EFI TBI Questions

StarDiero75

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Howdy guys,

I got a couple of questions here. Currently i have an Autolite 2100 on my 200 and I'd really like to go to one of the self learning TBI's like the Holley Sniper 2bbl or the 39001 Fitech 2bbl. Being that i have a DUI which is an HEI, I've been told it produces a dirty signal so this is not possible. I have also seen someone on here use a Fitech setup with his HEI. My question here is, if I'm not using timing control, is that still an issue? On the Fitech, it only has 4 connections: pump, key, power, tach. With the only connection to the dizzy being the tach, why couldn't i run it with an HEI? I'm kinda confused on that and i really don't want to have to spend another $400+ on a DSII and MSD module.

Thanks,
Ryan
 
Do it a step at a time. Get the EFI working then worry about timing control. Timing control can be done w/ both HEI and DSII for sure. They're both magnetic pickup distributors, and while not *recommended seem to work fine when implemented properly. That's what I'm going to do. One step at a time. Makes it easier to troubleshoot.
 
StarDiero75":q2s9yvlr said:
Howdy guys,

I got a couple of questions here. Currently i have an Autolite 2100 on my 200 and I'd really like to go to one of the self learning TBI's like the Holley Sniper 2bbl or the 39001 Fitech 2bbl. Being that i have a DUI which is an HEI, I've been told it produces a dirty signal so this is not possible. I have also seen someone on here use a Fitech setup with his HEI. My question here is, if I'm not using timing control, is that still an issue? On the Fitech, it only has 4 connections: pump, key, power, tach. With the only connection to the dizzy being the tach, why couldn't i run it with an HEI? I'm kinda confused on that and i really don't want to have to spend another $400+ on a DSII and MSD module.

Thanks,
Ryan
The HEI distributor has a tach signal connection.
The FiTech instructions clearly shows that W/O timing control the FiTech blue wire connects to the tach terminal of the HEI distributor.
 
pmuller9":20f73k9y said:
StarDiero75":20f73k9y said:
Howdy guys,

I got a couple of questions here. Currently i have an Autolite 2100 on my 200 and I'd really like to go to one of the self learning TBI's like the Holley Sniper 2bbl or the 39001 Fitech 2bbl. Being that i have a DUI which is an HEI, I've been told it produces a dirty signal so this is not possible. I have also seen someone on here use a Fitech setup with his HEI. My question here is, if I'm not using timing control, is that still an issue? On the Fitech, it only has 4 connections: pump, key, power, tach. With the only connection to the dizzy being the tach, why couldn't i run it with an HEI? I'm kinda confused on that and i really don't want to have to spend another $400+ on a DSII and MSD module.

Thanks,
Ryan
The HEI distributor has a tach signal connection.
The FiTech instructions clearly shows that W/O timing control the FiTech blue wire connects to the tach terminal of the HEI distributor.
Yes, i got that, but is it compatible? I don't plan on using timing control
 
Econoline":2sx2meem said:
Do it a step at a time. Get the EFI working then worry about timing control. Timing control can be done w/ both HEI and DSII for sure. They're both magnetic pickup distributors, and while not *recommended seem to work fine when implemented properly. That's what I'm going to do. One step at a time. Makes it easier to troubleshoot.
I don't plan on using timing control. Thats what I'm trying to get at, can i still use the EFI with the HEI if I'm not using timing control?
 
StarDiero75":zqamup7u said:
I don't plan on using timing control. Thats what I'm trying to get at, can i still use the EFI with the HEI if I'm not using timing control?
The FiTech installation instructions and the Holley Sniper instructions clearly says yes you can use the HEI tach signal to trigger the EFI unit without timing control.
I don't see anything as far as Q & A on their tech website that indicates a problem.
I would give their techs a call or email and ask the question.
 
StarDiero75":10513bqs said:
...Thats what I'm trying to get at, can i still use the EFI with the HEI if I'm not using timing control?

Yes. They use the tach output from the HEI for their rpm signal, nothing more.

Regarding EFI Timing Control, I have no idea about FiTech, but Holley recommends against having their Sniper control an HEI (it apparently can be done, but it's not easy and there are no guarantees it'll work)
 
Yes, it's basically a carburetor variably tuned to the afr. Venturi is meaningless b/c it doesn't rely on vacuum. That's why the same tbi unit can work on a VW or a 327. You could use points if you wanted to. Nothing changes on the ignition side. Whatever timing you've got now and advance curve will work the same.
 
