304 fuel delivery issues - JeepForum.com
 
LinkBack Thread Tools
post #1 of 12 Old 04-11-2019, 01:43 PM Thread Starter
jbk16619
Registered User
 
jbk16619's Avatar
1979 CJ5 
 
Join Date: Dec 2018
Location: Birmingham
Posts: 24
304 fuel delivery issues

I bought my Jeep ('79 CJ-5 with a 304) this February and noted from the test drive that it was burning rich, like real rich. So after doing other upgrades to the jeep I've gotten around to the fuel delivery system. The PO replace the mechanical fuel pump with a Holley Mighty Mite (12-427). I didn't know it at the time, but it is mounted not in the recommended location on the right front fender. The PO replaced the OEM fuel filter with see thru after market without the fuel return/vapor port. The jeep has an eldebrock intake and a Holley 4160 carb (80457-8--which on holley's site doesn't exist--numbers go thru 80457-7 for whatever that's worth). So I tried leaning out the carb (which helped) and even had a "carb guy" look at it, wondering if I needed new jets, he said "no". Timing is good and it isn't miss firing. It does have a mild cam in the engine I think but not sure.
So I have researched and read extensively and thought I would try a new fuel filter with a fuel return port. Well this worked for about 45 sec. The jeep sounded smoother and was idling nicely. Then I saw gas pouring out of the left rear of the jeep. Let me digress a minute. The old fuel return line was present and I blew it out to make sure it wasn't clogged. And it wasn't up to the liquid check valve. And from the check valve to the tank. It should be noted that the charcoal canister isn't present.
So I would like to be comfortable that my family isn't going to have toxic exposure to gasoline when we ride and/or smell like a gasoline attendant.
First thing to fix-- a safety shut off for the fuel pump ( its on the way-Revolution Electronics Electric Fuel Pump Controller )
Now the questions, What is the fix? And I mean a clean running engine.
1. Dump the carb and electronic fuel pump, go back stock mech fuel pump, stock 2 barrel carb, stock cam as well as stock fuel return lines except since I don't have the complete fuel return system (missing the charcoal canister and the rollover check valve ) route directly into the fuel tank?
2. Move the fuel pump the tank, adding the safety shut off, add a fuel regulator?
3. Ditch it all and go to EFI?

Any help, comments or advice appreciated. obviously I should have done a little more research before I purchased this Jeep but as I told my wife, this is our leaner Jeep......Just wish I wasn't leaning so much.

Attached Thumbnails
IMG_0492.jpg   IMG_0509 2.jpg   IMG_0510.jpg  

JBK
jbk16619 is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old 04-11-2019, 02:17 PM
Matt1981CJ7
Registered User
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 22,942
Don't you just love previous owners?

The first thing I'd do is check fuel pressure. Since it ran better with the fuel return line hooked up, that suggests there is too much pressure without the return line.

I'm a bit unclear why fuel was dumping from the left rear side of the Jeep. Was the return line connected to the tank properly? Are the roll over and liquid check valves in place and connected properly?

A lot of guys run without vapor canisters, but I won't. The one time I tried that, my clothes, my Jeep, and my garage reeked of fuel all the time.

Matt


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Matt1981CJ7 is offline  
post #3 of 12 Old 04-12-2019, 06:05 AM Thread Starter
jbk16619
Registered User
 
jbk16619's Avatar
1979 CJ5 
 
Join Date: Dec 2018
Location: Birmingham
Posts: 24
I have a pressure regulator and a pressure gauge on the way. So I agree there is too much pressure from the pump and appreciate the "like-mindedness". Ditto on the PO.
I thought the lines were connected properly except for the missing charcoal filter and roll over check valve but as I look at the diagram closer I see a fuel return line (labeled from the fuel filter) right next to the Fuel outlet line on the tank. And looking at the liquid check valve, those lines are labeled fuel tank vent hoses not return fuel lines. SO ...I don't think I had it connected correctly (thanks for the feedback). So is this the way the system should be assembled--> Fuel filter --> fuel return line to tank--> vent lines to LQV--> RCV-> Charcoal canister which ends the system? Or are there two lines coming from the charcoal canister ?? One to the roll-over valve and one to the tank ? I will search for a diagram of the charcoal canister in a sec.
I would like to repair the whole fuel/vapor return set up correctly but does anyone know where to find the charcoal canister? (I did a quick search and found nothing) I found a roll over valve albeit not a jeep that looks exactly like the jeeps. And does it matter if I have an electric fuel pump vs a mecahanical fuel pump with the system?
Thanks again for the feedback and advice. Greatly appreciated.

