Imp558 Posted January 7, 2018 Report Share Posted January 7, 2018 That cts is off Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 7, 2018 Author Report Share Posted January 7, 2018 That cts is off darn. I didn't think they partially failed like that! What's your vote, junkyard, or aftermarket? I've only heard bad things about aftermarket. I just hate putting used parts in my car! And I really wish that meant I didn't have to bleed the coolant system... Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 7, 2018 Report Share Posted January 7, 2018 If anything I'd expect it to be colder on the outside than inside. New, but a good one not a house brand or something that sounds exotic and is really just China. I'd probably do the $11 (DELPHI TS10032) or the $15 (ACDELCO 21381) from Rockauto. Likely not made in the USA but I'd expect some kind of tolerance from those two anyways. For $11 - $15 even if it doesn't cure the issue it's still cheaper than wasted fuel from a false low CTS reading over a short time. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 7, 2018 Report Share Posted January 7, 2018 On bleeding, if you run the front of the car up on ramps or on jackstands and get the radiator cap higher than the thermostat housing it should bleed easy out the cap with a few squeezes of the upper hose. Quote Link to comment Share on other sites More sharing options...
55trucker Posted January 7, 2018 Report Share Posted January 7, 2018 darn. I didn't think they partially failed like that! What's your vote, junkyard, or aftermarket? I've only heard bad things about aftermarket. I just hate putting used parts in my car! And I really wish that meant I didn't have to bleed the coolant system... Go out & purchase one of these fill systems from Lisle...it's a lifesaver, does away with the hassle of bleeding the coolant systems where the rad fill is not the highest point in the system, and I say this to everyone here. wstefan20 1 Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 7, 2018 Author Report Share Posted January 7, 2018 Thanks guys! I'll give it a try then when I get the chance. And thanks 55 trucker! Haven't seen anything like that before. If I can muster the funds, I'm totally getting this! Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 16, 2018 Author Report Share Posted January 16, 2018 Well, I'm finally starting to get serious before I go and tune my car so I don't tune in a vacuum leak or something stupid like that. Still waiting on the acdelco ECT sensor to come in, but just got the acdelco IAT sensor. Unfortunately just as predicted, no change. So, in the spirit of diy, I started building my own smoke machine for detecting vacuum leaks. I decided to go the less brutal method and use nichrome wire and tiki wicks to burn mineral oil run off the battery. I went a little more expensive and used an actual mini regulator in place of a propane regulator (I think it was $15 vs $10?). I can't take credit for the idea, found some youtube videos and adapted my own. If it works, I'll post a how-to later. Quote Link to comment Share on other sites More sharing options...
Nas Escobar Posted January 18, 2018 Report Share Posted January 18, 2018 Is it still running lean? Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 18, 2018 Author Report Share Posted January 18, 2018 Is it still running lean? Strangely enough, now it's running rich! Between -1 ltft idle and -14% when you accelerate. Very strange to me. Usually jumps between idle and giving it gas are vacuum leaks, but that's for running lean, so I'm basically planning on replacing the IAT, ECT, thermostat, MAP, and running the smoke test before I give up and get it tuned. Quote Link to comment Share on other sites More sharing options...
55trucker Posted January 18, 2018 Report Share Posted January 18, 2018 In my opinion instead of throwing more money at this get your voltmeter out & start back-probing the sensors to see what sort of reading you can get off them as you vary the input from low to high before you put the blame on them for this situation. You'll need a service manual to get the voltage calibrations for the sensors. I'm going on the assumption that you don't have a proper scanner to do this with. Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 18, 2018 Author Report Share Posted January 18, 2018 In my opinion instead of throwing more money at this get your voltmeter out & start back-probing the sensors to see what sort of reading you can get off them as you vary the input from low to high before you put the blame on them for this situation. You'll need a service manual to get the voltage calibrations for the sensors. I'm going on the assumption that you don't have a proper scanner to do this with. Got a proper scanner, have the readings and a factory service manual. Reason I'm replacing the ECT sensor is I noticed that I damaged the plug when changing the lower intake gasket, so it's open to corrosion and needs replacing. IAT just because it was cheap. Thermostat because even with the lyle radiator attachment, bleeding has been an issue, found out that the OEM thermostats have a bleed valve and the chepo stant ones do not, so air gets trapped and is harder to bleed. I'm doing the vacuum leak test because it would stink to tune it and fix the vacuum leak later and need another tune. I'm usually not a parts swapper like this, but I've tested everything and it's in spec, and literally every other part and sensor other than these has been replaced due to my engine rebuild so I planned on replacing them anyways eventually. The only sensor I can't test with extreme accuracy is the O2 sensor. My scan tool looks like it's reading correctly, but the frame rate isn't very high. Only way I could get a better rate is if I bought an oscilloscope, which I'm not about to do... Quote Link to comment Share on other sites More sharing options...
