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There is no RPM singal when cranking why?

When i am cranking the engine i don't see no RPM signal what's the cause for no RPM signal?

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  • Cars & Trucks Master
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If your looking at the dash, Most gauges don't move till the engine is running. If your looking at a scanner and no RPM's. Most likely it is the crank sensor. Could be the wiring/plug. Worse case is the PCM died.

Posted on Dec 11, 2016

  • Joe Russell Dec 11, 2016

    i am looking at the dash what type of scanner i need to check RPM with?

  • Randy Ohler Dec 11, 2016

    Scanners are expensive. There are some code readers out there that give some engine data. They run around $300.

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95 jeep wrangler 2.5L fi.very long crank time before engine starts.this system requires rpm signal before it will power up fuel pump.


Key on engine off , what is the fuel pressure ? When you turn the key to the on position ( not start ) the PCM will turn the fuel pump on for two or three seconds for system prim , then it needs a RPM signal (engine cranking) . In side the fuel pump module is a check valve that keeps pressure in the fuel lines , if weak will allow fuel to drain back to the fuel tank . This will cause long crank times . Put a fuel pressure gauge on the vehicle an see what the pressure is key on , does it come up to 40 psi ?

Oct 06, 2016 | Jeep Cars & Trucks

1 Answer

95 jeep wrangler extended crank time.


This system requires rpm signal before it will power up fuel pump .
THE PCM POWERS UP THE FUEL PUMP FOR TWO OR THREE SECONDS AT KEY ON !

Oct 06, 2016 | Jeep Cars & Trucks

2 Answers

Car shuts off while driving.If you wait a few minutes it will start.


What is year--make--model? How long since a tune-up? Can you check applicable trouble codes?

If it cranks good but won't start, when problem is ongoing, have a helper crank it, while you visually check for spark at the spark plugs, if you have spark plugs. If you have spark everywhere, use a gage and check proper fuel pressure. Also, check fuel injector pulse.

Check for rpm signal, engine cranking, when problem is ongoing. An intermittent rpm signal can cause you fits.

Jul 14, 2015 | Cars & Trucks

1 Answer

My 1996 Ciera Oldsmobile through a PO336 code?


Hi there:

DTC P0336 - Crankshaft Position Sensor A Circuit Range/Performance


The crankshaft position sensor (CKP) is usually a two wire sensor: a signal and a ground. The CKP sensor consists of (usually) a permanent magnent sensor that is mounted in front of a reluctor (toothed) wheel mounted to the crankshaft. As the reluctor wheel passes in front of the crank sensor, an A/C signal is produced that varies according to engine speed. The PCM (powertrain control module) uses this A/C signal to interpret engine RPM. Some crank sensors are hall-effect sensors instead of permanent magnent sensors. These are three wire sensors, provided with voltage, ground, and signal. They too have a reluctor wheel with vanes and "windows" that change the voltage signal to the PCM, providing a RPM signal. I will focus on the former, since they are simpler design and more common.



The crankshaft reluctor has a specific number of teeth and the PCM can determine the position of the crankshaft using only this sensor's signature pattern. The PCM uses this sensor to also determine cylinder misfires by measuring the reluctor teeth locations in the CKP sensor signal. In conjunction with the Camshaft position sensor (CMP) the PCM can determine timing of spark and fuel injection. If the PCM senses a loss of CKP sensor signal (RPM signal) even momentarily, P0336 may set.


Symptoms of a P0336 DTC may include:
Intermittent stalling & no start
No start
MIL (Malfunction Indicator Lamp) illumination
Intermittent misfire


Potential causes of a P0336 code include:
Bad crank sensor
Broken reluctor ring (missing teeth, debris lodged in ring)
Reluctor ring dislodged/stripped from it's stationary location
Wiring harness chafing causing short
Wiring open in CKP circuit


Possible Solutions: Crankshaft sensor problems are at times intermittent and the vehicle may start and run for some time until problem occurs. Try to reproduce the complaint. When engine stalls or if the engine will not start and continue to run, then crank engine while observing RPM reading. If there is no RPM reading, check for a signal coming out of the crank sensor. Using a scope is best, but since most DIYers don't have access to one you may be able to use a code reader or the tachometer to check for RPM signal.


