Trade a 1227727 Corvette and hardness for 1227730 and hardness:

[Racprops]

Thanks to the great post below trade offer is over.

Considering the current problems most likely for the best.

Thanks Dave W you saved me a ton of work.

Rich

[dave w]

The 93 G20 VAN computer can be modified and reprogrammed for a TPI engine.:jfj: The 93 G20 VAN harness can be converted to a TPI harness, by removing the TBI injector connectors and splicing a TPI eight injector pigtail. The IAC and TPS might need a new pigtails also.

The 1993 G20 VAN computer has more features and benefits that the 1227727 or 1227730 computer.

dave w

[Racprops]

Major thanks for your help. I had been looking for such information. I thought I had seen something covering this years ago. But after a number of searches I had given up looking.

Can you tell me more features and benefits??

Rich

[Racprops]

My 93 Van seems to be a odd man out, seems its PCM was a one year model, it is a 16186694PCM. Is there a better replacement? Seems to me such a one year model hints at a problem that was replaced the next model year.

I do know I already had to replace it due to what I believed to be transistor output failure, and currently have two of them, I was carrying a replacement just incase.

And for some reason I have had a number of the four legged modal under the small distributor cap fail on the road.

I even upgraded to a MSD distributor and coil and still had failures, I rigged a 30 AMP relay near the distributor controlled by the key, and added a extra ground strap. I think it is fixed by this more positive power and ground connections, but worry it may come back.

Any history on this problem?

Rich

[dave w]

I think 16186694 PCM is an invalid number, because Google can't find it and RockAuto can't find it.:confused:

The 1993 - 1995 PCM with Red / Blue Connectors can control either the electronic 4L60E transmission or electronic 4L80E transmission. The shift points are programmable with the electronic 4L60E and electronic 4L80E.

The 1227727 and 1227730 were used with the non-electronic 700R4. The non-electronic 700R4 uses a TV Cable to help establish shift points.

The 1993 - 1995 PCM with Red / Connectors has two fuel tables and two spark tables, Near Idle and Off Idle allowing better tuning / fine tuning for aftermarket engine performance parts. :jfj:

The 1993 - 1995 PCM with Red / Blue Connectors was used in Pickups, Vans, Suburbans, and S10 vehicles, making it low cost and easy to find.

The 1993 - 1995 PCM with Red / Blue Connectors along with the 1227727 and 1227730 are neck and neck with a tremendous amount of aftermarket tuning software / hardware support.

There is the option to upgrade the computer in the 93 G20 VAN to the 1993 - 1995 PCM with Red / Blue Connetors. Check out these internet article link were they upgraded PCM's https://www.thirdgen.org/forums/diy-prom/270266-tbi-guys-its-time.html & http://www.gearhead-efi.com/Fuel-Injection/showthread.php?173-1227747-to-16197427-Conversion-PCM-Swap-with-Wiring-Pinout-Directions!

Maybe it's time to "Double Down" --- upgrade PCM and do the MPFI conversion for the WINNING HAND? (Poker Humor):thumbsup:

dave w

[Racprops]

Darn I transported a number IT is a16168625, please tell me about this PCM.

OMG there is SO much...Thanks.

That raises the following two questions: MAF and sequentially fired injection?? Just to have my cake and eat it too.

I thing a good MAF it the most important one. MAF WITH MAP would be second.

Rich

[dave w]

We have a Winner!:thumbsup:

The 16168625 can be upgraded to MPFI, using Speed Density (aka MAP Sensor). There is information available about using MAF with the 16168625. I do not have personal experience using a MAF with the 16168625. I have had very good results using the 16168625 upgraded to MPFI with the MAP only, so if it's not broke why fix it? The 16168625 converted to MPFI will be controlling the injectors in Bank Fire same way the 1227727 and 1227730 control the injectors.

