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TBI Questions & Google Groups

JB
Jess Bressi
Mon, Mar 28, 2022 9:03 PM

Greetings all, I have some questions that perhaps you have answers to. I would direct these to the Google Howell group but it is not accepting new
members or is without an administrator. The context is I am installing a new to me Howell TBI system with embedded locker on my 455. BTW, I swapped
out the Holley TB for a GM from a 454 Chevy.
Question 1: I've tried to obtain access to both of the Howell-related Google Group sites dedicated to the Howell systems. I've received no response to
several requests for access rights.  Is there no "owner" or "administrator" taking care of them right now?  Suggestions?
Question 2:  Has anyone used Applied GMC's small surge tank with a FI system?  Did you plumb the bleeder valve output with a "tee" to your TB's fuel
return line?  Did you add a check valve?
Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan setups sold by Applied.  Has anyone used the fan output of the ECM to control a
relay powering the MB fan clutch?  Any issues?
Question 4: What are folks experiences in the ability of the built-in GM fuel regulator to deal with the higher pressure output of the TBI's fuel
pump, example an Airtex 2182?  Anyone modify their TBI to make the fuel regulator adjustable or add an external one?
Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB O2 sensor? It appears to me I'd just need ot add switched 12v power and
ground. Will the ECM accept the WB without re programing?
Many thanks, Jess

Jess Bressi
Orange County, CA
1972 and 1974 Cortez's
455's/3.70's/Patterson Q-Jets

Greetings all, I have some questions that perhaps you have answers to. I would direct these to the Google Howell group but it is not accepting new members or is without an administrator. The context is I am installing a new to me Howell TBI system with embedded locker on my 455. BTW, I swapped out the Holley TB for a GM from a 454 Chevy. Question 1: I've tried to obtain access to both of the Howell-related Google Group sites dedicated to the Howell systems. I've received no response to several requests for access rights. Is there no "owner" or "administrator" taking care of them right now? Suggestions? Question 2: Has anyone used Applied GMC's small surge tank with a FI system? Did you plumb the bleeder valve output with a "tee" to your TB's fuel return line? Did you add a check valve? Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan setups sold by Applied. Has anyone used the fan output of the ECM to control a relay powering the MB fan clutch? Any issues? Question 4: What are folks experiences in the ability of the built-in GM fuel regulator to deal with the higher pressure output of the TBI's fuel pump, example an Airtex 2182? Anyone modify their TBI to make the fuel regulator adjustable or add an external one? Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB O2 sensor? It appears to me I'd just need ot add switched 12v power and ground. Will the ECM accept the WB without re programing? Many thanks, Jess -- Jess Bressi Orange County, CA 1972 and 1974 Cortez's 455's/3.70's/Patterson Q-Jets
C
CJV
Mon, Mar 28, 2022 9:16 PM

Great questions! I too would like some answers....

CJ Vermeulen, Scribbler

From: "Jess Bressi" jbressi@cox.net
To: "gmclist" gmclist@list.gmcnet.org
Sent: Monday, March 28, 2022 4:03:09 PM
Subject: [GMCnet] TBI Questions & Google Groups

Greetings all, I have some questions that perhaps you have answers to. I would direct these to the Google Howell group but it is not accepting new
members or is without an administrator. The context is I am installing a new to me Howell TBI system with embedded locker on my 455. BTW, I swapped
out the Holley TB for a GM from a 454 Chevy.
Question 1: I've tried to obtain access to both of the Howell-related Google Group sites dedicated to the Howell systems. I've received no response to
several requests for access rights. Is there no "owner" or "administrator" taking care of them right now? Suggestions?
Question 2: Has anyone used Applied GMC's small surge tank with a FI system? Did you plumb the bleeder valve output with a "tee" to your TB's fuel
return line? Did you add a check valve?
Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan setups sold by Applied. Has anyone used the fan output of the ECM to control a
relay powering the MB fan clutch? Any issues?
Question 4: What are folks experiences in the ability of the built-in GM fuel regulator to deal with the higher pressure output of the TBI's fuel
pump, example an Airtex 2182? Anyone modify their TBI to make the fuel regulator adjustable or add an external one?
Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB O2 sensor? It appears to me I'd just need ot add switched 12v power and
ground. Will the ECM accept the WB without re programing?
Many thanks, Jess

Jess Bressi
Orange County, CA
1972 and 1974 Cortez's
455's/3.70's/Patterson Q-Jets


