Thank you stevie turbo and 350ss, as well as Joe nova and everyone else that has been so helpful to the situation!!! I was doing some looking before my "nap" last night haha. I've seen people on here and as well as the sloppy mechanics guy that seem to use the plastic IAT in the intake manifold, comes from a grandprix and they dont seem to have any problems with them. Also have seen lots of people go the threaded route with the old cyclone sensor. Any input is greatly appreciated as always! I like the idea of using the wires as a jumper at first. I was thinking I could hook the sensor up I have to the wires and testing it out first to see if it it recording properly in the pcm, and if it works then I'll go that route. I also made the changes to my base file as suggested by JoeNova and I'll be posting that up here shortly to make sure I didnt miss anything.
Kept my idle rpm and braf tables at what I had them set at. Changed my MAP settings to what I found on the HPtuners site for the calibration for my map. Still need to test it and verify its correct. High rpm disable set to 8000. Kept my injector data for my injectors. Closed loop enable set to 285, LTFTs disabled. OLEQ set to 1.0 140etc+. Stfts disabled. PE hyst reapplied. Need to reevaluate PE values and smooth them out. BE set to 1.0 for now. COT disabled, dfco disabled, timing tables reverted to stock, knock recovery rate halved, and burst knock removed. Tq management set to 640 for rpmvsgear, vsrpm, max torque, and tip in. Abuse mode disabled. Went through DTCs and my gosh, you guys were right needed to be gone through, went through that and made changes. Maf fail freq set to 0hz. Everything else is stock. Lemme know what you guys think! new file below!

 

My thought with the grand prix iat: it's in the hp tuners supported vehicles list. So I could download a stock tune from the repository and see if the values match with my existing calibration for IAT?

 

I always use the plastic GM sensor with a truck intake. Its just so easy to do. Drill out the evap hole a little bit and smack in the IAT with a rubber mallet or a dead blow and a piece of wood. Hitting the sensor directly with a hammer will break it.

 

Excellent!! Did you have to change the values for that IAT to make it work? Think it's even worth looking at the grand prix tune to see if the values are close?
I do have a 1/2" drill bit so, sweet!! And do you just put the sensor by itself in? Or do it with a grommet? I feel like the grommet may be the way to go to make sure it seals nicely. And I'll definitely make sure to be safe with the sensor

Found a sensor with pigtail connector incase I cant find mine, it has the sensor, and pigtail but it is a metal cased sensor. Looks like it's the same design as the original. Think this will work for me?

 

Got the vacuum part of the MAP testing complete. Seems alright so far. Just need to get a pressure pump Thursday so I can test out the other side of the scale to make sure that I have it calibrated correctly. But so far so good. Should be heading to the junkyard today to get myself an iat and connector. See how that goes! Would be super sweet if I could get that wired in today.

 

I didn't read the whole thread so sorry if this has been covered but what does your plumbing look like under the hood? Are you dumping the wastegate just into the engine bay or under the car? I've seen on other cars where the wg dumps too close to the turbo inlet and when it opens it literally starves the turbo of fresh air. Basically a huge egr valve at that point.

 

That's a good point I haven't thought about until you mentioned it! It does dump into the engine bay. Just a simple 90 dump, I had cut it originally so that I could merge it into the dump after the turbo, but haven't gotten around to it. I don't run the truck with a hood but still a great point, I'll make sure to get that attached to my dump or turn it over so it vents out the engine bay instead of in it.

 

Who on earth would dump their w/g into the turbo air inlet ?

 

LOL Also a good point!! Mine is definitely pointed away from my turbo inlet, But I could see where heat soak and stuff could play into that.

