ToolGuru

Haven't been here in a while mostly due to car being in paint jail. I plan on swapping a TPI onto my 350 doing a build like the GM HighTech Performance TPI 355 Something New, Something Old engine. Perfect for my street driven Camaro. I am gathering all the parts needed. I think a polished TPI unit is about the greatest looking induction system there is that is affordable.

My concern is this: how reliable is the GM TPI system? I look at all the threads in this forum and I read about fuel pressure problems, cold running problems, hot running problems, fuel pressure problems, and on and on. Is this just the result of old, oem sensors reaching their usable life and needing replacing? Is it a result of mismatched parts? Bad GM computers?

What are your thoughts on this? Thanks.

Fast355

iTrader: (2)

If it were me, I would go away from the TPI ECM and switch over to a 0411 LS1 silver box PCM running an Express van 350 Vortec tune. At the same time I would convert from a 700r4 to a 4L65E. Use a fresh set of injectors, new regulator, and all new OEM sensors.

ToolGuru

Well, that's interesting. However, it doesn't tell me why. I sure as don't know why I would want a Vortec Express van tune for a 400+ HP motor. I also have a built 200r4 so there won't be any parts swapping. Anything is fair game as far as the TPI goes. Again, I'll ask the question....how reliable is the GM TPI? Are the sensors a problem after so many years? The ECM?

lakin454

iTrader: (2)

The way I see it, the TPI might have been good and reliable back in the 80's. Don't get me wrong there are plenty still doing their job.

Now you can utilize newer technology into the older engines such as the 0411 PCM. I did the swap since I wanted to get the most out of my motor until the LS swap happens down the road.

Is the computer your using from circa 80 something..... Most likely not.

ploegi

I had 200K miles on my Formula 350 TPI when I finally sold it. It still ran like a raped ape.

aliceempire

iTrader: (14)

I don't really think that's a fair question.

On this site you'll definitely see a ridiculous amount of owners seeking answers for problems on their TPI. Of course. A 20-30 year old system that could be hacked and damaged by PO's and possible shotty mechanics. Where are they going to go for advice? HERE.

Also mind you, the system(s) is one of the earliest EFI. All EFI from that era has repetitive problems from the industry figuring out what works, what doesn't. And wiring and parts do age. Maybe the good reason FAST355 suggested moving up......

Does that mean they aren't reliable in this day and age? Don't know. My TPI works flawlessly on 24 year old wiring. And so do many others. But how often do people ask questions if their car is running too good?

So does that answer the question. I don't think so. Not a fair question.

TTOP350

iTrader: (8)

A lot of problems come from owners that "fix things" without a problem being there or not really knowing what they are doing.
Yes, these cars are old and the older they get, old and even new problems pop up.
I daily drove mine for years an yrs an put hundreds of thousands of miles on mine.
Even drive it half way across the country at 240,000 miles and she hasn't ever left me stranded.

vetteoz

iTrader: (13)

Use a new wiring harness and sensors and it is as reliable as back in the day when '000's came off the production line in the '80's
As already observed ;
use some 25 yo hacked up harness and a original sensor from 1985 then you are asking for problems

this forum is full of threads "
I bought this 25 yo POS car that hasn't been maintained in 20 years , was butchered by 10 shade tree PO's and I can't get it to run properly

therefore TPI is CR*P

ToolGuru

That is what I figured. Fresh wiring with fresh insulation and connections, new sensors and most of the problems I have read about go away. I am intrigued about the 0411 ECM as I need to get a ECM.

As to aliceempire, sorry it was and is a fair question. Its very simple, will a brand new TPI system be reliable? No different than "can I get theis much hp if I do this and that". Fast355 decided not to answer the question.

jbenge

iTrader: (2)

In my experience TPI engines are actually pretty reliable, especially if you replace the normal parts(injectors, fuel pump, etc) that cause issues when they are 20+ years old. But TPI is outdated 80s technology..the ls stuff or aftermarket efi setups are much better especially in tuning and diagnosing when you have a problem.

Fast355

iTrader: (2)

Actually, I just sat down after getting off work and mowing my yard. Not that I didn't want to answer your question, just got occupied with this thing called work.

My thought behind the 0411 is just the fact it uses a much more modern processor, offers sequential fuel injection and rather than burning chips you can simply flash the PCM to make changes with HP Tuners. Almost no tuning shops mess with OBD1 TPI. EVERYBODY tunes LS1s.

ToolGuru

Thanks, Fast. Brand new TPI harness with new sensors coupled with that 0411 ECM sounds like just the ticket.

