Hesitation I can't get ride of ... help!

[xory72]

Hey everyone,

I just got my NSX (96 3.0) back on the road about a month ago from some cosmetic upgrades and TB / WP I did over the winter.

I have a hesitation that I cannot get ride of. It seems that at 3200 RPM in all gears and at 2800 RPM in 2nd gear it breaks loose and all the power is back. This was happening before the TB replacement so it not new.

I have searched some threads to diagnose the problem and here is what I have done so far;

Cleaned the throtle body (did not remove just sprayed inside)
Replaced the fuel filter
Replaced all spark plugs (NGK Platinum)
Tested all coil packs and results are all same 1.3 ohms
Replaced Front Primary (Bank 1 Sensor1) O2 sensor due to Code
Tested Gas for contamination (all is good)
Replaced PCV
Checked all vacum hoses

Any ideas?

What do I tackle next?
Fuel pressure?
Fuel pressure regulator?
Fuel pump?
Use fuel injector cleaner?
test fuel injectors?
Valve Clearance?
Take the Throtle body off and clean?

Any advice is certainly appreciated. I have been messing with this for a few weeks now and am hoping with the help of Prime I can fix the problem a little quicker. I am not sure if I am even on the right track.

I look forward to all your advice.

Thanks,
Darrin
xory72

 

[Briank]

A fuel pressure check might be helpfull. Also pull the clock fuse to reset the ECU.

 

[MANIACura]

Are you having any trouble starting the car? Starting and then shutting off? I had an ignition switch go bad on me last month that eventually got so bad it was causing the car to shut off for a split second while driving. Felt like a hesitation because it would make contact quickly and drive fine for a while and then do it again. Just a thought......part # 35130-SL0-A01 $62.98 10 minute swap.

 

[xory72]

Are you having any trouble starting the car? Starting and then shutting off? I had an ignition switch go bad on me last month that eventually got so bad it was causing the car to shut off for a split second while driving. Felt like a hesitation because it would make contact quickly and drive fine for a while and then do it again. Just a thought......part # 35130-SL0-A01 $62.98 10 minute swap.

I've had no troubles starting or shutting the car off. Actually the car starts great. It seems the throttle response when depressing the gas peddle is very slow climbing unitl 3200 RPM (2800 2nd gear) then the power snaps loose.

I guess the fuel pressure check is next on the list. Any idea where I can get a fuel pressure tester? Autozone, Advanced Auto, Napa?

Any more ideas would be appreciated. Hoepfuly I can find this problem.

Darrin

 

[Larry Bastanza]

What you want to do is disconnect both PRIMARY oxygen sensor connectors located on each valve cover. This will cause a "CEL". Once the CEL is lit, take the car out and see if the issue goes away. If so, then replace them.

The PRIMARY's are BEFORE the cats.

HTH,
LarryB

 

[xory72]

What you want to do is disconnect both PRIMARY oxygen sensor connectors located on each valve cover. This will cause a "CEL". Once the CEL is lit, take the car out and see if the issue goes away. If so, then replace them.

The PRIMARY's are BEFORE the cats.

HTH,
LarryB

Larry,

Thanks for the advice. I just replaced the Bank 1 Sensor 1 (front primary)over the weekend, but have not touched Bank 2 Sensor 1 (Rear Primary). I'll disconnect both O2's tonight and then drive the car when it stops rainning. I replaced the O2 as I was getitng a PO172 code. I've since reset the MIL and drove the car but the hesitation still exsists. I'll disconnect both and see what happens.

Darrin

 

[Briank]

I guess the fuel pressure check is next on the list. Any idea where I can get a fuel pressure tester? Autozone, Advanced Auto, Napa?
Darrin

FYI but do what Larry says first.


http://www.scienceofspeed.com/produ...oducts/NSX/Cantrell_Concepts/fuel_pres_gauge/

 

[xory72]

FYI but do what Larry says first.


http://www.scienceofspeed.com/produ...oducts/NSX/Cantrell_Concepts/fuel_pres_gauge/

Briank,

Thanks .... I will try what Larry has suggested tonight. I am going to order a fuel pressure gauge anyways just to have it so thank you for the link.

I will re-post to let you all know the outcome of Larry's suggestion later tonight or tomorrow. (disconnecting the 2 front and rear Pre Cat O2 sensors)

Darrin

 

[xory72]

What you want to do is disconnect both PRIMARY oxygen sensor connectors located on each valve cover. This will cause a "CEL". Once the CEL is lit, take the car out and see if the issue goes away. If so, then replace them.

