Q45tech- Interprit these consult results!

[elwesso]

Tech,

one of our members, Matt sent me a consult printout, and maybe you can make some sense of it... Icouldnt really see anything wrong, but that says very little!

Heres the data monitor results, i think we can ignore the third test as it isnt at full operating temp.. and the first one bceause he barely gets off idle...

[elwesso]

Heres the PBT.

[Q45tech]

Injector #2 is dirty or failing. The MAF voltage is too low at high rpms and thus the injector open time appears low [could this be a modded ecu.....still seems low for even that???] Not necessarily too bad for the MAF voltage reading. Used to seeing 9-10-11 msec injector open times.

Dirty plenum/Maf/runners? low MAF ?

It appears that the initial advance is 16 [?] thus the high rpm advance is too high think 28 [not 30] is a good top WOT advance at 6500.

Really need more charts in the form I'm use to, to evaluate.

[elwesso]

this is a stock ECU as far as I can tell...

SO basically you think that this is a decent enough set of parameters... Maybe no perfect/ideal, but its "close", maybe?

[mattd1979]

Q45tech, I am the one that gave the test results to Wes. I was using a Consult II to get the data from my car. When I first started with the test run, it would only record for 5 seconds. I figured out how to increase the time up to 60 seconds but there are 2 speed adjustments that I can make on the speed. One was for the actual time frame and the other was for something that I have yet to figure out. When I ran got the results, I expected it to show readings from idle up to 60 MPH but it only gave me a small piece of the data. I was wanting to know if you could tell me how to set up the consult to get the best readings. I'd also like to say that the consult is only setup for Nissan vehicles. I don't have a specific card to put in it for Infiniti. I was originally getting the test run data to find out if it could tell me if the knock sensors were working when it would start to ping and also to use as a comparison to other Member's Q's that are stock to get a good comparison. My mom's car is a 91 with TCS and feels like it has a great deal more power then mine from start to finish so I was trying to figure out the cause. It all started with me replacing knock sensors to see if it would improve but nothing. Anyways, If you can tell me how to set the Consult II up correctly then I will use it on my mom's car to get a comparison. Thanks

MattJacksonville, FL

[Q45tech]

The thing that stands out is the LOW MAF voltage reading. In theory every CLEAN Q engine should injest/pump the same amount of air at the same rpm thus the same MAF reading in volts. The highest I have seen in cool air conditions [1000 ' AMSL] is 4.34- 4.4 volts. IF the MAF is accurate you are flowing 20-30% less than normal air at >6000 rpm.

What is the back pressure in front of each cat [Wild last resort test] after swapping MAF with no improvement.

Is air box and filter OEM [no mods no cones no K&N?].Is everything from MAF spotlessly clean all the way to the intake valves.

With Consult I I'm use to seeing 0.03 second [50 rpm intervals not 10x what you show. Why I am having difficulty with so much data skipped.

If the power is down and you can feel it, the power IS DOWN try a MAF first from ebay or swap the 2 from the cars and see if the lower voltage moves to the other car?Data log may be only 4 seconds so you have to do multiple feet of chart paper multiple times [many WOT runs] to get hundreds of factional sec points

[mattd1979]

I had already tried swapping the MAF from my mom's car with no noticeable gain in power at all. I also wondered if maybe I had restriction in the exhaust but am not sure how to test for that. My car as purchased had a K&N cone air-filter with a stillen intake adapter to adapt to the intake hose. I since bought a partial air-box from Wes (partial meaning that all of the sound baffling chambers had been removed) because I didn't trust the filteration of the cone filter. The box is pulling air in from all sides with the baffles removed. Wes said that he is going to send me the baffles when he gets the opportunity so that I can try to put it back like stock.

[mattd1979]

I'd also like to add that I have about 50,000 miles on the current sparkplugs.

[Q45tech]

Jacksonville = warm. Unclear is the entire inside the engine compartment air box intact so that the air comes from in front of core support?

At what ambient temperature were the Consult readings taken?

