Operation TPI Glory underway. Code 34 and Tuning
 

So, I just recently purchased an 88 IROC 5.7 TPI with a Vortech blower kit, Long Tubes, Nice True Y-Pipe, Nice Exhaust, Sub Frames, swapped 3.70 ratio. Big bonus is the car is very solid, no rust, body and interior are in great shape and only 62k miles. Nice shift kit, Paint has also be done and done right from what I can tell. As a child of the 80s and a high schooler of the 90s, I know the car isn't the fastest thing, but I love it. I believe the components are there to make a very strong respectable performer of a TPI.

Plans at this point are to not get crazy, but a Cam designed for a blower, nice stereo, and a nice set of wheels are the only further modifications I have planned.

Now the bad. It has a narrow band O2 sensor and its't reading are erratic. This will eventually be replaced by a wide band. Check Engine light is on and tossing a Code 34, and has a rough idle.

What I have discovered so far. Both MAF Relays have been replaced and so has the MAF. The Idle screw was adjusted out pretty far and I have rolled that back and got the TPS set at just a little over .5V at idle and not quite getting over 4V at WOT, reference Voltage is 5V. We will see if this becomes an issue.

So based off the trouble shooting tree, next is the ECM. I have ordered one and waiting on it.

Also, max boost shows only 4psi. The belt tension pully mount is maxed out. Possibly the belt is slipping. I will get to that after I know the rest of the system is healthy.

Plan is to get rid of the code. Then check base timing, IAC function, TPS setting, pull and check plugs - replace as needed. Then if all runs well, start diagnosing the boost issue. The injectors have been changed, but no chip work has been done. I imagine there is some untapped potential in there. I am thinking of getting the ECM modified for flash programming (EBL) and then getting her dialed in based off what we see. Then moving into the Cam with roller rockers and seeing where that can take it.

If I can get 275hp to the wheels out of a TPI without breaking into the bottom end, I will be happy. Anything else is just gravy. Maybe one day a 383 stroker.

This is the car I bought https://www.thirdgen.org/forums/cama...ro-iroc-z.html

Re: Operation TPI Glory underway. Code 34 and Tuning
 

So, still waiting on the ECM. Test says bad MAF... It has a new MAF, but its a substitute unit. The electronics inside the sensor are a different style than OEM. That has me concerned. I know I can order an OEM style (has the ring with the heater wire surrounded by heat sinks) so if the ECM doesn't fix it. It will be ordering a new, correct style, MAF next. Relays are fine. Have a new one, swap their position and nothing changes.

After resetting the ECM last night, it took forever before the car would even take a no load throttle tip-in without almost stalling (Tryign to rev in park to hold RMPs over 2k.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

I’m curious to se if the ecm fixes your issues. I’m in the same boat as you, I’m higher considering the EBL also.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

It didn't and I am not sure why. I am going to start another thread on the particular sequence of events. I got puzzling results.

Once I get it straightened out I will post a short summary on this thread as to what happened, but keep this thread a bit more general as there will be many steps along the way.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

It's been a while since I updated. I took some time to work on the corvette as it was just a tensioner, belt replacement, and peeling vinyl off. The Code 34 is proving to be an issue on the IROC. I have procured an XP laptop and just ordered my ALDL Cable from moats.net. When it arrives it will be time for some hard core diagnosis.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Did you check the fuel pressure yet? See if the fuel is bleeding down to zero after shutting the car off. Leaking injectors will cause a false code 34.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

I have not. Had family in visiting and a Corvette that needed some attention. In the meantime I procured an XP laptop and a ALDL to USB cable. Just finished a work bench so time to get back at it.

After capturing some live data, at idle... and it wants to stumble and die, my IAC counts are at a solid 160. I am going to address that first. At least as far as to take the IAC out, clean it, and then do the reset. Odd it's idle is low but the IAC is also closed.

BTW, it does not have the original injectors. I am not sure which ones are in it, but its not the original ones.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

A ecm could cause your issues. If your able to datalog I think your ecm might be ok.
http://www.chevythunder.com/maf_code_34.htm

Re: Operation TPI Glory underway. Code 34 and Tuning
 

I did datalog... well watch live data. The car idles low but IAC counts at 160. Then it wants to hesitate and sputter when the throttle is first opened. I have a feeling the IAC is causing some driveability issues. As soon as it is not 92* here I am going to get back on it. The car is supposed to be a fun project for enjoyment. Working in the garage when it's 90* is not fun.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Finished the IAC reset procedure with a new IAC... been a while because of family visits and high temperatures not making it fun to be in the garage.