JBK
jbk16619 is offline  
 
post #4 of 12 Old 04-12-2019, 06:50 AM
Matt1981CJ7
Registered User
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 22,942
Return line connects to the sending unit at the top of the tank. 2 vent lines connect to the bottom of liquid check valve. One vent line comes out of the top of the LCV and connects to the roll over check valve. One line connects the RCV to the charcoal canister.

So, it sounds like you hooked up the canister vent line to the fuel filter. That explains why fuel dumped out the rear left side. You're not the first one to make that mistake.

This is a suitable replacement for the canister.

Matt


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Matt1981CJ7 is offline  
post #5 of 12 Old 04-12-2019, 06:39 PM
Wizzal05
Registered User
 
Wizzal05's Avatar
1976 CJ5 
 
Join Date: Mar 2019
Location: milan
Posts: 31
Garage
I have had bad luck with electric fuel pumps. I have always had good luck with the mechanical pumps. As long as the return line is good it self regulates. I would return it to stock. Just my opinion. Matt is right though i Made the return line mistake also

Chris white
Wizzal05 is offline  
post #6 of 12 Old 04-13-2019, 05:54 PM Thread Starter
jbk16619
Registered User
 
jbk16619's Avatar
1979 CJ5 
 
Join Date: Dec 2018
Location: Birmingham
Posts: 24
Sorry for the slow reply. I have two young children and it is hard for me to get 5 minutes of free time but they are a gift and blessing.
And yes I hooked up the filter to the JCV. Lesson learned. So when I get some time I will attempt the correct hook up.
I am also going to redo the fuel line placing the fuel pump in the recommended location close to the tank. Since I already have the electronic fuel pump I will go with it. In general, I am a fan of putting things back the way they were made. If I can't get things worked out I will go back to mechanical fuel pump. I did talk to the PO by chance and he said he changed to electronic fuel pump because the jeep wasn't running good. (the PO strikes me as a "quick fix", "put a band aid on it" kinda of guy) So I don't really believe much what he has told me about the jeep.
Thank you guys so much for your advice and help. You have no idea how much I appreciate the help

JBK
jbk16619 is offline  
post #7 of 12 Old 04-13-2019, 06:31 PM
Matt1981CJ7
Registered User
 
Matt1981CJ7's Avatar
1981 CJ7 
 
Join Date: May 2011
Location: Elbert
Posts: 22,942
I've driven a CJ ever since I could reach the pedals. The mechanical fuel pump has never been a problem for me. I'll take mechanical over electrical almost every time, mostly because I suck at electrical.

If you go back to mechanic, don't buy the cheap re-man'd pumps they sell a most FLAPS. Get a new one from a reputable source. I had a re-man'd pump not work right out of the box. It was a Cardone brand, IIRC.

Matt


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Matt1981CJ7 is offline  
post #8 of 12 Old 04-13-2019, 10:03 PM
82JeepCJ7
Registered User
1982 CJ7 
 
Join Date: Jun 2010
Location: Marysville, WA
Posts: 5,677
Go back to a mechanical pump, stock type fuel filter (also acts like a pressure relief)
Make sure the fuel filter is oriented correctly, run a new return line
bypass the RCV, new lines to the sending unit.

BTW- electric plumps are pushers, not pullers. They need to be mounted close to the
Fuel tank

Beat it to fit, paint it to match!

Wheel, Wrench, Repeat.
82JeepCJ7 is offline  
post #9 of 12 Old 04-15-2019, 12:17 AM
turbogus
Registered User
1978 CJ5 
 
Join Date: Jun 2005
Location: Albany~town, Oregon
Posts: 2,776
Garage
'Black Betty' is a '78 CJ5 with a swapped in 360 with the stock mechanical pump and after some studying I learned that the MSD fix for pop snap fizzling Ford/AMC ignition cleaned up the combustion dramitically, and I'm running a Carter AFB.

