NORBI Posted January 25, 2004 Report Share Posted January 25, 2004 couple days ago my 2.8 in 88 CS broke a timing chain messing up the valves so now i want to get another replacement engine for it but i dont want the 2.8 anymore and i was thinking about 3.1 whcih feel much more powerful then 2.8 even though they only have 10more hp. Are there any differences between 2.8 and 3.1 and will it be just plug and play without any changes and what year 3.1 i coud put in my CS. i wish i could put 3800 or 3100 but i just cant afford that now and looking for the fastest and cheapest way to get my car up and running. And i know that the 3.1 had different air box was the sensor different in it and if it is what do i have to do to change it or make the old one form 2.8 work in the 3.1. Thanks a lot guys and need help ASAP because tomorrow we are ordering the engine. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 25, 2004 Report Share Posted January 25, 2004 Your 2.8 has a MAF sensor, right? Then the only plug and play would be another 2.8 with a MAF. You can use any 3.1 if you get the wiring harness and computer. Quote Link to comment Share on other sites More sharing options...
Baddflash Posted January 25, 2004 Report Share Posted January 25, 2004 Some 2.8L had the MAF sensor upgraded to a MAP so depending on the year of your car it may have this update.(my 87' cutlass had it) I would guess that anything that isn't the same can be easily changed cause the 2.8 and 3.1 are same engine just different stroke. I'm not sure if any other cars kept the 3.1L after 93' or if they'd all be 3100 after that so I'd guess up to 93'. Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 25, 2004 Author Report Share Posted January 25, 2004 I know my car had a map sensor in it because i changed it a lot of times. But i heard that computer on 2.8 and 3.1 are the same and i am using a computer on my CS from a 89 Grand Prix that had a 3.1 in it and works perfectly. Wiring i think its the same so if i drop a 3.1 from a 1989 or 1990 all i need to do it just connect it and everything will fit right in. i heard also that 3.1 was different because it had a different fuel injection but dont know what year that was and if i could use it in my car. All i am looking for is that 10 extra HP from 3.1 and no problems at all putting in my car without changing anything else except for the engine. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 25, 2004 Report Share Posted January 25, 2004 If you use your existing harness with a 3.1, do you have the plug for the map sensor? If not you'll need the harnass. Â The computers are the same but the chips are different. My 89 used to have a 2.8 but the previous owners put in a 3.1 without changing the chip. I was having idleing issues, bad gas mileage, and a few other things. Put in a chip for the 3.1 and it ran perfect and the gas mileage increased. Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 25, 2004 Author Report Share Posted January 25, 2004 If you use your existing harness with a 3.1, do you have the plug for the map sensor? If not you'll need the harnass. Â The computers are the same but the chips are different. My 89 used to have a 2.8 but the previous owners put in a 3.1 without changing the chip. I was having idleing issues, bad gas mileage, and a few other things. Put in a chip for the 3.1 and it ran perfect and the gas mileage increased. Â Â I know this may sound little stupid but what is a MAF sensor and my car has a MAP sensor on a back of the engine right next to the alternator and i didnt know that they had those cars without MAP sensor. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 25, 2004 Report Share Posted January 25, 2004 Do you have a maf or just the map? The maf sensor is between the airbox and the throttle body. Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 26, 2004 Author Report Share Posted January 26, 2004 I know i have a MAP sensor on a back of the engine a little black sensor with 3 wires going to it and one little hose and sensor right by air box that i think has another 3 or 2 wires running to it and yes it is between airbox and throttle body and when i disconnect it i get SES light so i think thats MAF. So if i have both of those i can safely put 3.1 in it. I need response as soon as possible becasue tomorrow we are ordering engine. Quote Link to comment Share on other sites More sharing options...
phantomFE3 Posted January 26, 2004 Report Share Posted January 26, 2004 if your gonna be changing the computer and shiot, why wouldnt you just go with a 3100? i dont think you would need a new transmission or anything, or am i missing something here? Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 26, 2004 Author Report Share Posted January 26, 2004 But will i dont want to change any wiring and just want engine that will plug in directly to my harness but i wouldnt want to put 2.8 in it anymore and 3100 i dont think will do that. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 26, 2004 Report Share Posted January 26, 2004 This is a maf sensor. It will be inline from the airbox to the throttle body. Â Â If you don't have one of those it should be plug and play. If you do, I would at least get the chip that goes with the new motor or swap the whole computer. If not your computer will be looking for a reading from the sensor and set an ses light. Quote Link to comment Share on other sites More sharing options...
Baddflash Posted January 26, 2004 Report Share Posted January 26, 2004 If you change the chip you probably won't get the SES light from disconnecting the MAF cause the MAP will be used. You'd have to compare a 2.8L and 3.1L to be sure but I imagine everything should hook up or be easily modified. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted January 26, 2004 Report Share Posted January 26, 2004 swapping the wiring harness isn't really hard at all, besides you can re-route and reloom the thing while you're at it you can even run a 3x00 engine on an earlier Gen-2 MPFI wiring harness/ECM if you want to (so i've heard). i believe the 3.1 MPFI was actually used up thru '94 in Luminas. Â it sounds like all you would have to do tho is swap the memcal for a 3.1 memcal and change the airbox. that is if you already have the MAP sensor. Â btw, why do you need to change the VSS? i'm curious because i put an '88 getrag 282 into my car a few months ago, and ever since then my speedo reads WAY too high. the VSS in the '90 282 i had earlier was perfectly accurate why would the VSS be different in a speed density system (MAP) and a mass air flow system? joshua Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 26, 2004 Author Report Share Posted January 26, 2004 Is it true that a 3.1 from a 93 is little different and may require different computer because it has different fuel injection because i found one on ebay from a 93 Lumina but i heard that electronics are little different on last 3.1 engines. ANd i have that MAF sensor and it looks like the one on pictures Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 26, 2004 Report Share Posted January 26, 2004 Since you do have the maf you will at least need to change the chip unless an ses light doesn't bother you. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted January 26, 2004 Report Share Posted January 26, 2004 VSS: The '88 has a different VSS than the '89 2.8L.. it has less teeth on the sprocket thingy.. I'd just put one from a 90+ 3.1 to be sure it will work 100% properly with the 3.1L engine. Also get a MEMCAL chip from a 3.1L engine. Â hmm, the VSS must be different betweent the 4T60 and the Getrag 5-speeds. my VSS has no teeth, just a big magnet. thanks for the info. joshua Quote Link to comment Share on other sites More sharing options...
phantomFE3 Posted January 26, 2004 Report Share Posted January 26, 2004 i still say go with the 3100, its not even that hard to replace the comnputer and the wriring harness, to me that would be worth it to have the extra 20 horsepower or whatever the 3100 has over the 3.1, that would be Very worth it to me, you already are going to have the engine out, why not got for more power? Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 27, 2004 Author Report Share Posted January 27, 2004 I already got a 3.1 engine today from a 1993 Oldsmobile with 60k miles for 650$, and we still have a lot of change like all the injectiors are different, EGR valve and couple vaccum hoses are different and thats little pain to change but it will be done tomorrow and my budget is little limited too so 3100 or 3400 probably would cost me more. Well my 1988 CS with 198k miles is getting a nice upgrade as a 93 engine. Was there a HP change in last 3.1 engines or they were still 140hp and 180lb. Quote Link to comment Share on other sites More sharing options...
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