IAC counts are down. still seems to not idle correctly :doh: TPS Voltage showed .59 in WINALDL. Going to adjust it, but can't imagine a .05V is too far off.

Still need to clear the computer and then see where I am. New problem seems to be the dash temp gage doesn't work. I don't remember that being an issue before, but on the scanner I can see coolant temperature.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

What scanner are you using? I should invest in one of those.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

WINALDL for software (free)
Windows XP laptop ($60)
cable from moats.net ($80)

Re: Operation TPI Glory underway. Code 34 and Tuning
 

If you dont want to learn winaldl, tunerpro, etc or dont have a laptop, then just get:
https://www.ebay.com/itm/12-Pin-ALDL...r/273066388728

Sync it up with your phone, and it comes with a free app that will dump values to a spreadsheet as it's running. Also display live data. If you ever have issues, john responds back usually same-day.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

So, Last night I had a no start and smelled fuel. Found a leak near the rear of the fuel rails, but can't determine where. So, as of today the upper intake is off. Tonight I will be looking for the leak :doh:

Also, on the supercharger elbow I found this:

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Here is the intake tube leading to the supercharger... nothing was plugged into the port where the PCV is supposed to go as well.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

So here she sits as of last night

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Located the leak. It is from the rear of the fuel rail. O-Ring kit ordered. Found a lot of information on fuel rail leaks here :search:

Will post back up once the parts are here.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

any updates on what's happening?

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Vacation at Cedar Point happened.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

https://cimg2.ibsrv.net/gimg/www.thi...e8555fa823.jpg
Fuel leak found on 9th injector tube.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

https://cimg3.ibsrv.net/gimg/www.thi...8ea717dcef.jpg
This is the intake elbow where the bypass valve and PCV enter in front of the supercharger. It looks suspect... yea. Well the kit is discontinued so no buying a new one. The fittings you see were already there. The pipe fell out and nothing was ever connected to the PCV. So, yep... goop it up with gasket maker, thread it back in and butter it around the edge. How *******, I know. I am not sure there is another option. So, I threaded the brass fitting inside and will put sealant on a bolt and install it. The PCV on my car still enters the manifold base as stock and since the PCV is a check valve should be fine under boost. Except that might be when in needs to vent most. Thoughts?

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Cheaper from Autozone for Viton O-rings.

https://www.autozone.com/fuel-delive...5_327287_24890

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Car is back together. Did a Key on/Engine off test and the leak was fixed. Didn't see any others, but more importantly didn't smell any gas. So, I proceeded to put the intake back together. It was getting close to the kid's bedtime so, I didn't have a lot more time to mess with it last night, but I did give it a start. Started better than it was previously, so maybe all is well. After work tonight, I will be resetting the computer, starting it, and scanning to see what it tells me. Possibly a test run.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Started great after resetting the computer. let it idle for about 5 minutes... and then shut it off to get the computer hooked up. Started back up and idled fine, then got crappy and died. :confused:

Started her back up, got the CEL back on, giving it throttle made it sound like it wanted to back fire, and now I believe it is a Code 36. I need to confirm this. Anyway, Idle was high to begin with. IAC counts were in the 30s, but when it wanted to die it was 160.

I believe I need to perform the IAC reset, timing check, and adjust the TPS again and do some reading on code 36.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

So now, it has a Code 36 and the idle problem. I put a new MAF burn off relay in just to be sure. The guy I bought it off of said he had replaced it, but it looked to me as though the power relay had been changed but not the burn off. It didn't fix it. 36 Still came back.

On the idle side, that is much better. As shown above, I found a fuel leak. Then while chasing it down I found that the connection to the blow off valve to the elbow was questionable and the PCV connection that is supposed to be used was left open and the PSV is still connected to the manifold in the factor connection. Well, without knowing all that was compromised, I had tried replacing the IAC and doing the reset/idle set procedure and it was just way off once the repairs were made. After allowing the ECM to reset the IAC , dialing back the set screw and bumping it up until the IAC was where I wanted it, and then adjusting the TPS to the proper volatage... idle was solid cold and warm. Let's hope that stays.