The PRIMARY's are BEFORE the cats.

HTH,
LarryB

Larry,

You hit the nail on the head! I disconnected both Primary O2's as you mentioned, started the car and almost instantly it through a CEL. Took the car for a drive and .... smooth as silk and power through all gears.

I guess I have to replace both Primary sensors. I mistaked in the initial thread, I replaced the Front Secondary O2. As soon as I replace both the primary O2's I will repost with the outcome, but I think you nailed it.

Larry thanks for your great advice.

Darrin

 

[goldNSX]

I'm interested in the outcome.

 

[xory72]

I'm interested in the outcome.

I'll be sure to post the outcome when I have the new O2 sensors in place and take it for a ride. I will be ordering them next week sometime so I guess expect a new post in 2 weeks or so.

Darrin

 

[MANIACura]

What you want to do is disconnect both PRIMARY oxygen sensor connectors located on each valve cover. This will cause a "CEL". Once the CEL is lit, take the car out and see if the issue goes away. If so, then replace them.

The PRIMARY's are BEFORE the cats.

HTH,
LarryB

Larry, you're my hero......seriously.

 

[xory72]

Re: Hesitation I can't get rid of ... help!

What you want to do is disconnect both PRIMARY oxygen sensor connectors located on each valve cover. This will cause a "CEL". Once the CEL is lit, take the car out and see if the issue goes away. If so, then replace them.

The PRIMARY's are BEFORE the cats.

HTH,
LarryB

Larry,

Once again thanks for the advice. I am going to order new Primary O2's soon but I have a CEL problem that I did not have before disconnecting the 2Primary O2's. Here is the story;

Prior to disconnecting the Primary O2's;

1. First Code P0172 Sys too Rich Rear Primary O2 etc.
2. Reset ECM
3. Got same Code again P0172
4. Posted on Prime about hesitation
5. Disconnected both primary O2's (as advised)
6. Got CODES P0155 (open or short Front Primary O2) makes sense
P0135 (open or short Rear Primary O2) makes sense
7. Reconnected Primary O2's
8. Reset ECM
9. Started car ... and now got
10. P0141 (Open or Short in Rear Secondary O2)
11. Stopped Car
12. Checked all O2 connections (disconencted & reconnected all O2's)
13. Reset ECM
14. Started car and got P0141 immeduiately again.

Could the rear secondary O2 go bad? I never touched it. I know the wires all run together up the rear valve cover. What do you think would be the cause of this. I have never got this code unitl after I disconnected the 2 primary O2's.

Thanks and I look forward to your reply.

Darrin

 

[Larry Bastanza]

Of course it is possible that the 02 sensor went bad, although it seems kind of suspicious. Find the secondary connector and separate it. Check to see if by some chance a pin in the connector body has been bent, pushed back in the housing, etc. Also make sure the connectors are completely seated and the tabs have snapped into place.

The P0141 code = Rear Secondary HO2S Heater Circuit Malfunction (Bank 1 Sensor 2)

This is a hard failure of the heater circuit in the 02 sensor. The 02 sensor has a 'filament"(heater) internally like a light bulb. For whatever reason the ECU thinks this is open or shorted. Check what I mentioned above.

Also if this does not seem to be it, I would go thorough the procedure in the service manual to check this curcuit

Regards,
LarryB

 

[xory72]

Larry,

Thanks for the reply. I've already done what you said in the first part of your post. I even used Electrial Contact Solution and it still through the code instantly. However, I did not check to see if the pins were pushed all the in the connector etc.

I will check all the pins and connections (hard palce to get to). I will also go through the test procedure this weekend (Sunday) to see what I come up with.

Once again thank you for the guidence. I think I am just going to order the three remaining O2's that I need .... that way all 4 have been done at the same time.

BTW ... I changed my avatar. I've done a few cosmetic upgrades to my car.

Have a great weekend and I will repost once I have all the O2's installed.

Darrin

 

[goldNSX]

The P0141 code = Rear Secondary HO2S Heater Circuit Malfunction (Bank 1 Sensor 2)

Not to throw an arrow in the wrong direction but I recall people with exactly the same error code and ended up buying a new ECU. So it's worth looking at the sensor and the wireness first.

Let us know.

 

[xory72]

Not to throw an arrow in the wrong direction but I recall people with exactly the same error code and ended up buying a new ECU. So it's worth looking at the sensor and the wireness first.

Let us know.

Dang ... not such great news. I will get the O2 first @$60 then see what happens.

