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Driko
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| Posted: Dec 25 2010 at 1:17am | IP Logged
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Hi guys . my D21 is overfueling extremely
i need help , i have done the basics like plugs , fuel pressure etc and found no fault
I dont get signal out of the AFm though , i did a comparison between my D21 and D22 , see attachment and saw that on the D22 i get signal out on ter D on the AFm , on the d21 no signal and even if i simulate it the vehicke dies immediatly even with a vootage as low as 0.05v
I need diagrams or advice please guys
| 1993 D21 Hardbody Pick up VG30 |
2006 D22 Hardbody Pick Up VG33 |
| RPM Sig |
Per revo |
360 |
RPM Sig |
Per revo |
360 |
| Cyl Pos |
Per revo |
5+1 |
Cyl Pos |
Per revo |
5+1 |
| ECT |
Input V |
0.2V (ground) |
ECT |
Input V |
0.2V (ground) |
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Output V |
1.65V |
|
Output V |
1.75V |
| TPS |
Input V |
5.4V |
TPS |
Input V |
5.25V |
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Output V idling |
0.85V |
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Output V idling |
0.65V |
| Inj P/W |
Running Temp |
8.9MS |
Inj P/W |
Running Temp |
3.7MS |
| AFM |
Ter A |
0.35 V |
AFM |
Ter A |
4.2V |
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Ter B |
13.95V |
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Ter B |
14V |
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Ter C |
0.2V (ground) |
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Ter C |
0.2V (ground) |
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Ter D |
0.0V |
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Ter D |
1.55V |
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Driko
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| Posted: Dec 27 2010 at 2:38pm | IP Logged
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OK so i got the D21 running again
After i founf some FSM in the DIY part of the forum , ( thanx to Spyder Z15 that posted it on clubfrontier ) i found that the VG30 Air Mass Meter outputs aprox 1,5v at idling so i went ahead and simulated a 1,5 to 1,6 v signal and found the truck to run sweet , even verified that with my 4 gas analyser
- Now the fix -
As you dont get VG30 Air Mass Meter here anymore i already bought a VG33 unit .
When i ran that on the VG30 at idling i only got a 1,1v output on my oscilloscope due to the larger bore of the unit and the smaller suction of the motor .
Now a clever thing my wife thats a metereologist taught me is that if air flows from a large space into a small space and back to a large space the air speed increases which in turn simulates a larger air mass so i did the following
I sealed off the inlet to the Air Mass Meter with a piece of plastic and cut a 40mm hole in it to start with ( directly in front of the Hot wire inlet of course ) low and behold a higher voltage was recorded on the scope , i kept enlarging the hole until a got to 1,6v at idling ( aprox 50mm dia hole ) and BOOM the VG30 runs with a VG33 Air Mass Meter , granted it currently has a little issue at 3000rpm in 2nd but it pulls like a banshee out of the blocks and at least it runs
Ill keep experimenting with the restrictor plate and venturi as time allows until i get it perfect or get my hands on a VG30 AMM , what i am of course now planning is to play with this effect on my VG33 as it seems to increase the bottom end drasticaly in the seat of your pants dyno , so as soon as i can get to a proper dyno ill try a few different size "venturi plates"and look at what i see on the dyno .
Anyone tried this yet? And if youre in a bind with your VG30 AMM at least ths offers a solution for the time being and makes for some interesting playtime over the weekend
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lakota
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Nissan Frontier Forums Moderator
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| Posted: Dec 27 2010 at 5:20pm | IP Logged
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..
Sounds like a great piece of ingenuity Thanks for the great post!
Have a good one.. Don S..
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PLEASE >>> A SIG similar to mine can be VERY HELPFUL to all the members!
'99 4x4 3.3 Frontier Se KC Auto, 48,000 miles
'76 4x4 401 Wagoneer QT
'04 FWD 1.8 Sentra '08 FWD 2.4 Camry LE
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Driko
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| Posted: Dec 28 2010 at 2:07pm | IP Logged
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Anytime , as long as it helps a fellow Nissan Nut im happy
I supply and train personall on Diagnostic equipment and Oscilloscope so if i can help out feel free to ask ,
No one knows it all but he might just know what you need
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frontierguy
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| Posted: Dec 28 2010 at 7:33pm | IP Logged
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Someone has WAY TOO much time for fun!!!!
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'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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frontierguy
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| Posted: Dec 28 2010 at 7:41pm | IP Logged
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Just had another thought, might want to verify good,
clean engine ground connections at the battery cable and
the two ECU grounds on the intake plenum. Does not hurt to
add additional ground support. Also check for voltage drop
at the MAFS(should be less than .009v). I like to see them
at .000v. Also, don't forget to use a Genuine Nissan oil
impregnated air filter. Cleaning the wires on the MAFS
helps at times also.
PS nice info.
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'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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Driko
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| Posted: Dec 29 2010 at 3:45pm | IP Logged
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WAY TOO much time for fun - im just lucky enough to get paid to play with technology - lol
As for the ground issue Frontierguy mentioned - thats exactly waht caused the issue - the truck had a very corroded body earth so all the sensor earth etc used the AMM as earth as that is bolted to the body in sorts - AMM was completely fried
Anyways my dad is now running the D21 and ill be focussing my playtime to the D22 VG33 , planning a 2"bl and then theres still that M62 thats just gathering dust on my garage shelves
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frontierguy
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| Posted: Dec 29 2010 at 7:42pm | IP Logged
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What's the AMM????????
__________________
'10 Altima SL
Traded 08 Frontier for 16 Frontier SV CC Long box, quite an upgrade. I do miss the 6 speed and Dynomax ex.
Nissan Technician 25 + years
2011 John Deere X720SE
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Driko
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| Posted: Dec 30 2010 at 3:18pm | IP Logged
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AMM - Air Mass Meter - the Nissan measures air mass not actual air flow . apologies for stating AFM ( air flow meter earlier ) the hot wire principal is calibrated to measure a certian mass of air flowing acros it by the amount it actually cools down the wire ( we can get real technincal hear but thats the basic principal i was taught anyway )
Unless i have it wrong? Nissan techs care to comment?
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Nissan Frontier Forums : Problems / Technical
Topic: D21 overfueling