VincentZ28

iTrader: (2)

TPI is reliable as it was brand new. The problem is that when a lot of these young guys by these cars, the first thing they want to do is start removing parts to clean up the engine bay. They can't just leave stuff alone. Then they start hacking up wires trying to get the fans to come on when they want it to not knowing that you can change the sensor in the passenger head to come on at 185*(2nd fan), and the primary fan can be change in the chip to come on sooner. These are just some of the problems why stuff gets screwed up. In short they don't know what their doing.

MoJoe

iTrader: (5)

The 411 ECM is from an LS1. Therefore you want an LS1 harness. The connectors will mostly match the sensors; such as injectors, TPS, IAC. Some of the sensors may need to be from the LS1 ... knock? then add crank & cam position sensors. You end up with electronics from the LS1 connected to your SBC with TPI intake manifold.

darbysan

Don't forget that for the 0411 ECM you will have to buy an expensive ($500-$900) programming package to program the 0411 ECM to go along with the LS1 style harness. You will also need a Vortec style distributor and coil, and a Crank Position Sensor and associated drive gear for the crank, along with a new timing chain cover. Forgot to mention that it won't work with a 200-4r/700r4 without special speed sensor adapters. Works easier with a 4l60 or newer trans.

I really wanted to do this swap on mine,but the cost of the programmer put it over the top of my budget ( since I had already replaced everything with new anyway).

As for the reliability, I concur with the others that it can be a very reliable package. Many here have over 200K miles. I did the swap a few years ago, and replaced all the sensors ( to ease installation issues). I've had no issues at all.

VincentZ28

iTrader: (2)

The only sensors that really go be are the O2 sensor and the MAF. Other than that the others still works after almost 30years. The hackers screws up the rest of them.

darbysan

For peace of mind and easier troubleshooting, I would consider replacing the stock injectors with re-manufactured Bosch III's, and rebuild/replace the Fuel Pressure Regulator. Check the EGR and temp sensor and replace if in doubt. All of these are under the plenum, and are much harder to fix after the fact. This also goes for the Air Temp sender in the plenum.

rusty vango

as will be stated. TPI is as reliable as the sensors and wiring that runs it.yes injectors and fuel delivery can be a problem on this almost 30 year old technology. but if your sensors and fuel system are correct,it is as reliable as it ever was.

TPI

To answer the man's question. Yes, Tuned Port Injection is reliable. I just drove from Arizona to Connecticut in the middle of summer, it was an amazing trip.

Get to know the system, keep it cool.. Do preventative maintenance and she wont let you down.

ToolGuru

Yes. In reading more about the 0411 pcm, total overkill for what I want to do. I am not interested in coil overs, crank trigger timing, etc. Will either megasquirt it or go GM ECM and reprogram.

Abubaca

iTrader: (3)

I've looked into the 411 pcm and all that goes with it, and there's no doubt it's an awesome upgrade. That being said, my main reason for wanting to do it was the availability of tuners. Either for my current plans or anything I may do in the future. My current L98/zz4 cam runs on the stock 89 hardware and runs AWESOME! No trouble with the sensors, the engine, the computer, or the tune. It runs really good on the stock "chip", and it runs a little bit better, albeit not much, on the PCM for less "chip".

Fast355

iTrader: (2)

I suggested it thinking, it would be a fresh build, with a 700r4 transmission. When you combine the 411 with an electronic transmission you start to get somewhere. Basically the next best thing to a LS swap.

Bob88GTA

iTrader: (2)

Oh Vincent...you nailed it!!!! "EGR DELETE"..."HEATERBOX DELETE"..."AC DELETE"..."SMOG PUMP DELETE"..."AUTO FANS SWITCH DELETE...............
And on and on. I was waiting to chime in but didn't want to be a ****!

Sorry if I offended anyone on here, but I see it allot

ToolGuru....Had my 88 since new, 193k miles. Keep it tuned and maintained and it runs like brand new. To each his/her own though

Street Lethal

iTrader: (16)

... no, it is the result of members not knowing what they are doing, and not having the funds to properly resolve the issue. Ninety nine percent of the time the problems are due to a failing fuel pump, bad injectors, faulty MAF, or a simple vacuum leak, and that isn't Tuned Port Injection's fault, it just comes with wear and tear. Air, fuel and spark, nothing has changed other than a more broader resolution, and mechanical enhancements, but it doesn't change the fact that even a carburetor can get the job done. How reliable is the GM TPI system you ask? It depends on what you are looking for in terms of RPM potential, it depends on your cam specs, it depends on your stall speed, it depends on a lot. Most guys who trash on TPI don't have engines that are built for TPI.

hellz_wings

iTrader: (2)

My TPI has been pretty awesome, one of the best aspects of the car IMO.. Ofcourse, I have invested in new sensors, blocking off AIR, EGR, 9th injector and ofcourse did some tuning to make it perform better and work with the physical changes I've made.

