, charging at 14.6v, has 40-43.5 psi fuel pressure when running and upon start up, 60psi oil pressure, new coil, new ICM with spacer mod, new TPS, new black #6 pin out wire. Why?Why?Why?
![Bang Head](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_banghead.gif)
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#27
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I am going to call Current Performance and see what the heck he set my idle at, it seems to idle down around 160 degrees, but still seems way to high for just driving around. The only code it throws is P1661. Will this code affect anything else other than just be a nuisance and pop up every time I scan? I don't need the SES light other than just to tell me to scan, right? I just don't see it causing the high idle.
Is there any other way to drop the idle other than in a tune? Looks like there is a set screw on the throttle Body, but I can't tell if it is flat, Phillips or torx and am not sure if it will change the idle anyway.
I also have to hold my foot to the floor to start it when warm, just like a flooded carburetor. Maybe this has to do with that set screw. The TPS sensor had to be rotated slightly to get the holes to line up kind of pre-loading it. Is this normal?
Is there any other way to drop the idle other than in a tune? Looks like there is a set screw on the throttle Body, but I can't tell if it is flat, Phillips or torx and am not sure if it will change the idle anyway.
I also have to hold my foot to the floor to start it when warm, just like a flooded carburetor. Maybe this has to do with that set screw. The TPS sensor had to be rotated slightly to get the holes to line up kind of pre-loading it. Is this normal?
#28
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CP wire says it is probably set around 750rpm, but it seems higher. I'll put a tach on it tonight and see. He didn't have a direct answer and said he will have to look through the file. Do you guys get a "tune sheet" with tunes from other companies. I asked for one and he basically said it would be a hassle, but I have had to call him at least 5 times to figure out what he has and hasn't done and we are in different time zones so that is a hassle.
He says it is set high because I am not running a VSS and doesn't want it to stall under hard braking, but this thing is in a slightly lifted daily driver with shitty brakes and I have run carbed motors with fuel slosh and all at a lower rpm without to much trouble. I'm willing to take the risk this thing needs to idle down.
He says it is set high because I am not running a VSS and doesn't want it to stall under hard braking, but this thing is in a slightly lifted daily driver with shitty brakes and I have run carbed motors with fuel slosh and all at a lower rpm without to much trouble. I'm willing to take the risk this thing needs to idle down.
#29
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Preloading the TPS is normal, I guess its just the way its designed, I was freaked out when I assembled my 58mm TB(first time installing a TPS, maybe all TPS are like this), but I've had no issues.
What is it idling at? Even if it was around 800-1000 rpm I wouldn't see that as high, or is it sitting around 1500 rpm? Sometimes if I have a hard time starting it but I've primed it a few times I will it see it idle at 1500rpm or so for about 30 seconds.
Can't change the idle mechanically, its all in the computer.
What is it idling at? Even if it was around 800-1000 rpm I wouldn't see that as high, or is it sitting around 1500 rpm? Sometimes if I have a hard time starting it but I've primed it a few times I will it see it idle at 1500rpm or so for about 30 seconds.
Can't change the idle mechanically, its all in the computer.
#30
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OK, so I can't change the idle.
New ideas-what about the air temp sensor in the intake elbow? If this is faulty wouldn't it make the motor think it is always drawing cold air possibly raising the idle? Seems like it would throw a code though.
O2s not reading correctly? Seems like that would just make it run rich and not the high idle. Wouldn't it throw a code?
Water pump temp sensor doing the same as the intake temp? The fan kicks on around 160 which is where it is set and it isn't throwing a code.
I'll have the idle lowered if I have to or deal with it high, but flooring the pedal to start a warm fuel injected motor is obsurd in my opinion. Keep the suggestions coming I am looking at anything and everything right now. Thanks guys.
New ideas-what about the air temp sensor in the intake elbow? If this is faulty wouldn't it make the motor think it is always drawing cold air possibly raising the idle? Seems like it would throw a code though.
O2s not reading correctly? Seems like that would just make it run rich and not the high idle. Wouldn't it throw a code?
Water pump temp sensor doing the same as the intake temp? The fan kicks on around 160 which is where it is set and it isn't throwing a code.
I'll have the idle lowered if I have to or deal with it high, but flooring the pedal to start a warm fuel injected motor is obsurd in my opinion. Keep the suggestions coming I am looking at anything and everything right now. Thanks guys.
#31
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Replaced the IAC idles down properly. Still has hot start problems. If you get it started it may run good until it is warm or has fouled the plugs, or starts missing and running rich as hell. F me it must be the damn opti. Damn gremlins are after me. Does this sound like the opti for sure??
#33
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Their tech said 1 in 4 was bad. Screw that I thought that they were the answer. Guess I'll be getting a a stock opticrap. I wish there was another way It is going to be exposed to water..it is in a Toyota 4runner...shoulda done an LS![Bang Head](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_banghead.gif)
. I can't drive it yet to see if it misses, but when it is hard to start I have to hold it to the floor to get it started and then keep it there or else it dies. Oh, yeah and all the while it is missing and blowing black smoke, and fouling the plugs![MAD](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_mad.gif)
![MAD](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_mad.gif)
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I can usually get a good cold start or a couple, but as soon as the motor is warm, problem after problem.
![Bang Head](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_banghead.gif)
![MAD](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_mad.gif)
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I can usually get a good cold start or a couple, but as soon as the motor is warm, problem after problem.
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#34
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Did you replace the ICM with a OEM part from the dealership? Aftermarket sensors like that are only about $5 cheaper at a parts store and I've had sensors like that **** out from the chain stores.
Everyone argues about the MSD opti, mine didn't let me down after three years and a ton of miles.
Everyone argues about the MSD opti, mine didn't let me down after three years and a ton of miles.
#35
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I don't think it was the ICM in the first place because I had it tested like 12 times at Napa, but yes it is from a parts store and it has these issues with the new and old TPS, ICM, and coil, and Bosch and NGK plugs, wires are MSD and new. Everything is seated and grounded, even added another block strap. I am going to try o2 sensors and a temp sensor tonight and then i think I have to order an opti, Sure wish I could find the MSD coil pack setup.
#36
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So ther is no MSD coil pack setup, it was a delteq with MSD coils and I got all excited. Not the o2s or temp, pulled the opti and it looks nasty inside. I have the MSD now (much nicer that the stocker!), I'll put it on Tomorrow, hopefully that fixes it all.
#37
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hey i was wondering if you ever got your problem fixed? im having similar peoblems with my 97 383 it surges while driving and runs like crap after it warms up, and if i kill it after warm up its a pain gettin it stared again. and mine blew black smoke out of the intake as well but the car was running and had no backfire when the smoke started, and is throwing a code but i dont remember what the number was but it said engine coolant, i have a pro billet msd with adjustable timing +/- 5 degrees with maybe 200 miles on it .... drove the car three weeks no problems the it ran outta gas one day and have been having prob. ever since.
i promise im not trying to steal your thread just trying to fig out my prob.
i promise im not trying to steal your thread just trying to fig out my prob.
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#38
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Coolant temp sensor. Go to parts store and have scanned. And yes coolant sensor can make it rum rich lean and idle up and dowm. Whun the connector is taken off it reads -40 degrees. Dont know why GM did that?