Hard starting? or just a simple mistake. - Team Camaro Tech
Engine General Engine Discussion.

 
LinkBack Thread Tools Display Modes
post #1 of 13 (permalink) Old Jun 18th, 15, 09:59 AM Thread Starter
Team Member
Ray
 
Join Date: Mar 2012
Location: North Jersey
Posts: 1,105
Garage
Hard starting? or just a simple mistake.

Hi all.
I rebuilt the quadrajet on my 68 350 this past fall season. All went well up until just these past two weeks while attending a few shows and weekly cruise nights.
It would start after a 15 second crank due to sitting in the garage, but that seemed to be normal for it. However, afterwards it would run great. While parked at the 2 to 3 hour cruise night, it would again have to crank 15 or more seconds to start. After a few nights it seemed to be getting worse.
This past Sunday I showed the car at a local meet and it sat in a very hot parking lot for about 7 hours. Well, when it was time to leave I had to let it crank for almost a full minute before it started, but again ran great.
I got the time this morning to check it out so I read all those web posts about Q-jets draining, fuel pump check valves, and even wrong types of air cleaner designs.
I don't know why, but I put a socket on one of the carb manifold bolts and it was loose, really loose, like finger loose.
What the hey! All four of the carb manifold bolts were finger loose!
Question is; could this be the cause of the long cranking to start?
Cruising tonight and I see if that was it. Sure not looking forward to having to seal the plugs on the bottom end of the carb, or having to replace the check valve in the fuel pump.
So another question is; do the carb bolts get lock washers or a dab of locktight? I don't remember if it had washers when I took it apart.

'68 rs/SS 350 M-21 posi
numbers matching
rgwiz is online now  
Sponsored Links
Advertisement
 
post #2 of 13 (permalink) Old Jun 18th, 15, 10:08 AM
Gold Lifetime Member
George
 
Gbauer's Avatar
 
Join Date: Nov 2012
Location: Frederick, MD
Posts: 8,047
Re: Hard starting? or just a simple mistake.

Sounds like the check valve is out. I don't know where it's located, though. Might be in the fuel sending unit? Is the float set properly? Somehow the fuel is draining back to the tank. That's too fast to be evaporation.

Sold:
1968 Base hardtop 250 with a P̶G̶ built 2004r
Offy intake
Holley 390 CFM carb
Langdon split header to a 2.5" exhaust
Mild cam
Custom interior
Gbauer is offline  
post #3 of 13 (permalink) Old Jun 18th, 15, 10:10 AM
Admin/Super Moderator
Brian
 
69-Pace's Avatar
 
Join Date: Jun 2010
Location: Connecticut USA
Posts: 12,509
Garage
Re: Hard starting? or just a simple mistake.

Check your timing again. Long cranks can either be spark - too much advance or retard on your timing, or fuel delivery - evaporated bowl or bad float empty bowl so you need to crank to refill. For the later do you have the correct sequence of gaskets, fiber and tin heat shield? For timing check your baseline against factory specs. I only know 69 L48 off the top of my head for a manual, but look yours up and get there and then set your idle circuits again and then re tune down to factory specs. Then see how she starts.


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

1969 Z11 Pace Car - L48 350cid/300hp - 4 Speed Muncie 12 bolt rear.

Super Moderator Team Camaro
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
to send me a private message
69-Pace is offline  
 
post #4 of 13 (permalink) Old Jun 18th, 15, 12:06 PM
Gold Lifetime Member
Fred
 
Join Date: Nov 2006
Location: Seabeck WA
Posts: 8,375
Re: Hard starting? or just a simple mistake.

Finger tight nuts? You must of tightened them properly, right? How did it start? You tried to start it, right?

One owner 69 Camaro,(yep, bought it new
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
)
RS SS Hugger Orange, L88, 4:10's tru-tack posi, ducted hood, Endura, spoilers.
TH400 (CX) with Coan 8" converter, GV-OD, 8 track still on console and best et 10.495,
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
128.79mph 1.428 60'
All with 1960's stuff. (except tires and converter)
+ MT Super Scavenger headers & 3" full exhaust with X pipe. 3700 lbs. with me in it.
1000cfm AED and HD Harold-Lunati SR, 725 lift with shaft rockers too.
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.
Fred Ficarra is offline  
post #5 of 13 (permalink) Old Jun 18th, 15, 01:12 PM Thread Starter
Team Member
Ray
 
Join Date: Mar 2012
Location: North Jersey
Posts: 1,105
Garage
Re: Hard starting? or just a simple mistake.

