PleaForPurge

I have a 1990 JDM swapped 300ZX. There are aftermarket downpipes, aftermarket catless H pipe, custom exhaust, K&N filter, and aluminum hard pipes on it. Not sure what other upgrades have been done, as I bought it as is for $7,000. I have what seems to be a common problem with these cars (cutting out, stuttering at full boost WOT) and had a few questions.

1) A few people have told me to get a mass air sensor for a different car that can handle more air flow than the stock one. A friend of mine heard of people using LS1 MAF's on SR20 swaps and didn't know if that is even possible.

2) I checked the numbers on my ECU and it came up as a 89.5-90 (late) 300ZX turbo automatic transmission ECU. It has obviously been opened up because of stripped screws holding the cover on and scratches from a screw driver prying the cover off. I was thinking of ordering another ECU to just start fresh.

Not to get off subject, but here's my story. When I was 8 years old my dad's boss just bought a brand new 1996 300ZX TT. My dad called my mom and made her bring me to his work so I could see it and I fell in love. It's been my dream car since then. I always told everyone I'd own one on day and everyone laughed, but here I am 15 years later with one sitting in my driveway. All I want is to make this car run right. If anyone could help me I would appreciate it so much. Thanks for your time! -Chris

Cap

You are trying to fix a problem, that you do not even know what it is..

My Stock Answer is " Get a Wideband ".. if you can Verify you have a Lean Condition, then Search for a Fuel Pressure Problem.. if it's not that, then is the Tune not right for your Set up..

Or is it something like you are running out of Spark.. the Points are endless.. but as a wise old man that I use to work with said.. " You have to be Smarter than your Problem.."

I'd love to say get a new "..." but it's not that easy..

Must Troubleshoot..

Cap

PleaForPurge

I don't have a wideband... all I have on the car is a boost gauge and pyrometer. So far I've tested the injectors by putting 12 volts to them and the connectors for the injectors. I replaced the MAF, fuel filter, plugs, and coolant temp sensor.

When I replaced the MAF it seemed to get better but only for a short while... If I get on it really hard sometimes it will bog so hard it will almost stall and then I have to shut it off and turn it back on for it to work again or hitting the gas pedal literally does nothing. Sometimes the check engine light will come on for a short period of time and I'll have to push in the clutch and rev it and it blows a bunch of black smoke and then runs ok again. This is my 4th boosted car and I know alot about cars and forced induction. This thing is driving me crazy though...

hoov100

After reading all this I kind of doubt that, it's a completely different game when you have people used to just bolting on parts who now actually have to think and diagnose something without plugging a computer in.

Pull the ECU codes, black smoke means rich, ohm the injectors, if you are running anything other then stock turbo's at stock boost with stock injectors you need a real tune, pull the ECU and see if there is a sticker or something inside it or if there is an EPROM. Pull all the plugs and describe the color of each, make sure you are running the correct plugs, check for vacuum leaks, check for corroded or broken connectors, look for any general hack jobs.

does the boost surge or "flicker" under load?

PleaForPurge

Well now something just happened while I was driving it. Check engine light is on, car idles fine but as soon as you give it any gas it stutters and bogs really bad. When I drive it, the boost gauge flutters and it backfires really really bad and is a complete dog. Oil is clean, antifreeze is clean, it still builds boost and theres no vaccuum leaks that I can find. When the car is hot and the hood is open smoke comes out from beside the battery and kind of smells like oil. I'm so confused now...

PleaForPurge

When I try to check the codes, the screw in my ECU spins endlessly so I can't get the LED to flash either.

Rupe

Maybe a bad turbo? You should check the stuff hoov and Cap have suggested, the worst case is you knock a few potential problems off the list. Well I guess worse would be finding out that everything is wrong, but I think you get what I mean.

PleaForPurge

Well, after looking over the whole car I found a fuel line was leaking really bad and the whole passenger side of the motor wasn't getting any fuel. After replacing it, it idled better and revved better so I took it for a drive. Still the same problem, but better. I check the timing and when I put the crankshaft at 0 the dimples are a whole tooth off. Could this be the problem? Have I caused any major damage by this happening?

Also, as I asked before, should I buy another ECU that's for a 300ZX TT stick being that mine is out of an automatic?

I really need to get this car running... it's killing me to not drive it.

PleaForPurge

....and how many times does the screw in the ECU spin before it stops? Maybe mine is broken?? I wish I could check the codes.. but I can't