To have sequential fuel injection, MAF and MAP is possible, if your willing to increase the budget for some OBD2 hardware / software upgrades. Sequential fuel injection requires a Cam Position Sensor and Crank Position Sensor. The 1996 - 2000 Vortec 5.7 liter is sequential fuel injection with MAF and MAP. I would not venture converting an OBD1 engine to OBD2, because the overall performance gain doesn't justify the expense (in my opinion). The reason for sequential fuel injection, MAF, and MAP was for reduced emissions at idle. Engine performance was about the same, Sequential vs. Bank Fire.

It's also possible to convert a TPI engine to sequential fuel injection, MAF, MAP and LS type coil pack ignition or Coil on Plug (COP).:happy:

dave w

[Racprops]

OK I need to ask what MPFI??

Rich

[Fast355]

OK I need to ask what MPFI??

Rich

Having done the OBD1 to OBD2 0411 PCM swap multiple times. HUGE difference in the way the engine runs before and after. Coil per cylinder ignition can fire a very lean mixture at part throttle cruise.

[Racprops]

So is the term MPFI means a OBDI to a conversion to a OBDII??

A few concerns in my case is all the major rewiring in my van, and as I understand things at this point, the OBDII Systems are very hard to get into to do tuning were the OBDI systems are basically wide open.

Also it seems much easily to enable the lean cruse system.

Lastly I want to tune for MPG and think a PCM with so called learning systems could fight and remove improvements in MPG to suit its core programing, where I think a OBDI system might be less able to reprogram fuel settings.

Rich




Having done the OBD1 to OBD2 0411 PCM swap multiple times. HUGE difference in the way the engine runs before and after. Coil per cylinder ignition can fire a very lean mixture at part throttle cruise.

[Racprops]

There are few questions to converting my Vans PCM to operate the TPI.

I know of batch fires systems, they fire 4 injectors at a time. BUT I will need to know which four, as I understand it is two on one bank and two on the other bank per one branch of the batch.

Are there any other things I might need to know?

Rich

[dave w]

The TPI batch fire is wired for cylinders 1,3,5,7 and cylinders 2,4,6,8.

dave w

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=448&d=1322074853

[Racprops]

Sorry that seems wrong, that is all on one side and all on the other, I believe it is something like: 1,4,6,7 and then 3,2,8,5. Two on one bank and two on the other bank.

I just don't know the pattern for a Chevy V8.

Also it might be important which of the two TBI injectors are connected to which set of injectors but perhaps not?

Rich

[1project2many]

Dave is correct. Chevrolet engines have odd cylinder numbers on the left and even on the right. The banks of injectors are wired "left" and "right" or "odd" and "even."

When thinking of fuel delivery it helps to understand the time between intake valve closing and the intake valve re-opening is often used to help vaporize fuel. There are multiple ways the injectors are triggered. Both banks of injectors can be triggered with every ignition pulse. Alternating banks banks of injectors can be triggered with every ignition pulse, or both banks can be fired independently of ignition pulses.

[Racprops]

That makes sense, so what is the best for my 383??

Rich

[dave w]

It's always fun to talk about upgrading a fuel injection system. Typically, upgrading to a newer fuel injection system is better. Typically, upgrading to newer fuel injection system is more expensive. More often than not, gearhead-efi members upgrade fuel injection systems with a very limited budget.

Cost vs. Performance

OBD1 (1987 - 1995) is affordable and provides good performance.
OBD2 (1996 & newer) is less affordable, and usually performs better than OBD1.

The injector batch firing sequence for TPI is 1,3,5,7 and 2,4,6,8, ... that's a sun rise in the East and sun set in the West statement ... Meaning that is just the way it is.:thumbsup:

MPFI - could mean Multi Point Fuel Injector, or could mean Multi Port Fuel Injection. When I see MPFI I think "One Injector Per Cylinder".