Today was a busy day, got the IAT and pigtail at my local wreckers, the sensor I picked up was the plastic IAT, had the same exact resistance as my MAF did. also verified with a temp gun that it was working alright before i plugged it into the tube. i let it sit outside in the heat and i waited til it said 99-100* according to the temp gun then turned on the computer, and viola! it was reading 99-100* just as my temp gun was. pretty nifty. I did notice that truck sounded A LOT different when I first started it up. It was saying I was pretty lean everywhere, cruising around, so added some more VE to the table to get it into the ballpark, still need to just cruise around with it tomorrow and see if I can get the non boosted VE numbers in check. It felt so much more responsive and stronger than it was before!! and did I mention spool time improved!?!?! seems like its way quicker to get into boost now. as soon as I go above 90kpa it says I'm way rich, about 5-10+% so instead of seeing my 11.91 AFR commanded, I'm seeing about 9.8 to 10.5 AFR. But that is with very few counts so who knows what it actually is. I just need to cruise around tomorrow, work on my VE in the below 100 KPA area, then start working on my WOT? today it cut out again, highest air intake temp I saw was just idling at a light and that was about 109*, but cruising around and barely getting into boost I was seeing about 93-104* intake temps, seems reasonable to me. Will update you guys on how the VE tuning stuff goes tomorrow. and hopefully I can get some good logs, and good data to you guys so we can continue on this. If you guys think of anything else I can try, change, look at etc, just let me know and Ill do my best, but thanks to everyone again so far!! I feel like I made a big step in the right direction today. lost all brake pressure again, and this time it affected my vacuum A LOT, I'm used to seeing around 10-12 INHg at idle but it was more like 6-7 INHg. I did noticed that when I took off my brake master cap that it was a little low, added to it, and I figured I'd start it up and pump the pedal a few times and when I started it up, with no foot on the brake, A GRIP of bubbles came out of my MASTER CYLINDER!!! that has to be an air leak right?? if not from my booster than the master cylinder itself? anyways, supper bubbly so I'll be looking at replacing that and the booster tomorrow most likely. pedal still just falls to the floor and I have like no brakes for even in gear idling, so that has to change. With the booster disconnected, I'm getting 15-16 INHg, thinking its gotta be leaking. Sorry for the long update, just super excited!!!

 

Alrighty guys... so my brakes were trashed, had to rebuild the front calipers,and some new rotors, pads, new wheel bearing grease and a good bleed and everything works great again. Still cutting out in boost areas though the response and everything else is still good, like a million times better, Gonna purchase a simple pump tomorrow morning with a guage so I can test the map sensor and make sure it's working correctly. With the scaling and everything, it worked for the vacuum portion. Time to see what is up with the boost areas. If that checks out well, any chance this could be the min/max MAP issues? Those values are stock. Or possibly the cylinder charge temperature enable/disable? Been hearing about those tables a bunch. Dont want to change them til I hear back from you guys about them. Calculated map max specifies the maximum MAP predicted based on TPS and RPM. And my max values are 105KPA. Could this be messing with me? As well with the min values table, it says it's a min of 10, and my map offset is 8.01 at 0 VDC. While testing my map sensor in positive pressure tomorrow I'll also re calibrate my wideband. Gosh I hope it's not that thing messing with me. Gonna try and get the VE settled tomorrow in non boost areas and maybe even try a time or two in boost. I feel like I'm so close to cracking this case. Everything you guys have told me has helped tremendously. But I'm still missing something... here's hoping!!

 

Alrighty guys.. nothing magical. Today tried tuning the VE and still more of the "I'm 8% rich, so take away 5% of fuel" and now I'm 5% lean thing. Double checked my fuel pressure and 58 KOEO, 55 running and gradually drops to 50psi when entering boost. I tested my map sensor today. Put 10 psi in it and got 175kpa, so I think I have the right settings for the calibration now. This is so frustrating. And I'm not one to just throw money at the problem, but the only thing left on my list is the new wideband. This really sucks. So much improvement over the past week, so close yet so far. I'm still not giving up just feel a little defeated at the moment. If anyone has any more ideas for diagnosis I'd love to hear them! But as it stands I'll be looking for a wideband today. Post up my results when I find one I like and see what you guys think of it. This is ridiculous. I dont see why she was working perfectly then just stopped. But time will tell. Thanks for the help guys

 

might take a step back and check what you can for free before throwing more money at the situation... just to brainstorm some ideas:

when you replaced the coils did you reuse the coil harness? could try a different one if you have a spare...

are the grounds for the coils good?

are your grounds in general good? block to frame, block to battery, ecm grounds, etc
there's at least one engine harness ground a the back of the motor that people sometimes have problems with...check all harness grounds

is the cam timing correct? did you degree the cam when installed?

any leaks in the manifold or pipe couplers that might not appear under vacuum but do under boost?

do you have any flex couplers in the exhaust that have failed either externally or internally? I've seen these fail internally and cause a huge exhaust restriction on one bank.

do you have a "mass air" tune that you could try to see if it is specifically speed density tune related? you don't have to get crazy with the boost, just enough to see if it has problems at the same point or not.

 

Thank you for the words of encouragement to continue with this bear!!
I did reuse the stock coil harness', just plugged the new coils into the brackets, I will make sure to to ohm out all those connections tomorrow and make sure I don't have have any opens or shorts etc in those circuits.

I have a ground from my battery to frame (rear mounted), as well as engine to firewall. I will check those as well as the ecm grounds. I originally didnt even have the ground from the engine block to the firewall but ended up adding it later on.

the cam timing is correct, I did degree it when first installed, but a little while after getting it running NA I had the thing apart, and put it back in dot to dot, which the guy I got my cam from said that was okay, and it worked when first boosted.

