Hard acceleration momentary cut-outs....

[Hagasan]

Hi Larry, it was a main dealer tester. Don't know what it was called but its a Honda badged Tablet type VDR screen unit that plugged in under the glovebox in the footwell somewhere...

The code it gave were

06-1 TVC Com1 Motor Check 1
07-1 TVC Com2 Check 1
07-2 TVC Motor Com2 Check 2


TVC I believe is throttle valve control?

Thanks,

Haga

 

[Larry Bastanza]

Sorry to say, I am not familair with this tester.

Regards,
LarryB

 

[Briank]

What does the dealer say it will take to fix the problem? Assuming it is the Throttle Valve control check and reseat the connections for the throttle body.

 

[Hagasan]

OK, so I've had some time to try out a few things and here is what I've found........BTW the dealer is booked up so it hasn't been back there yet.

I tried a replacement main relay and the fuel pump relay. Result, no change still getting the cutouts...... :-(

So I get hold of a throttle body from another car. This TB is from a 2004 car but on inspection it looks no different to one that was on my car (96 model) except for one extra pipe outlet on the top. Now this pipe doesn't appear to be doing anything so I blank off it's opening. There is no vacuum and nothing9as in coolant) coming out when the engine runs......I checked the wiring was all the same. Same colours to same positions on the plugs etc. Measured the bore and that is identical too.

I've just got back from taking the car for a spirited drive and well..........partial success!! The car is now driving/accelerating strongly with no cut-outs or hesitation at all. I was accelerating really hard and all has been ok going back & forth along a 3/4 mile stretch full throttle each way through the gears. Did this many many times......This is the same road I was testing in the past when I got the cut-outs.

My only problem now seems to be that when slowing down to a halt the car will stall. The revs just drop unless I try to catch it with the pedal but this is far from ideal....I tried removing the clock fuse to reset the ECU but it is still doing the same.

There is no CEL or any other lights so now I'm a bit confused. The thing is it wouldn't stall with the other throttle body!?!?!?

Could it just be needing the idle resetting? Any ideas? I know somwone may ignition switch, which is the one part I don't have to swap out, but why no wstall before.....ever? Except for when I removed the O2 sensor plugs as the first check?

Haga

 

[drew]

Can you measure what the coolant temperature sender is putting out?

I wondering if it is telling the ECU that the engine temperature is too high.

 

[Hagasan]

Can you measure what the coolant temperature sender is putting out?

I wondering if it is telling the ECU that the engine temperature is too high.

How/where would I do that? The temp gauge is still normal so wouldn't that mean the sensor is reading correctly?

 

[Larry Bastanza]

You mentioned your car was a 1996. If your original throttle body does not have the nipple you taped over, it is not a 1996 engine/throttle body.

The pipe you closed off for THAT throttle body is the idle circuit, no wonder it will not idle.

Please give us a pic of your original throttle body.

Question: Is this a US Spec car?

Regards,
LarryB

 

[Briank]

The gauge, the ecu and the fan control each have there own separate temp sensors and I have never heard of one failing. Swapping the throttle body was not a valid trouble shooting move since about the only problems associated with the throttle body are idle control issues. As noted above Main relay and ignition switch are the most likely cause if this issue. I believe that main relay has been tried so next is replacement of the ignition switch.

The idle speed is controlled by the ECU and is not adjustable; if your idle is slow something is clogged or dirty.

 

[Hagasan]

OK here is my original TB. It is a 96 car and this is the originall TB. It is a Euro/UK car. Maybe it's slightly different to US in the emission side of things? Stricter emissions came in later over here.

 

[Hagasan]

Swapping the throttle body was not a valid trouble shooting move since about the only problems associated with the throttle body are idle control issues. As noted above Main relay and ignition switch are the most likely cause if this issue. I believe that main relay has been tried so next is replacement of the ignition switch.

The idle speed is controlled by the ECU and is not adjustable; if your idle is slow something is clogged or dirty.

....but I changed the throttle body over because the car would not accelerate properly.

The dealer got codes saying the throttle valve control was bad. Since changing the TB the car is driving/accelerating hard without any glitches whatesoever.

The car has never ever stalled with the original TB, only now with the replacement. The only difference in TB's is the extra nipple but I don't know what it's purpose is. My original never had it.......I'm guessing it's some kind of recirculating of air thingy? Do I cap it, provide a vacuum to it??

Only NEW fault now is the stalling, no more cutting out......

 

[Larry Bastanza]

OK, so this is not a US Spec car. So the throttle body is different that what we have in the US. The throttle body that you have installed, as I mentioned, that pipe is the idle circuit, so that throttle bosy is not correct for your engine.

Sorry I cannot be of more help, but your original throttle body is different that any one we have here in the US. The one you used to swap is not compatible with your engine intake, it has a different idle system. I cannot comment on the details, I have never seen a throttle body like your original.

Regards,
LarryB

 

[Hagasan]

The extra nipple would appear to be part of the Fuel Injection Air system? My car does not have this. I think it must only be on later cars for cleaner emissions.....

