How do I set the TPS? I am getting some harder than normal 1st to 2nd shifts and I get an AT Check when doing an AT Diagnostic. Using OBD Scan Tech Nissan, the Inhibitor seems to be OK, the TPS ranges from .48 v. at hot idle to 3.93 v. at full throttle. The Kickdown Switch comes on at 2.7 v.

From reading other posts, Q45Tech said that the TPS should be “no more than .45v at hot idle” and others have said that not having it at .44 v could would cause hard 1st to 2nd shifts. How do I adjust the TPS? I can’t find anything in the FSM that tells how to do it. I tried the link http://www.nicoclub.com/archives/g50-th ... tment.html but just the paragraph titles come up not the information and Jesda is unable to fix. I have Consult clones to set it accurately but do not know how.

Background

I have a 94 Q45 Base with 90k miles that I have owned since 1997. It has been a second car and not driven much in the last five years. I have been working on it to get it in proper working order. I have replaced the PCV, air filter, oil and filter, cleaned the MAF, Throttle Body and grounds. I have had the injectors Seafoamed. The injectors ohmed between 10 and 12.4 except for #4 which ohms at 26.7 and the idle is a little rough. The KS ohm at 560k and I was getting a code 34 Knock Sensors but cleaning up the battery and alternator grounds fixed it. I have the base timing at 15 degrees BTDC and set the base idle at 600 rpm and it idles around 650 in gear. I had the transmission pan dropped and filter cleaned and it was in good shape. I had the tranny BG flushed and it is better but I would like to see if I can get it to shift from 1st to 2nd like butter again.

Can I assume you have checked the service manual?

Do you have a 8 MM (or 7MM) ratchet wrench? http://www.sears.com/shc/s/p_10153_1260 ... ockType=G2

How hard is the 1-2 shift? And does it shift that way only at low speed?

Is the PCV OEM from the dealer? Why was it replaced?

rkleff wrote:I have had the injectors Seafoamed. ... I had the transmission pan dropped and filter cleaned and it was in good shape. I had the tranny BG flushed and it is better but I would like to see if I can get it to shift from 1st to 2nd like butter again.

By adding it to the tank? Do you know of what Seafoam consists? It has no detergent agents whatsoever. Read its MSDS.

Did they not replace the gaskets and one time use bolts? So the screen had residue in it? Please describe it and the pan along with the condition (smell and color) of the ATF.

Are you now using the BG ATF? Precisely how long did the exchange take?

Infinitiguy19 wrote:Can I assume you have checked the service manual?

Do you have a 8 MM (or 7MM) ratchet wrench? http://www.sears.com/shc/s/p_10153_1260 ... ockType=G2

How hard is the 1-2 shift? And does it shift that way only at low speed?

Is the PCV OEM from the dealer? Why was it replaced?

I did check the service manual and found how to check it but but not how to adjust it.
I do have 8 mm/7 mm ratchet wrench.

The 1-2 shift is not real hard but harder than when it used to be and it shifts late around 12-14 instead of 8-11 per FSM. It is a little harder at WOT.

I replaced the PCV with a non OEM because that was an inexpensive starting point. The old one wouldn't rattle but I cleaned it mineral spirits and it rattles now. I still have the old one. Should I put it back in?

Adjusting it is easy as you only need to loosen those bolts and turn in what ever direction necessary. Turn slowly and make sure the car is warmed up to at least 176*F and stays above that. Also make sure to clear the self learn on the ECU.

The PCV is flow matched for the VH45DE according to Q45Tech. For the sake of keeping the car OEM I would put it back in.

Like Paul said, definitely make sure the car is fully warmed up before setting it. If not the fast idle cam will interefere with your voltage readings as it holds the throttle body open a bit.

Heath

Thanks guys, I just had some carotid artery surgery (getting old is hell) so I won’t be able to do this for a couple of weeks. I will let you know how it goes.

I finally got permission to resume normal activities after my surgery so I set out to adjust my TPS from .48v to .44v. My 94 Q requires a 7mm wrench and a ratcheting wrench is the way to go. After warming it up to 176 F, I made the adjustment using ECU Talk and set it to .44v. It was very easy.

I took it for a drive and I noticed some strange things going on. It was idling over 1000 rpms and the timing was at 26 degrees BTDC and did not run very well. I tried resetting the timing but did not have enough room to get it down to 15 degrees. The IACV was over 35 and I was getting really frustrated. I got back on this forum and did some searching and found this thread post5839478.html?hilit=throttle position sensor#p5839478
that says that the above can happen if the ECU does not get a Closed Throttle signal. I would guess it thinks you are driving along and advances the timing and opens the IACV.

I remembered that earlier I had adjusted the Throttle Drum Cable. Per the FSM, you make it tight and then loosen the nut by two turns. When I did this it seemed to have too much slack and I was only reading 3.83v on the TPS when floored. Sooooo, I tighted it about a turn to get it to read over 4.00v and I think this caused the problem with the Closed Throttle Switch.

Today I readjusted the Throttle Drum Cable to two turns back and the idle cam down, the timing was closer to normal and the Idle was in the 700 range. I used my inductive timing light to reset the base timing to 15 BTDC, adjusted the IACV to get base idle to 600. I also put my cleaned OEM PCV back in per Infinitiguy19’s recommendation. The car was a Q45 again and my hard 1-2 shifts were gone and it ran really well.

Sorry for the long post but I wanted to let those who helped me know that they did, to share my adventure with the throttle cable and to thank those who have posted so much great information on this forum so that someone with average mechanical ability can continue to enjoy this great car and feel a sense of accomplishment.

Great post! Glad to see you are doing better also.

Thank you for closing the issue and sharing some valuable information.

Craig

Shows that a simple problem is usually a combination of other maladjustments, worn parts, and/or deferred maintenance. It's all about systems and what the computers expect to see in terms of a range of values.