300ZX (Z31) Performance / Technical Discussions related to Turbo charging, Supercharging, Engine, ECU, exhaust, and etc. performance enhancements and Techical related.

RPM issue

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Old 01-27-2006 | 07:24 AM
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FranksZ31's's Avatar
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RPM issue

Hi everyone! I have an 85 z31 restored but I have an idle issue and need advice.
The problem is the car starts fine always however it will go up to 2200 RPM and drps. I can accelerate up to 2,200 RPM. Can anyone give me advice on where to start trouble shooting?
Thanks
Old 01-27-2006 | 02:09 PM
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Most common fault is the air flow meter or the connections between it an the ECU.
Old 01-28-2006 | 06:21 AM
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Thanks EZI will trouble shoot today, I do know my mass airflow is ok, So it might just be connection Do you also think it might be a Vacume Hose? if so ow do you search for that type of issue?
Thanks
Old 01-28-2006 | 10:15 AM
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Originally Posted by FranksZ31's
Do you also think it might be a Vacume Hose?
Nope. 2200 RPMs is the max RPM the ECU lets the car run in safe mode.
Old 01-28-2006 | 10:23 AM
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i am kinda confused on that, what do you mean safe mode?

ps, 2200 in idle or runnin?
Old 01-28-2006 | 10:29 AM
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safe mode is when the ECU has no idea what's going on, but it realizes you need to move the car to get it somewhere. It can't measure air coming in, so it doesn't know what the proper amount of fuel is to drop into the engine. It will allow you to run up to 2200 to 2500 rpms because it knows there is virtually no way you can damage the engine at those speeds.
Old 01-28-2006 | 02:18 PM
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nice, always good to know!!! thanx
Old 01-30-2006 | 05:16 AM
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Originally Posted by AZ-ZBum
Nope. 2200 RPMs is the max RPM the ECU lets the car run in safe mode.
Thanks, I will recheck the Mass Airflow unit, I realize now that the mechanic who tuned my car played with the air and fuel mixture, this might be the problem as well.
Old 01-30-2006 | 08:54 AM
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the smallest leak will kill a car, like, if your intake leaks after the mass, your car will make the mixture to lean per air amount. Check everything!!!! I missed a wire that was loose/ off. IT was on my fuel mixture control thingy!!! forgot the name.
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