1992 240 SX Convertible - Auto Trans. stays in 3rd gear.

[09quickly]

Will do, did not consider the possibility of two seals in the receptacle end of the TPS plug. P.S. - GET SOME SLEEP!!! I have been noticing the time associated with your responses and you are up and running entirely too early! 09quickly

[NISTECH]

LOL , I am on the west coast. It was about 5 am PT when I posted. I wake up some time around then. The alarm is set for 6 but I rarly have it wake me up as I wake up earlier.

[09quickly]

Re-checked the vaccuum connections as you suggested, all appear to be in good shape, no holes visible, and connected. The rubber snorkle tube from the plastic intake tube to the throttle body is starting to show some age in between some of the ribs, but no holes all the way through. When I removed the throttle body during the first go-around, I did not replace the thin, plastic gasket between the back of the throttle body and the intake funnel. All appeared to be okay, I just bolted it back up and tightened it down. Possibility of a leak there? After re-checking and re-tightening everything last night, it runs "a little" better, but still cuts out, runs rough, etc. when it starts to run rough or starts to stall and I depress the accelerator, the roughness actually gets worse, then the engine seems to catch up to where the accelerator is, and the rpm's go up and it smooths out. I guess I'm saying a severe hesitation in throttle response. Also, if I feather the accelerator with rapid depress/release, the increase in rpm's is smoother and quicker. I have a feeling I just explained myself in a complete circle, but that's the best I can do without showing you. 09quickly

[yellow_jacket]

After trying to read through this entire post, I hope I get your information right.

It sounds like you did not try to run the transmission through the gears manually after you fixed the shifter issue. Putting the shifter into the 1 position should eliminate any electrical issues are it should be running in pure hydraulic mode. This is not the case with all manufacturers, but I am pretty sure Nissan did this.

Also, have you tried completely disconnecting the control harness from the transmission? This should also kick it into a hydraulic mode which will cause the shift points to be raised, but it will shift through the gears.

If the car fails to shift under hydraulic power, this is an indication of an internal fairlure of the transmission.

[09quickly]

Hey NISTECH - Is the last post my next step? I doesn't address the vacuum leak issue anymore is why I ask. I will gladly take suggestions from folks in the know, I just want to make sure I keep going in one direction. 09quickly

[NISTECH]

I dont know where that info came from yellow jacket but it is absolutly false information. All nissan automatic trans built at least starting in the late 80's use and electronic revolution sensor to determine shift points. This sensor replaced the old governor. If you unplug the electrical harness to the trans it will go into third gear and stay there. That is done so you can at least get the car to a shop to get fixed. It will NEVER shift with out shift solonoid a and b directing the hydrolic pressure to the appropriate places in the valve body.

Jim, I would be suspect of your throttle gasket but honestly the way you just described the acceleration it sounds like an airflow problem, it did in the begining but I was basing the fact it didnt seem a problem initially so I went for hose leaks. Like I said there is like a 2 inch hose under that plastic tube that attaches to a baffle. That hose was my first thought cause it is big enough to cause severe maf reading problems. But you may have disturbed the airflow meter connection during the repair. SO unplug the airflow meter and see if your idle improves at all. Also look at the terminals and see if they have corrosion on them. Also take voltage readings off of it while its plugged in from the back of the terminals. You will need to gently pull back the rubber boot to gain access to the wires. You should see 3 voltages at idle. ~12v,~1.3v and less then .2v. If the lowest voltage wire is not less then .2v you need to add an additional ground. This is a pretty common problem on nissans. This will have nothing to do with your shift condition if it still exists ,I am unclear if that is still a problem or not. Did you get the TPS to plug in correctly?

[09quickly]

To the best of my knowledge, yes. When installing, I noted the positon of the flat part of throttle in the throttle body, (I'm sure it has a specific name, but that's the best way I can describe it) and matched i up with the flat part of the cam in the TPS. Once fully seated, I had to turn the TPS very little to get it to align toward the front of the engine and the receptacles it needs to connect to. If it needed to be installed on the throttle rod 180 degrees off and rotated in some fashion from that point toward the front, I did not do that. Still no shifting.

The hose you are describing sounds like the one directly under the plastic tubing, next to the radiator, about the size of a radiator hose. THAT hose has small, visible cracks and splits in it, but what I was able to see is above the clamp. I did not look a the entire thing, I couldn't figure out where it leads to to be honest with you. Is it a b***h to deal with?