I did log data, but realized all my USBs are here at work :doh: going to try to remember to take one home tonight so I can get the file off the old laptop and post it up here.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

No Data log needed actually. After going back through the IAC and Throttle set procedure, all is well. Guess it was just way off from all the leaks post MAF. The Code 36 is most likely due to the style of MAF I have and is having no effect on performance. Plan will be to just tune it out one day.

Now onto the shifting issue. I was told the previous owner had a shift kit installed, but the shift firmness seems excessive and I believe its hanging in gear a little late. So, went to adjust the TV cable and no ratcheting (clicks)... fun. Next step of the project is to make sure this is all set right.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Fortunately, new TV cables are still available. Be careful about the overall length, since there are variations.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Yup, and they are fairly cheap. Actually though, the through research I found the ratcheting function isn't a required function. While it is nice to think everything will self adjust, but it is not always that simple. I got it adjusted in by setting it, driving it, and setting it until the shift points and firmness behaved appropriately under light, part, and full throttle conditions. You can notice it is a quick shift, but not a "hard" shift under anything but WOT. At WOT, it will bark the tires nicely. Just like you would want it to.

Code 36 was also remedied, I found a loose wire.

So, Now all is looking pretty healthy. So now to move to tuning. Been a few weeks since I reset the computer, I need to hook up the scanner and see what my BLMs can tell me.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

I am thinking this weekend I am either redoing the front brakes (pulls to the right under initial pedal) or I am flushing the Dexcool out. Both are next on the "list". However, I am going to hit the brake section here and see what stock-ish upgrades there are.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

https://cimg8.ibsrv.net/gimg/www.thi...65cff0df7c.jpg
Flushing the Dexkill out of the engine this weekend. PO put it in for longer life and better cooling. My research indicates Dexcool itself isn't a bad coolant, but the older style gaskets are not made to be exposed to it, and the Dexcool itself is not made to run in a system open to the atmosphere. Our overflow tanks are open to vent, so I am going to back to the old green stuff. Going to drain, fill with flush and softened then 6 stage filtered water. Drive, drain, fill with straight water and a bit of the green stuff, and drain again. Hopefully 2 will be enough to no longer see any traces of the orange coolant.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

I can tell you, it takes a lot more than just a dump, fill, dump, flush, and fill to change a system over. I think I had to dump, fill, heat cycle and repeat 5 times before the system looked clear enough to put the flush in. Filled just about every spare container I have in the garage.

Also, while screwing around with the car while it was heat cycling, I noticed the tail lights didn't work. Should have checked the fuse first, but pulled the switch first. Switch checked good, blown fuse. To note from the wire diagram, if you brake lights don't work (not tails) check your hazards, they run through the same fuse.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

During the radiator flush, found the heat was no longer working. When did this happen, I'm not sure since I have only had the car since June, really haven't had to try the heat. I knew the A/C wasn't working, but this was new news. During the drive to circulate the flush fill I did, when I switched to heat, no heat.

Not your normal issue, no hiss and the selector works fine. All positions function. I found there was still "red" coolant in the lines going to the heater core. This told me the heater control valve was not functioning properly. Checked the vacuum line and couldn't hold a vacuum on it. Traced the lines and found no issues and no leaking hiss sounds. So, I removed the valve and bench tested it, it didn't shift. $20 and a trip to the parts store later, the IROC has heat. The new valve bench tested fine.

On with the drain and fill.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Got the O2 Sensor replaced this weekend. The deep creep did it's thing and made it an easier than expected job. Sprayed it multiple times over three days before ever trying o remove the senor and started it a few times to give it some heat. Also got the supercharger belt replaced as it was at the max travel of it's tensioner adjustment. Unfortunately, no results to post as it is still on jack stands. Next is to remedy the front brakes that create an initial pull to the right when applied.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Front Rotors and calipers arrived yesterday. I will post up some pics as soon as I get some garage time.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Front components are here:

https://cimg0.ibsrv.net/gimg/www.thi...a90d8b7824.jpg

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Just re-manufactured stockers with a powder coat. Just figured while I am in there might as well do it all instead of waiting for a 30 year old caliper to fail. They are not that expensive. The rotors needed replaced, rotors means new bearings, pads at 30-40% and not running used pads on new rotors,a hose for sure due to the steering jerk so why only replace one. So looking at that and knowing the hose was going to cause me to need to bleed the system, the additional cost of the calipers was not much ... Power Stop had this nice kit that wasn't that much more expensive than parts from the parts store, had drilled and slotted rotors, better pads, and pretty paint on the calipers.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Finished the front brakes. for details you can see this thread . No just waiting on all the rears items to come in. This was a nice kit that was as close to bolt in as you could expect.

https://cimg8.ibsrv.net/gimg/www.thi...cd42ab3d81.jpg

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Haven't posted in a while... been enjoying the car. So far Code 34 has stayed away... Code 36 is back as the signal is... out of spec often. Eventually I am going to turn in off in the PROM and be done with it. Front Brakes are excellent. Got the shipping notification the components for the rear are on their way. So, soon it will be going back up on stands.

Still have a sputter from off idle to about 800RPMs. I have a feeling it is because of the Bosch injectors. It's on the list. Going to be studying up on PROM burning over the winter and next spring get to working on dialing in the idle.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Spectre :(

But seems the MAF readings are fine.... If you read above you will see why I was having Code 34 issues since there was an open hole in the intake pipe post MAF.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

No I don't have a Bosch unit. This is what came on the car when I purchased it, unfortunately. I was unaware Jegs carried a wire filament. I checked with Autozone and Advance and both listed the wire style (by their on screen pictures) as no longer available. Makes me wonder... might just be worth the try.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Re: Operation TPI Glory underway. Code 34 and Tuning
 

I just ordered one from Advance. They had better pricing and free shipping. It was in the middle of summer when I was looking into this and had other issues to deal with... but that dang yellow light has gotten on my nerves. Plus, it never hurts to have a spare one. I remember back on my 86 T/A, there was often a wonder if the MAF was causing issues or not. That was 25 years ago before we all had lap tops we could use to scan and check. So, now I will have a spare ECM and MAF in my parts bin as back ups. I will swap the MAF, hopefully the Code 36 goes away, but store the one currently installed one away safely for the just in case.

Right now I am having fun with the rear Brakes... I will install the MAF once it is on the ground and I will update here about how the brakes come out.

Re: Operation TPI Glory underway. Code 34 and Tuning
 

Hi Kyle. Looks like a good project starter. A couple of notes on two things you've mentioned. PCV has two connections to the motor. The vacuum side connects from the PCV valve on the drivers side valve cover to the intake manifold. The make up air side connects to a grommet at the passenger side valve cover and intake air at the throttle body. If this is connected properly, you are okay to plug the make up air connection at the intake elbow. The PCV system needs to have both connections. The PCV valve allows the crankcase to vent under metered vacuum at idle. Under load, the valve closes and crankcase gases vent through the make up air tube into the open throttle body. If the make up air side is blocked, you get excessive crankcase pressure. If the makeup air side is open to unfiltered atmosphere, you get unfiltered air into the crankcase and will also get inaccurate MAF readings since air is getting into the motor around the MAF sensor.

On coolant, all automotive coolant is ethylene clycol. The difference is in the anti-corrosive package. Green coolant relies strictly on emulsified silica sand for corrosion protection. It was never very effective but we got by with it before we started mixing aluminum with iron. The silicate coolant is not good at protecting aluminum from the corrosive effects of mixing metals. Plus, the silica settles out of the mixture when the engine is left to sit for any length of time, then there is no protection at all. Modern OAT (organic acid technology) coolants are a vast improvement over glycol silicate for corrosion protection. OAT is a chemical blend that is part of the coolant mixture. It doesn't settle out. It also maintains its effectiveness for much longer, thus the 5 year/100Kmi service interval. Dexcool is a very early version of OAT which may be problematic in systems where the coolant is exposed to atmosphere. There are later versions of OAT that work very well in these early systems. The best of these is Zerex G05. G05 is an OAT coolant(5 year service life) that does not react with oxygen like dexcool might and also contains silicate for sealing of micro porosity, as this was one function of the old green silicate coolant.

Coolants are a vastly misunderstood area. I could go into more detail about this but really, all you need to know is switch to G05 the next chance you get. BTW. When you switch to G05 coolant, while its best to remove as much old coolant as possible, it's not vital. There is no ill effect to mixing G05 with glycol silicate.