2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Weak coils = poor hot engine start?

Thread Tools
 
Search this Thread
 
Old 10-05-16, 06:52 AM
  #1  
Senior Member

Thread Starter
iTrader: (6)
 
freq's Avatar
 
Join Date: Jan 2006
Location: Colorado
Posts: 679
Received 2 Likes on 2 Posts
Weak coils = poor hot engine start?

Can weak/failing coils cause an engine to not start when hot, but start with no problem when cold?
Old 10-05-16, 08:11 AM
  #2  
Licensed Zip Tie Mechanic

 
PinkRacer's Avatar
 
Join Date: May 2004
Location: Halifax, NS
Posts: 510
Likes: 0
Received 2 Likes on 2 Posts
Certainly possible. That or compression.
Old 10-05-16, 08:26 AM
  #3  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Or a problem with the pressure regulator control valve or a bad water thermosensor are two other possibilities.
Old 10-05-16, 08:56 AM
  #4  
MECP Certified Installer

 
jjwalker's Avatar
 
Join Date: Feb 2009
Location: Mesquite, TX-DFW
Posts: 3,176
Likes: 0
Received 2 Likes on 2 Posts
If you can bump the key to start (as in just, quickly tap the start position with the key) and then actually try and start the car and it fires right up, you have a fuel pressure issue.
Old 10-05-16, 09:40 AM
  #5  
Penis Healthy

iTrader: (5)
 
FührerTüner's Avatar
 
Join Date: Jul 2013
Location: █▬█ █▄█ █▬█ █▄██▬█ █▄█ █▬█ █▄█
Posts: 2,595
Received 795 Likes on 452 Posts
+1 on compression
Old 10-05-16, 09:43 AM
  #6  
Senior Member

Thread Starter
iTrader: (6)
 
freq's Avatar
 
Join Date: Jan 2006
Location: Colorado
Posts: 679
Received 2 Likes on 2 Posts
Originally Posted by jjwalker
If you can bump the key to start (as in just, quickly tap the start position with the key) and then actually try and start the car and it fires right up, you have a fuel pressure issue.
What does bump starting the car do? Does it give it an initial shot of fuel? FYI-I'm running a Haltech Sprint RE.
Old 10-05-16, 09:44 AM
  #7  
Senior Member

Thread Starter
iTrader: (6)
 
freq's Avatar
 
Join Date: Jan 2006
Location: Colorado
Posts: 679
Received 2 Likes on 2 Posts
Originally Posted by Fuhnortoner
+1 on compression
The compression is good.
Old 10-05-16, 09:47 AM
  #8  
MECP Certified Installer

 
jjwalker's Avatar
 
Join Date: Feb 2009
Location: Mesquite, TX-DFW
Posts: 3,176
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by freq
What does bump starting the car do? Does it give it an initial shot of fuel? FYI-I'm running a Haltech Sprint RE.
I missed the aftermarket computer part. On a stock car, it causes the fuel pump to prime the system for 3 seconds.

The FC ignition system is very stout and big, the only thing I can think of that may be a problem with it is from what I have read in the past, is Haltech computers hate the stock CAS.

Last edited by jjwalker; 10-05-16 at 09:55 AM. Reason: More info
Old 10-05-16, 09:54 AM
  #9  
Senior Member

Thread Starter
iTrader: (6)
 
freq's Avatar
 
Join Date: Jan 2006
Location: Colorado
Posts: 679
Received 2 Likes on 2 Posts
Originally Posted by jjwalker
I missed the aftermarket computer part. On a stock car, it causes the fuel pump to prime the system for 3 seconds.
Ok. There's a map called Prime Pulse Time in my Haltech that does something similar. Not sure if it's 3 seconds, but it does prime the system. I'll give that a shot.

Also, now that I'm thinking about it, I think I remember having to adjust that map a bit higher for the higher temps in order for easier starting.

--so, a failing fpr will have a hard time pressurizing at higher temps?
Old 10-05-16, 10:04 AM
  #10  
MECP Certified Installer

 
jjwalker's Avatar
 
Join Date: Feb 2009
Location: Mesquite, TX-DFW
Posts: 3,176
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by freq
Ok. There's a map called Prime Pulse Time in my Haltech that does something similar. Not sure if it's 3 seconds, but it does prime the system. I'll give that a shot.

Also, now that I'm thinking about it, I think I remember having to adjust that map a bit higher for the higher temps in order for easier starting.

--so, a failing fpr will have a hard time pressurizing at higher temps?
It can, but unlikely.

I had the same problem but could bump the key and fire the car right up. Weirdly enough, my fuel pump upper o-ring failed and was bleeding all the fuel back into the tank.
Old 10-05-16, 11:59 AM
  #11  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Originally Posted by freq
Ok. There's a map called Prime Pulse Time in my Haltech that does something similar. Not sure if it's 3 seconds, but it does prime the system. I'll give that a shot.

Also, now that I'm thinking about it, I think I remember having to adjust that map a bit higher for the higher temps in order for easier starting.

--so, a failing fpr will have a hard time pressurizing at higher temps?
If you are referring to the pressure regulator control valve it is a separate item from the fpr. The valve is used in hot starts as it adds pressure to the fuel system.

On a hot start there should be no vacuum on the hose connected to the FPR (no vacuum situation lasts for close to a minute depending on the model), otherwise there should always be vacuum.

Last edited by satch; 10-05-16 at 12:16 PM.
Old 10-05-16, 12:29 PM
  #12  
Senior Member

Thread Starter
iTrader: (6)
 
freq's Avatar
 
Join Date: Jan 2006
Location: Colorado
Posts: 679
Received 2 Likes on 2 Posts
Originally Posted by satch
If you are referring to the pressure regulator control valve it is a separate item from the fpr. The valve is used in hot starts as it adds pressure to the fuel system.

On a hot start there should be no vacuum on the hose connected to the FPR (no vacuum situation lasts for close to a minute depending on the model), otherwise there should always be vacuum.
Are you referring to #3 in the diagram? I don't have any of those solenoids. Haven't had them for several years now. I'm assuming that since this is a recent problem, that the Pressure Regulator Control Solenoid Valve isn't the issue. Please correct me if I'm wrong.


Old 10-05-16, 01:18 PM
  #13  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Originally Posted by freq
Are you referring to #3 in the diagram? I don't have any of those solenoids. Haven't had them for several years now. I'm assuming that since this is a recent problem, that the Pressure Regulator Control Solenoid Valve isn't the issue. Please correct me if I'm wrong.
Probably not then.

Last edited by satch; 10-05-16 at 01:20 PM.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
modernbeat
Introduce yourself
7
10-13-16 07:32 PM
fritts
Old School and Other Rotary
3
10-07-16 09:27 PM
pacman1969
Race Car Tech
0
10-02-16 06:29 AM



Quick Reply: Weak coils = poor hot engine start?



All times are GMT -5. The time now is 05:58 PM.