Code P0340!! Alternator???

[Hardwareman]

I just did a 2.5 swap into my 95 Ranger that had a 2.3 in it. Before you ask why, the reason was because my old 2.3 had 370,000 miles on it and the blowby and loss of power was horrible. I managed to fix my breaking timing belt tensioner problem as well.

Anyways before I did the swap I had a code of P0340 on the old 2.3. I figured old worn out motor, but after I installed the 2.5 I got the same code along with the random misfire and sputtering problem. What gives! A whole different engine and a whole different cam sensor too! I basically only used the 2.5 block so the problem has to lie somewhere within the older components right?

I did some online searching and found that the voltage regulator on the alternator can send wierd current through the wiring harness and cause my symptoms along with this code. And my wife and I were talking about when I got this alternator. It was right around April when I needed my smog check and I remember being worried because that's when the misfire started on the 2.3 (not as bad back then though) and I was praying my truck would pass.

Does this make sense to anyone? Thanks



Allen

 

[Hardwareman]

Well I changed the alternator out on Thursday and all seemed well until today when the CEL came on again with the same code.........P0340!!!

The sputtering/miss was and is gone while driving but it sounds like it's barely there out of the tailpipe when the motor's idling.

So I stopped at AutoZone and cleared out the code today. Let's see how long it stays off for this time. Another thing that's wierd is when I disconnect the IAC Valve or the TPS sensor there is no change in engine rpm's.

Maybe there is a ground problem somewhere after all in the wiring. Great! Any idea on where to look or should I remove the whole wiring harness and check it out? Thanks.



Allen

 

[pimtool]

I had the same code. 98 explorer with 4.0. I was back probing the computer and the cam sensor to get some voltage reading and such. I must have had a bad connection somewhere cause it went away after I poked and prodded a little.
Prior to doing this it woul set mil after two start ups.
I already changed the sensor and that didnt help.
Good luck.
I also disconnected the alternator and that did nothing.

 

[Hardwareman]

Thanks for the reply! My hair's getting really thin with this problem man!

I actually took it to a shop and left it overnight on Wednesday and picked it up on Thursday. When I dropped it off the guy told me he would tell me what's wrong with it for $75.00 and then if I had the repairs done there he would apply half of that towards the work. Turned out he ripped me off to the tune of $75.00 because he wanted an additional 3-4 hours time at $75.00 an hour. I was pissed.

What's puzzling me is the fact that the condition actually improved after I swapped alternators, but not enough to clear it up entirely.

Where were you prodding around at if I may ask? Thanks again.



Allen

 

[pimtool]

You should be able to do something about some of these F'ers ripping people off like its there job.

Anyway, mine is probably different than yours. My cam sensor has a three wire plug in.
I think the two on the ends are for power and ground, and the middle one is reference voltage to the computer. My computer is right there on the firewall. So first I was looking for continuity through each wire, which I had.
Then not really knowing what else to do, I figured I would back probe the computer reference wire to see if anything changed when running and not. Also seeing if I had 12 volt and ground on the others.
So I cleared the code for giggles and it hasn come back on yet. Its only been a day so we will see.
You may also have something else going on that is complicating the whole mess.

I just got lucky.