It's just odd that it gave this code after I reconnected the 2 primary's and did not give me the code anytime prior to that.

Thanks for the heads up goldNSX

Darrin

 

[xory72]

Hey all,

As promissed, I said I would post the outcome after I replaced the O2 sensors.

Ordered them from sparkplugs.com and installed the today (sunday) then reset the CPU. Started the car is the idle was noticably much smoother. Took the car fro a ride .... hesitation GONE!

I only have 50 miles on them so far ... so no codes yet. I am sure They will all be gone.

Larry called this one ... so thank you Larry! I appreciate all your help and I am sure Prime appreciates all you knowledge.


Thanks guys!

Darrin

 

[N Spec]

Cool, sounds like I may be having the same issue. How hard were they to install? Would you or anyone happen to have a pic or diagram of the location of the sensor plugs? I have an idea of where they are, but I just want to be sure. I think i will pull them today and see if I get the same results.

 

[xory72]

Cool, sounds like I may be having the same issue. How hard were they to install? Would you or anyone happen to have a pic or diagram of the location of the sensor plugs? I have an idea of where they are, but I just want to be sure. I think i will pull them today and see if I get the same results.

Mine were super easy to install. I actually replaced all four sensors and it took about an hour. I have DC headers so all the O2's (Primary and Secondary) are all easy to get to and located right before and after the CATS. You will need a 22mm wrench but I also had the O2 socket kit from Advance Auto (loan a tool) that really helped as I could use a breaker bar to get more leverage.

I am not sure where the o2's are locatd on the a stock exhuast manifold so maybe some one else can post and help you out there.

The hardest part for me was getting at all the connectors to unplug. Removing one of the rubber muffler hangers really helped which made some room to get my hand and arm up there.

The car runs so much better now and best of all ... no hesitation. Once again thanks Larry for your advice.

Darrin

 

[davidf]

I know it's probably money wasted but I've always replaced 02's as a pair. I feel better knowing their both new and I'm getting maximum fuel mileage.

 

[Jetpilot3]

Darin,

Its creepy that you had these issues as I'm just about to go thru the diagnosis on my car (just came back from 4 weeks at the interior shop).

I've almost got the same problem but I'm tempted to go the route you have as it sounds very similar (2800rpms - 3000rpms hesitation in 2nd gear almost like a power loss huh?)

http://www.nsxprime.com/forums/showthread.php?t=102798

That was my thread on the issue but I'll check out what you did first.

Jetpilot

 

[xory72]

Darin,

Its creepy that you had these issues as I'm just about to go thru the diagnosis on my car (just came back from 4 weeks at the interior shop).

I've almost got the same problem but I'm tempted to go the route you have as it sounds very similar (2800rpms - 3000rpms hesitation in 2nd gear almost like a power loss huh?)

http://www.nsxprime.com/forums/showthread.php?t=102798

That was my thread on the issue but I'll check out what you did first.

Jetpilot

Hey Jetpilot,

Thanks for the link to your last thread! After reading it and I now think back to my problems and things I went through, my TCS kept automatically shutting off (light comming on) and so did my ABS light. So ... I diagnosed that a wheel sensor was bad. Replaced it and TCS now worked fine, but hesitation still there. The MIL was on.

I then unhooked both Primary O2's as Larry suggested. When I started the car the Check Eng light immediately came on ... then I moved the car and the TCS light came on which I thought was strange as I had fixed that. Hesitation was gone, but now the Check Eng and TCS were on.

Once the new O2's arrived and I installed them ... sure enough no MIL and no TCS. So the ECU must send info to the TCS with regards to emmisions. If the O2's are bad ... then the TCS turns off.

I would do as Larry suggested for me. Disconnect the O2's at the corners of each valve cover and see if the hesitation goes away. If so ... you know the problem. It will most likly fix your TCS when you replace them as well.

Good luck.

 

[Jetpilot3]

Now my only question before I proceed is that I presently have my TCS disconnected. Should I expect anything different than what you've done?

 

[xory72]

The TCS did not make any difference on the hesitation. It was there regardless if the TCS was working (engaged) or not.

The TCS was fully functional and operated properply when I replaced the front wheel speed sensor. Then when I disconnected the O2's as Larry suggested, the TCS would turn itself off.

When I replaced the O2's and plugged everything back in ... TCS back to normal.

By having your TCS unpligged, it will not effect anything except that your TCS will not be working. The hesisation will or should still be there. I am curious if this hesitation goes away when you unplug the O2's.

Good luck

Darrin