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Big performance issue on my r50

Mike.Boeriu

By Mike.Boeriu,
in The Garage

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Mike.Boeriu NPORA Newbie

Mike.Boeriu

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Hey guys, new to this forum and believe this is my best chance at solving my problem. I recently picked up a 96 r50 and everything was going great, beast of road and what not, but before to lo I started having a big issue, it's lost almost all power. While in park if I put the pedal to the floor it will bog down to an almost stall, then bounce up to 1500rpm and then bounce between 1500 and 1000, if it gets above that it does the same thing (ie. between 2500 and 2000) I can get it up to about 40km using about an eighth of the throttle but any more makes it bog down hard. I've tried changing the fuel filter and gutting the cats, it has a check engine light due to o2 sensors but I don't believe that should do it. I'm personally thinking fuel pump or injectors, but would like some opinions before footing the bill on them as they are not cheap. Many thanks.

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bushnut NPORA Old-Timer

bushnut

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O2 sensors are cheaper than injectors. Have you done the usual? cleaned MAF? air filter etc...how's the exhaust ? major holes will rob power.

an engine needs to exhale as well as it inhales.

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Mike.Boeriu
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Mike.Boeriu

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Haven't cleaned the MAF yet, this issue is without an air filter, would o2 sensors really cause this kind of power loss tho? From my experience they would just affect fuel economy. Will try and clean the MAF tomorrow and post results. Also there are no exhaust leaks I'm aware of before the muffler that combines the 2 pipes, but I did remove the muffler at the very back, but it drover perfectly fine for a week after that.

 

 

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Precise1 NPORA Old-Timer

Precise1

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I've tried changing the fuel filter and gutting the cats, it has a check engine light due to o2 sensors but I don't believe that should do it. I'm personally thinking fuel pump or injectors, but would like some opinions before footing the bill on them as they are not cheap.

:doh:

Why would you gut the cats and ignore the codes when the computer that controls the motor is telling you what the problem is? Do you think injectors or a fuel pump is cheap? Why don't you start with the O2 sensors and save the second guessing for later?

This makes no sense... :wacko:

 

B

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Mike.Boeriu
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Mike.Boeriu

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I've run a lot of vehicles with no cats or a o2 sensor code and have yet to experience anything like this. I've been going for cheap/free things due to limited budget

 

 

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Kingman NPORA Old-Timer

Kingman

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If a lot of the vehicles you ran without O2 sensors were older OBDI, that's why there wasn't much difference in power. Newer OBDII systems freak unless the ECU is tuned to run without them. Post cat sensors don't do much other than inform the ECU that the cats are bad. The front ones do directly influence the fuel and timing maps.

Edited by Kingman
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  • 2 weeks later...
Precise1 NPORA Old-Timer

Precise1

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Update: new upstream o2 sensors have been installed, still surging, any further suggestions?

 

 

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Have you cleared the OBD2 codes and run it for a bit?

Any new codes? Old codes? what are the numbers?

 

A single downstream cat shouldn't cause surging. Have you followed the FSM diagnostic proceedure?

I once had a cyl #1 misfire and downstream O2 sensor codes. Once I replaced the #1 injector (took a bit to isolate, it only failed after hot/shut off/restart), the down stream O2 code went away.

 

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Slartibartfast NPORA Old-Timer

Slartibartfast

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The two down stream O2s are throwing codes because the cats are gutted. That alone shouldn't cause performance issues.

 

The FSM may be your best bet. Failing that, however, I'd start with the plugs for the MAF, throttle position sensor, and coolant temp sensor. Unplug, inspect the wiring, clean the plug contacts if necessary, stick them back together and see if that helps.

Edited by Slartibartfast
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