GMCnet mailing list
Unsubscribe or Change List Options:

Great questions! I too would like some answers.... CJ Vermeulen, Scribbler From: "Jess Bressi" <jbressi@cox.net> To: "gmclist" <gmclist@list.gmcnet.org> Sent: Monday, March 28, 2022 4:03:09 PM Subject: [GMCnet] TBI Questions & Google Groups Greetings all, I have some questions that perhaps you have answers to. I would direct these to the Google Howell group but it is not accepting new members or is without an administrator. The context is I am installing a new to me Howell TBI system with embedded locker on my 455. BTW, I swapped out the Holley TB for a GM from a 454 Chevy. Question 1: I've tried to obtain access to both of the Howell-related Google Group sites dedicated to the Howell systems. I've received no response to several requests for access rights. Is there no "owner" or "administrator" taking care of them right now? Suggestions? Question 2: Has anyone used Applied GMC's small surge tank with a FI system? Did you plumb the bleeder valve output with a "tee" to your TB's fuel return line? Did you add a check valve? Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan setups sold by Applied. Has anyone used the fan output of the ECM to control a relay powering the MB fan clutch? Any issues? Question 4: What are folks experiences in the ability of the built-in GM fuel regulator to deal with the higher pressure output of the TBI's fuel pump, example an Airtex 2182? Anyone modify their TBI to make the fuel regulator adjustable or add an external one? Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB O2 sensor? It appears to me I'd just need ot add switched 12v power and ground. Will the ECM accept the WB without re programing? Many thanks, Jess -- Jess Bressi Orange County, CA 1972 and 1974 Cortez's 455's/3.70's/Patterson Q-Jets _______________________________________________ GMCnet mailing list Unsubscribe or Change List Options:
JR
Jon Roche
Mon, Mar 28, 2022 11:20 PM

Let me look into why you cant get in the group.  I am traveling,  and they did make some changes a few months ago.

Wide band o2 is a function of the dynamic ebl system.

--
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/

Let me look into why you cant get in the group. I am traveling, and they did make some changes a few months ago. Wide band o2 is a function of the dynamic ebl system. -- Jon Roche 75 palm beach EBL EFI, manny headers, Micro Level, rebuilt most of coach now. St. Cloud, MN http://lqqkatjon.blogspot.com/
KH
Kenneth Henderson
Mon, Mar 28, 2022 11:24 PM

I've just approved 4 pending GMCMH-EFI membership requests.  I did not
approve a 5th one because there was no indication in its request of any
GMCMH association -- a mandatory requirement.  I apologize for the delay in
approving requests.  For a long time, I got an email notification every
time someone applied for membership and could immediately, in one or two
steps, approve/disapprove the request.  Then Google stopped sending those
notifications.  Now, they've made it even worse:  Instead of merely acting
on the request, I must copy the name and address, change to another web
page, enter that information (in another, never described, format, type a
greeting message (can't keep one), and execute several other steps.  TOO
MUCH TROUBLE, GOOGLE!  :-)

Welcome aboard, all 4 of you (I HOPE).

Ken H.

On Mon, Mar 28, 2022 at 5:16 PM CJV janvlen@mymts.net wrote:

Great questions! I too would like some answers....

CJ Vermeulen, Scribbler

From: "Jess Bressi" jbressi@cox.net
To: "gmclist" gmclist@list.gmcnet.org
Sent: Monday, March 28, 2022 4:03:09 PM
Subject: [GMCnet] TBI Questions & Google Groups

Greetings all, I have some questions that perhaps you have answers to. I
would direct these to the Google Howell group but it is not accepting new
members or is without an administrator. The context is I am installing a
new to me Howell TBI system with embedded locker on my 455. BTW, I swapped
out the Holley TB for a GM from a 454 Chevy.
Question 1: I've tried to obtain access to both of the Howell-related
Google Group sites dedicated to the Howell systems. I've received no
response to
several requests for access rights. Is there no "owner" or "administrator"
taking care of them right now? Suggestions?
Question 2: Has anyone used Applied GMC's small surge tank with a FI
system? Did you plumb the bleeder valve output with a "tee" to your TB's
fuel
return line? Did you add a check valve?
Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan
setups sold by Applied. Has anyone used the fan output of the ECM to
control a
relay powering the MB fan clutch? Any issues?
Question 4: What are folks experiences in the ability of the built-in GM
fuel regulator to deal with the higher pressure output of the TBI's fuel
pump, example an Airtex 2182? Anyone modify their TBI to make the fuel
regulator adjustable or add an external one?
Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB
O2 sensor? It appears to me I'd just need ot add switched 12v power and
ground. Will the ECM accept the WB without re programing?
Many thanks, Jess

