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Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
Not suprising at all, but it can be done cheaper by investing in a Prom Burner.
I have seen alot of TBI conversions run by the tach signal.
PS- I am not knocking your work at all, just giving an alternative for everyone else.
My Oldsmobile 307 TBI conversion runs on a CCC Q-Jet large cap HEI.
I know it may not seem like a big deal, but with lack of performance distributors for CC tbi cars. and with the numerous non-cc distributors being made for carbed cars. i figured this was an easy way to gain performance, and tunability without a laptop. not to mention i can hook up an ignition box such as MSD alot easier with this setup. it was quite a challenge to get this to work the right way. mainly because the way it's wired
Id love to convert over. the stock ignition system has always been an issue due to the lack of decent replacement parts. The only thing is that Id no longer have the flexibility of using the computer to control the timing. With the computer, setting the timing curve for the idle and open throttle is basically nothing more then banging on a keyboard for a few minutes. This and theres also alot more functionality for startup, idle speed control, and for preventing detonation.
Does anyone make any reasonably priced afterkmarkets that can be controlled by the computer?
The earlier HEIs work by the exact same basic principles as the later computer controlled ones. You won't find that a non-computer controlled HEI has any more juice than a computer controlled one. However, lacking a way of programming a computer controlled one it would certainly be a way of getting timing adjustment back to basic mechanical systems- springs, weights, vacuum advance. Given that the STOCK ignition curve on a TBI engine is rather weak and leaves a lot of performance on the table, I can imagine that going back to a early HEI and dialing in the timing curve could probably make the engine quite a bit stronger. Like was mentioned above, however, nothing that couldn't be done just as well or better by programming the computer controlled HEI's timing curve better than the stock programming.
My beef with the stock system is that there is no support. The only parts available are junk and constantly go dead. It sucks because its easier to tune and more flexible then using a non-CC HEI dist.
Ryan the mechanical HEI is rather large and would probably not fit behind the manifold. and so far i've tuned my hei for my car. and i can definatly tell you it woke my car up grately. i notice the most gain under 4000rpm. mainly cuz of the way the advance comes in kinda agressivly and where i want it. my car wouldn't spin the tires off the line more then 5 feet in the past. now it has the torque to spin them throughout 1st gear. The main reason i went mechanical is manily cuz i'm not a big fan of electronic stuff. but thats my own opinion.
My beef with the stock system is that there is no support. The only parts available are junk and constantly go dead. It sucks because its easier to tune and more flexible then using a non-CC HEI dist.
Dimented, have you tried GM stuff for the ignition module & shaft? I've found that the GM stuff does the job. I'll even buy a distributor from the junkyard if it has a GM ignition module. The other GM important part is the shaft with the 'star wheel' on it. The pickup coils I've gotten at places like NAPA & Car Quest.
When you convert a non-computer controlled large cap HEI over to an MSD box you bypass/remove the module completely. Wired striaght into the mag pickup. Very different install than with computer control.
Don't know. If he can trick the ECM into thinking the original distributor is still there, as he claims, then the ECM wouldn't know you put an MSD box on the actual distributor that's running the motor. Once the ECM is "blind" to the actual distributor that's running the motor it really wouldn't matter whether you added an MSD to it or not.
I'd like to know how he did it. Maybe he'll post it up for all to see.
I've been having trouble getting my scanner to work but if i can figure out how to post a picture of my wiring diagram i'll take a picture of it and upload it...anyone know how?
so i attemped this got it it runs amazing but im having one issue, the fuel pump wont prime and starts up like its fully carburetor in the winter! i was curious if anyone else who has did this doing the same? does this to after switching the distributor or if one of my wires r connections r just poor. i also have the base timing set at 4 degrees advanced which is stock because im trying to pass emissions.
D.U.I makes a computer controlled HEI distrubutor for the TPI cars. Im sure it'll fit in tbi cars. Is that what some of yall are needed? Summit sells them. If that's not what you meant sorry for wasting a post spot.
I have seen alot of TBI conversions run by the tach signal.
Bumping an OLD thread. The above quote has me curious.
Say I have an old school SBC with an HEI vacuum advance, coil in cap dizzy. Electronic ignition, not points. OK, now I want to put a TBI (1227747) setup on it to control fuel only, and leave the HEI alone.
Can I do this without running a 2nd ICM as discussed above? ECM needs to know RPM to run the injectors. Like, can I just run a signal off the tach wire to a pin on the ECM? Or does it need some conditioning? ECM has 4 pins: EST, Reference, bypass, Reflow. Can I just hook pin D4 (EST) to the tach side of the coil?
I know Howell makes a TBI unit (For Fords, Jeeps, etc) that does only fuel, uses a 1227747 ECM, and uses 1 wire to the ECM for tach signal. I'm trying to figure out how they do it, so I can do the same with a factory harness.
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
Interesting thread. I'm not used to seeing that much questionable or outright wrong information in one place, unless it involves air intake via open-element or "warm-air induction".
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
I know this is a really old thread, but maybe a little bit better pic to read for someone.
I don't understand this. The large-cap HEI module typically has four "blade" connections (plus the "hidden" ground connection to the distributor via one of the module hold-down screws.)
Two for the pickup coil, labeled W and G on the module, connected to White and Green wires from the pickup coil.
Module B+ which is also ignition coil B+ or "BATtery".
