Ugh Carb Issues on my 81-I HATE THIS CARB! - Page 4 - Corvette Forum : DigitalCorvettes.com Corvette Forums
 
 
Go Back   Corvette Forum : DigitalCorvettes.com Corvette Forums > C3 Corvette Forums > C3 Corvette
Register Forums Garage Garage Mark Forums Read Auto EscrowInsurance Advertise

Notices

C3 Corvette
C3 Corvette General | Technical | Performance | Aftermarket | Discussions

Other sections:
Corvettes Classifieds
Corvette Detailing & Car Care
Corvette Audio/Video/Radar
General Automotive/Shop/Tools
Corvette Performance Driving/Racing

( Sponsored by: Zip Corvette Parts )

Shops/Tuners
Custom Image Corvettes
A&A Corvette
Corvette tuner

Interior
Corvette aftermarket products

Insurance



Parts & Products
Race Ramps
Edelbrock
ATI/Procharger
Corvetteguys.com
Melrose Motorsports
Parts Taxi
Airaid
Pfadt Racing
Madvette Motorsports
Hi-tech Custom Concepts
Corvette Garage
Corvette Parts and Accessories
Corvette Car Care Products
Corvette HID

Tracks/Schools
Bob Bondurant School of High Performance Driving
Corvette driving school

Wheels/Tires
Cray Wheels

Services
BADWERKS.com
Reply
 
Thread Tools
Old 06-22-2018, 04:51 AM   #46
Maniacmechanic1
DC Crew
 
Posts: 5,331
Member #176497
Member since: Dec 2017

Thanks: 209
Thanked 220 Times in 200 Posts
Quote:
Originally Posted by Tom Mobley View Post
Holley 4-bbls don't work well on Q-jet manifolds, which is what he's got. He would have to run an adapter, which are often a source of vacuum leaks.Fuel line doesn't work, need a different one. most guys and up with a rubber hose, not a step forward. various lines would have to be sorted and re-attached, including the headlight doors and A/C. Air filter won't work, hits the float adjuster front and back. vacuum line to power brake booster won't work, have to replace the distributor, it won't work without the computer. carb may hit the EGR valve. new dual feed line will hit the heater hose. have to do something with the computer and wiring harness. Fix the check engine light. Fix all the vacuum lines from the canister, re-vamp the lines as the Holley doesn't have two 3/8, actually three needed. Holley doesn't have bowl vents to plumb to the canister. power brake booster, evap and PCV. Fix the throttle linkage and TV cable. This is not a simple bolt-on change-over, I've fixed a few of these, the term that comes to mind is "butchered up mess". Did I mention the hood probably won't close with Holley on an adapter? Will it ever pass smog check again?

Have you ever done this on a nice original car? OP states he bought the car new. Think he wants it chopped up? Like I said, careful and through search for vacuum leaks hasn't even been done.
I noted early on he hates this Smog era E4MC Q-jet.
Its in his thread title.
I Hate this Q-jet.
He states he knows a Holley 4-bbl carb inside out.
He states he was a Mechanic in the past.
Knows all but Electronics.

So it makes Logical sense to give him what he really desires.

Its Not a 1970 LT1 or LS5 So he does not have a good factory Q-jet.
In Doug Roes Book ROCHESTOR Q-jet he states its not a good carb either a E4MC.

Why keep Ficking with it when it gives nothing but Frustration.

ITS JUNK.
Makes his Corvette Ultra slow.
Get passed by a Honda Tuner Kid with a Fart Can Muffler.
That kid that Blew by You does not care about SMOG.
Maniacmechanic1 is offline   Reply w/quote Quick reply to this message
The Following User Says Thank You to Maniacmechanic1 For This Useful Post:
hamerDown (07-08-2018)
Sponsored Links
Advertisement
 
Old 07-08-2018, 04:35 PM   #47
hamerDown
DC Crew
 
hamerDown's Avatar
 
Posts: 266
Member #132562
Member since: Oct 2013
Location: Glenolden Pa USA

My Corvette(s)
1981

Thanks: 100
Thanked 4 Times in 4 Posts
UPDATE (and a real quick response to Tom Mobley)...EGR, air pump, Cat Converter all that was removed several years ago, heat risers plugged~engine ran better with no CEL light.

I did thoroughly check for vacuum leaks...went around everything I could (headlight vacuum hoses/pods too) spraying a little 'Starting Fluid' to see 'if' Engine raised RPM's...it did not...not until the carb got a sniff.