Jess Bressi
Orange County, CA
1972 and 1974 Cortez's
455's/3.70's/Patterson Q-Jets


GMCnet mailing list
Unsubscribe or Change List Options:


GMCnet mailing list
Unsubscribe or Change List Options:

I've just approved 4 pending GMCMH-EFI membership requests. I did not approve a 5th one because there was no indication in its request of any GMCMH association -- a mandatory requirement. I apologize for the delay in approving requests. For a long time, I got an email notification every time someone applied for membership and could immediately, in one or two steps, approve/disapprove the request. Then Google stopped sending those notifications. Now, they've made it even worse: Instead of merely acting on the request, I must copy the name and address, change to another web page, enter that information (in another, never described, format, type a greeting message (can't keep one), and execute several other steps. TOO MUCH TROUBLE, GOOGLE! :-) Welcome aboard, all 4 of you (I HOPE). Ken H. On Mon, Mar 28, 2022 at 5:16 PM CJV <janvlen@mymts.net> wrote: > Great questions! I too would like some answers.... > > CJ Vermeulen, Scribbler > > > From: "Jess Bressi" <jbressi@cox.net> > To: "gmclist" <gmclist@list.gmcnet.org> > Sent: Monday, March 28, 2022 4:03:09 PM > Subject: [GMCnet] TBI Questions & Google Groups > > Greetings all, I have some questions that perhaps you have answers to. I > would direct these to the Google Howell group but it is not accepting new > members or is without an administrator. The context is I am installing a > new to me Howell TBI system with embedded locker on my 455. BTW, I swapped > out the Holley TB for a GM from a 454 Chevy. > Question 1: I've tried to obtain access to both of the Howell-related > Google Group sites dedicated to the Howell systems. I've received no > response to > several requests for access rights. Is there no "owner" or "administrator" > taking care of them right now? Suggestions? > Question 2: Has anyone used Applied GMC's small surge tank with a FI > system? Did you plumb the bleeder valve output with a "tee" to your TB's > fuel > return line? Did you add a check valve? > Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan > setups sold by Applied. Has anyone used the fan output of the ECM to > control a > relay powering the MB fan clutch? Any issues? > Question 4: What are folks experiences in the ability of the built-in GM > fuel regulator to deal with the higher pressure output of the TBI's fuel > pump, example an Airtex 2182? Anyone modify their TBI to make the fuel > regulator adjustable or add an external one? > Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB > O2 sensor? It appears to me I'd just need ot add switched 12v power and > ground. Will the ECM accept the WB without re programing? > Many thanks, Jess > -- > Jess Bressi > Orange County, CA > 1972 and 1974 Cortez's > 455's/3.70's/Patterson Q-Jets > _______________________________________________ > GMCnet mailing list > Unsubscribe or Change List Options: > _______________________________________________ > GMCnet mailing list > Unsubscribe or Change List Options: >
RV
Randy Van Winkle
Tue, Mar 29, 2022 4:10 AM

Jess Bressi Cortez wrote on Mon, 28 March 2022 16:03

Greetings all, I have some questions that perhaps you have answers to. I would direct these to the Google Howell group but it is not accepting new
members or is without an administrator. The context is I am installing a new to me Howell TBI system with embedded locker on my 455. BTW, I swapped
out the Holley TB for a GM from a 454 Chevy.
Question 1: I've tried to obtain access to both of the Howell-related Google Group sites dedicated to the Howell systems. I've received no
response to several requests for access rights.  Is there no "owner" or "administrator" taking care of them right now?  Suggestions?
Question 2:  Has anyone used Applied GMC's small surge tank with a FI system?  Did you plumb the bleeder valve output with a "tee" to your TB's
fuel return line?  Did you add a check valve?
Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan setups sold by Applied.  Has anyone used the fan output of the ECM to
control a relay powering the MB fan clutch?  Any issues?
Question 4: What are folks experiences in the ability of the built-in GM fuel regulator to deal with the higher pressure output of the TBI's fuel
pump, example an Airtex 2182?  Anyone modify their TBI to make the fuel regulator adjustable or add an external one?
Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB O2 sensor? It appears to me I'd just need ot add switched 12v power and
ground. Will the ECM accept the WB without re programing?
Many thanks, Jess

Question 1:  I think Ken Henderson addressed this issue.  I also use to get those notifications but have not been getting those.