I don't think the nipple is the idle control? Wouldn't you agree? Are you orientating the TB correctly in your mind? It just seems odd that the car is accelarating perfectly now but ONLY stalling when coming to ahalt. Almost like an air leak perhaps? Maybe the nipple just needs capping? The car will restart and idle ok after it has stalled.

The PDF below is from an 02+ car but I just checked the 96 version and the page is identical. I'm guessing the only difference between a UK & US car is this nipple?

 

[Larry Bastanza]

There is no question this is the idle circuit on the US models. In the 1995+ US cars this nipple feeds air to the base of the fuel injectors for idle. It is the only way the car will idle. Since I am not familiar with your idle air intake system, I cannot comment about the details.

My recommentation is to seal it first, see whaqt happens, but do try to get an exact good throttle body to continue your diagnosis.

Regards,
LarryB

 

[Hagasan]

Hi Larry,

I have tried sealing it but still get the same problem. It would appear at least that the cutting out problem has indeed been solved by fitting another throttle body and my guess is that the motor or sensor inside my original one is faulty.

I'm not sure whether there is any difference internally with the airways etc between the two bodies I had tried and that perhaps this is why I am having the stalling...

Just to be clear in the terminology. My car will idle ok. It just stalls when coming to a halt....as in slowing down for a junction in say second gear then dipping the clutch as you finally stop. This is when the engine dies. When I turn the key she restarts and idles ok. Also, if the car is idling and I rev it up then come of the pedal it dies again. It's almost like it's not sensing the revs have dropped to cut over to the idling cct. Not sure if this may be a throttle set-up or electonic sensor issue.

I may be clutching at straws here but is there any chance that the extra length of the tube could help create and pressure/turbulence issues that may affect the closing of the throttle and switch over to idle?

The trouble is that a throttle is about $3000 over here so I don't want to have to pay that on a chance........I don't want to have to buy one full stop. I just wonder if it's possible to transplant the good internals from the test TB into my casing. I know my cutting out problem is 99.9% electrical now........

Also I don't want to discount Brians theory of the ignition switch but I don't have a spare to test with and I can't see how that fault would suddenly appear as soon as the throttle is changed. It would be there all the time surely?

 

[enkrypt3d]

Have you taken your air filter out and cleaned the throttle body very well?

I just looked at my air filter and even after the dealer said he cleaned it, it was caked with about 5mm of gunk. So I took the whole air box out and cleaned it and the air filter as well. I have the UNI filter so I followed the steps to clean it.

And then I checked the TB and saw that it also had gunk in it. Ran to autozone and got some TB cleaner... just follow the directions.

Before I cleaned everything, my idle was fine but after coming out of gear, the RPMS would dip to almost zero (almost stalling) then jumping back up to 800RPM or so..... now its running very smooth.

Let me know if you have done this. Its very easy to remove the air box to get to the TB.

btw im not sure if the newer TB will work and I have never seen a UK spec NSX's TB before :redface:

 

[Hagasan]

Have you taken your air filter out and cleaned the throttle body very well?


Before I cleaned everything, my idle was fine but after coming out of gear, the RPMS would dip to almost zero (almost stalling) then jumping back up to 800RPM or so..... now its running very smooth.

Let me know if you have done this. Its very easy to remove the air box to get to the TB.

btw im not sure if the newer TB will work and I have never seen a UK spec NSX's TB before :redface:

Well I haven't run any cleaner through the TB but I now have some and will give it a go however...........

I did an ECU reset on the car and then left it to idle for 10 mins or so and there is no more stalling!! The revs sometimes take a small dip but I ran the car with almost all electrics on, revved it up and the revs came back down and settled quickly...

I later tried to do a proper reset by removing the hose from the top of the TB, the one that goes to the EVAP canister. The manual says there should be no vacuum at idle. I am actually getting a strong vacuum at idle and I'm not sure why? I'm not sure the implications of ignoring this, high fuel consumption??

For now at least the car is now accelerating hard without any cutting out and it's no longer stalling as I come to a halt....that at least feels kinda good as I can drive the car properly now.

I am going to take a run up to the dealers tomorrow and see if any codes are still reported and see what they say about the tick-over vacuum....


Larry, the diagnostic equipment I was referring to a week or so ago was the HDS, Honda Diagnostic System...... It plugs into the 16pin (I think) socket under the glovebox. It is an approx 12" screen tablet form diag unit. are these not in the US.

Haga

 

[enkrypt3d]

Well I haven't run any cleaner through the TB but I now have some and will give it a go however...........

I did an ECU reset on the car and then left it to idle for 10 mins or so and there is no more stalling!! The revs sometimes take a small dip but I ran the car with almost all electrics on, revved it up and the revs came back down and settled quickly...

I later tried to do a proper reset by removing the hose from the top of the TB, the one that goes to the EVAP canister. The manual says there should be no vacuum at idle. I am actually getting a strong vacuum at idle and I'm not sure why? I'm not sure the implications of ignoring this, high fuel consumption??

For now at least the car is now accelerating hard without any cutting out and it's no longer stalling as I come to a halt....that at least feels kinda good as I can drive the car properly now.