Currently > > > Wish I could say I 'found and fixed' the problem but I did not...I removed the battery, disconnected the two large plugs and pulled the ECM out, kicked it around the garage floor, checked, cleaned the two large plugs, reinstalled it with the battery, maybe bumped some wires around and it's running like nothing ever happened however, the MCS still is not clicking at idle and I know it once did...but it's been some time.

(this Car should get better than 11 MPG around town and I baby it 140,500 pulled and rebuilt heads maybe 15 years ago, approx 3000 miles a year)

I borrowed the older Snap~On Scanner and everything from the O2 reading to Fuel Mixture and a few other readings from the Scanner were in the middle of the parameters, so it has me scratching my head...possible cracked solider joint in the ECM board? Possible funky connections at the two large ECM plugs (never touched since it was assembled in 1981)
I don't know, wish I did but, it's running just like it did prior to it running/idling bad...and especially like it seemed the ECM retarded the Timing a LOT!
Oh...and the MCS is still not 'clicking' at Idle and I know it did...because I remember it doing so, a while back.


Soooo that's my story and I'm sticking to it.
When it comes to "electronics/electrical" I'm still learning (truth is I still hate it and suck at it lol)
***All the feedback and time given doing so is greatly appreciated and I'm still reviewing all the posts
hamerDown is offline   Reply w/quote Quick reply to this message
Old 07-08-2018, 09:01 PM   #48
Maniacmechanic1
DC Crew
 
Posts: 5,331
Member #176497
Member since: Dec 2017

Thanks: 209
Thanked 220 Times in 200 Posts
Quote:
Originally Posted by hamerDown View Post
UPDATE (and a real quick response to Tom Mobley)...EGR, air pump, Cat Converter all that was removed several years ago, heat risers plugged~engine ran better with no CEL light.

I did thoroughly check for vacuum leaks...went around everything I could (headlight vacuum hoses/pods too) spraying a little 'Starting Fluid' to see 'if' Engine raised RPM's...it did not...not until the carb got a sniff.



Currently > > > Wish I could say I 'found and fixed' the problem but I did not...I removed the battery, disconnected the two large plugs and pulled the ECM out, kicked it around the garage floor, checked, cleaned the two large plugs, reinstalled it with the battery, maybe bumped some wires around and it's running like nothing ever happened however, the MCS still is not clicking at idle and I know it once did...but it's been some time.

(this Car should get better than 11 MPG around town and I baby it 140,500 pulled and rebuilt heads maybe 15 years ago, approx 3000 miles a year)

I borrowed the older Snap~On Scanner and everything from the O2 reading to Fuel Mixture and a few other readings from the Scanner were in the middle of the parameters, so it has me scratching my head...possible cracked solider joint in the ECM board? Possible funky connections at the two large ECM plugs (never touched since it was assembled in 1981)
I don't know, wish I did but, it's running just like it did prior to it running/idling bad...and especially like it seemed the ECM retarded the Timing a LOT!
Oh...and the MCS is still not 'clicking' at Idle and I know it did...because I remember it doing so, a while back.


Soooo that's my story and I'm sticking to it.
When it comes to "electronics/electrical" I'm still learning (truth is I still hate it and suck at it lol)
***All the feedback and time given doing so is greatly appreciated and I'm still reviewing all the posts
I am going with the ECM AT FAULT . BAD COLD SOLDER JOINT ON THE CIRCUIT BOARD.
YOU KICKED IT AROUND THE GARAGE AND BEAT THE SHIT OUT OF IT.
SHOWED WHO IS BOSS.

See What Gunny has to say & thinks.
Maniacmechanic1 is offline   Reply w/quote Quick reply to this message
The Following User Says Thank You to Maniacmechanic1 For This Useful Post:
hamerDown (07-09-2018)
 
Old 07-13-2018, 11:07 AM   #49
immortal
DC Crew
 
Posts: 5
Member #180100
Member since: Jul 2018

Thanks: 0
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by hamerDown View Post
UPDATE (and a real quick response to Tom Mobley)...EGR, air pump, Cat Converter all that was removed several years ago, heat risers plugged~engine ran better with no CEL light.

I did thoroughly check for vacuum leaks...went around everything I could (headlight vacuum hoses/pods too) spraying a little 'Starting Fluid' to see 'if' Engine raised RPM's...it did not...not until the carb got a sniff.