Years ago, Edelbrock offered a TBI to MPFI conversion fuel injection system. The system included a new intake manifold with 8 injectors "One Injector Per Engine Cylinder", custom chip, and a 8 injector pigtail to replace the TBI injector Connectors. It was a good system, that worked well for stock engines or engines modified with the "Edelbrock Camshaft Package". The Eledrock system did not "UPGRADE" the computer electronics for optimal injector firing. Link to the Edelbrock TBI to MPFI installation manual: https://static.summitracing.com/global/images/instructions/edl-35013502-performermulti-poin.pdf

The .pdf file posted above is a "How to OPTIMIZE" the 16168625 injector firing for MPFI - One Injector Per Cylinder.

Converting the 16168625 to MPFI has been very successful and a budget friendly upgrade for several gearhead-efi members.

dave w

[???]

the 7730 ecm only had one injector driver, so by batch fire they mean all 8 at a time. the 7749 had 2 drivers which is why they can be modified to do low impedance.

injector timing isn't all that important in a batch fire speed density setup with good quality small injectors. I think it means more when you're running big injectors with tiny open times at idle. that is where sequential injectors show good improvements in idle quality. but still not so much under load at higher rpm.

[Racprops]

Sorry to buck, I knew of a Caddy that had such a set up of two on one bank and two on the other.

I did not see the wiring diagram before...interesting and informing.

So was what I read about the PCM in my 93 being a one year PCM correct?? If so is there a direct replacement that is better?

And can you commit on my ideas:

A few concerns in my case is all the major rewiring in my van, and as I understand things at this point, the OBDII Systems are very hard to get into to do tuning were the OBDI systems are basically wide open.

Also it seems much easily to enable the lean cruse system.

Lastly I want to tune for MPG and think a PCM with so called learning systems could fight and remove improvements in MPG to suit its core programing, where I think a OBDI system might be less able to reprogram fuel settings.

Also my Chip was already programed for a V8 350, in my van with its current drive train...once I make to changes to it and the PCM to run the TPI I believe it is all set to run my new engine.

Also where is the Lean Cruse function? In the Eprong or in the Main PCM?? I had a tuner years ago say he programed a Lean Cruse into my eprong, even sent a tail pipe sniffer to refine it.

Was that on the level?? It did not seem to make any changes and MPG did not change.

Your opinions?

Thanks for helping me with this.

Rich

[Fast355]

That makes sense, so what is the best for my 383??

Rich

0411 sequential injection with coil per cylinder and a dual plane intake converted to EFI will make the most off-idle torque and give the best mileage. TPI is counter productive to torque in the RPM range you are looking to run. They are great for midrange in the 2,800-4,000 rpm range, not so good anywhere else.

I enable lean cruise all the time on 0411s.

The edelbrock TBI-MPFI intake would be great with an 0411 running it. Run the 0411 in speed density mode without the MAF. Then again your 4L60E would not play well with an 0411.

[Racprops]

Well in Car Craft’s May 1989 issue in their article TPI Shown Down: they tested a 1998 Corvette L96 with its aluminum heads, stock but for Edelbrock’s 6873 IROC Tubular Exhaust system running through a stock 88 Cat for the testing. This made 253HP 4500RPMs and 328 lbs-ft at 3000 to 3500 RPMs.

The tested on Edelbrock’s Superflow 901 Dyno, which was able to pull numbers every 5 seconds and at each 500RPMs from 2000 to 5000.

So this base line engine did the following:

Torque:

RPMs torque
2000 296
2500 313
3000 328
3500 328
4000 316

That was only a gain of 32 Ft-Lbs from 2000 to 3000, the peek.

The stock specs for that car was:

Horsepower 245 net @ 4300 RPM
Torque 340 lb. – ft. @ 3200 RPM


My stock Van G20 350 made:

Power 188 hp @ 3800 rpm.
Torque 300.19 lb.-ft. @ 2400 rpm.

I will be running a 383, 193 swill port heads, and a roller cam rated for 2200 RPM torque peek, which I plan on advancing 4 degrees, which should shift the power curve to 2000RPMc.

