TBI Throttle Body Injection discussion and questions. L03/CFI tech and other performance enhancements.

Car wonít start unless I press the gas

Old 07-09-2019, 02:15 AM
  #1  
Junior Member
Thread Starter
 
Join Date: Jul 2017
Posts: 42
Received 0 Likes on 0 Posts
Car: 1989 Chevy Camaro RS
Engine: 305 TBI
Transmission: 700R4
Car wonít start unless I press the gas

Everytime the car is cold, 100% of the time I have to use the gas to get it going. I usually rev it to 2k and keep it there for a sec after it cranks and then let it drop down slowly to idle. If i let go of the gas too quick, it shuts off. Also, if i rev it while its still cold, it shuts off. Now whenever the engine is hot, sometimes it will fire up without the gas. Also, when the engine is hot, I can rev it to whatever RPM I want and it will stay alive. This has been a problem for 2 years. I just need someone to narrow down the potential causes so I donít blow my high school budget away lol. Also worth noting, the car sometimes shuts off when im turning (at least it usually happens when im turning). There has been twice where it shuts off at a stop light. IDK if that has anything to with it. The car runs perfectly fine other than all that. It accelerates perfect and runs the highway perfect

What do I need to change/ inspect? Iíve heard PCV Valve, Fuel Filter, Fuel Pump, IAC Valve, EGR Valve, and MAF Sensor.

More info: 1989 Camaro 305 TBI All Stock, 90k miles

Sorry. Ik this is alot. Iím trying to give as much info as I can to give yall an idea of what it potentially could be.

- Thanks, Kyler
Kyler_89RS is offline  
Old 07-09-2019, 09:56 AM
  #2  
Member
 
Join Date: Feb 2008
Posts: 430
Likes: 0
Received 0 Likes on 0 Posts
Re: Car wonít start unless I press the gas

start with fuel pressure, you will need to get an adapter because there is no provision to check from factory. IIRC, you need 9-13 psi. I like to see 13-14 psi, no less. the stock regulator can be made adjustable. if you flick the throttle and see the needle move, replace the pump. I recommend a TPI pump from the same generation third gen. checking fuel pump voltage @ the tank with vehicle running is a good idea, should be same as battery voltage give or take a few milivolts. ability to datalog is invaluable as well with any EFI vehicle.
morgsie is offline  
Old 07-09-2019, 10:26 AM
  #3  
Junior Member
Thread Starter
 
Join Date: Jul 2017
Posts: 42
Received 0 Likes on 0 Posts
Car: 1989 Chevy Camaro RS
Engine: 305 TBI
Transmission: 700R4
Re: Car wonít start unless I press the gas

Originally Posted by morgsie View Post
start with fuel pressure, you will need to get an adapter because there is no provision to check from factory. IIRC, you need 9-13 psi. I like to see 13-14 psi, no less. the stock regulator can be made adjustable. if you flick the throttle and see the needle move, replace the pump. I recommend a TPI pump from the same generation third gen. checking fuel pump voltage @ the tank with vehicle running is a good idea, should be same as battery voltage give or take a few milivolts. ability to datalog is invaluable as well with any EFI vehicle.
Iíve never checked fuel pressure before. Where do I plug in the gauge at? Thanks for the reply.
Kyler_89RS is offline  
Old 07-09-2019, 10:48 AM
  #4  
Sponsor
iTrader: (82)
 
Tuned Performance's Avatar
 
Join Date: Dec 2004
Location: Mile High Country !!!
Posts: 11,937
Received 14 Likes on 14 Posts
Car: 1967 Camaro, 91 z28
Engine: Lb9
Transmission: M20
Axle/Gears: J65 pbr on stock posi 10bolt
Re: Car wonít start unless I press the gas

There are two ways of checking the fuel pressure. One adapter is for where the fuel filter is. There is another one for at the throttle body.
https://www.summitracing.com/parts/anm-01800001465
https://www.summitracing.com/parts/anm-cp7818/
a lot of parts stores rent the tester and have the adapters included.

Last edited by Tuned Performance; 07-09-2019 at 11:00 AM.
Tuned Performance is offline  
Old 07-09-2019, 07:41 PM
  #5  
Junior Member
Thread Starter
 
Join Date: Jul 2017
Posts: 42
Received 0 Likes on 0 Posts
Car: 1989 Chevy Camaro RS
Engine: 305 TBI
Transmission: 700R4
Re: Car wonít start unless I press the gas

Originally Posted by Tuned Performance View Post
There are two ways of checking the fuel pressure. One adapter is for where the fuel filter is. There is another one for at the throttle body.
https://www.summitracing.com/parts/anm-01800001465
https://www.summitracing.com/parts/anm-cp7818/
a lot of parts stores rent the tester and have the adapters included.
Hopefully Autozone has a rental. If my fuel pressure is too low, should I start by changing my fuel filter and test it again?
Kyler_89RS is offline  
Old 07-11-2019, 03:03 AM
  #6  
Supreme Member
 
Join Date: Feb 2011
Posts: 1,087
Likes: 0
Received 0 Likes on 0 Posts
Re: Car wonít start unless I press the gas

Originally Posted by Kyler_89RS View Post
Hopefully Autozone has a rental. If my fuel pressure is too low, should I start by changing my fuel filter and test it again?
Yes...but expect to need a fresh fuel pump. It's not likely the filter is the only problem when there's low fuel pressure.

