SBC 350 starting/stalling issues - JeepForum.com
 1Likes
Reply
 
LinkBack Thread Tools
post #1 of 20 Old 07-01-2020, 07:21 PM Thread Starter
Focoty
Registered User
1983 CJ7 
 
Join Date: Jul 2014
Location: Denver
Posts: 36
SBC 350 starting/stalling issues

Hi guys,

I’ve been having a couple issues with the CJ lately, and of course they have been happing when I have been trying to the the thing wrapped up for summer cruising.

Both issues seem to be related, at least I think so. The first issue is when I drive for a relatively short period of time, but it gets up to temp or relatively close. After 30 minutes or so of it being parked, there is a hard starting issue like it doesn’t want to crank over. The second issue just came about recently. I have a light in the dash that is somehow wired up to the fuel pump, that when you start the Jeep up you turn the key to “on”, the light comes on and the fuel pump cycles. Once the pump cycles it’s a push button start, the Jeep starts, and the light goes off. The other day after a bit longer of a drive, the fuel pump light came on, and shortly after that the engine completely died. I pulled off and at first pushing the start button the engine barely cranked. Eventually it started to crank and with some gas pedal pushing it turned over and i was able to drive home without any other issues.

I’m trying to figure out where best to begin diagnosing the issue. Fuel pump maybe? Ignition wise the spark plugs and distributor cap have been replaced recently. This has been a majority project Jeep so I can’t exactly say it’s a new problem since i haven’t really taken it out ok longer trips before without this happening. Thank you for any help!

Focoty is offline  
Sponsored Links
Advertisement
 
post #2 of 20 Old 07-01-2020, 07:47 PM
BagusJeep
Web Wheeler
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali
Posts: 7,681
Nice looking Cj7. You have a SBC with a new drivetrain which looks fabulous but apart from that we know very little about your rig. The more details you give the more accurate the wrong answer will be.

What type of fuel system are you using, carb or injection? How have you set up the fuel pump, filters and supply and return lines?

The hot start issue sounds like fuel vaporisation. Do you have a tank return line? Are your fuel lines well away from the exhaust and engine block? If you have a carb, did you put a phenolic spacer between carb and inlet manifold?

Your fuel pump light I guess is linked to the pump relay and is showing you that the relay is not energised. It is good practice to wire an electric fuel pump to Run through an oil pressure switch and relay, so when you stall or turn over the pump turns off even though the key is still in Run. You may be seeing a warning light to tell you that the relay is open.

When you stall the engine in gear, does the warning light come on? Does the fuel pump cut off by itself?

It is therefore also needful for an electrical feed to the pump to get it to fire before the oil pressure builds and the fuel pump relay engages. You can do this with a feed from Start or a timed relay that energises for a short period after moving the key to Run. The second is better for fuel injection as you need to build pressure, the first one is fine for carbs.

Does this sound like how the pump is wired? When it stopped working, did you hear the pump cycle before you tried to Start? Could it be that you built oil pressure by cranking for some time before the relay engaged?

BagusJeep lives in Bali.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline  
post #3 of 20 Old 07-02-2020, 12:04 AM
pedal2themetai
Registered User
1956 CJ5 
 
Join Date: Apr 2015
Location: Boise
Posts: 1,600
Hi, I think your confusing some stuff.. Does the light go off when the pump stops or just goes off once the motor is started..

I think what the light is, is oil pressure idiot light.. and goes off once the motor is started because you have oil pressure. Now for it turning on while driving sounds like the oil pump quit working or you are low on oil..Or NOW if the motor dies (quits running) the oil light would come on because there is no oil pressure with out the motor running.

Now for the hard starting HHMM do you have headers or stock manifolds.. If you got headers then the starter may be suffering for heat soak.. if it it close to the headers it can over heat the case making it swell and create a starting problem because when it overheats it cause the case to swell and makes it hard for it to turn over (it turns very slow) until it cools down. A cure for that is adding a heat shield of some kind between the header and the starter.

good luck
tim
pedal2themetai is offline  
 
post #4 of 20 Old 07-02-2020, 06:59 AM Thread Starter
Focoty
Registered User
1983 CJ7 
 
Join Date: Jul 2014
Location: Denver
Posts: 36
Quote:
Originally Posted by BagusJeep View Post
Nice looking Cj7. You have a SBC with a new drivetrain which looks fabulous but apart from that we know very little about your rig. The more details you give the more accurate the wrong answer will be.

What type of fuel system are you using, carb or injection? How have you set up the fuel pump, filters and supply and return lines?

The hot start issue sounds like fuel vaporisation. Do you have a tank return line? Are your fuel lines well away from the exhaust and engine block? If you have a carb, did you put a phenolic spacer between carb and inlet manifold?

Your fuel pump light I guess is linked to the pump relay and is showing you that the relay is not energised. It is good practice to wire an electric fuel pump to Run through an oil pressure switch and relay, so when you stall or turn over the pump turns off even though the key is still in Run. You may be seeing a warning light to tell you that the relay is open.

When you stall the engine in gear, does the warning light come on? Does the fuel pump cut off by itself?

It is therefore also needful for an electrical feed to the pump to get it to fire before the oil pressure builds and the fuel pump relay engages. You can do this with a feed from Start or a timed relay that energises for a short period after moving the key to Run. The second is better for fuel injection as you need to build pressure, the first one is fine for carbs.

Does this sound like how the pump is wired? When it stopped working, did you hear the pump cycle before you tried to Start? Could it be that you built oil pressure by cranking for some time before the relay engaged?
Sorry, I always seem to just spit out an issue and forget to provide the necessary additional info. TBI fuel injection. The filter and pump are mounted to the body underneath to the rise in the floor pan behind the front seats. The previous owner set this up, so I can definitely take a closer look at how it's all plumbed together. When these issues aren't happening the jeep runs great so that makes me think that it's more or less correct, there is just some little snag in the process. I wouldn't be surprised if it's an electrical type issue, before I got the jeep it sat for quite a while. There does look to be a spacer on the throttle body.

As far as stalling, the light will come on about a minute or two before it stalls out. I'm not exactly sure if that light indicates that the pump is running, or if it is oil pressure related. Tracing the wiring back from the light itself (one red, one black) it feeds through the firewall, I'll see if I can get a better idea of where it goes exactly, it just goes into a large sealed up loom. After the stall, I pulled over and turned the key to off. Turning it back to on again I did hear the pump cycle, but it just didn't really want to turn over and was struggling without a little help. Thank you so much for the helpful and detailed info!




Quote:
Originally Posted by pedal2themetai View Post
Hi, I think your confusing some stuff.. Does the light go off when the pump stops or just goes off once the motor is started..

I think what the light is, is oil pressure idiot light.. and goes off once the motor is started because you have oil pressure. Now for it turning on while driving sounds like the oil pump quit working or you are low on oil..Or NOW if the motor dies (quits running) the oil light would come on because there is no oil pressure with out the motor running.

Now for the hard starting HHMM do you have headers or stock manifolds.. If you got headers then the starter may be suffering for heat soak.. if it it close to the headers it can over heat the case making it swell and create a starting problem because when it overheats it cause the case to swell and makes it hard for it to turn over (it turns very slow) until it cools down. A cure for that is adding a heat shield of some kind between the header and the starter.

good luck
tim
You could certainly be right, that could be an oil pressure light. As far as the motor shutting off while driving, that particular light does come on about 2 or 3 minutes before it actually shut off. I've been driving around the neighborhood to test, and I know once that light comes on I should probably turn around and get as close to home as possible.

