# '86.5 D21 VG30i AT Hot weather problem



## Redi4NissanForum (Aug 25, 2008)

My truck stopped liking hot weather. 
At 95 degrees fahrenheit and above 
it will not climb beyond 2800-3000 rpm 
but "stalls" and stutters.

At first blush I changed the Throttle Position Sensor 
but the problem persists.

So, I'm inviting anyone monitoring this thread 
to test drive my truck with me. 
We'll drive it when the ambient temp is under 85, 
when it is over 95, 
on the flat, and on a grade.

Hop in:

Nissan D21 VG30i Test Drive

Let me know what you think.
Shared experience, comments and recommendations appreciated.


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## smikster (Aug 12, 2008)

well i could not get the video to play but the first frame said you had over 200k

is it running hot or just acting up when its hot?

do a seafoam and if that don't work it may be a worn out wire...be sure to check all you can...

and if you haven't done a tranny drain with freash fluid you may want to do that to


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## dvdswanson (Nov 6, 2005)

check the MAF sensor on the t-body


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## Redi4NissanForum (Aug 25, 2008)

thanks for the responses.

My next check was and is the MAF sensor connectors
someone said that the MAF seldom fails but the connections are infamous for corroding.

What is a seafoam?

I'm hoping against hope that it's not a broken/shorted wire.

Tranny flushed 8K ago and tech checked 200 ago.

Smikster I'm wondering why you could not see the video.
This is off topic so maybe we could/should converse off forum.
Don't see a private message option.
Tried the yahoo contact option but didn't work.

In the mean time, do you have flash player installed?

Thanks 
Cliff


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## zanegrey (Dec 5, 2005)

if you put any part on your truck w/o reading the codes ..you are just wasting your time and money...

read the codes...


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## Redi4NissanForum (Aug 25, 2008)

*re: '86.5 D21 VG30i AT Hot weather problem Codes*

Good point.
And, so I did.
The code read Throttle Position Sensor.
So I changed it and symptoms persist.
So, I read code in cool of morning with vehicle warmed up and no symptoms it read Heated O2 Sensor #33.
Then when the day warmed up, I test drove and produced symptoms and Code read #43 Throttle Position Sensor.
Go figure. Something odd.
Now maybe the TPS isn't adjusted properly.

My O2 sensor was changed 8k ago so I'm trying to ehaust all other possibilities before springing for another.

I'm getting feedback from others that the MAF connections should be checked. I looked this evening and indeed one terminal is pretty green.
I'm cleaning now and will test drive tomorrow.

Should be good weather for testing. Triple digits on the way here.

thanks for the interest and input.


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## smikster (Aug 12, 2008)

WOW time for some chem love

at half a tank pour a bottle of B12 in your tank and run till almost E

replace fuel filter

and/later

slowly pour searfoam threw the brake booster line (hose coming off top right by brake reservoir. will hiss when you pull it) pour slowly as not to kill the motor. when 1/3 is gone dump in there to try and kill motor...if motor don't die turn off When the can is 1/2 to 2/3 empy *also stick brake booster line back on*(will probably see smoke at this point) let set 5-15 min and start up (give it some gas) when started and running threw the rpm range smooth go and drive it hard till it stops smoking.

hows that maf coming along?


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## dvdswanson (Nov 6, 2005)

I was refering to this.... How To: MAF Cleaning for a better running engine! - Topic Powered by eve community


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## Redi4NissanForum (Aug 25, 2008)

*MAF, SeaFoam, TPS*

I realize that I know about Seafoam. Have and use it for my small portable pump. So, cleaning the injectors sounds like a good idea, but not necessarily directly applicable to my present circumstance. Thanks for the encouragement.

Here's an additional factor. I realized that it is not necessarily hot ambient temperatures that initiate my problem. It is when the truck sits in the sun during hot days. For example , I drive to town at 2:30 PM on a hot day, no symptoms. Park at the store for an hour in the sun. Come out at 3:30 PM and symptoms. I'm not sure it that changes one's diagnosis or not.

