1998 Ford Ranger Possible bad pcm

Tiny
40MPG
  • MEMBER
  • 1998 FORD RANGER
  • 2.5L
  • 4 CYL
  • 2WD
  • MANUAL
  • 140,000 MILES
Blown head gasket first, replaced head, and associated topend gaskets, including exaust, lower intake and upper plenum gasket, new plugs/wires, timing belt and water pump. Hard to start initially, runs but no power, checked for vacuum leaks found none. Drives like it is in limp mode, went to auto zone to see if there are any codes stored. There was no power at diagnostic port, verified fuses, relay and diode, all good. Checked voltage at IAC, 4 V. With engine running can disconnect maf and/or IAC, and engine still runs, any ideas?
Do you
have the same problem?
Yes
No
Friday, October 30th, 2015 AT 11:05 AM

3 Replies

Tiny
HMAC300
  • EXPERT
Make sure your cam timing is correct it may not be then have check for no power to read codes as you may have one or two and not know it.
Was this
answer
helpful?
Yes
No
Friday, October 30th, 2015 AT 12:02 PM
Tiny
40MPG
  • MEMBER
Found why I had no power at Diagnostic port, Some one prior had installed an Alarm or a Payment Device, that used a jumper (Obd2 male to Female) that scavenged Power and ground from the Obd connector, had come unplugged from the vehicle harness. I still have an issue with the engine running like it is in limp mode, will rev to around 2000 rpm and then fade and pulse, I have rechecked timing and I have ohm'ed out all sensors and replaced the IAC valve and have also checked the Compression, 190-193 on all cyl. Fuel pressure is around 65 psi at idle and did not drop when revved,
I plan on replacing the maf and Cam position sensors. I have read on another forum that a bad oil pressure check valve could cause the Hydraulic lifters to hold the valves open and cause lack of compression when revved, I have had the Vacuum line off of the brake booster, to check vacuum and when revved the vacuum drops and will Blow when the engine starts to fade at higher rpm,
Any thoughts or suggestions?
Was this
answer
helpful?
Yes
No
Tuesday, December 8th, 2015 AT 11:06 PM
Tiny
HMAC300
  • EXPERT
You can check your timing all you want but the pcm controls it. If you pulled the dist you need a local pro with a scanner to reset cam to crank sensor schyncronization, which you can't do. Your best bet is to scan for codes and check fuel pressure before you start to throw money away at good parts. Also check for vacuum leaks. Otherwise you are just throwing money at it until you actually either give up and have a pro look at it to see what is really wrong. Auto parts can scan for codes and rent gauge for fuel pressure.
Was this
answer
helpful?
Yes
No
Wednesday, December 9th, 2015 AT 7:07 AM

Please login or register to post a reply.

Recommended Guides