There are headers on there, and they do run past the starter that is mounted on the lower passenger side of the engine block. I suppose it definitely couldn't hurt to throw on a heat shield!
Focoty is offline  
post #5 of 20 Old 07-02-2020, 09:02 AM
Fourtrail
Registered User
1974 CJ6 
 
Join Date: Dec 2007
Location: Illinois
Posts: 4,630
That light is more then likely the check engine light, which on a tbi system will come one when you turn on the key and stay on until the engine starts. You need to find the ADL connector and jump the correct pins to read the codes and find out why your light is coming on while driving and why it is shutting off. Like below is a quick guide to which pins to jump and what the code that flashes means.


http://www.pattonmachine.com/TBI-Trouble-Codes.htm


As for the slow cranking, gm in their wisdom decided to put the starter solenoid on the starter and it suffers from bad heat soak. You can try a heat shield, but it may be time for a new starter and maybe battery cables depending on what kind of shape they are in.
pedal2themetai likes this.

80 CJ-5, 74 CJ-6, 56 CJ-5
Fourtrail is offline  
post #6 of 20 Old 07-02-2020, 09:33 AM Thread Starter
Focoty
Registered User
1983 CJ7 
 
Join Date: Jul 2014
Location: Denver
Posts: 36
Quote:
Originally Posted by Fourtrail View Post
That light is more then likely the check engine light, which on a tbi system will come one when you turn on the key and stay on until the engine starts. You need to find the ADL connector and jump the correct pins to read the codes and find out why your light is coming on while driving and why it is shutting off. Like below is a quick guide to which pins to jump and what the code that flashes means.


http://www.pattonmachine.com/TBI-Trouble-Codes.htm


As for the slow cranking, gm in their wisdom decided to put the starter solenoid on the starter and it suffers from bad heat soak. You can try a heat shield, but it may be time for a new starter and maybe battery cables depending on what kind of shape they are in.
That makes perfect sense! The ALDL has a 12 pin connector and I was considering trying to buy an adapter to the typical 16 pin to try and use a code reader. I had no idea you could just use a paper clip and count the flashes. I am going to give this a try right now and report back what I find out. Thanks!
Focoty is offline  
post #7 of 20 Old 07-02-2020, 10:29 AM
Axhammer
Web Wheeler
 
Axhammer's Avatar
1985 CJ7 
 
Join Date: Aug 2018
Location: Moyock
Posts: 1,225
Garage
Are you still running the OEM starter? If so, a gear reduction starter is what I would recommend for the hot start problem.


1985 CJ-7 Red with white hardtop, 258 auto
View my Pontiac in my profile
Axhammer is offline  
post #8 of 20 Old 07-02-2020, 11:37 AM
pedal2themetai
Registered User
1956 CJ5 
 
Join Date: Apr 2015
Location: Boise
Posts: 1,600
HI Not to Dis Fourtrail but its not the solenoid mounting , Ford can have the same problem and their solenoid is on the fender.. Its the starter case getting hot and swelling and making the tolerances tight so it can't turn until it cools off.. The solenoid Just engages the starter.
Now with that said, I have used just an old License plate and wired it around the headers.
good luck
tim
pedal2themetai is offline  
post #9 of 20 Old 07-02-2020, 07:27 PM Thread Starter
Focoty
Registered User
1983 CJ7 
 
Join Date: Jul 2014
Location: Denver
Posts: 36
So after some trial and error I did replicate the issue and I was getting a code 13, which is O2 sensor related. What I'm seeing that relates to is "Possible broken or burned O2 sensor wire." Now the issue I'm trying to figure out is 1) Does this mean a bad oxygen sensor, or the wiring that plugs into sensor? and 2)is this something that would cause a stall?

