samx

Hey everybody, real quick this is my first post at arrived. I bought a 1981 280zx turbo that had undergone body restoration and a T5 swap. I love the car, and I got a great deal on a complete car without a shady history. I'll get some pictures of the car up when I can.

The car has behaved very well with only minor problems. The car starts and drives beautifully throughout the entire RPM range, until recently. Last month, I found some corrosion on the air flow meter connector that was causing low voltage readings at the EDU, and a lean condition on acceleration causing stuttering and backfiring through the intake. That problem has been corrected.

Now, about a week after I solved that dilemma, the car has been stuttering and losing power at high RPM. Basically, be car will come into boost and accelerate fine, but it "flutters" and falls on it's face at high RPM. It also seemed to develop during the hottest days of the summer, but hasn't gone away on cool nights. I turned down boost thinking it was knock retard, but I don't really know what KR feels like and I don't think this it. Any I sight into the issue is appreciated.

duckyz

Hmmm.... Sounds like the TPS (throttle position sensor) is dirty. I know on n/a Zs , it's on the drivers side just above the cold start valve. It's a little black box about 1"x1". Take off the cover and spray electronic cleaner on the metal parts. See if that doesn't clear it up for ya.

samx

Thanks for the suggestion, i'll give it a shot. The thing is, from studying the Turbo model's factory service manual, its not really a position sensor, its a switch that detects if the throttle is either fully closed or fully open (double pole single throw), and that supposedly the WOT position of the switch is not used on the turbo model. I did clean some corrosion off the TPS connector the other day but it didn't correct the problem. I need to figure this out because my ability to downshift into 3rd and take off is shot right now.

samx

Thanks for the suggestion, i'll give it a shot. The thing is, from studying the Turbo model's factory service manual, its not really a position sensor, its a switch that detects if the throttle is either fully closed or fully open (double pole single throw), and that supposedly the WOT position of the switch is not used on the turbo model. I did clean some corrosion off the TPS connector the other day but it didn't correct the problem. I need to figure this out because my ability to downshift into 3rd and take off is shot right now.

NismoPick

Welcome to ZDriver!

Indeed the 280zxt tps is just a switch, but you do need to check ALL the basics first:

-Proper fuel pressure?
-Proper spark? (how do the spark plug tips look?)
-Proper a/f ratio?

Check connections for the AFM, CHTS, and ECU.
Check timing - stock is 24* BTDC
Check for vacuum leaks... you mentioned you "turned down the boost"... are you using a manual boost controller? BOV? IC? Pics of your setup help...

It really comes down to checking every sensor and connection to make sure it's working properly.

samx

Thanks for the tip. Yeah, it has a manual boost controller installed. The car is giving me quite the headache right now because it has returned to running lean all the time, which from reading around here it's apparently a common problem. Not sure if one faulty part or connection is causing both the lean condition and the stutter at high RPM. Right now I can't get it to a high enough RPM to see if it still stutters because it backfires and that freaks me out a bit haha.

convert280

I have a 1983 280zx turbo; did you ever figure this out? I am having the exact same problems as you! No high rpm power, stuttering all that! I was messing with the charcoal filter and it was kinda making it better or worse when i unplugged some tubes but i also think it may be electrical since it will just lose spark and die some times and not start back up for awhile. Will turn over and what not but there is no spark unless you wait. Ugh i want my baby back!