Currently > > > Wish I could say I 'found and fixed' the problem but I did not...I removed the battery, disconnected the two large plugs and pulled the ECM out, kicked it around the garage floor, checked, cleaned the two large plugs, reinstalled it with the battery, maybe bumped some wires around and it's running like nothing ever happened however, the MCS still is not clicking at idle and I know it once did...but it's been some time.

(this Car should get better than 11 MPG around town and I baby it 140,500 pulled and rebuilt heads maybe 15 years ago, approx 3000 miles a year)

I borrowed the older Snap~On Scanner and everything from the O2 reading to Fuel Mixture and a few other readings from the Scanner were in the middle of the parameters, so it has me scratching my head...possible cracked solider joint in the ECM board? Possible funky connections at the two large ECM plugs (never touched since it was assembled in 1981)
I don't know, wish I did but, it's running just like it did prior to it running/idling bad...and especially like it seemed the ECM retarded the Timing a LOT!
Oh...and the MCS is still not 'clicking' at Idle and I know it did...because I remember it doing so, a while back.


Soooo that's my story and I'm sticking to it.
When it comes to "electronics/electrical" I'm still learning (truth is I still hate it and suck at it lol)
***All the feedback and time given doing so is greatly appreciated and I'm still reviewing all the posts


as ii answered in previous post today the e4me/e4mc is a beast, 90 percent of the computer function is to provide a smooth idle it does this by adjusting the air/fuel mixture something like 10 times a second, but once its above idle the cpu stops doing pretty much anything it does control some aspects of auto transmission function but mostly all it does is make the carb idle, and the problem is u cannot just adjust the idle higher to make it not do this because you end up with a idle of 1500 rpm or more to not have the cpu interact. the proper way to tune this is to use a combination of dwell and vacuum gauges.
start by making sure the tps sensor has the correct voltage.. then attach vacuum and adjust idle mix until the vacuum gauge is at its highest, once idle mix is set from the base screws use the dwell meter to get the proper dwell by turning the mixture screw on top of the carb until dwell is correct,, now the agonizing part of this... these adjustments must be done with the car idling at temperature... and since your issue with mostly with it not idling the start is a lot of twiddling with screws to get it to idle. (pro tip here is to ensure ur 02 sensor and map sensor are working, if one of these aint then ur pretty much sol)
immortal is offline   Reply w/quote Quick reply to this message
The Following User Says Thank You to immortal For This Useful Post:
hamerDown (07-14-2018)
Old 08-26-2019, 09:15 PM   #50
hamerDown
DC Crew
 
hamerDown's Avatar
 
Posts: 266
Member #132562
Member since: Oct 2013
Location: Glenolden Pa USA

My Corvette(s)
1981

Thanks: 100
Thanked 4 Times in 4 Posts
Been sometime since I posted (really busy taking care of my 91 year old father) but...I did ditch the OE carb, had my old junky Qjet rebuilt and the care runs great!
I can't be more pleased that E4MC is OFF my engine!

Last edited by hamerDown; 08-27-2019 at 08:24 PM.
hamerDown is offline   Reply w/quote Quick reply to this message
Old 08-27-2019, 03:31 AM   #51
The Torch
DC PIT CREW BOSS
 
The Torch's Avatar
 
Posts: 35,254
Member #799
Member since: Apr 2003
Location: Western Kentucky

My Corvette(s)
2004 Black/Mod Red-Z06

Thanks: 276
Thanked 691 Times in 482 Posts
Good deal
The Torch is online now   Reply w/quote Quick reply to this message
RACING...Because with baseball, football, basketball, tennis, and golf, you only need one ball

I used to think that I had learned patience as I got older. Then I realized that I just didn't give a shit
The Following User Says Thank You to The Torch For This Useful Post:
hamerDown (08-27-2019)
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Corvette Forum : DigitalCorvettes.com Corvette Forums forums, you must first register.
Please enter your desired user name (12 CHARACTERS MAXIMUM), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
City / State / Country?
Where you live
What kind of Corvette(s) do you own?
This field is not required.
Insurance
Please select your insurance company (Optional)

Log-in


Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Powered by vBadvanced CMPS v3.2.2

All times are GMT -6. The time now is 05:47 AM.




Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Garage Plus vBulletin Plugins by Drive Thru Online, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
2003-2011, DigitalCorvettes.com - All Rights Reserved