To measure cat back pressure you unscrew O2 [one at a time and fabricate adapter that has a 2-3 ' metal hose then a rubber hose to a 0-20 psi gauge inside car and drive it WOT and read pressures graph at 2,3,4,5 6,6.5k rpmMake your own find one or pay $$$http://www.mytoolstore.com/toolaid/diagn04.html $35!http://www.aeswave.com/product...&sa=Yh ... -tool.html

I've never had to do the test on a Q but here are some examples of back pressure which will vary as cat heats up:

http://www.se-r.net/header_exhaust/gene ... xhaust.php

"The car came to the shop way down on power, and with a number of misfire codes in the PCM. A swap of the plugs and wires fixed the misfire problems, but an initial dyno baseline run showed 110HP. Stock these cars should make about 165-170 at the tires, and this car had a number of upgrades already on the car. As we installed an o2 sensor bung in the exhaust system, we used the access to run a backpressure test on the exhaust system. This showed 36PSI of back pressure in the exhaust system at 6000k RPM. Removal of the system for testing let the engine make an expected 165HP. Cutting the cat open revealed a severely damaged and burnt core. After a replacement was sourced and installed, another run was made and again the car made good power. New baseline numbers with the parts already on the car were 194HP and 164TQ. After tuning, the car made 211HP and 175TQ""

Happens all the time.

My guess is somewhere around 10 psi at 6500 rpm on the Q with oem stock exhaust asmeasured at each O2 location.

However pull the exhaust and look at precats and cats with flashlight before you consider replacing them.

http://www.mattsauto.com/catdiags.htm for OBD2 cats

[mattd1979]

I would say that the outside temp was around 68 degrees that night. I will go ahead and order that pressure gauge that you linked and see what measurements I get.

I almost wondered if there was a way that I could tell if my exhaust was clogged by comparing the exhaust output of my car with my mom's at the rear by feeling how hard the exhaust flows out on both cars. It wouldn't be an accurate way to measure though.

[Q45tech]

Actually you could use the plenum vacuum to check for exhaust restriction.

Each 28" water column above the first 28" is ~~ 10-15 HP restriction = 1 PSI. [The standard flow bench uses 28" water column to measure components]

This test requires accurate ROBUST test equipment to read water column or just a common vacuum gauge to read Hg"...........hard to differentiate between 1" HG vacuum and 2" HG at WOT 6500 rpm.......... Doesn't tell you which is bad only the sum of defects.

The above ASSUMES that the entire intake system is stock.

You can tee the vacuum line feeding the fuel pressure regulator. Must be done on the road max rpm in 1st gear. Do it 2-3 times cold [just a engine warms to center, then after 10 minutes of agressive driving.

[mattd1979]

I got to thinking and realized that my mom's car has more power at part throttle then mine so wouldn't that throw out the idea of the cats being clogged because I figured that the cats wouldn't be a noticeable restriction until I got up the rpm range to about 3000 rpms. My mom's '91 has more power just touching the throttle from a stand still. My car has less power than my mom's from part throttle to wide open.

[Q45tech]

DON"T RULE OUT UNTIL YOU MAKE MEASUREMENTS!

[mattd1979]

I have a regular vacuum gauge that I can hook up to the intake to see what the overall vacuum is while driving. Where on the intake can I attach it to get the best reading? I figured that this could give us some idea as what is going on until I get the cat pressure gauge that I ordered.

[Q45tech]

You can tee the vacuum line feeding the fuel pressure regulator. Must be done on the road max rpm in 1st gear. Do it 2-3 times cold [just as engine warms to center, then after 10 minutes of agressive driving.

The WOT vacuum should drop from 18-20" HG cruise to 1" WOT at higest rpm..................anything higher than 1-1.5" means a problem!

[mattd1979]

Ok, I performed the above test after I connected the vacuum gauge between the fuel pressure regulator and the vacuum source on the driverside and after I got up to 50 mph at 7000 rpm, the gauge did not drop any lower then 13 Hg. At cruise, it was between 18 and 20 Hg. WHen it was cold and in neutral, I could get it to go all the way to 1 Hg but once I had it under a load it was another story. You could sure hear the octane knock come and go at 7000. It started to knock when it got to around 4000.

I am going to do a comparison with my mom's car to see if there is a difference.

[mattd1979]

I just wanted to let you know that I performed the test again during my lunch break and this time I did not sustain the speed as I first thought I was supposed to do. This time after driving around aggressively as per the directions, I went WOT from dead stop until I reached redline in 1st gear 3 times. Each time it would go down to between 0 and 1 so I guess this part of the test says that everything is normal. I also realized that when I would accellerate to redline, when I would get to 5,000 rpm, it would really lay me back in the seat so I would figure that if it was a restricted exhaust then that would not happen. Instead I would think that it would just loose more power as it increased speed.