55trucker Posted January 18, 2018 Report Share Posted January 18, 2018 Tell me........ please describe *rebuild*?....as in entire machine shop rebuild or something else less than.....and did you have any of this situation before you got into the *rebuild*? Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 18, 2018 Author Report Share Posted January 18, 2018 Entire machine shop rebuild. And yes, I bought a pro dial bore gauge, machinists straight edge, dial indicator, calipers, etc. And checked clearances behind them. Replaced every single tty bolt, every bearing, over bore with new pistons, balanced, the block was acid cleaned and magnafluxed to check for cracks, all new gaskets, three angle valve cut, checked heads too, new springs and retainers, ground valves, checked guides and replaced as needed. New lifters, timing chain, polished both crank and cam and checked, so yes, the works. (Don't ask me the cost...). The engine has no misfire, idles smooth, has been running for over 5000 miles so far. No check engine codes, only noticed the issues when I hooked up the scan tool after noticing it struggling up hills before closed loop. It was rebuilt because the original engine threw a rod and I didn't want to throw in a stock junkyard engine. The engine I used was a 140,000 mile out of a Monte Carlo that was totaled in a collision with air bags deployed. And yes, in hind site, probably should have just run it into the ground... Imp558 1 Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 20, 2018 Author Report Share Posted January 20, 2018 Well, think I might have found part of the issue finally.... built a diy smoke machine for finding vacuum leaks, and within about thirty seconds, I found the issue.... a leak where my throttle body bolts to my adapter.... in short, turns out my throttle body is warped! This is officially the last part of my original engine other than the water pump pulley, a/c compressor, power steering pump, flywheel, and metal parts of the mounting brackets that came with my car. Every other piece and sensor has been replaced... lucky me... other issue it seems is the rear o2 sensor. I have code P0420 because my high flow cat stops conversion after a certain engine load (can't keep up), and a few people have told me this can also mess up fuel trims, so I'm hopefully getting it tuned tomorrow with the help of a few members here! Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 20, 2018 Report Share Posted January 20, 2018 Wow! I just love it when a DIY tool saves the day! Nas Escobar and wstefan20 2 Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 20, 2018 Author Report Share Posted January 20, 2018 Wow! I just love it when a DIY tool saves the day! Haha thanks imp! Me too! I've used several shop grade smoke machines, and I've got to say, it's crude, but this one actually works just as well if you only need it a few times and don't mind the dodgy construction! Lol Quote Link to comment Share on other sites More sharing options...
55trucker Posted January 20, 2018 Report Share Posted January 20, 2018 At least you've found the source of your problem, curious as to how the flange on the throttle body managed to warp itself, the gasket wasn't disfigured at all? Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 20, 2018 Author Report Share Posted January 20, 2018 At least you've found the source of your problem, curious as to how the flange on the throttle body managed to warp itself, the gasket wasn't disfigured at all? The original engine overheated and blew up (Don't worry, that's before I bought it), so just about everything warped (even the camshaft was bent!). I was hoping the tb wasn't affected, but never used a straight edge on it.... but that's the last main engine part from the original engine! Quote Link to comment Share on other sites More sharing options...
Imp558 Posted January 20, 2018 Report Share Posted January 20, 2018 You should post in my "Cool Tools" thread and link the build thread and this thread. You've got me thinking of building one too. Parts lists with sources are always an A+ too. wstefan20 1 Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 21, 2018 Author Report Share Posted January 21, 2018 You should post in my "Cool Tools" thread and link the build thread and this thread. You've got me thinking of building one too. Parts lists with sources are always an A+ too. I actually just posted a thread in the general section with parts list and everything! Sorry, I didn't know there was a cool tools thread! And go for it! Best diy tool I've owned yet! Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted January 31, 2018 Author Report Share Posted January 31, 2018 So the saga continues! I ended up replacing the ECT sensor, thermostat, and IAT with no change. Found an exhaust leak, so I swapped from my sd header gaskets to the mil oem acdelco gaskets (sprayed with copper gasket adhesive), used copper rtv on the crossover pipe and upgraded to stepped 2.25" band clamps, and exhaust leak is gone. Also went ahead and deleted my egr since I just got the code removed with the tune. Much more room now!Broke a spark plug wire in the process, so I got a replacement set from the junkyard (8mm ultra low resistance brand from summit racing).I'm thinking the old spark plug wires were higher resistance than the new ones because the power and throttle response made my car an entirely different ride! However, then I got a code for the bank 1 o2 sensor and found that the fastener had come loose and melted the plug, so for a quick fix, I used a good plug and spliced the wires.... yes, I know, not the best practice. Got a new acdelco sensor on the way. Even with it spliced for now though, I'm getting much better mpg and throttle response. No more P0420 now too since I used the spark arrester spacer trick. So to close, I'm at 0% stft and ltft idle and deceleration, and around -7% ltft on acceleration. Hopefully the new o2 sensor helps? If anyone has anything else for me to try, I'd be very open to suggestions! Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted February 13, 2018 Author Report Share Posted February 13, 2018 Installed the new o2 sensor. No change whatsoever. I'm going to perform another leak test for vacuum leaks, and one on the exhaust just to be safe. I think this might just be a stock issue. I've never seen long term fuel trims under acceleration posted by anyone before. If anyone comes across this, I'd be really curious to see what a "normal" stock long term fuel trim graph over normal driving conditions looks like on a base n/a grand prix. Quote Link to comment Share on other sites More sharing options...
bluegtp91 Posted February 14, 2018 Report Share Posted February 14, 2018 Did you ever put the rear o2 in it or just change the front sensor? BTW, checked my phone. I had a huge reply typed up to you and thought I sent it but never did. It's a bad habit lol Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted February 14, 2018 Report Share Posted February 14, 2018 Have you run a compression test? A burned valve, or excessive blowby can cause these symptoms...might be worthwhile to check. Quote Link to comment Share on other sites More sharing options...
wstefan20 Posted February 14, 2018 Author Report Share Posted February 14, 2018 Did you ever put the rear o2 in it or just change the front sensor? BTW, checked my phone. I had a huge reply typed up to you and thought I sent it but never did. It's a bad habit lol Haha you're fine man, I do that all the time! I put the rear back in with a spacer so it looks good now. Quote Link to comment Share on other sites More sharing options...
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