The TPIS system would not be a factor open VS closed loop. Force it to stay in open loop. Record data logs. Also record closed loop. Do you have a print out of your tune.

 

Something fishy here. All of the commonly used tuning tools have features to export the calibration data to text.

Do you have a copy of your bin?

Are you using an ostrich and/or burning eproms to make changes or are you working with pre-programmed eproms provided by your tuner?

 

Hal, congrats on the build!! Now what is the history of this car. Did you have fuel problems before this 383 - TPIS intake build? You personally do not have programming \ data record hardware or software? This is the stock ECU \ prom flash? You decide to sub out a engine build along with necessary tuning. This is your end results? With vague knowledge? Now forcing you to rely on subbing diagnostics. If this is a stock ECU \ prom combo. You should have asked for a backup of this bin. You now need to pull the prom have someone read & save the bin With the appropriate definition file. This can be printed to txt to view the updated tables. Or post the bin.

 

........... Go with Holley ... The Commander 950 is very affordable but you have to tune it yourself with a laptop ... the Terminator , Avenger and HP are self learners ... once you set up the base tune with a laptop , you drive the car and it tunes itself ... the Dominator is their top of the heap ... very expensive but very high tech ... still need a laptop to set the base ... this one is a self learner also ... I'm currently switching to one of these bad boys 'cause I changed the trans to a 4L60E and need the trans control plus some useful I/O's (I drag race a lot) ... Dominator also has a LARGE internal datalogging feature ....... But BEFORE you go with a different management system , you need to verify that your hardware (engine) is mechanically up to the task ...........

 

Update:

I have yanked the car out of the shop it had been in since August 2014. It is now in my garage. It does not run. I have an intact OBD1 TPIS system and am now seeking a new mechanic/tuner to go over this thing. I am located in Calvert County, Maryland. If you have contacts in the area that have capability and interest in getting this car to run and run strong, please post here. Thank you!!!

 

I had very similar problems like those your describing when I turned my 1990 Vette into a 383. It never ran worth a damm, I changed all the sensors, I changed to a Heated O2 sensor, and still it ran like ****. I recently replaced the TPI (Big mouth base, AS&M Tubes) with a modified Holly Stealth Ram and AFR Eliminator heads. Changed the fuel injectors again, this time to 32# pounders, and now the car runs super rich. All of this was with the factory computer and several prom changes.

To fix this expensive mess; I bought a FAST XFI from White racing. I also bought his adaptor harness, which allowed me to retain the vettes engine harness and all dash functions, except for the fuel economy readout. The car runs great now, and gives the LS3 Camaro down the street lots of trouble.
Take a look at the site: http://www.whiteracing.com/complete.html

 

In May I moved the car to a shop in Calvert County. They evaluated the car and determined there was a massive vacuum leak at the intake plenum where it sits on top of the motor. They reinstalled the plenum with a thicker gasket and the motor starts, runs and leans out properly on warm up. We are staying with the TPIS system for now. The car is now in the final stages of being put back together.

So the big lesson here, in my opinion, was that AV Autoworx in Delaware was not the shop for this job.

 

Wow....all along I was wondering what the outcome of this would be since everything I thought of was covered . TPIS although not perfect has decent products and Jim is pretty good.

All of this over a vacuum leak that no one could diagnose and repair...interesting....keep us posted....🍻

 

Happy to hear you finally solved this issue. Gee, I thought that the vac was checked. Well, that's performance. But nice to know it was not a major internal motor prob.

My C4 TPI works pretty well, and was a bit of a hassle too. But I've always felt that the ZZ4 motor was "Not quite up to Par" I'm going to pull the A/C pump back and see if the timing cover has the "Crank Sensor Bung" on the timing cover. I just don't remember- prob not.

I'm considering to ripping out the entire TPI system and converting to a LS1 ECU and harness. The Crank sensor is a little work if I end up changing the timing cover, never fun in a C4 but the Cam sensor is just a dizy mod. The motor would have a OBD2 system, which would give the motor 2 Ozy sensors, and 2 coils and a much better ECU.

Have you read much re this ECU update ?

 

I was assured that the installation work was completed correctly. Obviously, I was misled and I apologize to everyone following this thread with regard to the time and thought spent in replying to a situation which was rather ridiculous. There was no mechanical or electronic issue; in my opinion, there was a human issue and I wish I could fix stupid!!!

The TPIS system was not my first choice for upgrading the intake. I wanted to do an OBD2 system with harness to allow the existing computer to run the gauges. Unfortunately, during the summer of last year, the company we chose to supply the harness could give us no information because their one expert guy was on vacation for a month. I have since become aware that there are other sources for the harness. I would however, proceed with caution. I have researched a number of solutions, including one mentioned in this forum, and found that parts are discontinued and no longer available. I guess the number of cars with the C4 "situation" are dwindling.

I would like nothing better than an OBD2 system with LS architecture in my Vette. It isn't going to happen. If push comes to shove, look at the number of C6 Grand Sports that are coming on the used market for very reasonable prices. While I hope to enjoy my C4 with 400+ horsepower for another 5 years, I realize that I will be working blind with the TPIS OBD1 system. I think time is quickly passing on the TPIS solution. The number of cars on the road needing the OBD1 "fix" is quickly dwindling. I may be one the last few left in 5 years. At least I hope so!!!

 

The current shop has made mods to ensure proper performance. They have moved the air temp sensor from the air duct in front of the throttle body to the air box ensuring less influence of engine heat. They have moved the O2 sensor from the #7 header tube and put it down stream in the exhaust system so that it would take a reading from both sides of the exhaust flow and not just one tube on one cylinder. They have installed a 3-wire O2 sensor. They are also sticking with a fan switch that is cooler than the stock rating.

 

You should probably go back and edit/delete post 15. The things said about TPIS just aren't true. They have been around a very long time and deserve some respect...especially in light of the fact that it was a poorly installed intake causing all of the problems.

 

Well, these things happen, over and over again.

Sounds like you've make the best upgrades on the TPI, moving the temp & Oxy senors are a good idea. I did this as well.

But, I'm still leaning towards the LS1 ECU & harness. I mode'd the LS1 Harness for the LS1 that I installed in my 56 Coupe. It isn't that tough of a job. Just takes time & patience.

I've got two friends that are wanting to purchase my C4, difficult decision. I do need to sell two Cars, just to many. If I sell the '56 then I'll keep my C4 & gut the TPI electronics and install the LS1 system. Prob the entire dash too. My son recently bought a very low mile 2005 C5 Le Mans FRC ZO6, very nice Vette, but worsens our garage space. I'm really leaning towards selling the 56 and keeping the C4, All of the suspension, interior and complete running gear only has about 8k miles. It's just the TPI electronics that puts me off.

I'll sent you a PM re the conversion parts. I think your prob in great shape now on your car, so drive her and see how she performs for you.

Good luck and enjoy the Summer

Michael...