[Q45tech]

The high number 29 degrees of advance with low air flow [MAF voltage] and low injector open time above 6,000 rpms concerns me.Are you sure the initial crankshaft timing mark is set to 15 degrees before top dead center.

The plenum [vacuum should be <1" HG WOT from 4,000 rpm rising a tiny bit at you approach redline. Accuracy is important here as going from 0.86 to 1.5" HG is a very significant amount..........25">>>>>>43" of water column

Dyno the two cars so we will know the amount of power differences we are dealing with.

[mattd1979]

Is there a digital version of a vacuum gauge that I can get that will give you more specific readings? Does it still sound like it could be ristricted exhaust after the results given? will the gauge that I get that screws in place of the o2 sensor give a more accurate reading? And to check for the timing with a timing light, what is the best way to check it? I used Wes's method of hooking the pickup connector to the pigtail next to the box that controls the coils. There is one box on each bank. He said that it didn't matter which I used and that it was the easiest method to check. I did this not to long after I bought the car because I noticed the lack of power and thought that the timing may have been off. I did the same thing with the timing light on my mom's car and both were identical. I later used the consult on my car to check for codes and I think the last time I checked, the consult said that it was at 16 degrees but I'm not sure.

After looking at the consult data at the top I figured that I should have kept the car in 1st throughout the power band to get the best reading. I didn't think of that at the time.

[mattd1979]

I recieved my modded ECU from Robert today and after I swapped the connector over from the stock ECU to the new one and test drove it, there was no change. It performed exactly as it did with the stock unit and that was even in power level 3 mode. Wes told me that the vvt changes at 5000 rpm and to disconnect to see if there are any changes so I did and there were none. It still lagged abit atleast until it reached 5000 and then it started to set me back and then would ping at 6000 and keep me back until redline. Just so you know that the previous owner had Infiniti replace the timing chains and the guides. Wes thought that maybe they may have got the teeth on the sprockets off by maybe a tooth but I said that I remember hearing that even if it was off a tooth that the pistons would make contact with the valves if that were the case.

I also don't understand how the exhuast could be plugged if it can suddenly gain power at 5000 rpms. I figured that it would have fallen on its face before it even got to that point.

I don't know. as far as I know I have done everything until blue in the face.
Modified by mattd1979 at 8:40 PM 4/15/2006

[Q45tech]

The Consult ASSUMES an initial ACCURATE setting of 15 BTDC...........the ecu depends on the sequence of correctly setting the CAS to the crank pulley marks to be accurate and of course that the chain is not stretched otherwise the cams and CAS will be retarded by the amount of chain stretch.

[Q45tech]

WE MUST HAVE ACCURATE PRECISE DATA...........identical dyno charts between cars with identical tires and inflation, identical oil, ATF and diff fluid at identical temperatures if we are to evaluate within say +- 5%.

You cannot feel 10 HP difference between the cars, impossible. 20 HP might be noticeable to the sensitive.

You must provide PRECISE STOPWATCH times in a [locked in 2nd gear] 50-80MPH acceleration say 3 -5 times for each car so we can see deviations and average.

[mattd1979]

"I also don't understand how the exhuast could be plugged if it can suddenly gain power at 5000 rpms. I figured that it would have fallen on its face before it even got to that point."

I guess I should have posted the above in the form of a question.

How can I gain power at 5000 rpms if the exhaust is plugged?

Also from what I have been reading about the ECU mod, everybody else has noticed a significant increase in power but me. That is why I brought that up. I also wanted to let you know that changing the ECU didn't change anything as I was originally going to swap my mom's ECU to my car to check for a change. Now I am going to check compression to see if maybe the timing on one side of my engine is off.

Below is a clip from a post from fatboybell who seemed to have the same issues.

To all with rough idle and low power 5:55 PM 8/18/2005

--------------------------------------------------------------------------------

I have chased this problem for a couple of weeks now.My symptoms seemed common to alot of complaints I have seen on this forum.I tried all the advice and nothing helped the problem.I finally found the cause to my problem,and if you have had your timing guide update done you might have the same problem.It is very easy to screw up the cam timing when going back together with the chain.This is what happend to the previous owner of my car.The left bank cams were pretty far out of time.If you want to see if you could have the same problem do a compression check.In my case the right bank was a consistent 175 psi,the left bank were all 125.If you have some wrench exprience this problem can be corrected without removing the valve covers.Thanks for the help I received on this forum,it sure is nice to have a smooth idling car.