I am going to take a run up to the dealers tomorrow and see if any codes are still reported and see what they say about the tick-over vacuum....


Larry, the diagnostic equipment I was referring to a week or so ago was the HDS, Honda Diagnostic System...... It plugs into the 16pin (I think) socket under the glovebox. It is an approx 12" screen tablet form diag unit. are these not in the US.

Haga

Yea sounds like you've just about got this problem licked.

So yea take the air box out, and spray the TB cleaner with the butterfly plate open so you can reach the back side of the TB... also take a rag and clean the backside of this plate as best as u can.

There are sensors in there that monitor all sorts of crap inside the TB. As soon as mine was clean, my RPM issue was gone. Good luck!

 

[Jin1976]

I am having similar problem but now it comes down to either bad coil pack or bad fuel pump. Recently I have replaced Car Battery, Main Relay, Ignitor and O2 sensors. We do observe some corrosion on the almost 2 years old rear coil packs due to some water getting through the newly installed valve cover gasket.

Symptoms that I have observe is the engine take some cranking to start after a normal distance drive (~20 miles). Usually happen during hot day and when the fuel is below half on the fuel meter. Also car almost die if I idle on a sloping road. How much does the oem fuel pump cost?

 

[Hagasan]

....was looking on the Type-S thread and noticed this car in the US. Obviously as it's right hand drive it's a Japanese market car but being as the Types S was a 97 onwards car it's interesting to note that the throttle body doesn't have the extra nipple/pipework that the US cars have. I think the extra pipework is actually for emissions control by pumping air directly to the injector body to lean off the mixture rather than to hold the car at idle? I may be wrong but I can't see why the cars in the US would have a fundamentally different idle control....

My car is at the dealer today and the error codes are no longer with the replacement TB so it would appear that a TB from any "fly by wire" car is interchangable.....96 thru to 05.

For now at least I'm happy.....I can mash the throttle and get proper acceleration :biggrin:

Thanks to all who took the time to respond and help.

Haga

 

[usafdarkhorse]

Update:

Along with the momentary cutoffs, my car died after parking today. :frown:

Try to turn it over... click click click click. I'm thinking either the main relay or the ignition switch.

Took the battery out, tested it, it's good. Put a new one in just to try it... click click click....put the old one back in and it STARTS UP. I think I've got a bad ground or a dying relay.

 

[Hagasan]

Update:

Along with the momentary cutoffs, my car died after parking today. :frown:

Try to turn it over... click click click click. I'm thinking either the main relay or the ignition switch.

Took the battery out, tested it, it's good. Put a new one in just to try it... click click click....put the old one back in and it STARTS UP. I think I've got a bad ground or a dying relay.

This sounds more like a battery with a cell gone bad. The clicking isn't the starter motor solenoid is it? Sometimes leaving the battery alone for a short while allows it to recover a little to then be able to start the car....

When you say the battery was tested, was it just for voltage or drop teste? A duff cell won't always be obvious just putting a voltmeter across it. How do you know the replacement battery was fully charged?

 

[Hagasan]

Yea sounds like you've just about got this problem licked.

So yea take the air box out, and spray the TB cleaner with the butterfly plate open so you can reach the back side of the TB... also take a rag and clean the backside of this plate as best as u can.

There are sensors in there that monitor all sorts of crap inside the TB. As soon as mine was clean, my RPM issue was gone. Good luck!

So the idling or cutting out as I slowed down didn't actually go completey....

Main dealer couldn't work out why!!

I took the car home, swiped the airbox off and gave the throttle body a severe cleaning with carb cleaner........Guess what? Revs now dropping to ~650 directly without going to almost zero then hunting back or stalling.....

I am well happy, everything is working as it should:biggrin:

 

[enkrypt3d]

So the idling or cutting out as I slowed down didn't actually go completey....

Main dealer couldn't work out why!!

I took the car home, swiped the airbox off and gave the throttle body a severe cleaning with carb cleaner........Guess what? Revs now dropping to ~650 directly without going to almost zero then hunting back or stalling.....

I am well happy, everything is working as it should:biggrin:

good work... although I think you should only use TB cleaner not carb cleaner...

I should have mentioned that before hand..

If you want to take it a step further u can use a product called seafoam

http://www.seafoamsales.com/deepCreepTech.htm

I have not used this but i have heard good things about it. GL

 

[Bwood]

I also get the power loss issue.. but TCS light comes on (flashes) during these moments. My mechanic told me the TCS is coming on because my front to rear tire size ratio is not correct.

I have 235/40-17 up front and 265/35-18 in back. Im going to replace the 235's with 215's in the front. I need to do this anyway because I want to lower it and wont have room with the 235's up front.

 

[Hagasan]

good work... although I think you should only use TB cleaner not carb cleaner...

I should have mentioned that before hand..

GL

....well it was Wynns Fuel injection & carb cleaner. Sort of multi-purpose I guess? Whatever it's done the trick as I was out for a "hard" drive for an hour or so and no stalls at all. It's fantastic with the replacement throttle body being able to now rev the car all the way to the red line without it jolting and to listen to the wail without any interruption.....:biggrin::biggrin: