Ok guys, I have to get some new 3.4 injectors soon to complete my 2.8 to 3.4 swap.

However, comparing a bad 3.4 (1995) injector with the 2.8 (1989) injectors, I just noticed that the 3.4 and 2.8 injectors look different at the tips. The 2.8 injectors seem to have a longer "nose" or basically are a little longer overall and the o-ring sits above higher from the end of the injector when compared to the 3.4 injectors. Basically the 3.4 injectors look like the FWD injectors on my Pontaic 6000. I did a search and no one seems to mention this difference during the swap.

So here are the questions.....(dramatic drumroll please)

1. Do I just get stock 3.4 (1995) injectors that look different from the 2.8 injectors? Or is there a specific year that I should be using?

2. As far as o-rings go, I need to buy the o-ring set so do I buy it for the 2.8 or 3.4 injectors? Or are they more less the same? Thank you!

 

There is nothing wrong with the injectors. Even if you get after market 2.8 injectors they are shorter than the stock ones. Its a GM thing I would guess for better design than the original ones they were having issues with. I swapped out my 2.8 injectors with the 3.4s and had no issues. So happy trails and hope the swap goes good for you.

 

You have the right 3.4 injectors, they are very sunken in?

I have injectors from a 99 3.4 olds van, they look exactly like the 95 3.4 injectors

 

i have 6 1995 firebirde 3.4 injectors with 60k on them if ya want em

 

answer for #2:

the o-ring set will be the same. goop them up w/oil before slapping them on the intake & fuel block.

 

ok thanks for all the responses guys. Now all I have to do is slap this engine together and put it in......after I paint the engine bay of course lol

 

I have a few questions myself if nobody minds. I read somewhere awhile back that 2.8 fuel injectors allow more fuel to pass through than 3.1l fuel injectors.

1. If this is true, wouldn't it make your car to run too rich and/or cause it to use more fuel; causing worse gas mileage?

2. How would installing fuel injectors from either a 2.8 or 3.4 into a 3.1 cause it to run? ie. performance wise.

Thanks.

 

its possible the 2.8 ones have larger nozzels the the 3.1. But it all goes back to the ECM tuning. They can be set to not be open as long, thus allowing proper fuel.

As for swapping injectors around. These are my experiences....

3.1, stuck ford 14lbs in it, ran like *** and ran hot.
3.1, put 2.8 in. in, ran fine.
3.1, put 3.1 in. it, ran fine.
3.1, put ford19lb in it, ran rich, coughed at low end, but had nice top end
3.1, put 3.4/17lb in it, coughed at low end but not bad, gained some top end.

3.4, put 3.1 in it, ran lean n hot
3.4, put 3.4/17lb in it, ran fine
3.4, put ford19lb in it, ran decent
3.4, put buick18.55lb in it, ran decent

decent rule of thumb on these engines, for every 10hp you gain via air travel, you need 1 more lb of fuel. However, adjusting your ecm to max tune is the best and only right way to do it.

 

that is some excellent information, i appreciate it