Im going to be testing the cold side and manifold in the am with some nifty at home DIY boost leak tester thing I made today. I am really hoping to hear that whistle lol

I have one flex coupler in my exhuast U bend that connects the two manifolds, i hope that's not the issue!!

And I DO have a mass air tune, but no sensor hahaha

looks like I have quite the list for the AM before work.

Thanks Again!!! update tomorrow

 

After reading your last post, a couple things jump out-the bat has a ground to the frame, but the engine
only has a ground to firewall? It needs to go to the frame also. Some flex joints have come apart inside,
causing problems. If using a factory computer, no way to data log?
I feel your pain, I am fighting a problem with no solution yet, lol.

 

Thanks for the reply! You guys convinced me to add another ground Haha. I'll add that to the list to try. I'll run it from block to frame and see how that works out. I am using HP tuners for all my data logging needs. And you're the second person to mention the exhaust coupler coming apart so I'll try and check that too. After all, even though it's only one, it connects half of my flow to my turbo, so it's pretty important to this whole thing. I'm sorry to hear about your issue, first world problems right? Although it sucks, I'd rather spend the day working on my truck, than not have built it at all. Life is too short and too boring to go slow all the time.

 

Alrighty guys made it to the truck. Armed with the almighty checklist, fresh coffee, fresh pack of cigs and a new, strange and completely unwarranted new sense of optimism. I begin my journey this morning, gonna try to get as much of this stuff knocked off the list as I can. Figured you guys haven't seen the truck yet, so figured I'd take a few pics. Go easy on me xD this is my culmination of two years of effort dumping every "spare" dollar I have into this thing and as you all probably know, no garage, just me and the elements hahaha. She certainly wont win any beauty pageants, but when she was boosting really well, i did lay the long dick on an evo that i had seen earlier that day at the track that ran high 11's. she is gorgeous to me and I love this truck so much!!!

 

Holy crap boys!!! So.. I checked out the coil subharness' and everything looked good. I checked all of my grounds and sensor wires, took me about 45 minutes to disconnect all the plugs and ohm out EVERYTHING in my harness as requested. It all looked great!! .003-.004 Kohms on everything. I'm mighty impressed with this stock harness I modified. All of my other grounds in the harness and battery etc also tested out great! I have some 4ga cable that I'm going to use to make a ground from the engine block to frame. Took my exhaust u bend outAnd as far as I could tell, I didnt have any restrictions there. I capped one end up with a tiny hole for venting and pressurized the whole thing and it flowed really nicely according to my very untrained eye. May re visit later if I have a better way of testing it.

NOW... da-dida-da!!! I tested for leaks on my cold side. And I'm beginning to really kick myself in the pants for this xD I found a nasty leak from a coupler right after my intercooler. I tested it at 20psi. Its higher than the 7lbs I'm trying to run, but I figured to go above my actual pressure was the smartest thing, after all, I want to turn it up in the future
(Just a few more lbs I PROMISE &#129310 Nobody said no take backs!! Hahahahaha. As silly as this was, I was so happy to hear that leak. I'm going to tighten the bad boy up and re pressurize to make sure I haven't missed a leak. Thank you all sooo much for all if your insight into this issue. I'm gonna go ahead and make an *** out of you and me and assume that this boost leak could cause my map pressure to suddenly drop off? I've never been so happy to find an issue with a vehicle in my entire life. I feel like I'm on top of the world right now!! Once I get a new ground cable on this pig I'll be trying it out and seeing what happens!!! Definitely will post updates. Just wanted to let you guys know my findings before I continued with leak sealing. Every single one of you guys rock for having the patience and the know how to help me resolve this thus far. Even if I went through all the other stuff first, if anything you guys gave me the faith in all the other things to know this sucker is pretty solid. Back to leak finding!!

 

I'm not positive the leak would cause the issues you are having.

How are your coils grounded? The brown wire and black wire on the coil harness?

 

Quick update before I start cleaning up for the day, I found two more leaky couplers and got those tightened up. Also found a very small pinhole leak in my charge piping where I had welded it together *face palm* I sprayed everything down one connection at a time with soapy water to make sure there wasnt anything I missed. Kept blowing my oil cap off, so catch can is definitely next on my things to purchase. Gonna get the pipe welded up this evening after work. And retest it. If all goes to plan, hopefully I should be taking her out for a cruise first thing in the morning tomorrow!!

 

Ahh okay, well that's good to know! And yessir, the factory wires in the harness all of which ohmd out alright. Should I be trying to ground them a different way? Or perhaps run a different ground from each bracket to somewhere? And stupid question but I am missing hardware for the brackets, missing a few bolts out of each of the brackets. Could that be causing this possibly?