I definitely appreciate it

 

So the sensor in the picture I posted is for the injector fan. Well thats definitely out then... I dont even have the fan anymore.

Ill clean the plugs then im done for the night, AFM and CSV will do this weekend. Ill keep everyone updated (I hate reading through threads that have my exact symptoms, but a resolution never gets posted).

Thanks everyone for all the help!!

P.S. Its an XSi and I just got a Canon speedlight so I have been playing with it every chance I get!

 

Thats what were here for, to help each other out. Just dont want to stear anybody in the wrong direction. I'm out for the night, keep us posted.

 

One last thing... try unplugging the TPS & see what happens. I know FDC_GUY (a local Z'er here) had a hard time rev'ing his 280Z. He disconnected it & now it rev's fine.

 

does this model have a bcdd? Boost control Decel device. I am assuming it is the 83 280zx n/a (meaning Naturally Asperated?)

the bcdd should be an object hanging off the bottom of the throttle body/ butterfly valve. there should be vacuum lines to it, one of which should t into the vacuum advance line going to the distributor.

If the bcdd has been adjusted incorrectly it can give similar problems.

when the engine is first started cold, mash the throttle down full open and release quickly two times, does it backfire into the a/f meter as it decelerates?

 

So I just pulled the AFM and adjusted it. It was very easy to do and it feels like it restored some power to the car. I will have to take it out on a good drive on the highway to be sure.

I used the instructions that were linked on the top of the site but the pictures that were posted were terrible quality and it was hard to really see what was going on. I took some pictures of the inside of the AFM for other people to more clearly see what is going on inside.




You can clearly see the grooves that have been worn in here.

 

Did you adjust the spring tension and carbon track?

 

Just the carbon track

 

You can adjust the spring tension as well. With the cover off and the motor running, you can push or pull the spring either way... whichever way it runs better, that's the way you want to adjust it. Make sure you mark w/ a black marker the location of the cog, hold cog w/ finger, loosen the retaining screw, and adjust. Go only 2 or 3 teeth at a time. It's also good to do this w/ an A/F ratio gauge. DO NOT LET THE COG LOOSE W/ THE SCREW OUT!!!

 

So adjusting the carbon track on the AFM seems to have cured my hesitation problems and freed up some lost power. I have not felt a hesitation at all since the adjustment and the car pulls much stronger than it did before.

I was going to adjust the spring tension as NismoPick had suggested, but this seems to have fixed the problem so I am not going to bother. However, I still have to wait for my next tank of gas to see if my fuel mileage has increased. Although it will be hard to tell because I am having too much fun with having all this power restored

The the cold start issue is still there and unfortunately i did not get a chance to test out the CSV. I did notice that this morning it was in the low 20's and when I started it up it only ran on a few cylinders until i gave it some gas and it caught. Could this possibly be more evidence of a bad CSV?

 

I had a similar issue with mine. When cold, unitl warmed up, i could not rev at at all and it would bog. After a while it became more noticeable and irritating but then i heard a vacume leak type sound and chased it down to the BCDD. I disconnected it and it soved the issue for me with the only down side being that it made the car pop or gurgle on decceleration, but not backfire.
Durring the whole issue though i found that by pumping the gas pedle it seemed to coax the RPMs past the problem and warm it more quickly

 

i have the same issues with my 81 280zx n/a. you think it could be the same problem?

 

Yep......... or the cold start valve ..... or the air regulator .....

 

UPDATE: So adjusting the AFM carbon track seemed to cure my hesitations for a while, however they came back. The hesitations were becoming exponentially worse to the point where the car would not run anymore. At idle the engine would intermittently shudder and stall.

I tracked it down to the distributor. The bushing in the distributor was badly worn out causing the shaft to have so much play that the stator and reluctor would make contact. Also there was so much resistance that the shaft was very difficult to spin.

After further inspection I noticed that the vacuum advance was completely blown out causing a huge vacuum leak. This could have also contributed to some of my hesitations and definitely poor gas mileage.

I got a new distributor in and all is good now

Stator & Reluctor

 

i too have hesitation in my z and i was wondering if someone can post the link to adjust the afm, my Chilton didn't have it nor did the online service manual i looked at.

 

I knew I made that GENERAL TECH section for a reason...

https://www.zdriver.com/forums/240z-280zxt-s30-s130-tech-tips-275/js-how-rebuild-your-afm-15277/

 

oh, forgot to look through that, thanks for the link