HER2702
Member
- Joined
- Aug 7, 2016
- Messages
- 31
- Reaction score
- 1
- Points
- 8
- Location
- Arab, Alabama
- Vehicle Year
- 1994
- Make / Model
- Ford
- Engine Size
- 4.0L OHV
- Transmission
- Manual
Hey guys, it's me again. Well JY engine has turned out pretty well. I guess I got lucky on that one. It's been running smooth and strong until about 2 weeks ago. Cold / hot, it doesn't seem to matter much but when I start it up it runs fine for about 1 - 1 1/2 minutes then it starts to run rough and give off that raw fuel smell. This will continue for about another minute or so and then it smooths out and runs fine from then on. My first thought was ECT sensor sending bad info to the PCM. I'm pretty sure it was the original sensor so I changed it out. No improvement. Checked the FPR for leaking through, all good. Fuel pressure at 35-40 psi before, during, & afterwards. So NOW what? It also started doing some strange things in the dash at about the same time. OK, maybe I didn't get a good ground somewhere when I put the new engine in... I went through and double checked all the grounds even ohming them out back to the battery & chassis ground. Nothing amiss there either. Just to be sure I ran a couple of temporary redundant grounds to check. No difference. It was then that I saw the link to www.auto-diagnostics.info describing the problems with 25 year old EEC IV PCMs going bad. I had never really given much thought to the PCM going bad from age but the symptoms sounded pretty familiar. So I need a little advice from anybody that has run into this before. I'm relatively sure that's the problem just not sure enough to plop out $200 for a reman one. I know that the capacitors can be replaced but I'm not sure that I'm still steady enough to operate on it myself. Besides, if I gotta replace any part of it i'd rather replace it all with one that has at least been looked at and tested by somebody who knows better than me.
Here's all the symptoms:
1) Rough idle for 1-2 minutes after startup (cold or warm),
2) The idiot light for the battery sometimes comes on, sometimes flickers (14.3 to 14.6 at the time. Checked with a known good Fluke digital VOM),
3) The park brake light (which hasn't worked since I bought the truck many moons ago) sometimes lights up when I first start up. But only sometimes.
4) The cruise control has also stopped working although I don't think it's related to this problem.
Any ideas / suggestions are deeply appreciated. I'll be the 1st to admit that what I know is far less than what I don't know. Thanks guys.
Here's all the symptoms:
1) Rough idle for 1-2 minutes after startup (cold or warm),
2) The idiot light for the battery sometimes comes on, sometimes flickers (14.3 to 14.6 at the time. Checked with a known good Fluke digital VOM),
3) The park brake light (which hasn't worked since I bought the truck many moons ago) sometimes lights up when I first start up. But only sometimes.
4) The cruise control has also stopped working although I don't think it's related to this problem.
Any ideas / suggestions are deeply appreciated. I'll be the 1st to admit that what I know is far less than what I don't know. Thanks guys.