We'll i hope you guys get this problem sorted out. Im doing a new ACT/Fidanza install in a few weeks so if the problem is still out in the open, ill add my findings to the bunch. Maybe ittle help to get another opinion, i donno. Anyway, good luck everyone.

 

Could this possibly be cause by coils or something reltated to front suspension like ball joint...

I delivered pizza in the max tonight cause the pizza truck is broke for the time being. One thing I noticed is that its lower RPMS that this is relevent and it doenst have to be gas on gas off...all I need to do is punch it in the certain gear and I get that bog bog bog feeling...like 3rd throughout doenst really straighten out and be normal till about 3500-4500...Im beginning to think its a coil..anyone have a experience with bad coils ?? My idle is perfect and reving the car at idle is perfect

I dont think it could be the Flywheel because some dont have the problem and this problem and kinda gotten worse in a way

matt

 

Could be, but the only real way to find out if its a mechanical or electrical problem(besides throwing parts at the problem and hoping to stumble upon it) is to take it to a shop and pay for a diagnosis. There could be many problems that the ECU might not display as a problem(such as a intermentent coil pack, crank pos. sensor, ecu, etc.) that a only a scope will pick up. If they find nothing with the electrical system then they will check the front end. I'm sorry I can't give you a definite answer, but some problems you just can't figure out without the proper test equipment.

 

Do I go to a dealership to have it tested or a regular shop ??

I may go back to place that did my tranny last month...The Dealership doesnt sound like such a bad idea

-matt

 

The dealership will have the proper equipment and info, but if the shop that did your trans. also handles driveability problems and has up-to-date equipment you probably will pay less there. If you are unsure if they can handle it, take it to the dealer.

 

I have been trying to figure this problem out for a few months now and i have tested pretty much everything on the car. I have back probed the ecu with a scope checking for signals and have found only one problem. Due to the 96 i30 ecu in a 98 harness the signal wire for the rear o2 does not tie into the ecu, therefore my car is running in a open loop. With this open loop the car over richens the mixture to compensate for the no signal of the rear o2. My car already ran too rich without the rear o2 problem and with it has seemed to effected the driveablility of the car. I have also read on other cars that this seems not to have any effect on the car so this is just a guess.

Just to eliminate other variables my car has brand new balljoints, place racing motor mounts, energy suspension bushings, cattman suspension, and a fstb. My front end is solid so it isnt a front end problem for me. I have no check engine lights other than the rear o2, and i have a obd2 connection to my computer.

I dont know about dealerships around where some of you guys live but my local dealerships would never help me. First of all the products being used are not nissan parts and second that the only thing that they would do is take the aftermarket stuff out and put the nissan in. Also customers cant talk with the tech people in the first place.

I am still trying to figure out the o2 situation on my car, but i have a feeling that could be a source of the problem.

 

Well the thing is when I first start my car and its running cold (rich) I feel the problem less then when the car is hot, and its a hot day...if its a cool day out I feel it less..I have two brand new O2 senors right from Nissan...

Its definetly a hesitation in the car when Im at partial throttle...I cant figure it out...Have you checked the air/temp sensor, Coils, Plugs ??

What boggles my mind is that I DONT feel it in the car when I'm idle or when I rev it up at standstill...only when the car is moving so thats why i dont think its the coils/plugs

-matt

 

I have the fidanza/ACT combo and i get absolutely no shudder at all. Not even when cold. I also dont get any of the above mentioned heistation whatsoever. hmm strange. oh and the stock flywheel weighed 19lbs for me too. Why would anyone want to weigh it without the ring gear?

 

Can someone please help me figure out what my problem is...could it be one of the sensors gone bad on the bell housing ?? those black sensors ??

Will nissan check all that when I bring it in to have it looked at ?/

-matt

 

Have had a misfire hesitation and then I have had another type of hesitation or "bog" that is described in this thread. Two totally different feelings. Refer to my previous post about my expierence with what your describing Matt.

 

Yea i read that you think it has something to do with the surface of the Fidanza...but I dont only get this bog bog bog feeling inbetween shifts, Im also getting threw gears after the fidanza is gripped onto the clutch...after im in gear and i gas it...

Im not able to search your previously posted threads

-matt

 

I ment my previous post in this thread. It was just that I have had a the symptoms you describe after I installed the findanza. It was only a couple times and it has not happend in a long time. There is also a chance that what I felt was a problem with my shift points falling in line with where MEVI butterfly valves are set to open.