The cam specs of 1990–1992: Cadillac Brougham with 5.7 litres (350 cu in) L05/LLO FI V8,
Horsepower net: 175/185 hp (SAE net)

Torque net: 295 ft-lb @ apox 1800/1900 holds until 2300

To that I am adding a 383 and a tuned port system which is said to add 30% more Torque, HP and MPG to a stock engine.

So I should see 354 Ft-lb for a 350, how much more I will get with the 383 is not known but I bet it will be a little more. I found this: all other stuff left the same the difference between a 350 to a 383 a rough guesstimate is 35hp, 40 lb/ft torque.
So based on that I might see 394 ft-lb @ 2000 RPMs.




None the less is there any way to lower the tune port power curve??

Rich

[dave w]

Very minimal rewiring is needed to the G20 Van for OBD1 MPFI.

Extensive rewiring is needed for the OBD2 sequential fuel injection system unitizing MAF, MAP, and Coil On Plug.

The 16168625 MPFI injector wiring can be 4 cylinders Odd Bank then 4 cylinders Even Bank ... or ... 2 cylinder Odd Bank + 2 cylinder Even Bank then 2 cylinders Odd Bank + 2 cylinders Even Bank. There won't be any difference in performance.

The 1998 Corvette had engine option LS1.

In recent years, the LS 5.3 Liter has become the "Darling" engine to convert to. The internals of the 93 - 94 4L60E can be updated to allow using the "Darling '0411 OBD2 PCM."

dave w

[Racprops]

Well I am going for the simple and known set up, the Van's stock PCM and system has worked fine up to the oil lost.

So modifying it to run the TPI is the way I plan on going.

I got a TPI Fuel pump with one of my buys so I will test in the tank for pressure...

Once I mod the MedCal chip I take it as a V8 will work my system?

So other that some simple wiring I believe I am almost good to go.

Rich

[Racprops]

A couple of new questions about SD /MAP sensors.

One as I will be using my vans stock OBDI TBI PCM modified to MPFI TPI: will the knock sensor work? I read somewhere a TPI knock sensor is different to a TBI version.

Two, as this system was a MAP system, where does the MAP sensor go?? I have hardly done anything with them.
It seems they are just mounted just about anywhere as it seems they do not need to be inside any part of the engine??

I wonder if the heat of under the hood can affect the pressure readings?

[Fast355]

A couple of new questions about SD /MAP sensors.

One as I will be using my vans stock OBDI TBI PCM modified to MPFI TPI: will the knock sensor work? I read somewhere a TPI knock sensor is different to a TBI version.

Two, as this system was a MAP system, where does the MAP sensor go?? I have hardly done anything with them.
It seems they are just mounted just about anywhere as it seems they do not need to be inside any part of the engine??

I wonder if the heat of under the hood can affect the pressure readings?

If you run the stock TBI computer the stock TBI knock sensor is the one to use.

MAP sensor bolts to a bracket that bolts to the passenger side rear of the TPI plenum. A short rubber elbow connects the MAP to the vacuum fitting on the plenum.

I had to mod the injector drivers by eliminating the current sense resistors and soldering a short piece of wire in place of each. After the chip was dialed in for the setup it ran really well. That being said I woke my old Vortec head TPI 383 out of its slumber, drove it around the country property and loaded it on a trailer with an otherwise stock TBI chip. Was a little rich on cold start but ran great even with the stock TBI programming. So I have faith that it will run on the stock TBI computer with hardware mods well enough for you to start the tuning process.

[Racprops]

Thanks on the knock sensor.

And the MAP sensor is too easy...


Now about the Injection system: "I had to mod the injector drivers by eliminating the current sense resistors and soldering a short piece of wire in place of each. After the chip was dialed in for the setup it ran really well."

What PCM were you using?? Can you tell me more on this??

And " Was a little rich on cold start" could that because of the 9th cold start injector?

I read somewhere of a system to cut in the 9th injector at WOT for MORE power...

Lastly "So I have faith that it will run on the stock TBI computer with hardware mods well enough for you to start the tuning process. " Good to know, and how much tuning was needed to get her dialed in?

How well did your 383 work out?