Poor electrical supply to the pump (including the ground side of the circuit), clogged inlet "sock", and a plain ol' failed fuel pump are very likely root causes.

As far as the electrical supply, be sure to test both the voltage (near the pump) and the amperage draw of the pump.
Schurkey is offline  
Old 07-11-2019, 09:42 AM
  #7  
Supreme Member
 
Join Date: Jun 2002
Location: North East GA
Posts: 1,963
Likes: 0
Received 4 Likes on 4 Posts
Car: 1989 Firebird
Engine: 5.7 LS1
Transmission: T56
Re: Car wonít start unless I press the gas

I would also borrow a timing light from auto zone and check timing.

Has the car done this since you owned it? Did anything change before hand? Really bad or incorrectly gapped spark plugs is also something to look at (and its free to inspect )

If you determine low fuel pressure do not buy a cheap pump, that is literally the one part I always insist on being OEM or a high quality race part. Its too much work to replace to cheap out on.

I don't think the fuel pressure tester autozone has on their loaner program comes with the adapter, they do sell one for around $20. The TBI doesn't have a port to test on you have to take a line loose and put the adapter in place.
Aviator857 is offline  
Old 07-11-2019, 08:31 PM
  #8  
Junior Member
Thread Starter
 
Join Date: Jul 2017
Posts: 42
Received 0 Likes on 0 Posts
Car: 1989 Chevy Camaro RS
Engine: 305 TBI
Transmission: 700R4
Re: Car wonít start unless I press the gas

Originally Posted by Aviator857 View Post
Has the car done this since you owned it? Did anything change before hand? Really bad or incorrectly gapped spark plugs is also something to look at.
Iíve had the car for 2 years and this has always been a problem. I was only 15 when I got the car and someone told me that the car should do that because itís 30 years old I changed the spark plugs a year ago with the proper gap. Since then Iíve put maybe 1000 miles on it, so I donít think the problem is there. I havenít touched the plug wires though.
Kyler_89RS is offline  
Old 07-12-2019, 08:59 PM
  #9  
Junior Member
Thread Starter
 
Join Date: Jul 2017
Posts: 42
Received 0 Likes on 0 Posts
Car: 1989 Chevy Camaro RS
Engine: 305 TBI
Transmission: 700R4
Re: Car wonít start unless I press the gas

Originally Posted by Schurkey View Post
Yes...but expect to need a fresh fuel pump. It's not likely the filter is the only problem when there's low fuel pressure.

Poor electrical supply to the pump (including the ground side of the circuit), clogged inlet "sock", and a plain ol' failed fuel pump are very likely root causes.

As far as the electrical supply, be sure to test both the voltage (near the pump) and the amperage draw of the pump.
Changed the fuel filter. The fuel pump is making a growling noise now. Very loud. I made sure to put the filter in the right way. I was very careful because I donít want to snap or twist the fuel lines. No gas is leaking. Do you think itís about time to replace the pump?
Kyler_89RS is offline  
Old 07-13-2019, 05:52 PM
  #10  
Supreme Member
 
Join Date: Feb 2011
Posts: 1,087
Likes: 0
Received 0 Likes on 0 Posts
Re: Car wonít start unless I press the gas

Originally Posted by Kyler_89RS View Post
Changed the fuel filter. The fuel pump is making a growling noise now. Very loud. I made sure to put the filter in the right way. I was very careful because I donít want to snap or twist the fuel lines. No gas is leaking. Do you think itís about time to replace the pump?
In MY driveway, no fuel pump gets replaced without testing the electrical supply (and ground) first. Voltage AND amperage of the supply, voltage on the ground near the pump.

In your case, I think it's fairly certain that the pump is damaged. I'm a little mystified that the pump didn't make noise until after the fuel filter was replaced. That's not something I can explain.
Schurkey is offline  
Old 07-16-2019, 11:13 AM
  #11  
Supreme Member
iTrader: (1)
 
Join Date: Mar 2017
Location: Portland, OR
Posts: 2,498
Likes: 0
Received 17 Likes on 12 Posts
Car: 86 Imponte Ruiner 450 GT
Engine: Various
Transmission: 700R4 3000 stall.
Axle/Gears: 9 Bolt Torsen 3.70
Re: Car wonít start unless I press the gas

Originally Posted by Kyler_89RS View Post
Changed the fuel filter. The fuel pump is making a growling noise now. Very loud. I made sure to put the filter in the right way. I was very careful because I don’t want to snap or twist the fuel lines. No gas is leaking. Do you think it’s about time to replace the pump?
Plugged or partially plugged filters will put excessive load on the pump. Resulting in eventual damage. Likely the pump was working harder and turning slower before the filter change and is now running faster and that causes noises.

These old style pumps were junk then, and are even worse junk now. Get a Deatschwerks DW200 pump kit for a C4 vette.

GD
GeneralDisorder is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
TysonNorthcott9
Tech / General Engine
4
12-27-2013 07:44 AM
J0hn_J0hn08
Tech / General Engine
3
06-25-2010 02:01 PM
hambone1
TPI
4
06-09-2009 12:07 PM
fleahy
Electronics
1
10-14-2008 09:16 PM
Svelte_SS
TPI
1
11-27-2003 04:48 PM


Thread Tools
Search this Thread
Quick Reply: Car wonít start unless I press the gas


Contact Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: