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Mass Air Flow problem for Z31

11-13-2007, 10:33 PM
So a lil while back my car (1986 300zx) kinda lost it's will to live. It still runs today but it won't go over 75 (maybe 85 if it's a downhill). In 5th gear it's like it doesn't want to go over 3000 rpms. If you give it long enough it'll sometimes make it to 3100 or 3200. In all the lower gears it winds out pretty well but it's still missing a lot of it's power it feels like. When it lost it's will to live i took it in to the shop. The guy who worked on it said the spark plugs were pretty bad. So i got new plugs, wires, rotor, and cap. But it was still lagging horribly. He put it on the machine for me and he told me it was the MAF sensor. I finally hit a pick n pull today b/c i just got tired of getting half the regular gas mileage. I pulled a used MAF out of a 84 turbo. The car was actually one of the 50th anniversary editions. Just got it installed and it still feels exactly the same. It doesn't smell like it's running as rich now tho. Before it would idle and you could smell the unburnt gas from the exhaust. At idle my roommate described it as sounding like a lawn mower. Anyone got any ideas as to what could be causing my car to act like this?

11-14-2007, 05:46 PM
try running the ecu codes... it could still be a MAF issue, just something to do with wiring or the connector...

usually a dead MAF will cause the car to go into limp-home mode which will make it run VERY rich and not let you rev above 2k rpm

the procedure to run codes will be in any FSM (factory service manual) for the z31... look for the 84-86 manual.. links can be found at 88hybrid.com

11-15-2007, 04:12 PM
Yeah I've got the FSM and i ran them once before but I don't think I ever re-ran the codes after I got it back from the tune-up. I've found my project for today it seems. Will report back with any findings

11-17-2007, 06:04 PM
i was having a problem for a while where my car wouldnt rev past 4000rpm period, i found it was a combination of ignition timing and my egr was loose, check the two nuts holding the egr to the intake manifold and on the exhaust manifold, ive heard of the delete kits, but i dont know much about them or the benifit.

11-19-2007, 10:19 PM
Quick question, if my MAF was bad at all would I be able to rev over 5000 rpms in first or second? B/c i can definately do that. Also, today the thought occurred to me that maybe the mechanic who worked on my car didn't have the car at tdc when he checked the timing and that could be a possible reason for the poor performance of my car. I was gonna use one of the loaner timing lights at kragen tomorrow tho i've recently found myself a little bit broke :( so i'm gonna try to get that going later on this week maybe. My co-worker also recommended I try checking the compression as well one day when we went to BK for lunch and he got to hear it run. Oh yeah, I may have neglected to mention that I'm currently getting something close to 10-12 mpg at the moment. Sucks greatly as I really enjoy cruising. Possible causes anyone??

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