Are the Airflow Meter and the MAF one in the same? I know where the MAF is, and it appears a whole lot easier to work on than the TPS. Thanks for your continued guidance. 09quickly

[NISTECH]

MAF=Mass Air Flow meter. Same part. You put the TPS on right I was wondering if you got the connector issue resolved. The big hose underneath is not that bad to deal with. It should only be about 2 to 4 inches in lenght then attach to a plastic box type thing [baffle].

Get a look at your airflow readings at idle. But I am also perplexed as to why the trans is not shifting and there not being a code in the trans system. Total control shut down is what causes it to get stuck in fail safe third gear. Make sure you got the TCM plugged back in and any other wires near the TCM. Since you cant get the OD light to flash an all good signal something must not be hooked up. Also check your fuses for any blown. Could of accidently blown one during testing.

[09quickly]

Ah yes, the connector. Only one rubber gasket inside female end. I left it in, and (embarrassment here) used electrical tape to secure the two fittings together since the new TPS plug would not lock completely into the old fitting. I hate rigging things like that, but at the time, I thought that was the only hurdle I had left. Possibility of wrong TPS? Like I said, I ordered it from the Auto Parts warehouse online, $37.00 + shipping. I don't know anything about their reputation. I will attempt the other tests you recommended hopefully tomorrow after work. 09quickly

[yellow_jacket]

I dont know where that info came from yellow jacket but it is absolutly false information. All nissan automatic trans built at least starting in the late 80's use and electronic revolution sensor to determine shift points. This sensor replaced the old governor. If you unplug the electrical harness to the trans it will go into third gear and stay there. That is done so you can at least get the car to a shop to get fixed. It will NEVER shift with out shift solonoid a and b directing the hydrolic pressure to the appropriate places in the valve body.

Like I said, many other manufacturers have run that way. Nissan may not have, but when the transmission harness was unplugged from my 1992 auto it shifted through all the gears. Sure the shifts were harsh and always at higher rpms, but it still shifted. 95 Ford F-350, same deal.

Doesn't really matter though, best of luck to ya 09quickly

[09quickly]

Voltages at the MAF - 14.3, 1.7, and .013. ran worse when disconnected. could not give it any throttle without a miss.

Fuses by the battery all look good, no obvious breaks in the metal bands.Fuses under the dash also look good, I found the CONSULT plug....It looks mighty inviting... but Iwill forget about it for now.

You mentioned making sure I reconnected the TCU - I never disconnected it. I only removed it from its mounting point for access to the wires. It and my ECU and another little brass box that all mount in that little area are all laying on my passenger side floor still. Does having them mounted to the car frame complete a ground circuit maybe? 09quickly

The vacuum hose you mentioned last night is covered with oil and grease from my extremely bad oil leak (oil pan) I will attempt to look at the hose and the box it feeds into over the weekend.

[NISTECH]

The car wont accelerate properly with the maf disconnected but it should idle alot better. 1.7 volts at idle is a little high of a reading for the maf. Was your test done with the engine warmed up? IF not retest it at operating temps.Your ground and source looks ok though.If your test was done warm, can you get ahold of a spare MAF maybe borrow a known good one from someone? slap it on and retest to see if you got an improvement? Dont run out and buy one as your reading is borderline.

No you dont have to have them attached to the body to function properly just as long as they are plugged in.

Unless you have a consult dont screw with the consult plug. There is nothing you can manually do with that.

That 2 in hose is not a vaccum hose it is an air baffle to quite down your intake system. But if it develops a leak to atmosphere it will cause the car to run poor. However judgeing your maf voltage I would say you dont have any vaccum leaks cause it is registering higher then normal airflow through it.

[09quickly]

HEY, REMEMBER ME?! I fell off the face of the earth for awhile, but now I'm back. Work, Christmas Parties, Christmas decorations, etc., kept me occupied elsewhere, but I should be able to do what I want to do for a while.

Okay - voltage checks on the MAF - disconnected, idled to operating temp., connectors L to R (empty connector slot on the right): .005, .007, 14.04.MAF connected : 1.134 -1.154 (Sporadic reading, would not settle in on one reading), .012, 14.07.

