Early batch firing vs. later sequential injection

[WDoherty]

In august of 2004 i was shopping around for an SC400 before i was headed off to my next semester and found a 97' on ebay for a good price. I won the auction on ebay, but when i went to pick it up in Dallas i wasn't happy with the situation, the car had body and interior damage not shown and bald tires. I inspected it anyway. I was creeping around and crawling under the rear of the car and i felt heat from the exhuast. I did not even hear the car, that is how quiet it was. The exhuast was like a solid tone, no audible pulsations were present. I popped the hood and the engine was clean, had electric fans and an engine cover, it was so quiet. Unfortunately this place was like a chop shop, with luxury cars all over the place getting worked on and shined up, and there was no history of the car, it was bought at an auction and had 130000 miles, i was suspicious and didn't go through with the deal. I ended up buying a 92' sc400 for a $1000 more and it ended up having bald tires and non-working a/c and cd changer (all which the seller denied), but only 87500 miles, the paint was unbeleivable and he had lexus service records throughout including timing belt change, starter, plugs, and lots of other work at 60000. This engine is quiet and smooth, but not as smooth because i can hear the exhaust pulse at idle unlike the 97 with 47500 more miles and questionalbe past. Almost a year later i learned there were differences in the engines, one being that the 95-97's got sequential fuel injection and the 92 is batch fired. What kind of differences does this make? Does the sequential injection attribute to the 25 extra hp the later engines makes, i know the 10.4 compression and slightly different cam specs have something to do with it. I just know that the 1uz runs better with sequential injection and the question is can the earlier motor be converted by swaping for a later ecu? Are there other changes that would not permit this, such as cranshaft and camshaft sensors being different in order to allow sequential injection to work, or could this be a simple change?

 

[sideshow]

where did u find that the later modles have sequential

out of allthe diagrams i have only the 2000 onward models wiith vvti have sequential

but i doubt u would notice any difference


the 97 1uz is same as the 94

i think its when they went to vvti and the ecu plug changed to i think 5 big white plugs they went sequential and very very very hard to find ecu and wiring for these

 

[toad007]

sequential injection only makes a difference at idle and low engine rpm. above a certain rpm/injector duty cycle they become batch fired as there is not enough time during the opening of the intake valve to inject all the needed fuel into the intake.

 

[Peewee]

Sideshow, from 95on I think, the US SC400 went to sequential fire, yet nowhere else got this.

The hp is not from, the idle smoothness *may* be, but its probably from an exhaust change.

 

[WDoherty]

Sorry, didn't realize other parts of the world did not get the changes made to the 1uz in 95. The U.S. 95-97 1uz dynos 20rwhp more than the original 1uz.

 

[Peewee]

Thats from cam/ecu/compression changes.

 

[jibby]

Check out the site intellexual.com that breaks down the year by year changes on the sc400's. The VVTI is the big change in hp and that begins in the 98 and newer models. I inquired about the swap on an earlier post, not easy and practical to do.

It sounds like you have a nice riding and looking 92. I bought my 92 sc400 in the same fashion a little over a year ago. I Bought it locally from a doctor with 88,000 miles and was dealer maintained, clean and with records. It drove and looked like new, now today it drives fast and firm. It all started for me with the dragon torque converter, then the addiction to horsepower took over. Becareful, before you know it your $8,500 sc400 can quickly turn into a $15,500 car, but it will be a blast to drive, as I can attest to that.

Late-