 

The weight that fidanza and UR advertise is without the ring gear installed. So in order to get a fair comparison you have to either weigh with the ring gear installed on both or without it at all. Did your fidanza come with the ring gear attached?

If its running in open loop then the ECU doesn't use the O2 sensors for fuel trim. The rear 02 should have no effect on the fuel trim, its just a sensor to monitor catalyst efficency. You should find another dealership, it sounds like they have a crappy service advisor if they wont let you talk to the techs.

Actually the coils/plugs can be a problem because when you rev up there is very little load on the engine, when you are pulling the car with the motor the coils need more power to fire the cylinder and if they are weak they might not be up to the task. Especially if you are in a high vacuum, low rpm, high load situation.

If you want to check something though you can take out the Crank pos. sensor in the bellhousing(the black sensor at the front/middle of the bellhousing) and make sure that the magnet doesn't have alot of metal shavings on it. If it does just clean it off and see if it effects your problem.

 

I am going to clean that off tomorrow and install some new plugs..I want to get this thing all fixed before I go ahead and put in my S/C...I dont wanna be putting on this s/c with this problem still present

-matt

 

I just installed the Fidanza with an Exedy clutch. Its at 500 miles now so its almost broken in. I am having the same problem as you, Im getting the bog bog after the shift. It doesnt really bother me much unless its going to be doing this at WOT also. At first I thought the problem was because my rear main seal was leaking onto the clutch but I guess its just the flywheel then.

 

Its posts like that, that make me believe its the flywheel..

Its annoys me when I wanna drive like a nut..the car jumps and shimmys and bump bump bump's alot...annoying

-matt

 

bump to the top

 

anyone think this could be a Coil Problem ?? I read up alittle on Coils...but I have no idea still

-matt

 

no, I just think it is a flywheel problem...the only people reporting this problem are the ones that have the fidanza.....no one is having this problem with just clutch replacement. And my car never did this before but the day I changed my clutch/flywheel it started....I doubt a clutch/flywheel swap fouled a coil (but I could be wrong )

 

I would put my money on a sensor/emissions issue.

how many of you guys have actually replaced all you O2 sensors and can verify they're working properly?

most of the time when I was having bogging/driveability problems on my old GXE, it was because the O2 sensor got wet when I hit a puddle and it stopped working (lost the rubber seal inside the connector and never bothered to replace it). when it was dry out, the car ran great.
so I finally bought a new O2 sensor and sealed the connectors with RTV so no water could get in. never had a problem since.


You guys are confusing a driveability issue with a mechanical issue. Please explain why the ball joints would have anything to do with throttle response?
I'm not flaming you, but think about it for a few seconds and think of exactly what is happening (engine stumbling), and you can rule out 80% of the oddball problems you guys are jumping to, like ball joints, tie rods, engine mounts, etc.

After you check the O2 sensor, I'd also take a look at your MAF signal and your TPS. they should agree to some point- I wouldn't be surprised if they're showing slightly different numbers (dirty MAF, TPS needs calibration) and it's confusing the ECU.

you also mentioned this doesn't happen when the car is cold. why would the ball joints care how cold the engine is? The ECU does. The sensors do. The ECU doesn't even look at the O2 sensors until the engine is up to operating temps.

There's a few things for you to look at... good luck gentlemen.

 

If it were a sensor problem, etc. the flywheel could be making the problem more apparent. The ability for the engine to bog more easily from the flywheel will magnify any problem that would cause bogging. Just a guess.

 

That's a good point. Here's an article with a E36 getting it's 26lb dual mass flywheel getting replaced with the single mass 12lb flywheel. As you'll read, there are gains to be had, but they dynoed the car in all gears and the lightened flywheel actually showed losses of power in most of 1st and 2nd gear with some gains occuring above 5500rpms. Once in 3rd, the lightened flywheel matched and exceeded the OEM flywheel. Keep in mind this flywheel shaved 14lbs in weight compared to the 5lbs or so the Fidanza shaves so obviously the gains/losses won't be remotely as close.

The great thing about this article is that it proves that the "lowend" torque advantage people say they get with lightened flywheels/UDPs is not true and it makes a strong case as to why lightened flywheels are great for road racing and not drag racing. Lightened flywheels = reduced lowend torque in the lower gears, but make more power in the upper rpms of the higher gears.

http://www.europeancarweb.com/projec...109ec_projbmw/

 

Im getting such a hesitation though from the car...I really dont think its the flywheel. It feels like the car is studdering in a way after the car is already in gear.