Also, I read something in the FAQ's about proper grounding of the entire system. I set my multimeter to ohms, and , car running, put a lead on the negative battery post, the other on an unpainted screw. ohms read 1.2 for the most part, but did jump sporadically, sometimes up toward 7. Any concerns? 09quickly

[09quickly]

I FINALLY got it running smoothly, for 165,000 miles anyway. - Don't know what sequence caused it, but I disconnected the battery for about an hour then reconnected it. Also disconnected and reconnected ECM and TCM, checking wires and securing the tightening bolts very secure. Starts like a champ now, I hear a rattle at the front of the engine that sounds like the timing chain according to some of the other threads I have been reading, but I will check that out when I redo the oil pan and gasket. STILL.... stuck in 3rd gear. O/D light doesn't blink at all. comes on for 2-3 seconds, then goes out. Possibility I have the wrong or poorly connected TPS after all of this? I purchased it from Autoparts warehouse online, and it is stamped "made in Italy". 09quickly

[gehzumteufel]

haha sounds like the ECU just needed to be reset after replacing the TPS. well congrats on fixing it!

[09quickly]

Just an update to my l-o-n-g and slow project progress. NISTECH, again you were correct regarding the TPS issue. after replacing the TPS and still having a rough acceleration issue, you diagnosed a vacuum leak somewhere. I replaced the gasket at the throttle body and intake manifold (I had pulled it off during the TPS install, but didn't replace the gasket), and the hesitation issue cleared up. I also installed USC Justice's old automatic transmission (recently rebuilt), and it works like a champ. I drove the car around quite bit today, the first time in about 10 months. It was beautiful convertible weather. Still many things to do to it, but now I can say it runs. I also replaced struts, outer tie rods, sway bar bushings (all stock) and it drives great. If only I could work 2 days a week and work on the convertible 5, things would move along much more quickly.

[rogoman]

1) Oil pan gasket - In following the instructions for oil pan gasket replacement in the manual, it says to drop the front suspension cross member to get access to the pan. The motor mounts are on this cross member, not on the frame. Do I need to support the engine in some fashion before dropping this cross member on my head? Also, while I have the pan off, will the crankshaft seals be easily accessed to replace them at the same time as well? (Lying on my back with the car on jack stands, front only).

You do not have to remove the front cross member. - unbolt the motor mounts from the cross member.- remove the front sway bar.- jack the motor up in the front about 2" to 3".- put blocks of wood between the bottom of the motor mounts and the cross member. - unbolt the oil pan.- remove the oil pickup from the block; two bolts to remove and don't lose the O-ring or else you'll have no oil pressure after reassembly.- you should now be able to slide the oil pan forward and out.

Removing the oil pan will not give you access to the crankshaft seals. The seals can be replaced without removing the oil pan.- to access the front seal, the front crank pulley needs to be removed.- to access the rear seal, the transmission and the flywheel needs to be removed.

[09quickly]

Yeah, I already went that route. I suspended the engine from the shock towers with a homemade rig, and dropped EVERYTHING from underneath. Wheels off (of course), struts, sway bar, power steering rack, lines, (which led to my other thread). I still had an issue with free movement of the pan after loosening it, as well as trying to put it back in place with the oil pick up set up the way it is. With the space I had to work in etc., I ended up sliding the pan, apparently too much. Now that I am going to tackle it again, let me ask some questions I should have asked before: 1) Permatex gray is the sealer I used. The right one? Or is there a more specific liquid sealer to be used? 2) How long after install should I wait before getting some heat to the sealer? I waited months between installing the new pan and actually starting it. Is it possible the sealer did not set up correctly? 3) I replaced the front and rear crank seals the first time around, they have less than 3 months and 100 miles on them. If I decide to look at them again, do I need to replace them with new ones if I pull them off to inspect them now? 4) Torque specs. for the oil pan bolts? I tried not to over tighten them, but I only used the calibrated elbow tool, not a torque wrench.

[Zmaller]

what does that diagnose? i did it today in my 94 vert and it blinked in intervals of ten every ten it would blink one long one then 10 fast ones, what does that mean?also i unplugged the rev sensor and it seems to shift fine and no o/d light flashed at all, speedo worked but when accelerating into 4th if you let of the gas a bit it immediately downshifts into 3rd. so basically engine breaking on the highway so you cant just cruise in 4th. it will go into 4th though.thank you so much NISTECH you've helped me so much and i idolize you.thanks again.-Zach