Last to first reply; I'm almost sure that I tightened the two back nuts and two front bolts. That is, I, uh, was supposed to...It ran great! But at that time there was no cruise, sit and drive home late nights. Basically, just go for a long drive and park it until next week.

The sequence of manifold gaskets is; fiber heat resistant, then thin factory metal that blocks smiley face trough in manifold, then thicker fiber type. Yes, timing could go a tick advanced. Was 12 Deg advanced, now it's 10 because it idled better quarter turn lean. But, that was in late September's 60 degrees weather.

Yes, I'm pretty sure the float is set right. While the rebuild, I checked it a couple of times. Specs in Walker rebuild kit says 3/8" above flat spot on throttle body. (high HP & big blocks are more) The float is brandy new brass.

I hope the check valve is ok. Because if not, I don't know if I can get one. The fuel pump is an aftermarket chrome one and I can't see any name brand on it. It dose however have a small bolt head on the underside.

Thanks for helping out. I can't imagine that the loose front bolts and loose rear nuts are not a problem waiting to happen. I also can see where it could run fine once started due to a good vacuum, then shut down and sitting in the heat for hours could cause evaporation. Just saying.

Then there is the problems associated with ethanol additives at the pumps.

'68 rs/SS 350 M-21 posi
numbers matching

Last edited by rgwiz; Jun 18th, 15 at 01:28 PM.
rgwiz is online now  
post #6 of 13 (permalink) Old Jun 18th, 15, 01:24 PM
Admin/Super Moderator
Brian
 
69-Pace's Avatar
 
Join Date: Jun 2010
Location: Connecticut USA
Posts: 12,509
Garage
Re: Hard starting? or just a simple mistake.

You can follow the fuel pump test in the service manual. But a simple test is to pour about an ounce of fuel down the vent on top and start her. If she roars to life immediately then your issue is float or bowl or pump related. If she still needs endless crank to start your issue is more than likely timing and or spark.


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

1969 Z11 Pace Car - L48 350cid/300hp - 4 Speed Muncie 12 bolt rear.

Super Moderator Team Camaro
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
to send me a private message
69-Pace is offline  
post #7 of 13 (permalink) Old Jun 18th, 15, 01:40 PM Thread Starter
Team Member
Ray
 
Join Date: Mar 2012
Location: North Jersey
Posts: 1,105
Garage
Re: Hard starting? or just a simple mistake.

Ok thanks. I assume the "vent" is the hole closest the front on the Q-jet. The hole that some people mistake as the air cleaner bolt hole.

Like a mentioned, I always had a long crank after she sits for a week. I thought it was normal. Figured that gravity will always drain the line from carb back to the fuel pump. Thinking that my "normal" long crank was filling the vertical run to the carb.

I'll have to try the timing again. Spark is good.

Thinking about what I said about the gravity draining the line. That can only happen if there is an air source at the highest point. Like the carburetor. Maybe the loose bolts and rear nuts let in enough air while she sat. Vacuum closed it back off after getting her started, like good enough to drive. Then shut off again and air seeps back in, draining the line. and the problem was getting worse as the bolts and nuts got looser and looser.

It's almost time to go to cruise night. I'll see what happens. Wish me luck!

'68 rs/SS 350 M-21 posi
numbers matching
rgwiz is online now  
post #8 of 13 (permalink) Old Jun 18th, 15, 01:54 PM
Admin/Super Moderator
Brian
 
69-Pace's Avatar
 
Join Date: Jun 2010
Location: Connecticut USA
Posts: 12,509
Garage
Re: Hard starting? or just a simple mistake.

Yes that's the one. The check valve in the Quadrajet filter should prevent fuel flowing back to the pump, but boil off and or evaporation will empty the bowl.

So question: If you start her, and after a few minutes shut off, and then in a few minutes start her up, does she quick start?

