1991 Plymouth Sundance Swapping my dead 2.2 for 2.5

Tiny
AISHA16
  • MEMBER
  • 1991 PLYMOUTH SUNDANCE
  • 2.5L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 80,000 MILES
Hello,
My 2.2 engine died, holes blown through the 2 centre pistons. I got a good deal on a 2.5 L Sundance engine. It looks exactly the same, except a bit bigger of course. My question is, will the transmission fit this engine? My friend, who is putting it in, doesn't see why it wouldn't, but I want to make sure before we put in the work.

Hope to hear from you soon.

Thank you.

-Aisha
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Thursday, June 18th, 2015 AT 12:41 PM

3 Replies

Tiny
CARADIODOC
  • EXPERT
The engines are basically identical, but the 2.5L has an extra balance shaft to reduce normal engine vibrations that you feel. The oil pans will be a little different.

The question is if the original Engine Computer will run the new engine. The larger engine needs more fuel. That will either be done by using an injector that flows more fuel, or by using a computer programmed to hold the injector open longer during each pulse.
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Thursday, June 18th, 2015 AT 3:56 PM
Tiny
AISHA16
  • MEMBER
Okay, so I should definitely get a different computer then? Or would the injector be the cheaper option? I am on a student budget so the cheaper the better lol.
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Friday, June 19th, 2015 AT 6:19 AM
Tiny
CARADIODOC
  • EXPERT
Student, huh? I spent nine years telling my students, "what you heard is not what I said". I don't know if the new engine will run just fine with the old computer. I DO know people are switching from the 2.7L to the much better 3.5L on newer Chrysler products and the same computer can be used. Chrysler has always been famous for excellent parts interchangeability between years, models, and engines. That is the original reason I first became a fan of the company.

When I worked at the dealership though, we never got involved in things like this. You usually won't find a mechanic or a shop willing to change engine sizes either because emissions laws come into play. In this case, once the engine is running properly, the emissions will likely be the same as when it was in its original car, but it will not match what is on the sticker under the hood. That's where the over-eager, idiot politicians have their noses stuck, (up your tail pipe), and have made life miserable for us.
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Friday, June 19th, 2015 AT 9:35 PM

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