car starts than stops.... - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
LinkBack Thread Tools Display Modes
post #1 of 5 (permalink) Old Aug 17th, 06, 10:16 PM Thread Starter
 
Join Date: Aug 2006
Posts: 6
car starts than stops....

Well, here it goes, I started on my project to turn an 89 rs with a tpi system into a carb. I finally finished with the entire set up, but the thing wont stay running. I can get it to turn over, but as soon as it does, it revs to 8000 rpms than drops and shuts off. I'm thinking that it could be a possible fuel problem. I'm using a mechanical fuel pump for an 84 z28. I notice that it pumps fuel, but it doesn't seem to flow as well as my 78 does, even though the pump is new. What do you think.
78z28 is offline  
Sponsored Links
Advertisement
 
post #2 of 5 (permalink) Old Aug 18th, 06, 03:30 AM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,584
Garage
Re: car starts than stops....

Quote:
Originally Posted by 78z28
I can get it to turn over, but as soon as it does, it revs to 8000 rpms than drops and shuts off. I'm thinking that it could be a possible fuel problem.
Is the carb stuck at WOT?
Quote:
I'm using a mechanical fuel pump for an 84 z28. I notice that it pumps fuel, but it doesn't seem to flow as well as my 78 does, even though the pump is new. What do you think.
The mech pump is pumping fuel through the OE fuel pump in the tank.

Either remove the in-tank fuel pump and replace with a pump-less pickup, or turn on the pump and use a bypass regulator and return the fuel back to the tank as in the OE TPI setup and remove the mechanical pump.

Give a man a rescued dog for the health of both their souls. May 2017 ROTM Winner - Thank you!
'
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CUBS - 2016 World Series Champions - maybe this year, 2019 ...
Everett#2390 is offline  
post #3 of 5 (permalink) Old Aug 19th, 06, 11:49 PM Thread Starter
 
Join Date: Aug 2006
Posts: 6
Re: car starts than stops....

Thinks, but I actually found the problem this morning. I got alittle frustrated and ripped the whole thing apart and I found a hole on the back side of the intake. What was happening was that, it would start normally, but because of the hole, a vacumm was created in the back of the intake that pulled excess air in and caused it to rev. Once it rev to max, which is about 8500 rpms, the pump wasn't able to keep up causing a sever lean mixture forcing the rpms down. The rpms would drop so rapidly, that when the air mixture became normal, it couldn't push the engine to run again and just shut down. I plugged the hle using a set screw and silicon gasket maker, and the engine starts up fine and settles at a nice 1000 rpm idle. Sounds great and runs good, but ran into another problem. It stalls when attempting to increase rpms. I have another thread on that. The fuel pressure is good (7 psi), the timing is good and there are no leaks. It will increase if I adjust the idle screw, but not when I move the throttle, regardless of how slow or fast I turn it.
78z28 is offline  
 
post #4 of 5 (permalink) Old Aug 21st, 06, 07:17 AM
Senior Tech
 
Join Date: Mar 2002
Location: Austin, TX, USA
Posts: 5,277
Re: car starts than stops....

Quote:
Originally Posted by 78z28
... I plugged the hle using a set screw and silicon gasket maker, and the engine ...
Good detective work. Beware of silicon sealers in cars with O2 sensors. The silicon in the sealer can render your O2 sensor useless in a short amount of time. Look for sealers that say "O2 sensor safe".

Dave
========================
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
dnult is offline  
post #5 of 5 (permalink) Old Aug 21st, 06, 08:35 AM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,584
Garage
Re: car starts than stops....

Quote:
Originally Posted by 78z28
Once it rev to max, which is about 8500 rpms, the pump wasn't able to keep up causing a sever lean mixture forcing the rpms down.
I guess this is a good thing since the engine did not stay very long at 8500 rpm.
Quote:
It will increase if I adjust the idle screw, but not when I move the throttle, regardless of how slow or fast I turn it.
Could too little inital timing. You might try timing around 8*-12*, or even 14* BTDC at idle.

Another check is for every minute movement of the throttle plates, there should be fuel being dispensed from the accelerator pump squirter at the same time, no lag.

You may also need to increase the squirter size. Most Holley carbs have a 25 squirter. Going to a 27 or 29 may help. If you have a Q-jet, placing the linkage in the outer most hole works good, along with a pump replacement. Same goes for a Carter/Edelbrock AFB carb.

Give a man a rescued dog for the health of both their souls. May 2017 ROTM Winner - Thank you!
'
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CUBS - 2016 World Series Champions - maybe this year, 2019 ...
Everett#2390 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



Similar Threads
Thread Thread Starter Forum Replies Last Post
Unusual JL8 Car Found travlinz28 Tag Team 48 Aug 5th, 08 05:36 AM
car starts then cuts off in 15-20 mins. goldyiroc Electrical & Wiring 3 Feb 2nd, 06 08:50 PM
When car is in drive, it looses power victimizati0n Transmission & Driveline 9 Jul 21st, 05 02:41 PM
Starts then let go of key and it stops NOMANRS Troubleshooting 4 May 29th, 02 06:07 PM
starts then stops 68softy Troubleshooting 4 Mar 3rd, 01 05:58 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 On
Pingbacks are On
Refbacks are On

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