If not try this before doing anything like running the starter for a period of time known to start her which will force the pump to fill the bowl, use a float measure stick through the vent tube if you still have yours from your rebuild kit, a bamboo stick or chop stick will also work to mark the level of fuel in the bowl.

If she is low or empty, and you actually smell gasoline you may have leaking float that is dumping gas into the intake.

I know in my 69 Quadrajets, if I let her sit there is low fuel in the bowl unless I have put the carb maintenance cover on. So I regularly prime the bowl through the vent if I haven't started her in a day or two. Starting every day is not an issue if she is in the garage.


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

1969 Z11 Pace Car - L48 350cid/300hp - 4 Speed Muncie 12 bolt rear.

Super Moderator Team Camaro
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
to send me a private message
69-Pace is offline  
post #9 of 13 (permalink) Old Jun 27th, 15, 06:08 AM
Gold Lifetime Member
Dan
 
Join Date: Jul 2014
Location: Northern Indiana
Posts: 17
Re: Hard starting? or just a simple mistake.

Not to start new debate. Does this car happen to have a oil pressure switch that controls ignition. Thats just a shot in the dark. If it's not a fuel issue. Long crank time to build OP. Have had it happen to me.

Hgtech
HGTECH is offline  
post #10 of 13 (permalink) Old Jun 27th, 15, 06:18 AM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,077
Re: Hard starting? or just a simple mistake.

I recently ran into similar issues (all due to over rich conditions). Qjet, had similar issues, float stuck to bowl, ethanol film stuck in primary jet, gummed up base plate (not letting secondaries close) and I think leaking JBwelds (on the well bottoms).

I fixed the bowl and jet issues, better, then had high idle, cleaned the baseplate, I also ground down the previous JB weld the rebuilder put on and put new on. The carb was rebuilt over 15 years ago and the JB weld was really soft. I think 10 years is about the life of the JB weld

Put it back together and running strong now! I have only had it out once since fixing, time will tell if I still have anymore gremlins.

Kevin


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.

Last edited by KevinW; Jun 27th, 15 at 10:04 AM.
KevinW is offline  
post #11 of 13 (permalink) Old Jun 27th, 15, 09:00 AM
Gold Lifetime Member
Scott
 
scblucam's Avatar
 
Join Date: May 2005
Location: Houston, TX
Posts: 2,442
Garage
Re: Hard starting? or just a simple mistake.

I don't know about Q-jets but on a Holley once the fuel is in the bowl the only ways out are a visual leak on the bowl, evaporation(E10 does faster that real gas) or sucked into the engine while running. I don't believe the bowl can drain back to the tank the way the bowl and fuel passages are designed.

68 302 M20 - 85 IROC Z
The older I get the faster I was.
scblucam is offline  
post #12 of 13 (permalink) Old Jun 27th, 15, 02:56 PM
Senior Tech
mike
 
Join Date: Jan 2011
Location: east coast
Posts: 2,288
Re: Hard starting? or just a simple mistake.

Probably a silly question but how do you attempt to start the car. Do you pump the gas at all? When it finally starts is it very rich(flooding)? Do you have to hold the pedal all the way down? I know with the old cabs you would have to stab the pedal to the floor once or twice then don't touch the pedal again, if the choke worked correctly.
bigblockragtop is offline  
post #13 of 13 (permalink) Old Jun 28th, 15, 08:16 AM
Senior Tech
Lonnie
 
Lonnie P's Avatar
 
Join Date: Sep 2008
Location: Pittsburgh, pa
Posts: 586
Re: Hard starting? or just a simple mistake.

Qjets were notorious for the well plugs to leak, draining fuel into the intake when parked.

This results in having an empty carb that required extensive cranking after sitting for long periods & also a flooded engine after short term hot soak conditions.

An easy check is if you are having a hard time starting it after a short period (warm engine), carefully push the throttle down a ways & hold before while cranking the engine... do not pump the throttle as it is likely already has enough fuel, it needs more air.

The above trick to seal the well plugs is good, but I recommend a traditional epoxy instead of JB weld as it tends to soften when saturated in fuel.
Lonnie P is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech 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 email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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 On
Pingbacks are On
Refbacks are On

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