Question 2:  I do not know of anyone using that surge tank.  Should not be a problem to use.  Personally, I do not think a surge tank is needed. My
approach is to get complexity to a minimum.  I always recommend two fuel pumps with each pump having its own filter. That way you always have built-in
redundancy.  If one pump or filter goes bad switch to the other and finish your trip and fix it when you get home.  I've only had a couple of
experiences where I had a slight stumble on a corner when I was almost empty in both tanks. One should never get that low on fuel or run the risk of
being on the side of the road waiting to get enough fuel to get going again.

Question 3:  Yes, there are several using the EBL to control the MB electronic clutch fans.  This is a relatively easy hook-up and requires a couple
of parameter changes to the programming to set the on temp and off temp.

Question 4:  This answer depends on the Throttle Body.  If using the Howell system, it has an adjustable regulator.  It can become a little
temperamental above 18 or 19 psi but can be set to satisfy our engines.  The Rochester TB has a fixed pressure regulator and is designed to regulate
fuel pressure from a high-pressure pump to the correct pressure for the system.  Sometimes the springs get weakened with age - new springs are
available. I believe some people have modified the setup to make it adjustable.  However, that is usually not necessary because the regulator is set
to the appropriate pressure for the injectors used in the Throttle Body.
Question 5:  The ECM requires a NB O2 Sensor input for it to properly adjust the fuel mixture. Some WB O2 sensors can provide a NB input to the ECM
but I don't recommend that because I don't believe that is as reliable as the NB.  A separate WB-O2 sensor can be added and the EBL will display this
output on the What's Up Display.  Also, the EBL can use WB-O2 sensor input for more in-depth tuning.  I find that this is more for high-performance
tuning (hot-rodders) and not as effective for how we run our engines.  The basic self learn functions using BLM tables that the EBL does for
self-tuning is more than adequate for our needs.

Feel free to contact me directly if you have any further questions.  I have sent you a Private Message with contact information.

Randy & Margie
'77 Eleganza II '403'
Battlefield, MO

Jess Bressi Cortez wrote on Mon, 28 March 2022 16:03 > Greetings all, I have some questions that perhaps you have answers to. I would direct these to the Google Howell group but it is not accepting new > members or is without an administrator. The context is I am installing a new to me Howell TBI system with embedded locker on my 455. BTW, I swapped > out the Holley TB for a GM from a 454 Chevy. > Question 1: I've tried to obtain access to both of the Howell-related Google Group sites dedicated to the Howell systems. I've received no > response to several requests for access rights. Is there no "owner" or "administrator" taking care of them right now? Suggestions? > Question 2: Has anyone used Applied GMC's small surge tank with a FI system? Did you plumb the bleeder valve output with a "tee" to your TB's > fuel return line? Did you add a check valve? > Question 3: I have one of Tom Pryor's MB Diesel electronic clutch fan setups sold by Applied. Has anyone used the fan output of the ECM to > control a relay powering the MB fan clutch? Any issues? > Question 4: What are folks experiences in the ability of the built-in GM fuel regulator to deal with the higher pressure output of the TBI's fuel > pump, example an Airtex 2182? Anyone modify their TBI to make the fuel regulator adjustable or add an external one? > Question 5: Anyone change from a one-wire NB O2 sensor to a three-wire WB O2 sensor? It appears to me I'd just need ot add switched 12v power and > ground. Will the ECM accept the WB without re programing? > Many thanks, Jess Question 1: I think Ken Henderson addressed this issue. I also use to get those notifications but have not been getting those. Question 2: I do not know of anyone using that surge tank. Should not be a problem to use. Personally, I do not think a surge tank is needed. My approach is to get complexity to a minimum. I always recommend two fuel pumps with each pump having its own filter. That way you always have built-in redundancy. If one pump or filter goes bad switch to the other and finish your trip and fix it when you get home. I've only had a couple of experiences where I had a slight stumble on a corner when I was almost empty in both tanks. One should never get that low on fuel or run the risk of being on the side of the road waiting to get enough fuel to get going again. Question 3: Yes, there are several using the EBL to control the MB electronic clutch fans. This is a relatively easy hook-up and requires a couple of parameter changes to the programming to set the on temp and off temp. Question 4: This answer depends on the Throttle Body. If using the Howell system, it has an adjustable regulator. It can become a little temperamental above 18 or 19 psi but can be set to satisfy our engines. The Rochester TB has a fixed pressure regulator and is designed to regulate fuel pressure from a high-pressure pump to the correct pressure for the system. Sometimes the springs get weakened with age - new springs are available. I believe some people have modified the setup to make it adjustable. However, that is usually not necessary because the regulator is set to the appropriate pressure for the injectors used in the Throttle Body. Question 5: The ECM requires a NB O2 Sensor input for it to properly adjust the fuel mixture. Some WB O2 sensors can provide a NB input to the ECM but I don't recommend that because I don't believe that is as reliable as the NB. A separate WB-O2 sensor can be added and the EBL will display this output on the What's Up Display. Also, the EBL can use WB-O2 sensor input for more in-depth tuning. I find that this is more for high-performance tuning (hot-rodders) and not as effective for how we run our engines. The basic self learn functions using BLM tables that the EBL does for self-tuning is more than adequate for our needs. Feel free to contact me directly if you have any further questions. I have sent you a Private Message with contact information. -- Randy & Margie '77 Eleganza II '403' Battlefield, MO
BH
Bruce Hislop
Tue, Mar 29, 2022 10:06 AM

