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Hi gang a friend of mine has called with another jeep in trouble.  He has change the engine from one that was running but wrecked, into one that had a trashed engine.  He has had it running once, and now it will crank but stalls before it even has a chance to idle, it fires and dies. I was leaning to wards the map sensor any thoughts on this?  

plug in a scan tool.....   looking at the live data displayed from the various sensors will tell you which one is acting up....

there are differences in sensors between some years...

did all the ground wires get hooked up properly...  

Hi Wayne, did the scan deal but keeps giving the same results, came sensor, and crank sensor, we have changed them both twice same results. I did check the ground but will recheck them tomorrow.  We had a Buick in that we replaced the engine in and it ran fine for two days and stopped.  I got into that today and found the harmonic balancer had broken at the crankshaft key, I got three pieces out, well new seal and donor balancer from another engine, and swap of the triggering ring and back to OK.  One of the boys said they say another prying on it as they set the engine in. but I did not think that would put enough pressure on it to cause that trouble.  Well good to hear from you Later.  

post exact jeep info, engine size and exact code....


without knowing everything.. there can be so many different things...


google the code also...   sometimes you can find info there..

does the scan tool you are using.. display live data...  can you see the cam signal or signals also???      does it display proper cam and crank sync.?????

i have had trouble with some aftermarket sensors...

some scan tools have the ability to display graphs of the sensor voltages...???????  

any chance its a 4.0 and the distributer gear roll pin sheared..
if it has a distributer...

do you get any spark????  if so.,..   can you do a spark output test???   if it has a single coil...    a 3/4" blue spark is required..  anything less and you might also need a new coil...  

Hello again Wayne the Young man working that jeep has only used the key read out, very not so cool.  I got my hands on a scanner today that will give live readouts, my home work tonight is to do the paper work on how it is used. I will get the year and all that for you, just now I have six jobs going, and I want to make sure that I give you all the correct info, but I think it is a 4.7, it came from a pickup truck and was running, they drove it from one end of the yard to the other moving it around to make room till this job came up.  Sensors are all from the wrecked truck, so one would think it would run in this one but something dose not jive. I have one to paint tomorrow so it will be earlier when I knock off, so I will get the rest of the info. talk to ya later.  

Hi Wayne, got the info on that jeep, first the power plant is out of a dodge Ram, year 6-2004 I could not get any readings out of the obII, But I did find out that he set several ground to the same post,I will get to that job on Monday, all the sensors are from the pickup but not the ecm, the dodge ran well and smooth, but nothing after install into the jeep, now it is starting and shutting down like you turn the key off. I feel like it is going to be in the fuel control system, or the ecm is not compatible from the jeep to the dodge sensors, any how I will have a well charged battery Monday and text you back Monday eve.   Thanks again see ya    

lets start with some learning about the 4.7...

i will continue to edit and add more links over the weekend..

http://www.enginebuildermag.com/Article/2000/pera_core_corner.aspx

snipped from above link

There are three different flavors of this engine: Standard, HO and NGC (Next Generation Controller). Where did Chrysler put this engine and when? In 1999-2004 the Grand Cherokee got the Standard engine and in 2002-’04 the HO was an option on certain models. The Standard engine was also in the 2000-’02 Dakota and Durango with the Ram P/U being added in 2002 as well. In the latter half of 2002 the Durango received the NGC engine and in 2003 Dakota and Ram were added to that collection. To the best of our information right now, certain models of the Grand Cherokee are the only HO applications

something important on installing the cam shafts..

http://www.enginebuildermag.com/Article/1418/tech_notes.aspx  

Thanks Wayne, I enjoyed what I have read so far,thank you again for your help.    

what i am getting at is you need to find out if the 2006 moor is a NGC motor... with different counts on the reluctor teeth it won't run without the proper matching controller..  

Yes I get the point that the sensors must match the sending units,but the thing was running and each of the sensors are as they were in the pickup truck thats why I mentioned the ECM. You have given me some good info to look at and decide what engine it is that we are working with by checking the heads for HO marking if it dose not have that then it will be the NGC power plant. will find out.
 Now I have found that the wiring harness had some connectors that did not fit the sensor from the pickup, I will have to ask him what they are or go back to the harness and figure it all out. cool talk you later