Cherokee`89. there is a spark,injec.are not
08-07-2011, 11:29 AM
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Cherokee`89. there is a spark,injec.are not
Hello!
Sorry, I am writing from Russia through the Google translator.
My Cherokee 1989, AMC242, Renix. The problem - the ignition spark is, and the ECU does not send pulses to the injector. When you turn the key the fuel pump runs 1-3 seconds - the norm. All power supply ECU seems checked - normal. Please tell me what could be the problem? Capacitors ECU?
Or tell me where to read on the subject. I understand electronics well. There is an oscilloscope. Master of Cherokee wrote that in the driver's door has a switch (something like an immobilizer). That the failure of this switch can provide a fault. Have you ever heard of it?
Thanks
Sergey.
Sorry, I am writing from Russia through the Google translator.
My Cherokee 1989, AMC242, Renix. The problem - the ignition spark is, and the ECU does not send pulses to the injector. When you turn the key the fuel pump runs 1-3 seconds - the norm. All power supply ECU seems checked - normal. Please tell me what could be the problem? Capacitors ECU?
Or tell me where to read on the subject. I understand electronics well. There is an oscilloscope. Master of Cherokee wrote that in the driver's door has a switch (something like an immobilizer). That the failure of this switch can provide a fault. Have you ever heard of it?
Thanks
Sergey.
08-08-2011, 01:51 AM
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Year: 1990
Model: Cherokee
Engine: The venerable 4.0
Sorry, the translator is just a little rough. Might be the ecu.... the injectors get their pulse straight from there.... I nave heard of the immobilizer but haven't had personal experience. The only things I've dealt with that were comparable were on gm products. I believe the ones used in jeeps unlock through a radio signal from the key? By the way the crankshaft position sensor does control injector pulse. I believe the camshaft position sensor also effects injector pulse.
Last edited by Slick761; 08-08-2011 at 02:00 AM.
08-08-2011, 06:46 AM
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Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
The camshaft sensor, or sync generator, inside the distributor only makes sure the injectors fire sequentially by giving a signal to the ECU. If it's bad the Jeep will run and most people wouldn't know it since it defaults to a batch-fire mode.
Look closely where the injector harness is routed from the firewall to the rear of the valve cover. They were known for chafing there.
While cranking have someone wiggle the harness in case there is a bad ground connection in there.
Look closely where the injector harness is routed from the firewall to the rear of the valve cover. They were known for chafing there.
While cranking have someone wiggle the harness in case there is a bad ground connection in there.
08-08-2011, 09:26 AM
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I have checked the grounding. On the grounding to me wrote a man from Minnesota Momentum injectors not to transistors in the ECU. :-(. I was hoping that you tell me about these faults. I'll try to check the small details the ECU. But if the faulty processor in the ECU - badly.
Tell me if you know about the man who repaired the ECU Cherokee.
I repaired the ECU Toyota, Nissan, Mitsubishi. Cherokee first.
Thank you.
Tell me if you know about the man who repaired the ECU Cherokee.
I repaired the ECU Toyota, Nissan, Mitsubishi. Cherokee first.
Thank you.
08-09-2011, 10:54 AM
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While repairing my ECU. Replaced all the capacitors. After that start to blink occasionally lamp on the instrument panel and at this moment there are impulses to the injectors.
Lamp - "up-arrow (forward)." What does this lamp? This is analogous to "CHECK ENGINE"??
I connected an oscilloscope. Traced the signals to the processor. Everything is fine.
I'll try all the soldered board. Unsolder and test resistors, diodes and ceramic capacitors. I think it's in a small detail.
Sergey.
Lamp - "up-arrow (forward)." What does this lamp? This is analogous to "CHECK ENGINE"??
I connected an oscilloscope. Traced the signals to the processor. Everything is fine.
I'll try all the soldered board. Unsolder and test resistors, diodes and ceramic capacitors. I think it's in a small detail.
Sergey.
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08-09-2011, 11:50 AM
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Year: 1996
Model: Cherokee
Engine: 4.0
The up-arrow indicator light is the ECU telling the driver it's time to shift to the next gear (manual transmission only).
It should only light up when you are driving, at higher engine RPM's and light load.
If it lights up when you are trying to start, you may have accidentally shorted some pins or traces in the ECU when you were repairing?
It should only light up when you are driving, at higher engine RPM's and light load.
If it lights up when you are trying to start, you may have accidentally shorted some pins or traces in the ECU when you were repairing?
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