For the Wide-Band O2 sensor, you can't just hook it directly to the EBL equipped 7747 ECM.  It needs to be connected to an interface box which takes
the WB O2 signal and outputs a linear 0-5 volt signal to the ECM.

http://dynamicefi.com/TT-1.php

I use Dynamic EFI's TT-1 Wide-Band kit.  I use it for displaying the actual Air Fuel Ratio (AFR) on the What's Up Display.  I use a separate Narrow
Band O2 sensor for the actual closed loop operation.

I have a Rochester TB and noticed when I first installed it the fuel pressure on on the low side, about 11.5PSI  if I recall.  I was able to turn the
adjusting screw (not easy) and got it up to near 13PSI.  It has slowly dropped over the years to about 12PSI now, so I'm going to look into a
replacement regulator spring as pointed out by Randy.

I also do not use a surge tank.  Once the fuel level gets to the 1/2 mark, I start looking for a gas station to refill.  By that time I've drive
200-250 miles, about 4 hours and I need a break too.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that

For the Wide-Band O2 sensor, you can't just hook it directly to the EBL equipped 7747 ECM. It needs to be connected to an interface box which takes the WB O2 signal and outputs a linear 0-5 volt signal to the ECM. http://dynamicefi.com/TT-1.php I use Dynamic EFI's TT-1 Wide-Band kit. I use it for displaying the actual Air Fuel Ratio (AFR) on the What's Up Display. I use a separate Narrow Band O2 sensor for the actual closed loop operation. I have a Rochester TB and noticed when I first installed it the fuel pressure on on the low side, about 11.5PSI if I recall. I was able to turn the adjusting screw (not easy) and got it up to near 13PSI. It has slowly dropped over the years to about 12PSI now, so I'm going to look into a replacement regulator spring as pointed out by Randy. I also do not use a surge tank. Once the fuel level gets to the 1/2 mark, I start looking for a gas station to refill. By that time I've drive 200-250 miles, about 4 hours and I need a break too. -- Bruce Hislop ON Canada 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001 My Staff says I never listen to them, or something like that
KV
Keith V
Tue, Mar 29, 2022 1:31 PM

I use a surge tank, I think it's worth it, but I'm an over engineering kinda guy.
I have 3 fuel pumps, 2 lift pumps that feed the surge tank and then the TBI pump that pulls from the surge tank. The return from the TBI goes to the surge tank

Here's a picture
http://www.gmcmhphotos.com/photos/data/7303/medium/PumpV2.jpg

Keith Vasilakes
Mounds View MN
76 exRoyale
MicroLevelhttp://www.gmcmotorhomemarketplace.com/vasilakes/microlevel_intro.pdf

[http://www.gmcmhphotos.com/photos/data/7303/medium/PumpV2.jpg]


From: Bruce Hislop bhislop76@gmail.com
Sent: Tuesday, March 29, 2022 5:06 AM
To: gmclist@list.gmcnet.org gmclist@list.gmcnet.org
Subject: [GMCnet] Re: TBI Questions & Google Groups

For the Wide-Band O2 sensor, you can't just hook it directly to the EBL equipped 7747 ECM.  It needs to be connected to an interface box which takes
the WB O2 signal and outputs a linear 0-5 volt signal to the ECM.

http://dynamicefi.com/TT-1.php

I use Dynamic EFI's TT-1 Wide-Band kit.  I use it for displaying the actual Air Fuel Ratio (AFR) on the What's Up Display.  I use a separate Narrow
Band O2 sensor for the actual closed loop operation.