Visually check the CKP harness for damage or cracking in the wiring insulation. Repair as necessary. Make sure the wiring isn't mis-routed near high voltage spark plug wires. Check for loose connection or broken lock at the sensor connector. Repair as necessary. Obtain a resistance spec for the Crank sensor. Remove and check it. If it doesn't pass, replace it. If it checks out okay, check the reluctor ring for damage, broken teeth, or debris lodged in the ring. Make sure the reluctor ring isn't dislodged. It should be stationary on the crankshaft. Carefully repair/replace as necessary. Note: some reluctor rings are located in the bell housing of the transmission or behind the front engine cover and cannot be easily accessed.


If the vehicle intermittently stalls and after stalling you have no RPM signal and you have verified the wiring to the CKP sensor is good, then try replacing the sensor. If that doesn't take care of it, and you can't access the reluctor ring, seek help from an automotive professional.


Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Jun 27, 2012 | 1996 Oldsmobile Cutlass Ciera

1 Answer

I recieved Code 12 from diagnosis


For 83-86 Camry, 87 corolla, 84-87 pickups and 4-runner: Code 12 = knock sensor or circuit (distributor or circuit on Cressida, Supra, and Celica 3S-GE)

87-90 Camry, all other models 88-90: Code 12 = Rpm signal/no NE or G signal to ECU within several seconds after engine is cranked.

All models from 1991 on: Code 12 = Rpm signal No "Ne" signal to the ECM within several seconds after the engine is cranked. No "G" signal to the ECM two times in Succession when engine speed is between 500 rpm and 4000 rpm.

Feb 08, 2011 | Toyota 4Runner Cars & Trucks

1 Answer

Engine cranks but wont start


Usually if no rpm signal, the vehicle won't start. Engine cranking, did you check for spark at the spark plugs? The fuel pressure you listed may have been the initial prime. It sounds like no injector pulse. The rpm signal comes from crank sensor. If your missing rpm signal, may thought is the crank sensor.
Were there any applicable trouble codes?

Apr 06, 2017 | 2001 Ford F150 Styleside SuperCrew

1 Answer

P1613 fault code & engine will not rev over 3000 rpm when you get to 3000rpm it then fluctutated between 2500 rpm & 3000 rpm causing the car to buckaroo


Crank sensor or engine speed sensor is faulty.

Fault:
Irregular power loss on accelerating
The speed of the engine is limited till 2500rpm
Frequent loss of crankshaft position sensor signal

Cause:
It is caused due to leaking from thermostat housing into crankshaft position sensor harness multi-plug

Remedy:
Check and clean the crankshaft position sensor harness multi-plug contacts. Rectify the engine coolant leak from the thermostat housing if found. Take a note of the engine coolant level and monitor it for changes, showing a leak is indeed occurring.

Oct 24, 2009 | 2005 Peugeot 405

3 Answers

My car is not firing . i replaced the ignition controle module and it's still not firing.


You need to 1st determine if the computer is even trying to start it before you start lobbing parts. Look at the CHECK ENGINE lamp while you crank it. If it stays on bright while cranking, the engine will not get any signal to fire spark or fuel because the computer is not seeing RPM signal while cranking. If the light goes OFF while cranking, the crank signal was seen, however there could still be fuel or spark issues from other causes. You really need to determine if you have spark or fuel as the next step after verifying rpm signal. There are no cheap tricks for most of this work, it takes tools and training to determine the exact cause of failures. Does the ECM communicate? Is the EEC relay functioning, does the fuel pump prime up at Key On? Is there injector pulse? Fuel pressure? 30kv of Spark that is also reaching the plugs?
These are the steps to check to determine how to not buy a wasted part as the next step.

Sep 15, 2009 | 1993 Ford Mustang

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