2001 WJ - no spark at cyl. #1 and #2 - DTC P0340

[firstgenbird]

Hi guys, I'm new to the forum and this is my first post.

I have a 2001 WJ grand cherokee 4.7L which cranks over fine but won't start. I checked the coils for spark and cylinders #1 and #2 (both left and right cylinders on the front of the engine) are not getting any spark. The rest of the plugs have spark. I checked the wiring of the coils and they seem ok. I'm getting a DTC P0340 on the odometer when I do the on-off-on-off-on-off-on sequence with the key in the ignition. I'm not sure if the DTC is related with the no spark condition on 1st and 2nd cylinders but I thought I should fix it anyway, so ...

I know the P0340 code is related to the camshaft position sensor. I live on the other side of the planet (that is Turkey) and I wasn't able to find a new replacement sensor close to where I live, so I did some tests to verify if the camshaft sensor is working properly.

I removed the camshaft position sensor connector and checked the voltage at the connector pins. The results are as follows:

pin 1 (signal): +5v
pin 2 (ground): 0 ohm resistance
pin 3 (voltage supply) +5v

I checked the resistance between pin 2 and 3, I get 0 ohms at those too. I think all is fine to this point.

Then I decided to check the signal voltage while cranking the engine, so I inserted a cable into the signal pin and plugged the connector back on the sensor. I cranked the engine and noted I'm getting a pulse between 0v and +11v but I think the proper value should be pulsing between 0 and 5 volts. Can any of you guys verify this? am I getting too high of a signal or not?

If I'm positively sure it's a faulty sensor, I'll order a new sensor by mail and hope it arrives in 2 weeks. But I'm still not sure if a new sensor will cure the no spark at coils #1 and #2. I looked everywhere on the internet and the service manual but can't find any information about what could possibly be causing this. I'd appreciate any help or guesses.

Thanks for taking the time to read all of this mess.

[WJCraig]

Keep us up to date if you find an answer. I'll see if there's anything I can dig up in the meantime.

[firstgenbird]

After spending 10 days, I found out the short block had a NGC tonewheel at the crankshaft which had 32 teeth. As my vehicle has a JTEC computer, I had to replace the crankshaft tone wheel with the proper JTEC one, which has 16 teeth. I should have checked it at the first place. I had to remove the engine and disassemble it completely to replace it. By the way, though the short block was a brand new replacement, I found out that the piston rings were stuck and the cylinder bores had surface rust towards the bottom, probably due to sitting on the warehouse. So I think it's a good idea to disassemble and inspect any engine when you buy one, even though it's brand new.

After everything was done and set, it fired up instantly. By the way, you can remove the crankshaft sensor and check the tone wheel's teeth with your finger. JTEC's have a wide notch while the NGC's have a narrow notch which you can barely get your fingertip in between, so it's easy to tell.