You may want to iron out the issues with map/fuel sync first. I have have heard people had to drill out the idle screw adjustment cap on the throttle body and increase it so the engine will idle with the mods to the motor. Another idea may be to put in a PCM for a 360.

 

Did some experimenting today: 02 sensor reads 0.86v. Disconnecting it reads basically 5V and has no effect on the motor. Disconnecting the CTS (coolant temp sensor) makes it run worst if at all. Am now able to upload the Actron Scan tool datastream files. (see attached file) Researching MegaSquirt3.

 

Your truck run on natural gas??

 

And people wonder why I would rather work on a CARBURETOR especially on a modified engine. Just finished a 360 in my son's 89 Ramcharger, was TBI, the worst fuel system ever created/ has been nothing but problems (and 1st year of that system) so we put a wiring harness and gas tank from an 87 on there and went with the old standby 4 pin ECU... Magnum head conversion and COMP 260 cam.... Edelbrock Performer intake and carb.. was a piece of cake to dial in... screw computers.
That said, I looked at a 2018 Ram 1500 reg cab/8' bed a few days ago, while the salesman was playing the typical games they play I was undecided/ on the fence/ do I sign or don't I... during one of his escapades to "talk to the sales manager" I went outside and crawled underneath and gave this truck a good looking over.... besides too much plastic and tinny bumpers, I got to thinking about the MDS (cylinder deactivation) and all of the electronic BS, and suddenly I got cold feet, could not commit to 7 years of payments... largely because I don't like a lot of the "features" of today's trucks.... I have an eye on a 87 D 150, 2 blocks from my house, that I have been watching sit and collect tree sap, that is rust free and has a very clean interior that I would much rather have..... there aint anything that I can't fix on the 87 but eventually that 2018 would be out of warranty and I'd be having to work on it... I like simple. I have put notes in the guys mailbox asking for a phone call if he would sell.... still waiting

 

A breakthrough of sorts:

As it turns out I made a parts mistake - There are two gaskets you can use between the throttle body and the manifold 2bbl adapter. The original factory style or the one they give you with the Hughes airgap manifold. They are the same except the Hughes has a closed area where it meets the 2bbl adapter. The original factory is open for the IAC. I put on the wrong one creating a big vacuum leak. So I corrected that.

Now the engine won't start at all (it pops some and warms the headers a little). To restore the "leak" I experimented with and eventually settled on opening two intake ports to the atmosphere. Lo and behold the engine is back to it's shi_ty self of dying after a couple of minutes. But I learned something here (and from Matt and Jerrys fuel injection book). That leak allowed the motor to idle and allow me to verify that everything works including enough vacuum to run the power brake booster?. Which according to the web requires at least 18hg! I don't understand how this is possible though when I have a good sized leak in the manifold? This would not work on a carb! Will be putting a vacuum gauge on it during the next run.

With the Cam and bigger valves it is pulling in a lot more air. To much air for the factory settings to compensate for. Instead the motor is using the extra unmetered air to feed it self with the IAC providing fine tuning. This is why I have no vacuum for the MAP to use and allow the throttle to work.

So I have to figure out how to give it that same air but in metered form so the OBD1 ECU will see a varying MAP sensor signal. I already pulled out the IAC and am prepared to adjust the "factory only" throttle plate opening screw. I want to get this at least half A_s working on the OBD1 ECU so I know I am working with a good engine when I install the MS3. More to come.

 

I have wondered if something like Holley HP would work on a mopar. I really like the idea of self tuning!!

 

Pulled the IAC and it started but only lasted about 15sec. With the IAC out I put a piece of metal in between the throttle plate stop and the idle screw to open the throttle a little. Wouldn't start. Disconnected the TPS so the PCM doesn't see the throttle opening. Plugged up the manifold again and it worked just enough to get some Datastream. Which shows injector pulse widths of over 38ms and all of this keeps flooding the motor. So I'm done - no more OBD1. I am going the standalone EFI way. A modern 100% tunable system that can be adjusted to anything new that I do like a 4bbl throttle body etc... Looks like I need the MS3X MegaSquirt 3 with Expansion and two harnesses.