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You mention backfire, Is it out the exhaust or the intake? This is what is in the factory manual for the fuel sync. Keep in mind this is not for a motor that has wear, That's where the scanner comes in to see where it is. I don't think that is your issue though.
If you can get a hold of a scanner that reads live data you may be able to see whats going on when it does decide to take off with out issue. I know you checked the fuel pressure but i have seen pressure drop randomly. If you could monitor it while driving that would rule it out.
As for the crank sensor, aside for the fact the mounting bracket was not as thick as the old one, the distance from the base of said bracket to the tip of sensor was identical...But it was acting this way with the old or new sensor installed.
good point on the running fuel pressure I dont recall testing that. At idle it holds a steady 45 psi, running down the road is an issue as I cant get it rev up but just occasionally, but I can try to get it to rev in the shop.
As for the backfire, and where it comes from...its just a light popping at both the exhaust and the intake, one time one place the other the other place. Never what I would consider a true solid loud backfire, and usually only on the down throttle.
On the fuel sync, when I had it at TDC 0, that is pretty much where the dis button and plate marking were aligned, exact? little before or after? that I couldnt say. I plan to check all of this in detail maybe this eve if I get home in time to do any sort of shop tinkering.
Depends on the scanner. Some will just read codes and others will interpret the inputs from the sensors and tell you what is going on(same as what the pcm sees). You can even a get blu tooth scanner(OBDll) that will read live data on your smart phone.
one more.....you seem pretty knowledgeable on the Dakota. Ive come to find out one thing in the last 20 years and auto forums, one may know alot about working on vehicles, but when it comes to make and model specifics put your trust and respect into those that know that particular subject matter best.
Moparite.....I have a few readers, most of them only read codes and very limited actual readings. However a few months back I acquired one from amazon that bluetooths up to my cell and does show a lot of online readings, however its not so much what it will connect to as what the PCM will allow to be read. didn't have time tonight, but will get back on this tomorrow....that one you link is the exact one I have. I use the APP Torque to connect to it (the paid version)
Thanks for the link....not too bad if I choose to go that route. I want to go through all of the testers I have and see if any will do similar first. Got in too late yesterday after helping a freind so maybe can get back at it tonight.
I took the time this eve to check the fuel sync manually....may be on to something. It was a bit out of wack so tried to set it to the recommended +3 but it ran even worse. So backed up and set it as close to zero as I could do by eye. Now it revs maybe 70% of the time but still has that down throttle back fire. While in there figured I would test the Pickup coil I have again. It does toggle from 0 to 5vdc when the engine is turned over, but In doing so using the FSm I noticed the following.
The FSM clearly shows that the inlet VDC to the pickupcoil is 8V based on the FSM schematic. Thought this might have been a typo but I see that many things show a 8v feed where others show 5v. However on the inlet to my coil I only showed 5v in and 5v out....wondering is this 5v vs 8v might be an issue.
I ran out of time to backtrace the source voltage, but unless I find some corrosion resistance figure I'll find 5v at the PCM. I do have a new pickup coil on the way, so will not make a rash decision on the PCM based on this find until I show that the new coil does nothing.
I got out my bluetooth live scanner but it would not show any live data of any sort of either the cam or crank sensor. I checked all the ones I could and all looked as they should. Looks like only the Snapon scanner will show the exacts of fuel sync readings.
It's a typo unless your manual is from a newer year. I checked it with mine(96 ram truck 1500-3500) and both crank and cam sensor use a 5 volt supply voltage. Actually all the sensors use it for feed back to the pcm. Either way if you didn't have feed back to the pcm it would not run at all. Can you get it to back fire in park or do you have to have it under load?