I have a Rochester TB and noticed when I first installed it the fuel pressure on on the low side, about 11.5PSI  if I recall.  I was able to turn the
adjusting screw (not easy) and got it up to near 13PSI.  It has slowly dropped over the years to about 12PSI now, so I'm going to look into a
replacement regulator spring as pointed out by Randy.

I also do not use a surge tank.  Once the fuel level gets to the 1/2 mark, I start looking for a gas station to refill.  By that time I've drive
200-250 miles, about 4 hours and I need a break too.

--
Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that


GMCnet mailing list
Unsubscribe or Change List Options:

I use a surge tank, I think it's worth it, but I'm an over engineering kinda guy. I have 3 fuel pumps, 2 lift pumps that feed the surge tank and then the TBI pump that pulls from the surge tank. The return from the TBI goes to the surge tank Here's a picture http://www.gmcmhphotos.com/photos/data/7303/medium/PumpV2.jpg Keith Vasilakes Mounds View MN 76 exRoyale MicroLevel<http://www.gmcmotorhomemarketplace.com/vasilakes/microlevel_intro.pdf> [http://www.gmcmhphotos.com/photos/data/7303/medium/PumpV2.jpg] ________________________________ From: Bruce Hislop <bhislop76@gmail.com> Sent: Tuesday, March 29, 2022 5:06 AM To: gmclist@list.gmcnet.org <gmclist@list.gmcnet.org> Subject: [GMCnet] Re: TBI Questions & Google Groups For the Wide-Band O2 sensor, you can't just hook it directly to the EBL equipped 7747 ECM. It needs to be connected to an interface box which takes the WB O2 signal and outputs a linear 0-5 volt signal to the ECM. http://dynamicefi.com/TT-1.php I use Dynamic EFI's TT-1 Wide-Band kit. I use it for displaying the actual Air Fuel Ratio (AFR) on the What's Up Display. I use a separate Narrow Band O2 sensor for the actual closed loop operation. I have a Rochester TB and noticed when I first installed it the fuel pressure on on the low side, about 11.5PSI if I recall. I was able to turn the adjusting screw (not easy) and got it up to near 13PSI. It has slowly dropped over the years to about 12PSI now, so I'm going to look into a replacement regulator spring as pointed out by Randy. I also do not use a surge tank. Once the fuel level gets to the 1/2 mark, I start looking for a gas station to refill. By that time I've drive 200-250 miles, about 4 hours and I need a break too. -- Bruce Hislop ON Canada 77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.1 ton front end http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001 My Staff says I never listen to them, or something like that _______________________________________________ GMCnet mailing list Unsubscribe or Change List Options:
ES
Eric Schmidt
Sat, Apr 2, 2022 4:44 PM

I have to chime in... I use a surge tank, and it made plumbing very simple and reliable. Before I installed EFI, I just had the mechanical pump up
front with no problems. When I installed EFI, I put a single low pressure electric fuel pump back by the tank switching valve to feed the surge tank.
I used the very inexpensive pump that Manny T. installs on all the rigs he works on, and keep a new one as a spare. Again, they are very inexpensive
and it works as it should. Without a surge tank, the plumbing can be a lot to deal with. The hardest part was plumbing in the return line. Many
choices, and the EFI kit can with a self sealing connector to put it back to the tank or wherever you choose. Bottom line, I would recommend using a
surge tank with the high pressure pump inside.

I have to chime in... I use a surge tank, and it made plumbing very simple and reliable. Before I installed EFI, I just had the mechanical pump up front with no problems. When I installed EFI, I put a single low pressure electric fuel pump back by the tank switching valve to feed the surge tank. I used the very inexpensive pump that Manny T. installs on all the rigs he works on, and keep a new one as a spare. Again, they are very inexpensive and it works as it should. Without a surge tank, the plumbing can be a lot to deal with. The hardest part was plumbing in the return line. Many choices, and the EFI kit can with a self sealing connector to put it back to the tank or wherever you choose. Bottom line, I would recommend using a surge tank with the high pressure pump inside.