Module C- which is also ignition coil C-, or the TACH terminal on the side of the cap. (you get a spark from the coil when the module opens the C- circuit.)
Your diagram is missing the + and - wires to the ignition coil. In your diagram, the C- from the "New HEI Distributor Control Module" is connected to the PCM. I don't think this is correct. It should connect to the coil C- (TACH) terminal. There should be another splice in the B+ circuit, going to ignition coil B+ (BAT). Now the "new HEI" module controls the coil.
The whole point of running two modules is so that the OEM, computer-controlled system can "dry-fire"; it works as normal but it's not connected to an ignition coil. It's just along for the ride, so that the computer thinks it's functional. While the computer-controlled module ***********, the 4-pin HEI module actually controls the coil, so that the centrifugal and vacuum advance affect spark timing instead of the computer--which is too stupid to know what's really going on.
This is really clever. I'd have never thought of it independently; although I did read about it on another forum. The only questionable part is whether the pickup coil can provide enough power to activate two loads instead of just one; and apparently it can--but I bet at low cranking rpm (cold weather, thick oil, low battery voltage) all bets are off.
Last edited by Schurkey; Nov 22, 2019 at 10:51 PM.
I don't understand this. The large-cap HEI module typically has four "blade" connections (plus the "hidden" ground connection to the distributor via one of the module hold-down screws.)
Two for the pickup coil, labeled W and G on the module, connected to White and Green wires from the pickup coil.
Module B+ which is also ignition coil B+ or "BATtery".
Module C- which is also ignition coil C-, or the TACH terminal on the side of the cap. (you get a spark from the coil when the module opens the C- circuit.)
Your diagram is missing the + and - wires to the ignition coil. In your diagram, the C- is connected to the PCM.
Take a look at post #16. It's the same thing, just made it easier to understand. If it's wrong and I didn't verify it, then the OP was wrong. Sorry.
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
I would like to see wire diagram doing the swap on my 95 chevy
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
I have a 1992 silverado with TBI Im trying to use a HEI distribuitor, can yoh send me the wire harness diagram please.
Thank you
That's clearly what they are asking to do. Adapt a vacuum/centrifugal non-ESC distributor. I doubt they even know that large cap ESC distributors exist.
That's clearly what they are asking to do. Adapt a vacuum/centrifugal non-ESC distributor. I doubt they even know that large cap ESC distributors exist.
GD
Wouldn't matter. The point is to get the ignition advance controlled via a mechanism they can "tune", instead of having to re-program a computer, which they can't. (No offense, I can't reprogram either.)
So to get "achievable" advance tuning, but NOT activate the "check engine" light, they use both modules, one to actually create sparks, and one to hand-job the computer to keep it happy.
Are people still this computer illiterate? i mean hell at a minimum get an msd box that is completely programmable based on map, tps, and rpm. especially for a street car.
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
Can you Send me the diagram please i really want to do this thank you
Well i have discovered a way to use a performance ignition with my stock TBI. and what a diffrence it made! if anyone is intersted in how i accomplished this let me know i can send my wiring digram of how i trick the PCM into thinking there is a stock distributor there. my engine revs so much quicker, and because of the advance curve feels like it has more power at low rpms.
How did you do that can you send me a wire diagram of how I can run HEI distributer to my TBI carburetor... please and thank you!!!
[QUOTE=Schurkey;6340832]No entiendo esto. El módulo HEI de gran capacidad generalmente tiene cuatro conexiones de "cuchilla" (más la conexión a tierra "oculta" al distribuidor a través de uno de los tornillos de sujeción del módulo).
Dos para la bobina captadora, etiquetadas como W y G en el módulo, conectadas a los cables blanco y verde de la bobina captadora.
Módulo B+ que también es bobina de encendido B+ o "BATtery".
Módulo C- que también es bobina de encendido C-, o el terminal TACH en el costado de la tapa. (Obtiene una chispa de la bobina cuando el módulo abre el circuito C).
A su diagrama le faltan los cables + y - a la bobina de encendido. En su diagrama, el C- del "Nuevo módulo de control del distribuidor HEI" está conectado al PCM. No creo que esto sea correcto. Debe conectarse al terminal C- (TACH) de la bobina. Debería haber otro empalme en el circuito B+, yendo a la bobina de encendido B+ (BAT). Ahora el módulo "nuevo HEI" controla la bobina.
El objetivo de ejecutar dos módulos es que el sistema OEM controlado por computadora pueda "disparar en seco"; funciona normalmente pero no está conectado a una bobina de encendido. Es solo para el viaje, por lo que la computadora piensa que es funcional. Mientras que el módulo controlado por computadora se masturba, el módulo HEI de 4 pines en realidad controla la bobina, de modo que el avance centrífugo y de vacío afecta el tiempo de chispa en lugar de la computadora, lo cual es demasiado estúpido para saber lo que realmente está pasando.
Esto es realmente inteligente. Nunca lo habría pensado de forma independiente; aunque lo leí en otro foro. La única parte cuestionable es si la bobina captadora puede proporcionar suficiente energía para activar dos cargas en lugar de solo una; y aparentemente puede, pero apuesto a que a bajas revoluciones de arranque (clima frío, aceite espeso, bajo voltaje de la batería) todas las apuestas están descartadas.[/CITA
]hello I have the same problem
i removed an electronic distributor and installed an HEI distributor these are my steps
1 cut the pink or red wire and put it in the battery.
