I need to know how to compare fuel injectors, specifically ones for 87.5/ 88 S4 engine models.

Basically, how can I tell if I'm getting the right secondary injector. I've been told that since my car is an 88 S4, I probably need the later version of the secondaries, in which Mazda lowered the resistance/ impendence?

 

Check the FAQ. Injector information is already there. Just compare the part numbers or measure the resistance if you are unsure.

 

I've looked at the FAQ, but it does not list any differences between the primaries and secondaries, as far as resistance and/or capacity of flow. I also happen to be without my haynes manual right now.

Right now, I'm just asking sellers for 460cc secondaries, but I'd like to know how to distinguish for myself between primaries and secondaries.

 

They're the same.

 

Hmmm... ok... maybe you can help me out here:

I had to replace a coolant hose on the car, so I did that, and as I was putting the upper manifold back on, I must have crushed the end of one secondary injector. So, I simply replaced it with a primary that I had sitting around. The car started then, but would barely run and sputtered and backfired. So someone told me that I might have put in wrong injectors - primaries, instead of secondaries.

So what could be my problem be? urgggg... this has just become more frustrating.

 

Since all the injectors are the same, I would assume that you just have a vacuum leak or your ignition got wet during the hose problem.