I know this has been visited before.

I know TomP put 3.1 injectors in his 2.8er, he mentioned a power gain but was not sure if it was due to the injectors he installed, or just a difference of not having dirty ones.

Did you ever find out whether the 3.1's actually provided any performance increase?

For that matter, has anyone tried the 3.1 or other injectors in their 2.8er and found any gain/loss in performance?

Were there any issues with the install? Adjustments to be made etc?

Thanks.

:lala:

 

According to Parts America. The injectors for a 2.8 and the 3.1 are identical.

Injector part #'s are the same for both applications.

 

Ah, thanks.

:hail:

 

Now hold on just one minute. The 3.1 is a stroked 2.8, correct? Doesn't that mean that the injectors have to supply more fuel for the larger volume of air?

I have to ask this because I replaced 2 2.8 injectors with two from a FWD 3.1 (from a Lumina, I believe), and I don't really want the A/F ratio to be completely thrown off by the two heavier duty injectors...

 

Just go to the Parts America website and cross reference the part #'s for 2.8 and 3.1 injectors. They're both the same in Bosch and other brands offered there.

 

This could become interesting, since the word up until now has been 2.8 == 13pph and 3.1 == 15pph ...

 

I'm not trying to burst anyones bubble , but that's the plain info that I saw on their website. Check it out . I even double checked it with different brand names besides Bosch.

 

I'll have to check this one out myself. I am not sure as to exactly what GM part number is on my injectors that were removed (too covered in gunk) but GMPartsDirect mentions that the ones in my 2.8 are xxxxx297's and the ones for the 3.1 are 747's. But at the main parts supply houses, there is one part number in common...

 

I think this generally shows that there is a separate 3.1l injector, but it is considered acceptable to toss them on a 2.8.... I would not however reccomend doing this without a full set.

 

Seperate for what reason , and for what application?

Could some of those variants be applied to California's and other states stringent smog regulations?

 

Separate, because as far as I know, 3.1l injectors are larger. There's generally two sets of part numbers for the 2.8, and only one for the 3.1... generally leading me to believe that while both are acceptable for the 2.8, one of them is smaller and insufficient for 3.1 fuel demands.. different flow rates mean don't mix them, stick with one type.

Above grid was comparison between 1986 and 1992 camaros.

 

Can anyone guess how bad a curve ball a 3.1L injector in both the 2+4 cylinders will throw at my ECM? I just bought two because I needed only one (leaking injector, and both that were replaced were missing pintle caps and any retention for the o-rings) and the price was right at the time. I don't really care if the car runs like crap as long as it runs BY ITSELF(I.E. no foot on pedal) for more than 30 seconds at a time.

I NEVER buy electronics from junkyard unless they have been certified to work, and none of my local junkyards except one has ANY injectors, or rails either, for that matter.

 

If run until it goes into closed loop, you stand a chance of leaning out the 4 cylinders not using 3.1 injectors, will all the fun a lean condition can cause (mechanical damage).. Lumina 3.1s use the same injectors as F-body 3.1s

 

However, if I read correctly on another thread somewhere on these boards. Weren't there two different types of injectors as far as the pintle end of the injector goes? Bosch has one design and Miltech [sp] had a different design? Maybe that's why there are several different part#'s especially if they're rebuilt injectors.

Unless the 3.1 is turbocharged or supercharged I can't see why there would be a need for a larger injector. That CID difference isn't that radical.

 

What kind of mechanical damage? How's about using just one? The number 2 is the one I am most certain is the leaky one, and I just replaced the number 4 because I had the parts...

I just need this thing to run long enough to turn it around in the street and put it back in the driveway straight, so it isn't resting in a garden anymore, and also long enough to say that it runs by ITSELF...

BTW, I do think that anyone reading this would know that a 3.1 is the same as a 3.1 in a FWD application...

 

Actually, they're not the same 3.1s... GM actually worked on improving the FWD 60 degree, and some of their components are superior to RWD versions... at any rate, though, it'll run fine cold. 2 and 4 will just run rich. It will only lean out in closed loop. Only using one 15pph injector would decrease the likelyhood of mecahnical damage in closed loop operation, but if you're just getting it off the lawn, there's little concern. Mechanical damage means things like severe detonation, which leads to things like replacing more pistons, rods, head gaskets, valves....

 

I guess I'll have to keep the one 2.8 injector for the time being and search for another one or a whole set of 3.1's then...

I haven't done anything other than clip them to the rails... Have to go out tomorrow and buy a $17 head bolt set (NAPA P/N GS33284 for anyone curious) so I can perform a compression test so I can get the valves RIGHT for a change without a blind guess, so I can get it going...

And I'll take a pic tomorrow of the differences between the old style and new style injectors. Don't remember just what the difference is, but it has something to do with the tendency for the older style to gum up and freeze easier, either letting too much fuel flow or none at all, or the exposal of the electronics to the fuel stream or something...

I also read something in another post about a "plug" for the CSI port. Where do I get one? I just want to cap off the rail end. I am not using it and don't want it to be hooked up because it is just one more thing to possibly leak on me...

 

Need a number check!

I have the four remaining injectors that were in place when I bought the car. (I must have thrown the other two out or something... ) Well, anyways, these don't have a GM part number, but the only number on them is 5235210.

I seem to recall the two injectors I removed having either a 5 or a 3 in their part numbers, but the numbers don't match GMPartsDirect either... they were the old style pintle cap type things, not the newer ones.