I had the day of and just got my test pipe installed to replace my cat. So I said what the hell, I went and finally got my dyno. I must say that I am really disappointed at the numbers. The guy says that I am running really rich so that's why my numbers are bad. They plugged some sensor to my exhaust and this device read out 14.9. Dunno what that meant. With all my mods I should not be producing these numbers.. Take a look for yourself. Anyone have any ideas on why my numbers suck? Bad plugs? O2 sensor? I have no SES or CEL lights.. Car runs fine other then I get like 300 at the tank..

http://www.redrival.com/pcguru2k/dyno.htm

Mods (That would affect dyno)
- Hybrid PR Upper Tube with Apexi Filter
- PR UDP
- Lightweight SSR G1 Integral 17" Rims
- Custom Test Pipe
- Cattman Y-Pipe
- Greddy Full Cat-Back w/ Evo exhaust

 

you might wanna pull the codes and see if you get a KS code... what gear did you dyno in?

Your graph is nig while the plot is very small...and your an auto I see..but that is really low..also looking at the end of the plot the VIM seems not to be coming on..your power dies out like the 4th gen

 

Looks like another 00-01 5th gen experiencing a VIM failure. It also looks like another dyno shop that doesn't know how to dyno an auto.

You're running rich because you removed the cat. The O2 sensors are getting scary readings so it's going to make the ECU revert to a rich program. I suggest going the environment and you car a favor and put the cat back in.

Dave

 

Can you rescan the graph? The actual graph portion isn't showing up correctly.

One thing that definitely appears to be wrong, is your HP is falling off after 5000. It should not do that, it should increase to redline.

It is likely the sign of a variable intake manifold failure.

Attached is a dyno of my car with the variable intake enabled (run 15) on one plot and disabled (run 16) on the other plot.


http://web.tampabay.rr.com/maxgator/VIMonVSVIMoff2.bmp

You can see that the disabled plot (run 16 blue) peaks at 5000 at about 165hp and trails off to less than 150 at redline. The enabled plot peaks at redline at around 185 (it was hot and humid that day)and goes up from 5000.

Yours looks like my Variable intake disabled plot. You lose hp from 5500 to redline. However, it doesn't fall quite like mine.

One thing I learned from my VIAS problem was that when you have mods on the 5th gen, they really only seem to make a substantial difference AFTER 4500-5000. What I found out was that when I had the vias failure and my mods, it disguised the graph and the graph looked more like yours. Look at this graph:

http://web.tampabay.rr.com/maxgator/...revsafter3.bmp

Look at run 11 - my hp peaked at 191 and leveled off to redline - very similar to yours.

I can't explain why your numbers at 5000 rpm are that low with your mods, though.

If you want more info on the variable intake failure just search the FAQs and 5th gen forum for VIAS.

 

That is not entirely true. The Cali spec versions dont have any O2 sensors anywhere near the cat or after it. The Cali spec ones have their O2 sensors on the header and Ypipe only. Putting a testpipe CANNOT affect that and cause the car to run rich.

On the FedSpec, there is a O2 sensor right behind the cat, but if you make a custom testpipe with a O2 bung, again, you cannot have any problems of running way to rich.

Running 14.9 is something else. Something needs to be checked.

Dixit

 

bags533: What's KS? I believe they did the dyno with manually shifting. 1,2,D. Both with overdrive on and off.

maxgator: I noticed that recently I can't pull above 120.. And I def have no limiter because I have the RSM installed. Even at WOT floored, I seem to loose power at 120. It takes forever to climb any higher. I know with all my mods I shouldn't have these problems. Could it really be a VIM problem?

 

KS= Knock Sensor.. in the 4th gens it will not cause the CEL to come on

and the dyno should be done in D/3rd gear .. the closest gear to 1:1 in an maxima auto..leave OD off..just stop right before the limiter

and on the VIM.. drive a 2000-2001 maxima with the same mods and redline 1st and 2nd.. then drive your car...

you will know if there is a problem or not.. but the IVM seems to have had many problems as others stated

 

Its the VIM, the graph looks normal for an auto 5th gen, up till 5500.

 

Check the flex section of your cattman y-pipe. You can't tell externally you have to take off the cat and take a good look inside the flex.

Could also be ignition coil.

or

VI as others have said.

 

Sure sounds like it with that description. The way I established I had the problem was to run another 5spd with similar mods - at high speed it just wouldn't go.

I'd check what the others have suggested. Read this post on how to test your variable intake (by the way it is called VIAS in Nissan speak).

http://forums.maxima.org/showthread....ve+vias+thread

 

hmm......possible VIAS problem perhaps?

 

the run where u made 170ish torque, says ur putting down the right numbers, but the other 2 runs where ur torque was 150ish doesnt sound right. according to the run with 170ish, says ur VIAS isnt working, but the runs with the lower torque numbers says something else could be wrong.

 

Thanks for all the suggestions.. I'll check all that out this weekend. Anyone know how much a new VIAS? would cost.. I dun think nissan dealer would agree with my mods

 

put on ur stock intake, and cat and try for warranty work. It SHOULD be covered, but Nissan is kinda a PITA to get warranty work done with even the slightest mods, jsut put stock intake so they cant blame that for VIAS failure, and try a few dealerships ... u would save urself a good amount of money if u can get warranty to do it.

 

Do you know how much one would cost if I can't get it warrantied?

 

If you've read my threads, you know it can be a hassle to get it warrantied. But do the diagnosis in those threads.

I doubt they'll do it without de-modifying but another guy maxjp2000 I think got his done with no hassle.

If I recall correctly it was something like 400-500 for the variable intake manifold - the whole thing needs to be replaced. Plus labor.