Thanks again for your help.

Rich








If you run the stock TBI computer the stock TBI knock sensor is the one to use.

MAP sensor bolts to a bracket that bolts to the passenger side rear of the TPI plenum. A short rubber elbow connects the MAP to the vacuum fitting on the plenum.

I had to mod the injector drivers by eliminating the current sense resistors and soldering a short piece of wire in place of each. After the chip was dialed in for the setup it ran really well. That being said I woke my old Vortec head TPI 383 out of its slumber, drove it around the country property and loaded it on a trailer with an otherwise stock TBI chip. Was a little rich on cold start but ran great even with the stock TBI programming. So I have faith that it will run on the stock TBI computer with hardware mods well enough for you to start the tuning process.

[Racprops]

New question: Have you used Rhoads lifters??

They now have roller lifters and I am very interested in using them in my engine.

The concept of making a cam into a broadband cam is a great idea, I would really like my engine to have a torque curve from 1500 to 3500RPM, giving it a great power as at 3500RPM HP should also be showing so it COULD run strong all the way to 4500/5000RPMs.

I am NOW looking into running a higher power cam and using Rhoads V-Max OE Roller lifters because they can give me my low RPM Torque and then allow the more power of a larger cam.

So if these are a good idea then I am looking for Chevy roller cam with these specs: (used would be good)

As close as possible to this: 184 to 206 intake duration 194 to 212 Exhaust duration, and 384 IT lift and 407 Ex lift.

Rich

[dave w]

New question: Have you used Rhoads lifters??
Rich

I have not used Rhoads Lifters.

I'm wondering how Rhoads Lifters will affect vacuum? If the vacuum signal is 100% consistent, then tuning will be predictable. The MAP sensor is used to control the fuel. If the vacuum signal going to the MAP is not consistent, then the fuel from the injectors will not be consistent either.

The future is a camless engine:
https://www.motortrend.com/news/is-the-era-of-the-camless-valvetrain-finally-upon-us-technologue/

https://www.youtube.com/watch?v=S3cFfM3r510

dave w

[Racprops]

Rhoads lifters have been around a long time. I have followed them slightly, but because of a failure to advertise better had ruled them out for two reasons.

First they fail to show that they make roller lifters on their own web page, so I had not known anything about these roller lifters.

Second they were reported to make some noise, clicking, and were reported to cause problems with knock sensors. So they were said to not work well with FI engines.

Lastly they seem to be love them or hate them reaction.

Sense it was suggested I run them by a person on Third Gen Camaro as he claimed a flat torque power band from 2000 to 4000 in a fuel injected Camaro, and when I asked was told he was running the newer Rhoads V-Max OE Roller Variable Duration Lifters, I have looked up reports of users.

It seems pure power nuts prefer not to run them as the want ALL the HP they can get and feel it is not there all across their power band. Others LOVE them for their use.

As advertised most use them to tame hot cams. Which they were mainly invented to do. Variable Duration Lifters, or variable cams are becoming in much use in newer engines so these ideas are used more.

I am looking into them to broaden my own power band, I am looking into the idea of having a power band from 1500 to say 3000/3500 at which point I believe HP would take over all the way to the max of 5000.

I talked with Jack Rhoads himself (son of Mr. Rhords) about what I wanted to do and he suggested as they can shift a cam down by 20% I get a nearly stock cam one with say 20% more duration so that I would have my low RPM torque and with his lifters then have the full power of said cam at higher RPMS.

I was a little concerned with the torque power band of my engine, it being from 1800 to 2300, I was worried it would kind of fall on its face dropping power over 2300, so these seems to solve that problem.

The new Rhoads V-Max OE Roller Variable Duration Roller Lifters seems to have fixed the two main problems that had me ruling them out, they are making rollers and there are only a slight chance or problems with Fuel injections and clicking noise.

