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SVO injectors in, AFM adjustment help please


lifegrddude

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I recently posted on zcar about some help on the SVO injector installation (thanks Spork if you're on this forum), and I got them in. I adjusted my AFM 18 teeth like I read in another post somewhere, yet my car still doesn't want to idle. I tried 18 teeth from the front tooth that I marked, then I tried 18 teeth from the back tooth that I marked from the stock position, yet the car does not want to idle still.

 

When I adjusted it the first time (18 from the front tooth), the car idled a little rough and would sputter some with vacuum reading about 300mm Hg. When I adjusted it from the back tooth, the car idled worse even though the mixture was leaner than the first adjustment. The vacuum reading was lumpy ranging from 180-320 mm Hg. The car would practically die when put in drive. It was almost as though I had installed a massive cam in the car.

 

For those of you who are running with 370's, how much did you adjust your AFM and did you have to do anything else besides that? Thanks a great bunch in advance, I can not wait to get the Z back on the road, it's been 3 days now and I'm in "withdrawal"! :wink:

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Guest jjohart

At the risk of being over my head, as I already am with my 280ZXT I/C project (I don't know RRFPR from wideband!), but in a word, 02. At least that's what my semi-local racing equipment installer said, in so far as upgrading the fuel systems and then injectors.."when you add more fuel, you need to add more air". Unfortunately, that's when he started about my needing an AFC or a JCW chip, as well as the injectors. Methinks there's probably more than an air layer of truth, that perhaps the air factor needs to be dialed in by some means, and I don't think that means a CAI, though he tried to get me in on that aswell!

Sorry, I don't have any specific suggestions, but that's better than the couch potato suggestion, in'it?

John

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adjusting teeth on th afm door will keep you leaner at toe-in and on throttle until the afm is maxed. you need to adjust the idle air screw out to allow it to bypass more air. the screw is probably covered with a black plastic round piece that needs to be drilled out (carefully). that will correct your idle. you should go to a dyno for the door adjustment

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it's inside the afm but unless someone has messed with it, you'll have to drill into the covering. i can't remember if it's plastic or has a metallic covering. i know it's round and if you're looking down at the afm it's on the lower right corner. it has a round ridge outline as well.......it's been so long since i've had an afm.

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it cant be just the afm you need to adjust i think. something else is off.

Ive seen 370cc installs that bearly even needed afm adjustments.

what else did you do before installing the injectors, did you have them checked or anything, lumpy condition can also come from faulty injectors as well, which is why I will really never buy a used injector unless I know who had them before me and knew how the car ran. I am a cheap bastard like everyone else, but when it comes to my boost, fuel, tires, and sparks, I dont mess around...

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Guest bastaad525

I second fl327... used injectors can be a pain, and every time I've bought a set for one Z or another at least one of them was bad. At the very least it's a good idea to take them to a place that will check them and clean them, I dont think the service is too expensive. When I swapped in some used python injectors my car started really running lumpy, backfiring... misfiring... turns out two of the injectors were just stuck open all the time.

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Thanks for the suggestions, I'll pull them out and have them checked. I'll also look for that idle adjustment screw in the AFM. As far as I know, I've only messed with the injectors and AFM. I haven't touched anything else that would affect the car in any other way besides the AFM and upping the idle a little bit. Thanks though, I'll definitely check the injectors again.

John 82ZXT

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I put the 370cc's in my '82L28ET, twisted the AFM 18 teeth clockwise and it runs real good and strong. I'm not saying this is right for every Z, just filling you in on my experience. When i put my 370's in, i attached them all to the fuel rail, flipped an old valve cover over, placed it below them to catch the fuel, held the rail up above it while i had a friend crank the Z. Yes, there was a fire show once because i thought my friend unplugged the wires sending signal to the coil, not just the coil wire itself like he did. Yes, it's dangerous, but it works for me. One of the 370's was basically shooting a stream instead of the nice atomization the others seems to be spraying and after a little coaxing, the troubled 370 was spraying just as well as the others. Again, this is just what i did and yes, i tend to do unsafe things sometimes :twisted: I posted a pic of the inside of my AFM HERE in case it helps at all. Good luck and keep us posted on what you figure out.

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Thanks for the info too Jersey, your way of checking is a good way to see if I do have a dead injector, even if I have to carry a fire extinguisher. lol It'd make for an easy preliminary look at the injectors. I'm going to see if I can check over Thanksgiving since I'll have a break from class. Right now as it is, I have the AFM cranked 15 teeth. It idles a bit rough, but after 1300rpm it is fine. I'm pretty sure one of the injectors is probably bad since from what everyone else is saying, their car idles fine after adjusting the AFM a bit.

John 82ZXT

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