Now,yesterday, I cleaned the MAF sensor connections and filaments. Then I parked the truck in the sun for a couple hours. Then, I ran the ECU test and it came up #43-Throttle Position Sensor. Remember, I have new TPS installed. Then I test drove and symptoms prevailed even into the evening.

I guess I need to inspect and clean TPS connections and test for proper TPS adjustment.

Other suggestions are appreciated.

For your convenience here again is the link to my test drive:
Nissan D21 VG30i Test Drive


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## Redi4NissanForum (Aug 25, 2008)

So here's the latest.

The observation that a specific part of the vehicle heating up (rather than general air temp) might be the problem led me to test the ECU for heat effect.

Today was a perfect day for testing as ambient temp reached 107 degrees.

In the A.M. the truck was in partial shade but the sun was hitting the ECU (I have the passenger seat out) and the ECU test indicated problem #43. I backed out into the noon day sun and put an ice pack on the ECU. When it was good and cold the test lights indicated no problems. I drove into town for a usual Thursday shopping where the truck sits in the sun, this time all the while with ice pack on ECU and never a symptom. 

When I returned home at 3:30 PM I took off the ice pack and let the truck sit in the sun for an hour and a half. The ECU was hot to the touch and after a test drive where the symptoms emerged it tested #43. 

So, can one get into the ECU or is this a replacement issue?


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## Redi4NissanForum (Aug 25, 2008)

*'86.5 D21 VG30i AT Hot weather problem- ECM problem solved*

It’s been almost a year since the last post on this problem and I just resolve it last month.
But, since these threads serve as a kind of problem/troubleshooting archive, I’ll post the history of my solution.

I decided to send my ECM (EECU) to a “rebuilder” and chose Direct Automotive Products (DirectAuto.com) who subed-out their ECU repairs to an outfit named Python. Python was unable to detect a problem but re-soldered the CBs and charged me for a “rebuild”. The returned ECM preformed with the same malfunction.

DAP and Python accepted a warranty return, but again were unable to bench reproduce the problem. They continued insisting that the error was on my end, even though I provided detailed report and evidence of my extensive on-board testing and determination that the problem was in the ECU itself. 

DAPs web site promised that there would be no charge if the ECU was un-repairable (they’ve changed their web site now). In the end, after I got Discover Card involved, DAP agreed to charge me for testing only, and refunded the balance. 

My intention here is not to flame DAP, but in retrospect if I’d known in advance that one could never speak directly to a DAP warranty agent (e-mail only) I certainly would have considered alternative vendors (“your mileage may vary”).

A local technician recommended Auto ECMs (AutoEcms.com 877-687-3267). AutoECM sends you a replacement in exchange for your core. In contrast to DAP, you have no down time. However, another tech told me that in their experience, they would receive a replacement that had different problems and had to keep exchanging until they received a working unit.

In the end, I purchased a factory refurbished unit from the Nissan Dealer and the problem disappeared.

Observations and speculation

* All the techs with whom I discussed the problem stated that they rarely see ECM problems.

* DAP & Python stated that most problems were resolved by resoldering, that is to say, cracked solder joints are the common problem.

* I suspect that Python and other non-factory “rebuilders” only resolder and play the percentages.

* Even a vendor who exchanges may merely send used, untested and/or merely resoldered units and also play the percentages.

* Historically the USA auto fleet turns over very 15 years, but some reports suggest that this will likely change (with difficult economic times) and extend to 20 or 25 years.

* It seems likely that older vehicles will begin showing component failure in the electronics.

hth


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## zanegrey (Dec 5, 2005)

i have run into this ..but most times cleaning up the grounds for the ecm and cleaning contact points fixed the problem..

may i ask what they chargerd you for a ecm...?

thanks


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## Redi4NissanForum (Aug 25, 2008)

Wouldn't that be a hoot if I changed the ECU unnecessarily. But, I did try to clean contact points. And also made a concerted effort to isolate the contacts in my heat tests, i.e. using heat shield and heat sink, attempting to heat and cool the box and contacts separately. It seemed clear, beyond reasonable doubt to me anyway, that the problem was in the box itself.

Dealer hit me for $602 for "factory refurbished" unit.

c


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