[elwesso]

It looks like you have something to bite on now Matt...... Go do it!!!!

[elwesso]

Heres the transcript of an email I sent to Scott (NISTECH). It has been edited slightly from its original verison, but all information remains sage.

.Wes Stinson <[email protected]> wrote:zerothread?id=163994http://forums.nicoc ... ?id=168553

Abstract- Guy has lack of power, and detonation above 5000 RPM.. Replaced KS, and a ton of other crap…… Chain guides have been replaced. It doesn’t seem like anything is wrong, posted some consult data…..

Compression numbers-

1- 1812- 1803- 1754- 1905- 1806- 1857- 1808- 190

I am thinking that the timing has skipped possibly..

-----Original Message-----From: scott Sent: Monday, April 17, 2006 8:17 PMTo: Wes StinsonSubject: Re: Help with a Q45 guy...

Ok Wesley. I read both posts completely. Dennis is right on about his problem. The MAF is reading to low. He needs to swap the MAF again except he needs to reset the ecm when he does it. Before plugging it into his car have him disconnect the battery and tie the to cable ends together for a half an hour to completely drain the voltage from the systems. Throw in the maf while its doing that. Then before starting the car cycle the key on 5 seconds off 10 seconds 3 times. Tell him DO NOT rush the procedure. My reasoning. The mixture test although stating ok it clearly isnt, the damn thing said it was at 114% alpha??? 109 is max.His PB tests are usless as they all came back with different numbers. Looking at his recorded consult readings his right bank was running on the lean side during accel the mixture count also reflected that. So its one of 2 things here. Either the maf is shot as I suspect or he is having injector issues and not spraying the correct amount or pattern of fuel into the cyl. This is where I have to question the matching of the injector to what was already in the car? was it on the R bank?

[mattd1979]

Ok Q45tech, I got the results from the dyno. Here it is.

The top line is my mom's car and the one below it is mine.

Mine is also set to the high performance setting and my mom's is stock. The difference in horsepower is only 5 between stock and high performance on my car. The other thing that I noticed is that on my car in stock mode, it wouldn't go past 112 until I set it to level 1 which deactivates the speed limiter. I thought that the factory speed limiter didn't come in until over 150 mph. When my mom's car was put on there, we were surprised to find that it went past 112 on up to 138 in 3rd with no problem.
Modified by mattd1979 at 1:07 PM 4/26/2006

[Q45tech]

You must determine WHY the MAF is reading 0.2 volts low normal > 6,000 rpm. Swap unit and retest

Also what is fuel pressure at 6000 rpm should be 43.4 psi. Check and make sure fuel dampener air hose is connected to air duct just after MAF.

TPS WOT voltage is lower than average

[mattd1979]

The above dyno run was performed with my mom's MAF sensor on my car. My MAF was on her car. Is the fuel dampener hose one of the 2 little hoses that connect in the side of the air duct after the MAF? Those are connected along with both PCV hoses. I don't have access right now to a consult so should I swap throttle sensors to see if I get an improvement?
Modified by mattd1979 at 10:51 AM 4/27/2006

[Q45tech]

You never gave us a fuel pressure vs rpm chart, nor an exhaust back pressure vs rpm chart.

[mattd1979]

U did not answer my question. I know what I haven't done yet and I do plan on it but for now I just wanted to know if what I said is what you were talking about. I don't mean to sound harsh but I just don't feel I am getting anywhere with this and everywhere I look it is fine. I don't have access to a consult right now so I am limited to what I can do.

" Is the fuel dampener hose one of the 2 little hoses that connect in the side of the air duct after the MAF? "

I am going to have DynoTune check for backpressure in about 2 weeks when I have the money. It will cost me $75 to have it checked and I don't get paid until next week. I get paid commision so some days are better then others. I will attempt to check the fuel pressure just before the fuel rails at 1000 rpm increments if that is good enough. I don't know how specific you want the measurements taken in. The only other thing I could do is video the gauge next to the tach so you could see what the tach and gauge read at said RPM.

I wish I could find somebody here locally that knows this stuff like you and be willing to just help me out on the side without charging becuase it is frustrating to have to explain and diagnose all of this back and fourth over 3 weeks worth what could probably be checked out and the problem ID'ed in a couple of days or more. I'd like to just get this fixed and behind me without having to pay an arm and two legs for what it would cost to take to a dealer to be diagnosed.