RPM Bouncing

200SX SE-R · Dec 26th, 2005, 08:33 PM

I've searched the forum but havent really gotten a straight answer. Ever since I replaced my ole SR20 with a new JDM SR20 the RPM has been bouncing in idle, i've checked the coolant for any bubbles but it didnt fix it. also my check engine light comes on but there is nothing wrong with the car as it drives smoother than it did with the old engine, Any other tips would be appreciated

Thanks

NismoSentra2b · Dec 26th, 2005, 10:35 PM

Quote:

Originally Posted by 200SX SE-R

I've searched the forum but havent really gotten a straight answer. Ever since I replaced my ole SR20 with a new JDM SR20 the RPM has been bouncing in idle, i've checked the coolant for any bubbles but it didnt fix it. also my check engine light comes on but there is nothing wrong with the car as it drives smoother than it did with the old engine, Any other tips would be appreciated

Thanks

throttle body gasket? vacuum leak

HATEnFATE · Dec 27th, 2005, 02:39 PM

IAC valve. vacume leak. timing.
Did you swap sensors from your old engine to your new engine? Your ECU can't speak japanese and your new engines stock sensors can't speak english.

KMG9185 · Dec 27th, 2005, 07:11 PM

Quote:

Originally Posted by HATEnFATE

IAC valve. vacume leak. timing.
Did you swap sensors from your old engine to your new engine? Your ECU can't speak japanese and your new engines stock sensors can't speak english.

sensor work the same...either read resistance, or resistance...haha

Kevin

HATEnFATE · Dec 29th, 2005, 05:57 PM

That was a figure of speach.

They don't all read the same voltages and ohms. some of them are different then others. Japan car don't run EGR systems so they run different temps then our engines. The sensors need to be changed.

94sentragtr · Dec 29th, 2005, 06:01 PM

Get your usdm sensors in.

KMG9185 · Dec 30th, 2005, 09:58 AM

Quote:

Originally Posted by HATEnFATE

That was a figure of speach.

They don't all read the same voltages and ohms. some of them are different then others. Japan car don't run EGR systems so they run different temps then our engines. The sensors need to be changed.

i was joking too.....haha..... the values or thresholds are changed to match the prupose or use of each sensor....but basics are still basics....

kevin

HATEnFATE · Dec 30th, 2005, 12:31 PM

Thats cool.....I've found the description that I used is usually easier for the youngins to understand.

**wes** · Dec 30th, 2005, 01:58 PM

Quote:

Originally Posted by 200SX SE-R

I've searched the forum but havent really gotten a straight answer. Ever since I replaced my ole SR20 with a new JDM SR20 the RPM has been bouncing in idle, i've checked the coolant for any bubbles but it didnt fix it. also my check engine light comes on but there is nothing wrong with the car as it drives smoother than it did with the old engine, Any other tips would be appreciated

Thanks

Did you use the USDM or JDM intake manifold? The JDM coolant temp sensor is not compatible with the USDM harness and ECU. If you did not swap the hard coolant lines and IM from your old motor to the new JDM motor you need to swap the coolant temp sensor.

200SX SE-R · Dec 31st, 2005, 05:23 PM

Quote:

Originally Posted by wes

Did you use the USDM or JDM intake manifold? The JDM coolant temp sensor is not compatible with the USDM harness and ECU. If you did not swap the hard coolant lines and IM from your old motor to the new JDM motor you need to swap the coolant temp sensor.

Yea i used the USDM intake manifold because of the egr valve, also is there any major differences between the USDM SR20 and the JDM SR20?

**wes** · Jan 1st, 2006, 12:23 PM

Quote:

Originally Posted by 200SX SE-R

Yea i used the USDM intake manifold because of the egr valve, also is there any major differences between the USDM SR20 and the JDM SR20?

What about the hard coolant lines on the back of the motor, did you swap those from your US motor? Those are the lines that contain the temp. sensors.