Ok so after changing the solenoids in this god forsaken 4L60E it ran fine for a day. Well now it's back to running fine after I fire it up, through one set of shifts, or until I stop the first time, then it's third gear unless I pull it down to second manually and no overdrive. Yet no ses light, I had it scanned before and no codes, so I have to ask, what are the main things I should look @ to start running this problem down? I pulled the ecm fuse and got 2 stops out of it before it went into default. So I think that's a good sign that it's some form of glitch and not the tranny shot to hell. That being said, when it goes into default it has a different sounding idle, and wants to idle higher, typical for default I'm told. So where should I start? Back @ aquare one with the volt ohm meter and spec out everything from the maf, map, iac, tps, iat, and so on? Just to be sure once again that the obd system is operational I disconnected the tps and the fans kicked and the ses came on. I'm literally @ my breaking point here. Any and all help would be appreciated. Or @ least a bang head here sign that's not already covered with blood.

 

Have you used a scanner to see if the park/neutral position is being indicated correctly (wild guess)?

 

No sir I haven't, that would make it so I have one up shift, and then lose first and fourth? I will look into that, can I check that without a scanner? Jic this scanner won't show that.

 

Not sure, just a wild guess. You didn't mention it, so I brought it up. Maybe people that frequent the drivetrain forum would be better equipped to answer. You could use a schematic and check for operation of the p/n switch, but only a scanner will tell you if the computer is actually seeing it.

 

Thank u very much, I appreciate the info, it's sure a possibility that I would've never thought of. I'm thinking it's probably something little that I'm overlooking, also, what ever it is, changes the idle of the car, when I first start the car, and if I keep it in first gear, and creep it around, and stop, everything is fine, the idle is normal, but as soon as I let it shift into second, that's when it all changes, and I lose first and 4th, and my idle sounds way different, and tends to want to idle high. I'm just @ the end of my rope here. Obd2 cars though more complex are easier to work on. Never had this much trouble diagnosing a nissan lol. The big thing that really sucks is with the car doing this I don't want to drive it and possibly do damage to anything, and the local chevy dealership had a fire a while ago and lost all of the tools for scanning the obd1 cars. Have to go all the way to beaumont for that, not a real long drive, but something I don't want to put the car through. Guess I may have to though. But all that said, this could be as simple as a wire grounded or something shorting out. Do u have a list of components and conditions that don't cause ses lights that when combined would cause limp mode? I know it's a lot to ask, but your THE MAN when it comes to this. So if anybody may be able to steer me in the right direction, it's u. Thanx for the help, I appreciate it moe than u know.

 

I'm not a transmission person, but there is a list of conditions and transmission trouble codes on my website. There is a trouble code link in my sig. Anyone that works on their own car really needs to own a scanner.

 

If you feel this is a tranny problem, and not engine related, it belongs on the "Drivetrain" forum.

 

Then you may want to merge it with the one he subsequently started there.

 

I'm pretty sure this is engine related, idk if it's a sensor or what, but my tranny supposedly checks out. Just found that out today.

 

Sorry if I broke any rules in starting threads in 2 different areas, it wasn't my intention. When u said ask someone in the drivetrain area, I did just that. So my tranny has checked out, so I'm sure that this problem is electrical, but no codes. I'm kind of getting the feeling that possibly my pcm is fried. I've read that when a pcm starts to go for the obd1 cars, a sign is that it won't store or log codes. With all of the issues I've had with the car it should've given me some form of an ses. Is it true that I could get an obd 2 pcm and have the things I don't need or have tuned out and run an obd2 pcm? I don't know what should throw a code, but it stands to reason that if I had a 1-2 shift solenoid failure on my previous tranny, and it didn't throw a code, and several other conditions, including vacuum, egr, disconnected sensors like the ait and even a cut wire on my tps, and none threw an ses, I think it's a somewhat logical conclusion that I may be looking @ a pcm malfunction. So if my reasoning is correct, should I start looking for a good pcm, and swap just to see what happens, and go from there? Also I've heard rumors that an obd2 pcm is somehow a 10hp upgrade? Idk if that's even accurate, something to do with the speed of the pcm, and some other stuff I don't recall. But the fact is that it does have more leeway for tunning, and is able to handle more lines of code, so could I really go wrong by having an obd2 pcm programmed and replacing my obd1 paperweight? TIA

 

There are way more people that swap FROM OBD-II to I for tuning purposes. If you are going the replacement route, my advice is to stay with OBD-I. There is no 10HP difference in PCMs and I is cheaper to tune.

 

If I thought there was a problem, I would have closed one of the threads and merged them. But this is a case where it could go either way, so it makes some sense to ask on two different forums.

We've been wrestling with realigning and simplifying the forum lineup for almost a year, and Jason has announced there are changes coming. I hope they make them soon.

 

Well I've embarked on the hunt for what ever I can possibly find in the wiring. When I opened up the dash, I saw a big problem, I had a wiring diagram, but the harness was added to, after market alarm that stacked onto the key less remote entry. No biggy except it had been sort of removed. The shock sensor, the wires, all of it except the alarm unit were still in there, and whom ever did the install of the alarm did a very bad job. Wires appear to be striped from some other cars harness, didn't insulate connections, or even bare wires after removing the alarm. One athing that quickly drew my eye was that there is a wide white electrical connector, it has 18 wires going into it, but it's not hooked up to anything. I may be off on my guess as to the purposebof the connector, but it looks factory, and it's harness has been spliced into, and the addition of 2 small fuse blocks, each holding a 20 amp fuse. Does anyone have a pic if this connector? Oh drivers side under the dash. I am actually looking for some pics to compare mine to, that is if anybody is willing to share. I would like to see what the factory, or @ least straighten the mess up. All help is appreciated. .also depending on we find out under connections. Thanx for all the help.

 

Ok so I now am in the process of running down wires and circuits from the pcm, not to sound to stupid, but I don't know as much about these cars as I'd like to. That said, the amps from the pcm to the component, do they step down anywhere from the pcm to the part the go to? I wouldn't think so, but I just want to make sure that if there isn't already a problem, I don't cause one by using an assumption or mis information on my behalf. Is the a wiring diagram that would simply show the wires and their perspective destinations along with voltage and amperes values. Thanx for the help. And I apologize for the laughable question, but I'd rather ask and be given the correct info, and not mess up my pcm.

 

The PCM pinouts on my website list the voltage potentials on the wires, but if you are looking for drawings of where everything goes, the manual has literally hundreds of them. My advice is to find a used factory manual.