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Discussion Starter · #1 · (Edited)
The first: where is the oil sending unit? I have craned my neck everywhere and poured over my new Chilton's book. It never mentions an oil sending unit. Stumped.

The second: I just got the car. It was hesitating and stumbling on acceleration. I replaced the plugs (wires aren't that old) and the fuel filter. It made no difference. It stumbles in every gear, but not consistantly. Sometimes it's all through the rpm range, or it's at the beginning or end. And I think once or twice it hasn't stumbled at all (or it could have been wishful thinking-- in other words, it stumbles harder at times than others). It seems to happen about the time I'd expect the turbo to kick in. What do I do next?

And one more thought. When I was under the hood and revving the engine by hand, it was quite a lot of noise coming back through the intake filter. It has some kind of aftermarket filter. I don't think it's a K&N. My question is: is this normal? I haven't heard it before when I had a Z32, so I just thought I'd mention it.

Thanks again guys.

Rob
 

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The oil press. sending unit is to the left of the oil filter. Might want to check the fuel filter for the stumbling.
 

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Discussion Starter · #3 ·
?AsleepZ? said:
The oil press. sending unit is to the left of the oil filter. Might want to check the fuel filter for the stumbling.
Thanks for the info on the sending unit. Is that something that you replace from the top or the bottom?

I have replaced the fuel filter. Don't know where to go next.

Rob
 

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Check the plugs, and you can replace from the top if you don't have cruise and some other crap on the passenger bank of the engine.
 

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The filter thing is normal man. with the stumbling......why dont you check out all the vacuum lines coming from the plenum. check near all the solenoids on the drivers side etc............if theyre good the check your timing-----ignition and cam timing- you dont really need to pull the whole cover to check it-- just bring the crank to tdc and check to make sure the cams line up . Is it a turbo or n/a ? I dont know that low oil pressure would make it stumble- you would have crazy valve knock though.....
 

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Discussion Starter · #6 ·
?AsleepZ? said:
Check the plugs, and you can replace from the top if you don't have cruise and some other crap on the passenger bank of the engine.
I just replaced the plugs and fuel filter.

I do have all of that crap on that side of the engine so I guess I'll be removing all of it to replace the sending unit.

Rob
 

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check the plugs, wires, distributor cap, and rotor button. if the stumbling is not Ignition related you may have an Overboost problem. in that case Check the turbo from under the car and make sure the Vaccum line to the wastegate is intact i.e. no holes, rips etc.
 

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BadBoy91 said:
check the plugs, wires, distributor cap, and rotor button. if the stumbling is not Ignition related you may have an Overboost problem. in that case Check the turbo from under the car and make sure the Vaccum line to the wastegate is intact i.e. no holes, rips etc.
He said it stumbled when the turbo should be coming in (hence isn't making boost yet)
 

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♣AsleepZ♣ said:
He said it stumbled when the turbo should be coming in (hence isn't making boost yet)
still worth checking, also may be an injector problem
 

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BadBoy91 said:
still worth checking, also may be an injector problem
Intake problem, I suspect. Boost leaks are common even on turbo cars from the 90s, let alone older one's. I wonder if he got that fixed yet?
 

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Discussion Starter · #11 ·
not fixed yet

I have inspected what I can from the top, but have not found anything. I'm going to have to jack it up and inspect from the bottom. I'm also going to change the rotor button and cap. It seems like several of you think it could be a boost leak, so that's where I'm going to focus my attention. It's just so darn tight in there!

Rob
 

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Could also be a bad plug wire. It's fine under atmospheric pressure to fire off a spark plug, but when the turbo starts going under boost suddenly the resistance is too much for it to send enough juice to fire off the plug. Maybe you understood that, maybe you didn't. If you're not getting any issues at idle or off boost then you can likely rule out the distributor cap and rotor.
 

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I see in your first post you said you replaced the plug wires, so nevermind on that. Does it stumble harder as boost gets higher and finally bogs down, or is it just a fairly consistent stumble.......
 

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Discussion Starter · #14 ·
Actually I haven't replaced the wires. I appreciate the advice though. I'll be doing that also. It doesn't have and REAL issues at idle, but it's a little rougher than I'd like, so I'm going to go ahead and replace the cap and button anyway.

Sometimes it will stumble a little harder as boost increases, sometimes not. Just the other day I drove it into town and it didn't stumble at all. I was shocked. Then coming back home it was back to its old tricks.

Rob
 

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Thats pretty wierd...why dont you go over everything Check the whole Ignition system, check all the vacuum lines and then check all your eletrical connections (maf sensor, aiv solenoid, tpd etc) That still sounds like something in the ignition system though. When was the last time that stuff was replaced?
 

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Check the suspected vacuum lines by running some starter fluid or propane over the hose. If you hear the rpms increase, there's a leak in that line that's letting the starter fluid or propane in. Remember....unlit propane...no flame...I know you're not stupid, but we all can look over stuff.
 

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Domdogg123 said:
Check the suspected vacuum lines by running some starter fluid or propane over the hose. If you hear the rpms increase, there's a leak in that line that's letting the starter fluid or propane in. Remember....unlit propane...no flame...I know you're not stupid, but we all can look over stuff.
I don't recommend starter fluid because it could conceivably cause a fire. Carb/throttle body cleaner is somewhat less flammable and gives the same results. Heck, for that matter so does WD-40......
 
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