-matt

 

mine does it when already in gear also, but I still think it is the flywheel. I guess i'll find out when I swap out the fidanza for the stock unit in a couple weeks.

 

I was reading some posts about flywheels one of the WRX sites and they said that lightened flywheels typically throw misfire codes on the WRX. Many of the WRX tuners believe this code is thrown because the relation between throttle inputs and rpm become mismatched and the ECU sees this as some sort of misfire, especially on deceleration and shifts. The engine isn't misfiring, but the ECU seems to read it as a misfire. Many WRX owners describe the same stumble/studder also.

 

I've never encountered any of these problems.

And I believe the hp/toruqe gains should be higher in the lower numerical gears as those gears have the highest torque multiplication factors. Gains from the light flywheel diminishes as the gear ratios approach 1:1

 

Well I also feel the same "shudder" at high speeds of say 70-80...even in 5th gear...gas on gas off gas back on, shudder shudder shudder...

-matt

 

hmm...interesting point.

i noticed the bogging today on a 300 mile trip. it was raining basically all day while i was driving. and i am trying to recall the other times i have experienced the bogging/stuttering/stumbling/surging. as i was driving i was pondering the thought of either the o2 or knock sensor getting flukey.

now that i think about it, it seems as though it occurs in a more noticeable when its VERY humid or raining. so maybe the flywheel is not fully or even reponsible in any way. maybe its a combination of the flywheel and the sensors tricking out the ECU.

something to think about i guess.

--Paul

 

I dont really understand how it could be a flywheel problem completey. Granted the flywheel shaves off some weight and makes the car somewhat harder to drive, but a flywheel is a flywheel, there isnt much to it. Its got a surface to grip and just turns round and round. As long as that surface is ok, there really should be no reason for it to seriously skrew up the engine in all that much. Maybe the flywheel causes something else in the engine to get all messed up, like it cant understand whats going on or something, but **** its a pretty simple piece of equipment and really shouldnt be causing this many problems. Dont mean to shoot down anyone with other ideas, but im just putting my two cents worth in.

 

Yea thats how I feel...I think that after the Flywheel is Clamped onto the Clutch, I dont know how it could cause a shuddering problem in the engine....Makes no sence

-matt

 

maybe the fidanza is not as thick as the stock flywheel at the friction surface area, and its causing the clutch to slip a little at low rpm's.

I replaced my coils yesterday and it had no effect on this issue at all.

 

This article says that you will lose midrange torque but it also says that you will feel it much more in the lower gears.

 

Man, id hate to think that the fidanza is the cause of all these problems but if so, i think the company should be notified. You never know what might happen with it, but sometimes companies will pull a recall or something. I doubt that would happen, but maby it would at least give them the heads up to check the flywheel out and possibly fix the design error. Just a thought.

 

Well I would call Fidanza but with alot of the people on this board that have fidanza's and DONT have this problem, makes me second guess that its a flywheel issue. If someone would drive my car they would totally understand that its a problem and maybe isnt the flywheel. Its just that maybe people that arent haveing the problem, just arent that sensative to there car and there faults, but with my problem, anyone would pick it up.

Picture getting in your car and driveing like a nut. In and out of traffic, shifting, wheeving and stuff..if I would do that I would get alot of bog and shudder from my car on the shifts and low rpms...

Im a volunteer fireman so alot of the time im jumpin in my car to rush to the fire house when theres a call...well I feel it alot when I need to get somewhere fast

Maybe ill call and talk to fidanza...

-matt

 

Theres no way its the Flywheel...ill be driving on monday to have this figured out..Ill be testing everything on the car

-matt

 

How can you prove it's not? This problem is only being reported by those that have gone with lightended flywheels and many are saying thier problems started shortly after getting the flywheel.

 

Well in my case this has gotten worse..I talked to a family friend that is a macanic and pretty much the only person I would let touch my car and said the weight of the flywheel should have NO bearing on a hesitation in the engine.

Many people on here also report NO experience of a stumble or hesitation and have been running Fidanza's...

-matt

 

We'll ill be doing a brand new findanza and act install in a couple weeks, hopefully before i head off to college, so youll get my two cents worth on that one. If it happens right after i install the two, im thinkin ittle definately be a flywheel issue. Wouldnt make any sense at all, but.....you never know.

 

well, I did the plugs today and no change...time to go to a macanic and hook it up to a machine

-matt

 

Man, I got a fidanza and I got the same problems as most of you...with the boggin n sh*t. My dad has a stock maxima and his dont do that