That’s my setup. Fitech controls fueling and my HEI setup runs the ignition. The fitech gets its signal from the tach output. I run a second wire for my tach and twist the wire pair. Its worked fine over two plus years and 9k miles.
 
Excellent. This is what I've wanted to know. Thank you guys. I'll be looking into the Holley Sniper and Fitech. I know gus here has experience with the Fitech, does anyone have any with the Sniper? I was originally looking at the Sniper and was curious about how to pick which one?

Thanks,
Ryan
 
65coupei6":8z04j647 said:
OR / You know I love google.
Marco means VMdot com aahahahaaa
(y)
 
I've got almost a year experience with the Holley Sniper on a stock Chevy 350, glad to answer any questions you've got about the system.
 
pmuller9":3eto8eni said:
StarDiero75":3eto8eni said:
Excellent. This is what I've wanted to know. Thank you guys. I'll be looking into the Holley Sniper and Fitech. I know gus here has experience with the Fitech, does anyone have any with the Sniper? I was originally looking at the Sniper and was curious about how to pick which one?

Thanks,
Ryan
https://www.ford-trucks.com/forums/1557 ... st18225044
I actually already checked that one out. Neat build!
 
jamyers":2jzrea4b said:
I've got almost a year experience with the Holley Sniper on a stock Chevy 350, glad to answer any questions you've got about the system.
How was getting it all tuned up and dialed in? Did you have any issues? How'd you fix them?
 
hey star, check out the megasquirt systems available. you can build from scratch, or buy controller already built, and just wire up what you need. the system is quite flexible. you can use timing control or not. they are even getting into transmission control as well if you wan tot go that route by installing an electronically controlled trans in your car. check out this site;

http://megasquirt.info/
 
StarDiero75":lyxthimq said:
jamyers":lyxthimq said:
I've got almost a year experience with the Holley Sniper on a stock Chevy 350, glad to answer any questions you've got about the system.
How was getting it all tuned up and dialed in? Did you have any issues? How'd you fix them?

These are the things that I've learned, mostly from experience ('cause I'm sometimes a moron) :banghead: :banghead: :banghead:

Installation:
1. Make DAMSHURE your ignition system is 100% from top to bottom - the slightest ignition misfire will be amplified by EFI because it will interpret it as a lean condition, add fuel, foul the plugs, misfire more, interpret it as a lean condition, add fuel, misfire more, etc, etc, etc.

2. Make DAMSHURE your exhaust has ZERO leaks. The slightest crack / loose fastener will let outside air in (and I thought exhaust gasses only leaked out, silly boy), and the EFI will then think it's too lean, add fuel, etc, etc, etc.

3. Pay CLOSE attention to the wiring instructions, and go overboard on the quality of connections, the number of grounds, and wire routing - keep it AWAY from the alternator and sparkplug wires - Holley (and I don't think anybody else) does NOT do a great job shielding their systems from EMI/RFI, which will cause all sorts of havoc with the system.

4. One thing that the all kinda gloss over is the "Target A/F Ratios". They'll say something like "enter your Target AFRs here..." then move right on. The thing is, the Target AFR is going to be unique to each engine, and a difference of .2 can make a major difference (especially at idle, where EFI seems to like a much richer AFR than you'd think (ours is 13.0 AFR, 600rpm, 23' vacuum). My suggestion is to search the internet for Idle, Cruise, and WOT AFR ratios for similar engines, but those are only starting points - you've got to experiment and see what your engine likes best - which takes time and some driving around.

5. Once you get the system installed, started, and some halfway-decent Target AFRs entered, it's a pretty darned good upgrade - starts as fast as the best carb engine I've ever had (1/2 second cold starts, just bump the starter when warm). Idle is dead smooth, and driving is very nice. Gas mileage in our '69 Chevy C10 (stock 350, 700R4, 3.73 gears) went from averaging 10-11 to 13-14.

6. The Holley Sniper online forums are pretty good, just be ready for people to tell you to make sure your grounds, wiring, etc are good first. Lots of good info there (like OEM replacement part numbers for sensors, etc), just keep in mind that the Target AFR is the "King" of the whole system.

7. EFI in General CONS: * cost, *complexity (troubleshooting can be a real PITA,

8. Holley Sniper CONS: *less than great EMI/RFI shielding, * some components aren't highest quality (like the temp sensor, pressure regulator)

Other stray thoughts...
* get some spare components to keep on hand for replacement or troubleshooting: TPS, IAC, O2, Temp sensor, etc. Some parts may be OEM, but (like the IAC) won't be stocked on hand at your local store.
* I'd recommend getting an in-tank fuel pump over an inline external one. We got the external one, and it's noisy (plus we murdered it recently (not the pumps fault), so we're switching to an intank pump which should longer, be less likely to be murdered, be quieter, etc. The kits people sell seem overpriced to me - I'd think you could source the AN fittings, hose, clamps, pump, etc online for a good bit less.

