RayG1988 Posted July 17, 2008 Share Posted July 17, 2008 So my AFM is in a pretty bad area and I don't think it's getting enough air so it ends up choking, backfiring and not letting me get any boost at all. The car starts dying and won't get higher than 2500ish rpm. Jeffer949 showed me how he did his AFM and I was thinking about using hsi method of moving the AFM back by cutting the boot in half or cutting the boot altogether so the AFM would sit farther back and actually get air since it's obviously not getting enough by the radiator. Thoughts? Also changing oil, sparkplugs, sparkplug cables, AFM filter, pcv valve, and pcv valve filter. Doing everything I can to get the car running at maximum stock efficiency before I go crazy with all the cool stuff I got for it. All of you who know my car as unreliable are in for a treat, I've been working on getting everything good so my wiring is now really nice. Quote Link to comment Share on other sites More sharing options...
(goldfish) Posted July 21, 2008 Share Posted July 21, 2008 Have you checked the TPS and tried unplugged the ecu connectors? The AFM would really have to be plugged up not to let the engine run. You could open it up and see if it swings freely. Quote Link to comment Share on other sites More sharing options...
JSM Posted July 21, 2008 Share Posted July 21, 2008 Have you taken your AFM boot completely off the car yet and checked it for cracks by carefully stretching it? Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted July 22, 2008 Author Share Posted July 22, 2008 Have you checked the TPS and tried unplugged the ecu connectors? The AFM would really have to be plugged up not to let the engine run. You could open it up and see if it swings freely. Yeah, cleaned up connections and did the whole ECU trick. No go. Have you taken your AFM boot completely off the car yet and checked it for cracks by carefully stretching it? Yup, the problem is in positioning imho. Tried cutting the boot but meh...got another one but I need couplers before I get the car running. Quote Link to comment Share on other sites More sharing options...
Challenger Posted July 22, 2008 Share Posted July 22, 2008 Would there be any benefit in having the AFM really close to the turbo? Leaving room for a connection to reroute air from the BOV to. Quote Link to comment Share on other sites More sharing options...
woldson Posted July 22, 2008 Share Posted July 22, 2008 Move the AFM to the circular file and go MS?? Quote Link to comment Share on other sites More sharing options...
JSM Posted July 22, 2008 Share Posted July 22, 2008 Move the AFM to the circular file and go MS?? Agreed, he's going this route, but I suggested he gets his current setup running properly first so he understands everything that is going on. This is his daily driver and the down time would be to long to start such a swap. Quote Link to comment Share on other sites More sharing options...
woldson Posted July 22, 2008 Share Posted July 22, 2008 Your right, just was adding a little levity to the thread;) Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted July 27, 2008 Author Share Posted July 27, 2008 Meh, so I have a new intake hose on it. Got my couplers everything seems to be connected correctly and the car sounds worse and is undrivable. It freakin' sounds like a lawnmower so I'mtrying to find out what wrong with it after switching the AFM boot. Also, completely unrelated but my clutch feels like its completely gone. Checked my fluids and they're all there so I'm unsure. This car has become a headache. I love it but it's becoming really annoying. Quote Link to comment Share on other sites More sharing options...
Challenger Posted July 27, 2008 Share Posted July 27, 2008 Is there any law/rule on how close the afm can be to the turbo? Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted July 27, 2008 Author Share Posted July 27, 2008 I don't think so, but this car sure is ticking me off. This is a love hate relationship, she consumes all my money and never runs right. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 27, 2008 Share Posted July 27, 2008 I'm at a loss why you think positioning of the AFM would have anything to do with your issues. I have placed them in front of the radiator bulkhead crossways, as well as behind the radiator bulkhead straight, and never closer to the turbo than they are stock in several S30 conversions. Methinks your issue is not with the position of the AFM, but in something else allowing false air, or other standard ECCS Malady. The closer the turbo is to the turbo, the more flow disruption you will have going into the turbo, and the more likely you will alter it's surge line. Generally, the ideal situation is that the inlet to the turbo (any turbo) will have at least 4 to 12 inlet diameters of straight tubing run ahead of the impellers...so if that has a 3" inlet, the ideal situation would be a minimum of 12" straight tubing before the turbo for maximum airflow through the unit... Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted July 27, 2008 Share Posted July 27, 2008 Tony. I had my afm located on the fender bolted upside down. I had the afm boot cut in half and then mounted that way. From what i could tell it had no ill effects. I had the car running perfectly in my opinion. Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted July 27, 2008 Author Share Posted July 27, 2008 Well, just so you guys know the AFM ended up in the same place pretty much. The old boot had a small hole, but now it has more problems. The crank case ventilation tube came out but that problem shouldn't have anything to do with it. Especially since I put it back (while it is a little loose), I'm really lost as to why I'm having this problem at all. Prior to this I had no problems except for the car choking every now and then. Today I'm going to make sure that me changing the little filter on the pvc thought I doubt that should have anything to do with that. I checked to see if my rotor was loose, if my plugs cables were in the wrong order or anything that may have caused that and I can't find the culprit. Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted July 27, 2008 Share Posted July 27, 2008 Is there any place that is letting unmetered air in after the afm? like where did the crank case vent went to maybe idk. If you had pics it would help alot. Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted July 27, 2008 Author Share Posted July 27, 2008 The couplers I used were air tight, to my knowledge nothing should be getting into the AFM. Joe (240ztt) helped me in this topic: http://forums.hybridz.org/showthread.php?t=136616 Here's a picture of where the crank case ventilation hosew goes: http://forums.hybridz.org/attachment.php?attachmentid=8136&d=1216572495 Sorry it's a big file, the red circle is where it goes. To my knowledge though it isn't 100% needed really and you can just put a filter on it instead of the hose so it shouldn't really give me the problems I'm having. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 27, 2008 Share Posted July 27, 2008 Tony. I had my afm located on the fender bolted upside down. I had the afm boot cut in half and then mounted that way. From what i could tell it had no ill effects. I had the car running perfectly in my opinion. That's kind of what I'm getting at, position is pretty much irrelevant, and mounting it closer to the turbo will have no effect other than to disrupt airflow. The further away from the turbo inlet, the better. I have also mounted them upside down, no problems there either. Ianz's car (the maroon roadster) has an upside down mounted AFM right AT the radiator core with a stub of PCV through the core hole, suspended by it and the piping to the turbo...and IT even runs fine. I mean, I may be missing something in this scenario, but this is a 260Z, so all the fuel lines should be properly sized for a stock setup no problem. Was the alternator converted to the internally-regulated unit from the ZXT? Was the old regulator removed and diode-capped to prevent run-on... Lots of vague symptoms and a LOT of jumping around grasping at straws. Troubleshooting takes sticking it out, and working one problem at a time. Fixing it properly, and moving on. Lots of people don't like to do it, because it reveals all the shortcuts taken earlier in the conversion process...but that is what is required when things don't run right. I mean, this whole thread was predicated on the premise that the AFM position had some radically detrimental effect on airflow---and such is not the case. I just can't figure out where 'The AFM not getting enough airflow by the radiator' train of thought came into this at all---just can't follow that line of logic. Like you surmised with all this talk about PCV Filters being replaced, then part of the PCV System falling off I would much more suspect false air through the valve cover into the intake tract or through the open PCV hose under the intake than AFM Position! The PCV is a closed system, and 'sticking a filter on it' is not going to make your car run properly if you are still sucking air in through the valve cover, through the block, and then into the intake manifold through the PCV! That's "False Air" and bad in this system. The PCV is CLOSED LOOP. A tube from between the AFM and the Turbo supplies AFM-Metered air to the valve cover, it passes through the crankcase and into the intake manifold at high-vacuum situations---this air is figured into the equation. Under boost, the PCV is closed, and venting of blowby occurs through reverse-flow from the valve cover into the piping between the AFM and the Turbo Inlet. It's a very simple system, and works very well. About the only thing one needs to add is possibly a mech catch-can to do extra knockout duty if you have a lot of blowby on a tired engine... Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted July 27, 2008 Author Share Posted July 27, 2008 Car has an 82ZXT alternator, the reason I thought the AFM boot was the problem was because if I moved the AFM it would run better. My assumption was that it wasn'tg getting enough air. I now know my assumption was wrong. The car wasn't always stuck at the 2500rpm wall, if I moved it I could fix the car. Figured there was a hole somewhere or the general position was possibly upsetting how it worked. I have since not only replaced the boot with a brand new generic intake hose but I have also got a new filter, etc. I'm really lost right now because first of all I'm not the best mechanic in the world I pretty much just use my factory service manual and my EFI Bible. I then started thinking that the problem stemmed from the Crank case ventilation hose, since it did pop off when I was moving the AFM aroundm, but I don't know anymore. I'm overwhelmed at the moment, but it's not even like I could begin to do anything at the moment because I'm at work. I'm about ready to throw in the towel but I won't because this car is my dream car, even after all the problems, the car accidents, and the fact that it's a huge money pit. I guess I have to wait until I get home and see whats up. Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted July 27, 2008 Share Posted July 27, 2008 Its not the part on the case we are worried about for the pcv system. Its the other end. DId you cap off the pcv valve? Or did you just put a filter on teh crank case vent and call it good? If that is what you did i think we found your problem. Tony i completely agree with everything you said. We all know its hard to help some one figure a problem out when we arent at the car. Its even harder when you have someone that isnt experienced with cars telling you what its doing because it could be something completely irrelevantly that they are telling you. He bought the car already swapped so he is just trying to uncover the PO's mistakes. Which we all know is twice as hard to figure out. Quote Link to comment Share on other sites More sharing options...
RayG1988 Posted July 27, 2008 Author Share Posted July 27, 2008 I didn't do anything to the crank ventilation hose but put it back to it's place. As for the PCV, I swapped just the filter (looks like an intake hose). Oh, and thanks so much for having patience with me. I know I'm a huge pain. Quote Link to comment Share on other sites More sharing options...
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