2001 3.3 caravan NO START!!!

[djc2222]

Allright, i got this van with a blowed up 3.3 engine. Threw a rod but still ran. Sounded good other than the knock. Bought a junkyard engine with 100,000 K on it supposedly out of a 2001 town and country. It won't start. No codes. On initial cranking each time will fire the front plug a couple times then quit. A buddy connected his $12,000.00 snap on scanner to it and can make the pcm fire each coil pack, so I'm assuming communication between pcm and coil pack is good. The one thing that's goofy is that as the engine cranks, the scan tool shows the cam sensor and the crank sensor get out of sync. I'm assuming that's where the loss of spark is happening. I used the original flywheel, put in a new crank sensor and inspected the cam sensor( also the original one that came out of the running van). Checked all grounds. I'm pulling my hair out. Anybody got any ideas?

[djc2222]

Originally Posted by djc2222

Allright, i got this van with a blowed up 3.3 engine. Threw a rod but still ran. Sounded good other than the knock. Bought a junkyard engine with 100,000 K on it supposedly out of a 2001 town and country. It won't start. No codes. On initial cranking each time will fire the front plug a couple times then quit. A buddy connected his $12,000.00 snap on scanner to it and can make the pcm fire each coil pack, so I'm assuming communication between pcm and coil pack is good. The one thing that's goofy is that as the engine cranks, the scan tool shows the cam sensor and the crank sensor get out of sync. I'm assuming that's where the loss of spark is happening. I used the original flywheel, put in a new crank sensor and inspected the cam sensor( also the original one that came out of the running van). Checked all grounds. I'm pulling my hair out. Anybody got any ideas?

A couple additional things I forgot to mention...the original engine was a "G" and the replacement engine is a "3". Checked compression on 2,4&6 and got a 180, 180 and a 160 respectively. as far as the initial cranking goes, No.2&5 will fire up to 3 times, no. 4&3 will fire once and no. 6&3 don't fire at all. Will do this each time you crank the engine. Once again, at the time of disassembly, the van started and ran well. Was there any timing gear differences that would affect the cam sensor readings that could cause this? Thanks for any help. Denny
BTW, I found out the Snap On Verus isn't quite that pricey, but still big bucks!

[hundahunta]

is the cam sensor bolt hole slotted if so you will need to install a spacer on the sensor for the correct air gap....

[djc2222]

I don't remember for sure, but it does seem like it was slotted. I will check that out. How would you set the air gap on it? thanks, Denny

[djc2222]

Well, I got an answer from another source. I'm going to give it a shot and I'll let you know what I find out. Here is the answer I got.

(The earlier vans used the SBEC design engine controller. Starting for the 2003 model year with the 3.3 and 3.8 engines these vans phased over to the NGC engine controller. The only vans available with the SBEC in this year had a 2.4. The NGC controllers used a different tone wheel pattern on both the cam sprocket and the flexplate for the sensors to run off of. If you put either engine in each other's package it will give the exact symptoms you are having. The sensors will start to sync up and then go out of sync. If you've put a 2003 engine into a 2001 van and haven't swapped the cam sprocket from the old engine over to the replacement, there is no doubt whatsoever that you have the wrong sprocket in the van now. You'll need to swap the sprocket from the old engine into the new one and it should fire right up.)

[hundahunta]

that's correct the slots on the cam gears are different...you need to verify the correct year of the engine...

[djc2222]

Well, we pulled the cam gear and it is a perfect match to the old gear. Same part number as well. I'm going to replace the water pump, idler and tensioner pullies and the belt since i'm already here. Much easier at this point. The tech with the scanner did some research and told me he thinks that there is a problem at the ASD relay. He believes that there is no voltage to a pin that is suppose to supply voltage to the coil and injectors. I'm not sure how much i'll be allowed to work on it today but will keep you informed of what I find out.
Happy turkey day to all. Denny

[hundahunta]

remove 1 injector connector, install a noid light and crank the vehicle...also remove the coil connector there are 4 wires, 1 wire is asd, should have 12 volts key on for a few seconds next connect a test light with the clip end to power, with the key on check for ground on the 3 different circuits the light should not light up....with the engine cranking re-check the 3 circuits the light should flicker...

[djc2222]

I checked the power at the coil yesterday. B+ pin powers up then goes out with key on. Pin powers up steady while cranking. I will install noid light on injector harness wire and check the coil trigger wires. We replaced the cam sensor ( with an aftermarket from O'reilly's ) that had the .030 spacer glued on it. At the first attempt to start it the engine fired up for a split second then immediately returned to a no start situation. I cranked the engine with a plug in #2 wire to se if we had spark and found we had none. That's when I checked the power at the coil as mentioned above. I pulled the cam sensor back out and the spacer was slightly sheared off as I'm assuming it is supposed to do. Re-installed sensor and still nothing. Installed test tool below ASD and checked pins with a test light. Two pins are hot at all times, one pin is hot for a few seconds with key on and constantly hot while cranking. Fourth pin makes the starter relay click each time you touch it. When I first checked the pins, after the key had been on for a few seconds, the coil supply pin and the one that clicks the starter relay had a very small amount of voltage,less at the starter relay pin, and just enough to barely light the bulb with the key on and not cranking the engine. It seems that after a few times of cranking the engine over that I lost the low voltage at these pins coinciding with the no spark at the plugs. Almost like something was backfeeding the relay. I still feel that it's going to be a connection or ground issue, but last time scanner was reading data it showed that grounding was good and was communicating with all pertinent sources. Tech friend is going to come back out on Sunday and check with scanner again. Will keep y'all informed. thanks, Denny

[djc2222]

Checked for 8 volts at the cam sensor and crank sensor. Found power at both locations. Checked for the 12v supply at the coil. Found good power supply. Checked pulse signal at each pin while cranking and each showed pulses while cranking. I noticed that when I went to unplug the connector at the coil that it was not seated entirely, which probably had been left that way when checking for power at the coil previously. Once I reconnected the coil and attempted to start the vehicle, it started up and ran fine. So, i'm pretty sure that the cam sensor was at fault, whether the gap setting on the first one was to far out for it to be read by the pcm correctly or, it was indeed bad and therefore the new one corrected the problem. One thing far sure, it was a learning experience as usual and will help me to diagnose future problems in the correct order. Thanks hundahunta for all the info. You definetly were right on with your analysis and checkpoint items. I hope this thread helps someone else down the road. Denny

[hundahunta]

your welcome, just glad that it's fixed!!!!