From Jpegs wed site:

“For maximum increases in low-end torque, engine vacuum and improved idle quality, our newly developed and newly patented Rhoads V-Max OE Roller Variable Duration Lifters are the answer. They increase low-end torque and engine vacuum up to 50% more than Orginal Rhoads Lifters...and they rev higher too. This makes them the best choice for hot street, performance marine and all racing applications. Typical vacuum increases range between 3 to 5 inches at idle when used with bigger cams. They are fully adjustable and require an adjustable valve train. Adjustment is similar to solid lifters. Simply use a feeler gauge to adjust the exact amount of lift reduction you want, anywhere from .010" to .030", and that is exactly what you get at idle. Duration is reduced between 5 and 20 degrees at .050" lift depending on the adjustment. As the rpm increases, so does the lift and duration. Full restoration takes place at approximately 4000 rpm. For engines equipped with adjustable valve trains, Rhoads V-Max OE Roller Lifters are definitely the best choice. They are particularly suited for racing applications with vacuum rules. You can run more cam than your competition while still meeting vacuum requirements, giving you the performance advantage. They are also useful in allowing larger cams to be used in computer controlled engines without disrupting proper computer functions.

Super Lube Groove

This option adds maximum lubrication and valve train longevity and is available with either Original or V-Max design lifters. A patented groove runs down the entire length of the lifter, constantly injecting oil on vital wear surfaces where lifter and cam face meet, eliminating the need for costly grooving modifications to the lifter bores in the engine block. Best of all, this addition does not in any way alter Rhoads lifter performance.

https://www.jegs.com/p/Rhoads-Lifters/Rhoads-Hydraulic-V-Max-Lifters/813784/10002/-1”

So as I am sold on them the quest is for a stock mild cam as near as I can get to 184 to 206 intake duration 194 to 212 Exhaust duration, and 384 IT lift and 407 Ex lift.

OR perhaps a change to 1.6 lifters, IF I remember correctly they shift the duration by 20% and raise the lift.

Rich

[dave w]

I've had very good results using a low cost re-ground stock L31 Vortec 5.7 roller camshaft, re-manufactured roller lifters, and expensive 1.6 ratio roller tip rocker arms. To me very good results = 5.7 TBI engine accelerating a 5200 Lb. 4WD Pickup ... Zero to 60 MPH in just under 7 seconds. Custom Chip tuning required.

dave w

[Racprops]

I've had very good results using a low cost re-ground stock L31 Vortec 5.7 roller camshaft, re-manufactured roller lifters, and expensive 1.6 ratio roller tip rocker arms. To me very good results = 5.7 TBI engine accelerating a 5200 Lb. 4WD Pickup ... Zero to 60 MPH in just under 7 seconds. Custom Chip tuning required.

dave w

I read reground cam shafts do not last, but that was so true with flat lifters…are you saying your reground cam shaft have not gotten lost lobes??

If so, are yours coming from one company?? If so perhaps I should consider having my cam reground.

One of the concerns is the re-treatment on the surface.

And rather they can just up the duration and lift just a little bit.

Rich

[dave w]

I read reground cam shafts do not last, but that was so true with flat lifters…are you saying your reground cam shaft have not gotten lost lobes??

If so, are yours coming from one company?? If so perhaps I should consider having my cam reground.

One of the concerns is the re-treatment on the surface.

And rather they can just up the duration and lift just a little bit.

Rich

I've had 100% Success / ZERO% Failures with the re-ground camshafts I've purchased from Oregon Camshaft: http://www.oregoncamshaft.com/

dave w

[Racprops]

Thanks after a talk with a person named Ken at Oregoncamshaft, I mailed my old cam for a stronger cam regrind.

The cam I am getting is their strongest towing cam, with the following specs: 203 208 410 425 and 114 lobe, was told power range was 1000 to 4500RPMs.

I hope there is a program to show how an engine will run on the cam specs entered; all I have found is one that shows the cams specs like the photo:

I think I saw one that you inter all your engine specs and it would project how the engine would perform.

I am looking for one that will calculate the power curves, showing the torque curve and horse power curve at projected RPM.

Thanks.

Rich

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