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Engine running issues, starting and idle

225 Views 6 Replies 6 Participants Last post by  kickstand80
Last week I picked up an 83 280zx base coupe, got it running but it high idled at 3k rpms, cleaned in intake, bypass and throttle valve, clean contacts ect. Now it just cranks ands won't start at all. It will occasionally sputter like it's almost there but won't fire up.
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Spray some starting fluid into the intake. Will it start then?
What do the plugs look like?
Have you confirmed spark?

Check everything you messed with to see if you didn't put something back together right.

Use the FSM to help with diagnostics and troubleshooting. XenonZcar.com S130 Factory Service manuals
Did you check the rotor and distributor cap? How about setting the timing?
Its like loosing your keys or now a days your phone. Back track and test and validate everything you touched. I had something similar happen once. Drove me Nuts for days almost to deep depression, until I realized my mistake of not re-connecting the PVC hose hiding under the intake baffle. Boom Fixed!
Throttle position sensor, had to replace it on mine, same symptoms. TPS is a pretty common problem on e30s. I think you can actually clean them too but I was doing a restore so I just replaced it. There's a ton of forum talk about it though. I posted a link to an article about TPS failing symptoms etc.
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Thank you for the replies, backtracked and checked all my connections, got the car to run but it's inconsistent. Lately it runs but has a surging high idle and will die if the throttle is applied to suddenly. I cracked open my afm as I suspected it was the problem and no amount of adjustment or preloading it seems to help. One thing that did allow the car too accept throttle was if I physically held the sensor so the car wouldn't read incoming air, in that condition it would Rev up, and by pushing the flow meter in without throttle the idle would calm down. This would indicate some vaccume leak but I can't find anything other than an exhaust leak. I've tooled with the timing and idle adjustment to no avail. I could try tearing down my intake and torque everything and adjust everything, that way I could try to find my exhaust leak too. I would appreciate any suggestions. I'll be away for the month but I'll be right back at it when I return.
Its good that you checked the AFM by holding the flapper and reving it. It not so good that you messed with the factory settings inside the AFM, what is done is done. It does seem that you have unregulated (bypassing the AFM) air entering your engine somewhere. It may take removing the intake manifold to find the issue, but I would exhaust every other possibility before taking on that challenge.
Are you sure that your PSV system is all there. The hose from the valve cover to intake boot? The hose from the block vent pipe (under the front of the intake) to the bottom of your intake where the PCV valve is located. No cracks or bad hoses.
Remove the intake boot that is on the outlet of the AFM and inlet of the intake manifold and look for cracks. Is the seal on your oil cap? Are the hoses to and from your Aux Air Regulator good?
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