TwinTurbo.NET: Nissan 300ZX forum - Lagged idle response from idle: Part 4
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Subject Lagged idle response from idle: Part 4
     
Posted by Draker (Eugene, OR) on July 24, 2011 at 1:51 PM
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Message Back to present:

Since my last post I haven't done much:

- Tightened throttle cable to remove slack
- Verified throttle bodies are synced.

While replacing my radiator fan last night, I look a look at my CAS and noticed it's clocked all the way clockwise. This seemed odd to me so I searched around and found this might be a sign I am off a tooth somewhere. As I posted above, when I did the 60k I counted teeth 3-5 times. Turned the engine over a few times, and ensured the gap was set at 4mm. My timing is dead on @ 15° checked at the PTU loop and on DataScan. It doesn't bounce around and advances as it should.

Is this a sign? Where should the CAS be positioned normally?



Heres a recap:

First Post - La-Z-Link

I just noticed my Z is poor to respond when trying to accelerating quickly from idle. For example, if at a stop light and it turns green and I get on it, it's very sluggish but it doesn't really bog down. It does the same thing if I blip the throttle while in neutral. I also noticed a little bit of an irratic shift or incorrect shift points in the transmission (auto). See below.
A little background, I finished swapping a different TT engine into my car last year. I don't really drive it much. Probably less than 500 miles in the last year. Partially because of the swap. During the swap I did a 60k and set the timing, counted teeth about 3-5 times. I installed a new EFI harnesss. Everything seemed good, it runs fine in the upper RPMS. Idle is fine.
I've checked the TPS and set it per the service manual. It was already set correctly.

I am thinking I will probably put new spark plugs in it. I didn't put new plugs during the 60k because I had them from my old engine with only about 20k on them. They are the correct plugs for a stock Z, which mine is.

I also have a spare MAF I might put on it to see if there is any difference. The MAF I have on it now was sitting around for a while during the swap and I could see element inside collecting a little dirt. Might try cleaning it as well.

I know I set the TPS per the service manual, but I do have a spare to throw at it also.

I did a boost leak test and it seemed fine might be time to do it again. Last time it leaked down at 10sec/lb. OR 50 seconds for 5 lbs and so on.

I've yet to check the fuel pressure, I figured I would swap out a few things here and there. The first thing I thought of was the TPS and it needing adjustment. I know if it's out it can cause the transmission to shift at strange points. But sure enough it was adjusted correctly. I checked for codes in the ECU and TCU, none in either at this point.

The car is stock, have a 95 engine with new style injectors, new style cas.

Please let me know if I might be missing something here. If you have had this issue, what did you do to solve it? I've ran through the 6p's after the swap everything seemed okay. Now, not so much.

Thanks.


Second Post - La-Z-Link

Steps I took:

- Checked if TPS needed adjustment. Found to be @ .46v and no adjustment made.
- Replaced MAF with spare, problem still present.
- Leak checked with smoke machine, none found.
- Boost leak checked, None.
- Pulled TPS to clean, found lower mounting bolt missing. Opened TPS, found to be clean. Reinstalled with 2 mounting bolts. Test drove. Shifting is now accurate, and throttle response has greatly improved from idle.


Third Post - La-Z-Link


Steps I took:
- Replaced pfr5b-11 with brand new ones.
- Purchased blaZt cable and software
- Verified Temp Sensor Reading is good. (@ 170-180°F)
- Monitored O2's. Found one to switch slow, replaced with spare and now both are normal.
- Power Balance test
- Verified Timing set at 15° and steady
- Replaced EGR Temp sensor (Which was hanging in engine bay due to no EGR) with resistor.


     
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