BTW, I had a code 36 that suggested MAF Burnoff Diagnostic was faulty or wtv.. I ended up taking apart intake tract, cleaning filters, cleaning intake tract, cleaning MAF screens, blowing pressurized AIR in the MAF sensor (there was crud everywhere inside and out) and cleaned inside throttle body and the code went away. Some people suggested getting a new MAF which solved their problem, but maybe the problem was just that it needed to be cleaned, well, for me that was the issue. Point being, sometimes on forums people complain and maybe just change the whole part but it was not actually required to spend that money in the first place.

Fred SS

iTrader: (3)

ToolGuru, I think the TPI system is fairly reliable. Start with a good wiring harness, replace all the sensors and relays and get a GM shop manual. Know the limitations. The early MAF systems can accept cam and head changes up to a point without having to change the ECM programming. When I did the TPI swap on my 87 Monte Carlo SS, I kept on the conservative side. I've been running it for about 2 years now without any major problems. Knock on wood! The first problem I had when I did the swap was the motor would not start. Eventually I re-checked my ECM pin-out and compared to the shop manual. I forgot to insert a pin in the harness for the VATS signal, dumb mistake. The other problem I had was a weird idling issue. Discovered the wires to the IAC were mixed up. Fixed that and been fine since.

3.8TransAM

Pretty much dead reliable.

GTA bought at 19k miles, 67k on it now.

91 Formula bought at 40k, 122k on it now.

In stock incarnations and a lot of miles on each I lost an alternator at 80k on the Formula, fuel pump at 90k or so.

GTA lost the injectors in the low 20k range. GM injectors used on TPI(and some others) were known to fail however so not unexpected.

I have come to the conclusion using the 0411 on older small blocks is a waste of time and money unless u possess the skills to do it yourself(which I could). If your going to buy it all to plug in play you might as well hunt down a LSx swap for that kind of money. If you do it yourself junkyard style, it would be a nice upgrade.

IF you have a good harness or a new harness for TPI this is your best option out there:
http://www.dynamicefi.com/

Nice setup, stock based along with self tuning.

Learn about how TPI works, understand the system and get it running 100% before attempting any mods goes a long way to solving a ton of issues.

Bigfoottpi11

They are very reliable, once you get past the maintenance like various sensors gone bad.

Veaceonee

iTrader: (1)

The thing i like about TPI is what I tell a lot of people, "Easy enough to work on at home, complex enough to make you look good". No special tools except a Laptop and cable required.

I have a good story about my experience with TPI. Got off of work, and the fuel pump died. Was able to start it and drive it home (albeit maintaining no less than 2500 RPMs at all times) for almost 15 miles. Burned up all the spark plugs and cooked the injectors, BUT it did get me home. Try doing that on a "modern" system. There is a reason why the SBC was left pretty much unchanged for 40+ years.

Yes, the haters will hate. But, if you don't f- with it, and just MAINTAIN it, it is just as reliable, if not more, than any other system out there.

hellz_wings

iTrader: (2)

I can attest to this. Change out for new sensors (which are pretty cheap btw) and if it hasn't been all hacked up or messed up by a previous owner, then it's damn reliable. Never had an issue with TPI really (the MAF TPI systems also do very well at compensating for cam/heads upgrades).

Fast355

iTrader: (2)

My old G20 did the same thing one day driving home from work. Just cruising along and suddenly was powerless on the highway. Push the gas and it would bog, let off and it would idle. Downshifted to 3rd, then to 2nd, keeping the RPMs over 3K. Managed to limp it all the way home. Found my fuel pressure was under 20 psi. I thought the parts house pump I had installed when I converted to TPI had died. Turns out it was just the short section of fuel line between the pump and sending unit in the tank that came in the fuel pump kit was not rated for immersion in fuel, had swollen and ruptured. Searched all over town for fuel line rated for immersion and when I finally found it, paid about $20.00 for 1 foot of the stuff. Ran flawlessly with 46 psi fuel pressure after.

Veaceonee

iTrader: (1)

I don't remember the website, but I picked up a 6" piece of Chrysler rated submersible fuel hose for something like $3. Works just as good as the expensive stuff.