dealer consult worth it?

[willmoodom]

i am thinking of taking the car to infiniti for a full diag. my main concern is engine and transmission. 125 for the service to tell me the condition of all my sensors. is the consult all its cracked up to be?

[elwesso]

I don't really think it is.. I'd say I'm as good at diagnosing issues and I've never used a consult, primarily due to the fact that the consult port on my car doesnt work.

If theres something wrong, its usually easy to find, and other stuff is just kinda nice to know I guess....

[willmoodom]

when i first got the car, shifting was a bit off and the tsc slip light was on. after doing some work and repairing the brake sensor, those lights went off but still a slight shifting issue. today i put the hood on started the car and the tcs slip light back on.

[willmoodom]

right now my trans will not shift manually into 1st or 2nd. In "D" mode i think the transmission is starting out in 3rd upto a speed of-i estimate to be of-around 45 and then it shifts to 4th. this is in the nieghborhood. havent been onthe highway yet since doing the work. what i can tell you you is when i last drove it on the highway, it felt like the switch for OD was backwards. what i mean is under sixty was all 3rd gear. over sixty it would shift into overdrive with my foot off the gas and coasting. press the gas and it drops down to 3rd. let off back into overdrive. with all the things i found wrong such as vac leaks, broken knock sensors, clogged injectors, oil drenched spark plugs, loose intake, broken timing guides and out of adjustment tps, i thought would cure the transmission woes. tps still a little off. it was at 55. i got it down to like 46.

[elwesso]

Hmm have you done the AT check? That would be the first thing I'd check in this case.

Here is the bottom line with the consult though: People think that with these hard to trace issues, the consult is gonna be the "magical box of answers", and the truth is its not. Its a convenient way to diagnose certain issues, but it certainly does not say "fix this" with any sort of certainty... Anyone who has used a consult will tell you this..

If its starting in 3rd gear it sounds like its either in fail-safe (which will be told on the AT check), or the trans is cooked. Normally transmission related electronics are solid, so unless you have a bad connection somewhere (possible if there's been fiddling), the trans is probably cooked and needs replaced.

[willmoodom]

ok, i did the self diag on the transmission. code that came up was "at check" according to the manual, if everything was good it would say "ok". in my case "a/t check"= inhibitor,closed throttle, kick down,1 position,diag display disconnected or damaged tcu. the book does give instructions on checking voltage on each of those items, but is it possible the tcu is dead?

[maxnix]

Did you check the linkage and neutral switch?

[willmoodom]

Did you check the linkage and neutral switch?

no, however, what i did do is swap tcu's. i got a 1st gear start from Wes and after talking to him, decided to throw it in before going any further. also i learned from Wes that the transmission is a 4speed. i ignorantly assumed it was 5 speed. that false knowledge contributed to what i thought the transmission was doing. Anyway, the result is light accel, i get the proper 1-2-3 shift. Wes said the system tries to stay in that third gear. i get fourth but it shifts back and forth often. as for wot, the shifts are a little off. 1-2, 2-3 delays a bit too long for my taste. my tps still needs a little adjusting, and that may clear some of that up. i still havent been back on the highway yet but soon. still got rear brakes, exhaust, and some electrical gremlins to track down.

[maxnix]

So, why don't you inform us of the transmission maintenance history? Auxiliary ATF cooler?

If you are lugging it at 2500 rpm and you have a filthy plenum, TB, EGR and IAC valves it will lock and unlock constantly. Try to keep it in 3 in town and not let it lock up until you get to 60 mph on the highway.

[elwesso]

A slow 2-3 shift is a pretty common issue on these trans and I don't think is a cause for immediate concern. Like Brian said, keep it in 3 unless you know you'll be maintaining over 55 mph

[willmoodom]

Ok, at a slow steady accel, half or less throttle, she shifts find, 1-2-3.
WOT is where it gets a bit scary. it funny being in such a big v8 that can rev so high. Anyway, during wot it feels as if she hangs between shifts to the point that ill let off the gas a bit. i dont want to blow my engine. during one of these wot runs, ive peeked the rpm hitting above red line. is the longer than normal delay between wot shifts normal for the q45?

[elwesso]

it will actually do that with the 94 TCU and without the NICO ECU. Throw in the NICO ECU and see if that helps.

[willmoodom]

Emailed you Wes.