Helllo- New member with a SBC TBI equipped Jeep

[tplasek]

After a long and unsuccessful journey with a TBI 383 and a "popular" TBI mail order tuner, I have been very reluctant to make any changes to my SBC 350 jeep with a TBI, factory cam, factory TBI intake, and factory tuned motor. It is a 1970's 4 bolt 350 with 1970's 441 heads and a 93 intake, TBI, and distributor setup. It doesn't have gobs of power, but after it warms up, it runs smooth, doesn't miss a beat, and runs well here at sea level in Houston and at 12,000 ft in Colorado. BUT!!! I have the bug and want to make some changes in suspension, and motor. I would like to add a very small Summit K1101 cam (or other cam if someone with more knowledge than me recommends it), a simple Edelbrock Performer intake, and a 46mm throttle body, for a little more mid power. I am having a hard time pulling the trigger after the fiasco with the 383 project that ultimately had to be sold at a loss out of frustration. I still have a few bit and pieces from the 383 like, USB data log cable with the 10k switch, a Moates eprom programmer and a few extra chips, but I have completely forgotten the process and I was only data logging while the "tbi specialist" was making the changes.

With the help provided on this website, I think I am going to move forward with the changes and try to learn the tuning process. I am not too far off from stock and I hope I can figure out how to make some small tweaks and get her running with new spirit. However I am carefully going to remove and save all the factory parts to put back in if I can't gt it right.

I just recently discovered this website. I have a lot of reading to do and a long journey ahead of me.

Tim
Houston, Tx

[buddrow]

Welcome to the forum. If you are having issues with you current tune, start off with a factory unmodified bin and tune from there. What ecm are you using?

Buddrow

[dave w]

Myself and other members like using TunerPro RT to tune TBI with. I developed an Excel spreadsheet that is very helpful with TBI tuning. See attached pics.

dave w

[tplasek]

Buddrow- I read through this site and made some progress last night. I discovered that I have the 7747 ECM. I also figured out how remove the factory style 2732A chip from the 7747 ECU and I successfully read the BIN file from the prom using a Moates Burn 1 Prom reader. I opened the Bin file using TurnerPro with XDF and ADx files I located on this site provided by Dave. I saw actual data in the tables so I think I am making progress. I ordered the 7747 computer and chip over ten years ago with a factory tune and only requested that it programmed for manual transmission and no EGR. Currently, with mostly factory GM TBI parts and engine accessories, the Jeep runs fine after it warms up. There is some surging until it reaches operating temps.

Dave- from reading your posts, you are a wealth of information and very patient with people trying to learn this process. From my reading last night, I located several files you posted to this site all related to my 7747 setup. I also read through your intro to TurnerPro twice to help me get started.

ALL- I am at a starting point in the process from changing a factory TBI setup into something different. I have two pretty solid yet different directions I can take this project.

1: I can continue with the 7747 setup and the TBI. Items required for power improvements will be: Edelbrock Performer intake $150 (possibly EPS but I have concerns of TBI on a square bore intake), 46mm bored Throttle Body $200, some sort of Cam and lifter package $150 or maybe roller cam +$ and as I found out last night, I need a G2 adapter for my 7747 ECM. I am looking for smooth clean crisp power from idle to 4500 rpms. This is a jeep that spends most of its lift climbing a hillside in that RPM range.

2: Many moons ago I purchased a complete TPI setup off of what I think was a 95 setup. I have: Distributor, ECU, labeled painless wiring harness, fuel rails, fuel injectors, and complete intake. Someone purchased this kit from a fuel injection specialties place, but like me never installed it. This is another route I could take which would save the cost of the 46mm bored throttle body and Edelbrock intake. However, I am at a point in my life where I do not have to pinch pennies anymore. I don't like to waste money, but I am a firm believer in DO IT RIGHT THE FIRST TIME. Buy what you need, buy the best stuff and be happy.

Thus in the end, without worrying about the cost, would option 1 or option 2 be the best way to proceed for an idle to 4500 great running, smooth idle, crisp and clean well tuned motor that will operate at sea level in Houston as well as at 10,000 + feet in Colorado.

Thank you for the input. I am ready to start buying parts and moving forward, just need to figure out which direction to take.

Since I am getting past the intro stage and getting into tech questions, should I continue this here or start a new thread in the tech sections?

Tim

[dave w]

I favor the TPI system with using a stock or nearly stock TPI roller camshaft. The stock 1996 - 99 Vortec 5.7 roller camshaft is a good budget option for a roller camshaft also (TBI or TPI). I would use the TPI ECM #1227730 (MAP Sensor). The TPI system is a better fuel delivery system vs. TBI. The TPI system, in stock form, provides good low to mid range RPM performance. The TPI MAP Sensor system works well with altitude changes.

Some TBI engines, that have a fuel pump block off plate bolted to the block, can be converted to roller camshaft using factory parts. Most TBI engines require aftermarket ($$$) roller lifters to be converted to roller camshaft.

dave w

[tplasek]

I finally opened up the box for the TPI that I purchased over ten years ago. I dug through the box and it appears that all intake components, distributor, painless wiring harness and ecu are there. After looking things over, it appears that the intake setup is for a pre 87 F body intake system as the two center bolts on the lower intake are still angled, and not vertical like post 87 intakes, the fuel rails have the 90 degree bends under the throttle body, and there is a hole for the EGR valve but no EGR valve itself. There is also a 9th different looking injector in the box with the rest of fuel injectors. This will actually simplify things things as I currently have a 1970's block and heads. This TPI intake will bolt right up to my current setup. The ECU supplied is the weatherproof 1227727 and not the 1227730 as you prefer above. I'm not sure if this ecu will create problems for tuning. If a 7730 is required, they have those on Ebay.

Now for the confusing part. I read that all 86-89 TPI systems were MAF systems, however, a MAF sensor was not supplied in the box of supplied parts but instead I located a MAP sensor. I checked the wiring harness and it is wired for the three wire MAP sensor and does NOT have any provisions for the MAF sensor. Also a bit confusing is that the injectors are all 5235302 injectors. When I looked these up they appear to be 22lb 5.7L corvette injectors and not 305 F-Body injectors like the fuel rails indicate.

I am new to the world of TPI but the more I read it appears that the previous owner of this system supplied parts to convert an old 9 injector MAF system into the newer speed density style. I hope you can confirm that this conversion is possible and that I didn't receive a box of mismatched parts.

I am willing to buy a new 77030 ECU if the 7727 ECU supplied will not work, but I really don't want to buy new injectors, MAF sensors and a bunch of new parts if the parts I listed above will not work. The answer to this post will determine which way I proceed: either with option 1 or 2 posted above. I still prefer the "cool factor" of the TPI and your preference to tuning with a TPI (as well as high elevation characteristics), but I don't want the TPI project to get out of hand when I have a perfectly working TBI setup already on the jeep. If someone can confirm that with the parts I listed above I am at a good starting place for TPI, I say lets move forward with the TPI and I'll figure out how to get a roller cam in that 1970's block. If the TPI works, this will save $ on parts I was going to buy for TBI setup which can be dedicated to the roller setup.

Thank you for the assistance. I also sent you a PM regarding retaining your programming services after I get either option 1 or 2 installed.

Tim P
Houston, Tx

[Fast355]

I finally opened up the box for the TPI that I purchased over ten years ago. I dug through the box and it appears that all intake components, distributor, painless wiring harness and ecu are there. After looking things over, it appears that the intake setup is for a pre 87 F body intake system as the two center bolts on the lower intake are still angled, and not vertical like post 87 intakes, the fuel rails have the 90 degree bends under the throttle body, and there is a hole for the EGR valve but no EGR valve itself. There is also a 9th different looking injector in the box with the rest of fuel injectors. This will actually simplify things things as I currently have a 1970's block and heads. This TPI intake will bolt right up to my current setup. The ECU supplied is the weatherproof 1227727 and not the 1227730 as you prefer above. I'm not sure if this ecu will create problems for tuning. If a 7730 is required, they have those on Ebay.

Now for the confusing part. I read that all 86-89 TPI systems were MAF systems, however, a MAF sensor was not supplied in the box of supplied parts but instead I located a MAP sensor. I checked the wiring harness and it is wired for the three wire MAP sensor and does NOT have any provisions for the MAF sensor. Also a bit confusing is that the injectors are all 5235302 injectors. When I looked these up they appear to be 22lb 5.7L corvette injectors and not 305 F-Body injectors like the fuel rails indicate.

I am new to the world of TPI but the more I read it appears that the previous owner of this system supplied parts to convert an old 9 injector MAF system into the newer speed density style. I hope you can confirm that this conversion is possible and that I didn't receive a box of mismatched parts.

I am willing to buy a new 77030 ECU if the 7727 ECU supplied will not work, but I really don't want to buy new injectors, MAF sensors and a bunch of new parts if the parts I listed above will not work. The answer to this post will determine which way I proceed: either with option 1 or 2 posted above. I still prefer the "cool factor" of the TPI and your preference to tuning with a TPI (as well as high elevation characteristics), but I don't want the TPI project to get out of hand when I have a perfectly working TBI setup already on the jeep. If someone can confirm that with the parts I listed above I am at a good starting place for TPI, I say lets move forward with the TPI and I'll figure out how to get a roller cam in that 1970's block. If the TPI works, this will save $ on parts I was going to buy for TBI setup which can be dedicated to the roller setup.

Thank you for the assistance. I also sent you a PM regarding retaining your programming services after I get either option 1 or 2 installed.

Tim P
Houston, Tx

Tim,

Having had both a TBI and TPI setup on the same engine in the same vehicle, stay TBI. Much easier to mess with if you have to end up working on it on the trail somewhere. If you can get away without EGR I would go with a TBI to Carb adapter on a highrise dual plane manifold like the performer RPM. Keep the cam on the small side, single pattern on a slightly tighter than stock LSA and make sure it is 4° advanced. In a torque monster 350 TBI build I really like a cam around 252/252 @ .006, 206/206 @ .050, .450/.450" lift, 110° LSA and 4° advance on a 106° ICL.

[tplasek]

I have no need for EGR and was originally looking at either the spread bore performer or spread bore performer RPM intake if I stay with the TBI. Unless I am mistaken, it appears the the TBI throttle bodies are too wide and too far apart to fit properly on a square bore intake. I have seen adapter plates for TBI to square bore intakes but they all have a pretty sharp and abrupt adjustment just below the throttle body to narrow the passages down to the square bore intake widths. If I am buying new anyways I figured the Q-jet RPM spread bore would be the one to pick. I am currently on the factory TBI intake.

I am only looking for a very mild cam to replace the factory one currently installed. The Summit K1101 was recommended which is a 194 / 204 @.050 112 LSA. You are the second person who recommended a single pattern cam though. I'll have to read up on those. Do you have a particular one you can point me to?

Also what about 46mm TBI units? Do you have any experience with those?

Tim

[dave w]

The internal electronics of the '7730 and '7727 are identical. The Memcal chips are also interchangeable. The '7730 is an "underdash" ECM and the '7727 is an "underhood" weatherproof ECM. For off-road applications, the '7727 is usually favored. In recent years, it's become very challenging to find all new parts to build a '7727 wiring harness with.

dave w