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autotech155
autotech155, ASE Certified Technician
Category: Car
Satisfied Customers: 429
Experience:  29 years ,drivability brakes ,a/c,trans repair,engine repair
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1999 cadillac deville: run fine..cruise speeed on highway..rpms

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i have a 1999 cadillac deville de elagance i recently changed engine and i replaced a y engine with a 9 engine will i need to do any thng else to car to make this work right car seems to run fine but has a surging issue at low speeds 40mph and at cruise speeed on highway also noticed the car shifts at lower rpms than 9 engine shud and will only go 110mph how can i fix these problems do i need do switch computers and will it work with digital dash
Hello welcome to JA, The 2 motors will as i have changed them with out any problems, you may have a vacuum leak at the throttle bodyb housing and that woud cause the surging problem and may als affect the operation of he transas well. The only differemce between the 2 motors is onwe is a hig performabce and the other is your standard engine, You may want to have a scann run on the car and see if maybe one of the sensors is not working right on if you do have a small vacuum leak. Eric
Customer: replied 8 years ago.
Relist: I prefer a second opinion.
Hello what is it that yoju need a second opioionm opn if i maty ask Eric
Customer: replied 8 years ago.
i need to no if the computers are different pretty sure i do not hav vacumm leak and if throttle body is bigger or injectors are different between the 9 and the y engine
The injectors are the same ,but the computers i dont think are the same because the fule and timming will be diifferent. I wouls check the wiring going down to the cran sesnors and make sure the wiring isnt soaked with oil,because this wouyld cause the woring to become bare and then not let the car start. Eric
Customer: replied 8 years ago.
can i switch computers isit compatible with digital dash where most 9's are analog dash
Yes you have a diffderent computer thst contrils the dash functions Eric
Customer: replied 8 years ago.
do u mean i can switch engine computer but thers seperate computer 4 dash
yes tetre is another computer its called a bcm body control module. Eric
Customer: replied 8 years ago.
so more than likely i need a 9 computer probly fix my surging issues and better shifts wher do i find engine computr and and how do itell them apart
OK there will be numbers in the side if the computer,but you may be able to take the old computer out and have it reprgamed for the 9 computer. Eric
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