The parts shop that stocks part for Skylab II will not have parts for our year/model of Jeep
We cannot accurately judge the trajectory of a speeding critter (cat, dog, sasquatch)
Record heat waves and floods only occur when we visit that area
turbogus is offline  
post #10 of 12 Old 04-15-2019, 09:53 PM
BagusJeep
Registered User
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali
Posts: 8,385
The Mighty Mite is not the source of your problems. Apart from needing to be sited a bit lower in the engine bay, it is a reliable solenoid type pump with 4-7 psi capabilities. If it ticks, it is a solenoid. I have several such pumps on my CJs thanks to POs, though the Holley is $47 and probably three times as much as my POs spent.

The problem is possibly with the carb inlet valve leaking and float levels. It will perform better if excess pressure is bled off through the three way filter as Jeep intended. Having teh tank return hooked up is possibly all you need, no daft FPR etc for this little pump.

BagusJeep lives in Bali with far too many 4x4s:
1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
1980 Land Rover Series III 109" troop carrier - ROVER
BagusJeep is offline  
post #11 of 12 Old 04-15-2019, 10:02 PM
Cutlass327
Web Wheeler
 
Cutlass327's Avatar
1978 CJ5 
 
Join Date: Jan 2009
Location: Beach City
Posts: 6,912
One thing too to consider. Catalytic converters. If that has been removed (and since the charcoal can is gone, I bet it is too), the exhaust will always smell richer than you are used to with newer vehicles. Have cat(s) put back on it, even if you don't have inspections. It helps the odor a lot!

Rick

1978 CJ5 5.0HO/T177/D300 TerraLow 4:1 kit, '86 D30/D44 3.54 WT axles w/Aussies, 'glass body, 33x12.5 ProComp A/T, TDK galv'd frame, 2.5 OME YJ lift - DD and weekend toy


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Cutlass327 is offline  
post #12 of 12 Old 04-17-2019, 12:08 PM Thread Starter
jbk16619
Registered User
 
jbk16619's Avatar
1979 CJ5 
 
Join Date: Dec 2018
Location: Birmingham
Posts: 24
Thanks Guys for all the advice. It is very helpful.
Since I have the electric fuel pump I am going to use it. I did move it to the back of the Jeep, close to the tank. I replaced the fuel filter with the stock fuel filter (oriented with the return line on top). Got everything hooked up and went for a 25 min test drive. It idles better, runs better (doesn't sound like I need to pump the throttle to prevent it shutting off ) and the gas smell was almost completely gone.
Correct me if I am wrong but this also seemed to help with the vapor lock issue that I haven't mentioned (pushing fuel works better than sucking fumes --from a gas line running next to the header)
It doesn't have a CC and that is a good thought. I will look into that.
I am going to replace the missing charcoal canister and hopefully that will help with the fumes as well.
Couple of questions.
Do you all have an opinion on gas lines? stainless vs PVC or other material? I wonder about heat transfer from the header--would stainless be a better shield? I routed an AC delco PVC line that looks awful but seems to be working.
And for my education and possibly future, would EFI be the way to go? (more efficient, less gas/fume smell, more reliable ??
Thanks again

JBK
jbk16619 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, 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 e-mail address for yourself.



Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Adjustable FPR and cross flow fuel rail on the cheap Cobra Jeep YJ Wrangler Technical Forum 6 12-30-2018 07:22 AM
Help, my wife put gas in our CRD by mistake Zroe89 WK Grand Cherokee & XK Commander Forum 26 11-09-2018 04:34 PM
CRD WK Start/Crank Issues - Second Opinion Tetto WK Grand Cherokee & XK Commander Forum 19 10-15-2018 09:04 AM
Help with identifying part. jordanperkins03 XJ Cherokee Technical Forum 11 10-05-2018 02:32 PM
2.7 CRD - anyone install fuel pump in fuel tank? tahoeJeep WJ Grand Cherokee Forum 2 04-16-2018 12:50 PM

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
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome