I am a newby as I just bought a 1993 Q a month ago - it's in fairly good condition as I knew the former Arizona owner who says he bought it new - anyway I was wondering if there is a way to tell by looking at particular date codes or part of the VIN, what production revisions (if any) were made on my car as far as 1st-gear takeoff in the transmission and the metal timing chain guides - I have been told by Scottsdale Infiniti that sometime in the '93 model year the factory switched to installing metal guides from the plastic - I just need to know when they did - I also read that in the '93 model year the 2nd-gear start was updated to 1st-gear start - now my car was mfg'd in Nov. '92 [for 1993 - I assume] - I would rather avoid the needless (expense) tearing this car apart if I don't really need to - ditto on the transmission - it shifts so smoothly that I can't really tell if it's taking off in 1st or 2nd- any sugg's? - anyone??

Well, I've seen two posts on here (you can find them if you search) of 93s with metal timing guides. In both cases the posters mentioned that the guides were cast with the same production month as the car.

One was dated 8/92, the other 10/92. Mine is 9/92 and yours is 11/92. You might assume that all after 8/92 had metal, but there is no way to know if it was a "rolling" change, or occured all at once. I have yet to find evidence of a 93 built later than 8/92 with plastic guides, but with such a small sample size that does not mean anything.

There was ONE person a month or so ago that claimed to have a 93 that had PLASTIC guides, but he would not answer my requests for production date and has not posted since.

Another person came on more recently, claiming to have a 93 with metal guides, but he also would not answer my request for production month.

I find it strange that two people would not answer requests about their car's production month, especially if it would help out the rest of us with 93s.

Anyone who reads this, please give any evidence you have one way or the other.

As for the transmission, can't you tell if it is starting in first gear or not? Manually shift to first to see what it feels like, then stop and start off in D. If it feels the same, you've got a first gear start TCU.

What is a more interesting question, IMHO is when the first gear ratio changed. Mine has the same ratio as the '94 up, but some people have claimed that the '93s came with the earlier, lower first gear. Not much hard evidence either way, but I have read talk of two different '93 TCUs - maybe one was for the low first gear and the other for the higher first gear.

Hmm interesting information, i didnt know they changed the tranny midway.. I thought they had the TCU differences for shift complaints... You dont have the 2.8 1st gear, you have the 2.5?

Yes, according to my FSM and my calculations, my transmission has the 2.5 ratio gear. The rest is just speculation on my part.

From the eveidence this board has seen, there is no definitive VIN nor date that guarantees the new guides were installed.

It was hypothesized that engines were mated to chassis in no particular order and that some good guides/engine combination were installed before the factory ran out of old guides/engine combination.

Short story, one cannot be sure without looking.

While I suspect that you are right for a very narrow range of production months, I'm sure there is a definitive date by which all were built with the new guides. If that were not true, it wouldn't be possible to say definitively that all 1994 cars were built with the later guides. At any rate I doubt that the overlap is more than two or three months at most - don't forget they were turning these cars out by the thousands during that period.

I just wish there was more information out there.

RobertsnewQ wrote:While I suspect that you are right for a very narrow range of production months, I'm sure there is a definitive date by which all were built with the new guides. If that were not true, it wouldn't be possible to say definitively that all 1994 cars were built with the later guides. At any rate I doubt that the overlap is more than two or three months at most - don't forget they were turning these cars out by the thousands during that period.

I just wish there was more information out there.

Well the 94 engines were a different spec than the 92-93 engines, so thats why no 94s would have regular guides..