Notices
1987 - 1996 F150 & Larger F-Series Trucks 1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks
Sponsored by:
Sponsored by:

Possible PCM Failure

Thread Tools
 
Search this Thread
 
  #1  
Old 02-05-2012, 06:28 PM
Bobby Brown's Avatar
Bobby Brown
Bobby Brown is offline
New User
Thread Starter
Join Date: Feb 2012
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Possible PCM Failure

A coupld of days ago my '95 F15 4.9L started but ran very rough. I turned it off, tried it again with same result. I had to wait til the next day to try it agin and it ran fine. Today, it will not start. I noticed that the fuel pumps ( I tried both tanks) continued to run with the KOEO condition.I have good spark, fuel in both tanks, the fuel filter is two months old. Threads here indicate a bad PCM but there doesn't seem to be any positive way to trouble shoot the problem beyond the fuel pump continuing to run rather than time out. I would rather not start changing expensive parts as a troubleshooting method.
I would greatly appreciate any advice.
Thanks in advance.
 
  #2  
Old 02-06-2012, 06:45 AM
Lazy K's Avatar
Lazy K
Lazy K is offline
Post Fiend
Join Date: Jan 2005
Posts: 8,402
Likes: 0
Received 7 Likes on 7 Posts
On advice from subford if you unplug the PCM and the fuel pump then stops running it is a good bet that the PCM is bad.
 
  #3  
Old 02-06-2012, 06:56 AM
Bobby Brown's Avatar
Bobby Brown
Bobby Brown is offline
New User
Thread Starter
Join Date: Feb 2012
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Sounds reasonable. Wish they would have put the thing in a more accessible location. Arms not long enough.
Thanks
 
  #4  
Old 02-06-2012, 07:55 AM
subford's Avatar
subford
subford is offline
Fleet Owner
Join Date: Aug 2005
Location: Easton,Ks
Posts: 23,602
Likes: 0
Received 225 Likes on 176 Posts
Sounds like the injectors have quit firing also now. Take the PCM Computer out and open it up. You should be able to see what is wrong in the area around the electrolytic capacitors in it.
Some posters have replaced the electrolytic capacitors if nothing else looks burned up and that fixed it.

If you send it off that is about the only thing that gets done (electrolytic capacitors replaced) by the repair places that fixes them.
That is why they do not always work like they should when you get a rebuilt one from an auto parts store as it was something else wrong with it other than the filter caps.
 
  #5  
Old 02-06-2012, 12:26 PM
Bobby Brown's Avatar
Bobby Brown
Bobby Brown is offline
New User
Thread Starter
Join Date: Feb 2012
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
I will get a new unit but I am having a problem identifying the component. I saw in a photo that it is on the firewall under the left hood hinge. There are two devices ther annd the one outboard closest to the fender well was indicated as the PCM. I opened that and it appears to be only a bulkhead connector. I intend to open the other device now to what is there.
Thanks to all for the help.
 
  #6  
Old 02-06-2012, 01:28 PM
subford's Avatar
subford
subford is offline
Fleet Owner
Join Date: Aug 2005
Location: Easton,Ks
Posts: 23,602
Likes: 0
Received 225 Likes on 176 Posts
Here is the location:



It looks like this:


/
 
  #7  
Old 02-06-2012, 02:46 PM
Bobby Brown's Avatar
Bobby Brown
Bobby Brown is offline
New User
Thread Starter
Join Date: Feb 2012
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
I really appreciate your time and knowledge. I now have removed the connector and the boot. I tried to pull the device out through the firewall, but it hits the fenderwell. I cant see it inside the cab at all. Does it come out behind the kick panel inside?

Thanks again
 
  #8  
Old 02-06-2012, 04:39 PM
rla2005's Avatar
rla2005
rla2005 is offline
Hotshot
Join Date: Oct 2005
Location: Kentucky
Posts: 19,573
Received 1,157 Likes on 915 Posts
Use a broom handle to push down on the plastic inner fender to gain some clearance to pull out the PCM or remove the screws that attach the liner and remove it.

No, the PCM comes out from the engine side.
 
  #9  
Old 02-06-2012, 06:25 PM
Bobby Brown's Avatar
Bobby Brown
Bobby Brown is offline
New User
Thread Starter
Join Date: Feb 2012
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Thanks to all. I have it out-now to find a reliable replacement. i have two options, O'Reilly or an independent company that can exchange mine for a re-conditioned one. Dont have price on either, but have to get it.

Again, I wish to thank all of you for your help. Could not have done it without you.
 
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bigredtruck
1987 - 1996 F150 & Larger F-Series Trucks
83
06-14-2020 02:14 PM
Mattladoux
Small Block V8 (221, 260, 289, 5.0/302, 5.8/351W)
4
04-29-2017 04:15 PM
debsco731
1997 - 2003 F150
9
02-05-2017 10:04 AM
Veritas167
1987 - 1996 F150 & Larger F-Series Trucks
3
07-03-2007 04:43 AM
tampabandit
1987 - 1996 F150 & Larger F-Series Trucks
5
11-08-2004 10:49 PM



Quick Reply: Possible PCM Failure



All times are GMT -5. The time now is 06:14 PM.