Good Day everyone, i have quite the Conundrum which I’m needing some guidance on.
We have a 1994 Damon Intruder Motorhome on a Ford Chassis with a Ford 460 Engine with an E4OD Transmission.
Three weeks ago, we installed an electric vacuum pump to run our Dash AC as quite often while going up a hill, we would lose vacuum and the AC would start coming out of the Defrost vents, which is quite annoying when it is hot out. While we were repairing that, we noticed quite a large hose that was kinked. We assumed it shouldn’t have been kinked so we reworked the hose with some elbows to allow it to breathe (see picture 1).
When we went to back the Motorhome out of the shop, the engine began running very rough and would stall out as soon as we would start the engine. To back it out, we would have to pin the accelerator to get it to move.
We checked the codes, many of which are old codes which we have had previously fixed the issues that corresponded to the codes. The ones we noted were: 117, 638, 112, 112, 327, 654, 513, 553, 565, 556, 558, 521, 622, 631, 629, 626, 625. We noticed a very rich smell coming from the engine, which we discovered was an issue with the throttle body sensor. We replaced the Air Intake Temperature Sensor and ECT Sensor, which made a slight improvement. We have also replaced the Throttle Position Sensor as well as used Throttle Body Spray, which has as well made a slight improvement.
We found a vacuum line (see picture 2) which was rotting on the outside and was quite plugged on the inside. We replaced that, which also made a slight improvement.
One other thing we came across was a broken vacuum line which was plugged at one end on purpose which we have also replaced.
We are now at the point where the engine will not idle unless the AC line is taken off or we take the plug out of the end of the hose. It still tends to stall out when we attempt to begin driving in D as well as in gear 1.
When we are in D, the transmission jerks quite violently when it tries to shift and is very rough shifting. We are unsure of what our next step to replacing sensors or repairing should be and would appreciate any advice.

 

I can't tell what the item is in the photos, but from the majority of the codes listed either the 5 volt reference voltage supplied by the computer is absent or a shorted path is pulling down the voltage to the various sensors.
This is what you might try;
disconnect the battery so all the codes get erased. Then look for a pinched wire from any one of the sensors that were replaced or, pinched in a maintenance procedure.
There is a 5 volt reference voltage provided by the computer to most of the sensors. If any one of those supply wires to any of the sensors is pinched or grounded it causes the voltage to all the involved sensors to not function correctly and produce codes to that effect. This will require some careful checking and if a voltmeter were available it would allow checking when disconnecting the sensors one at a time to determine if one of them were shorted. Hopefully the problem has not cooked the computer which is not replaced until all the checks confirm there is no short circuit involving that 5 volt reference supply.

Where was the added pump power obtained, could that possibly be the cause of the problem?

If you completely removed all the connections for the add on appliance , see what you get.