* Oh, and if you decide to get a Holley, I *strongly* recommend getting it through https://www.efisystempro.com/
They've often got great deals, and they are known for their after-the-sale support.
 
jamyers":3sec6anl said:
StarDiero75":3sec6anl said:
jamyers":3sec6anl said:
I've got almost a year experience with the Holley Sniper on a stock Chevy 350, glad to answer any questions you've got about the system.
How was getting it all tuned up and dialed in? Did you have any issues? How'd you fix them?

These are the things that I've learned, mostly from experience ('cause I'm sometimes a moron) :banghead: :banghead: :banghead:

Installation:
1. Make DAMSHURE your ignition system is 100% from top to bottom - the slightest ignition misfire will be amplified by EFI because it will interpret it as a lean condition, add fuel, foul the plugs, misfire more, interpret it as a lean condition, add fuel, misfire more, etc, etc, etc.

2. Make DAMSHURE your exhaust has ZERO leaks. The slightest crack / loose fastener will let outside air in (and I thought exhaust gasses only leaked out, silly boy), and the EFI will then think it's too lean, add fuel, etc, etc, etc.

3. Pay CLOSE attention to the wiring instructions, and go overboard on the quality of connections, the number of grounds, and wire routing - keep it AWAY from the alternator and sparkplug wires - Holley (and I don't think anybody else) does NOT do a great job shielding their systems from EMI/RFI, which will cause all sorts of havoc with the system.

4. One thing that the all kinda gloss over is the "Target A/F Ratios". They'll say something like "enter your Target AFRs here..." then move right on. The thing is, the Target AFR is going to be unique to each engine, and a difference of .2 can make a major difference (especially at idle, where EFI seems to like a much richer AFR than you'd think (ours is 13.0 AFR, 600rpm, 23' vacuum). My suggestion is to search the internet for Idle, Cruise, and WOT AFR ratios for similar engines, but those are only starting points - you've got to experiment and see what your engine likes best - which takes time and some driving around.

5. Once you get the system installed, started, and some halfway-decent Target AFRs entered, it's a pretty darned good upgrade - starts as fast as the best carb engine I've ever had (1/2 second cold starts, just bump the starter when warm). Idle is dead smooth, and driving is very nice. Gas mileage in our '69 Chevy C10 (stock 350, 700R4, 3.73 gears) went from averaging 10-11 to 13-14.

6. The Holley Sniper online forums are pretty good, just be ready for people to tell you to make sure your grounds, wiring, etc are good first. Lots of good info there (like OEM replacement part numbers for sensors, etc), just keep in mind that the Target AFR is the "King" of the whole system.

7. EFI in General CONS: * cost, *complexity (troubleshooting can be a real PITA,

8. Holley Sniper CONS: *less than great EMI/RFI shielding, * some components aren't highest quality (like the temp sensor, pressure regulator)

Other stray thoughts...
* get some spare components to keep on hand for replacement or troubleshooting: TPS, IAC, O2, Temp sensor, etc. Some parts may be OEM, but (like the IAC) won't be stocked on hand at your local store.
* I'd recommend getting an in-tank fuel pump over an inline external one. We got the external one, and it's noisy (plus we murdered it recently (not the pumps fault), so we're switching to an intank pump which should longer, be less likely to be murdered, be quieter, etc. The kits people sell seem overpriced to me - I'd think you could source the AN fittings, hose, clamps, pump, etc online for a good bit less.

* Oh, and if you decide to get a Holley, I *strongly* recommend getting it through https://www.efisystempro.com/
They've often got great deals, and they are known for their after-the-sale support.
Man appreciate all that. Thats a lot of info and its all stuff i definitely woulda ended up posting about lol. Especially the exhaust leak and possibly ignition. I will definitely be looking into EFI here when I can afford it. I'm looking at the complete kit and on on the EFI system pro, its about $1200ish. Thats not bad for everything. but big initial investment. I'm definitely tired of screwing with these 2bbls. I almost feel like I had less issues with my Holley 1904, but the 1904 don't spin the tires lol. If you think of anything else feel free to add it man. I want my good gas mileage, smooth and consistent idle, a choke that doesn't come off super early, and no vapor lock.

Thanks again and keep it coming,
Ryan
 
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