I've got a dual exhaust, with only the driver's side having an O2 sensor in it. I don't know enough about the GM ECU, is it ok to only have a sensor in one side? Or does it expect to see 2 and that would cause the error? I had unplugged the battery overnight to work on some other things, so that had cleared the code. I drove it around some today to get the "check engine" light to come back on and it did, but pretty much as soon as it came on I pulled off into a lot to check the code so I didn't replicate the stall. So I can't exactly say if they are related or not, it's a little nerve wracking to drive the thing with the goal of getting the motor to shut off on the road
Focoty is offline  
post #10 of 20 Old 07-02-2020, 08:41 PM
BagusJeep
Web Wheeler
 
BagusJeep's Avatar
1981 CJ7 
 
Join Date: Jul 2009
Location: Bali
Posts: 7,681
You are making progress with identifying it. The damaged cable reference means the computer is intermittently losing the input from the sensor. check the cable and connectors, if not for melting then for corrosion. It does not matter that there is only one sensor.

BagusJeep lives in Bali.

1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1951 Willys CJ3A/MB/M38 - Little Willy
1995 Cherokee 4.0 - CHEROKEE
BagusJeep is offline  
post #11 of 20 Old 07-03-2020, 01:09 AM
ddawg16
Registered User
 
ddawg16's Avatar
1984 CJ7 
 
Join Date: Oct 2018
Location: South Bay
Posts: 733
Garage
I have a CJ7...with a 5.7L TBI.....
you're fuel pump/filter setup is wrong. It needs to be as close to the tank a possible. Electric fuel pumps need to be as close to the tank as possible. The push much better than sucking.....

If you have 'any' kind of leak in your fuel line....you will have issues.

I have my pump and filter on the frame rail right in front of the tank. No issues.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
ddawg16 is offline  
post #12 of 20 Old 07-03-2020, 07:23 AM Thread Starter
Focoty
Registered User
1983 CJ7 
 
Join Date: Jul 2014
Location: Denver
Posts: 36
Quote:
Originally Posted by ddawg16 View Post
I have a CJ7...with a 5.7L TBI.....
you're fuel pump/filter setup is wrong. It needs to be as close to the tank a possible. Electric fuel pumps need to be as close to the tank as possible. The push much better than sucking.....

If you have 'any' kind of leak in your fuel line....you will have issues.

I have my pump and filter on the frame rail right in front of the tank. No issues.
Sorry it’s not the best pic, here is where the filter and pump are mounted. On the back side of that little rise that is behind the seat. Is this far enough away to cause issues?
Attached Thumbnails
FFD87E37-4AA8-428D-8BFA-51361F2ACEA3_1593782570411.jpg  
Focoty is offline  
post #13 of 20 Old 07-03-2020, 08:32 AM
pedal2themetai
Registered User
1956 CJ5 
 
Join Date: Apr 2015
Location: Boise
Posts: 1,600
Hi your going to want to extend your exhaust out side from under the jeep.. it traps a lot of deadly fumes under the jeep as well as its dumping a lot of heat right under your fuel filter and pump and could cause some vapor locking problems as well as over heat the pump..
good luck
tim
pedal2themetai is offline  
post #14 of 20 Old 07-03-2020, 08:42 AM
RiverandSand
Registered User
1980 CJ5 
 
Join Date: Jun 2016
Location: Yuma
Posts: 131
Garage
Holley makes an intank pump for the stock CJ tank, if your thinking of moving in that direction.
RiverandSand is offline  
post #15 of 20 Old 07-03-2020, 08:43 AM Thread Starter
Focoty
Registered User
1983 CJ7 
 
Join Date: Jul 2014
Location: Denver
Posts: 36
Quote:
Originally Posted by pedal2themetai View Post
Hi your going to want to extend your exhaust out side from under the jeep.. it traps a lot of deadly fumes under the jeep as well as its dumping a lot of heat right under your fuel filter and pump and could cause some vapor locking problems as well as over heat the pump..
good luck
tim
I actually was planning to put on some new mufflers and some turn out tail pipes and just haven’t gotten around to it. I might as well take care of that now just in case it is contributing at all. Thanks for the advice!
Focoty 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



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