Fuel injection installed

Sasquatch · June 13, 2012, 09:26 AM

There has been just a little bit of info here and there about conversion to fuel injection. I want to start this thread as I just completed the project and will be leaving on a trip this weekend so I can get real world data. First, here is some data on the coach and what engine mods have been done so you can compare to your situation.

1976 Executive 26', M500 Chassis, 440-3.
Doug Thorley 1 3/4" Long tube headers
3" exhaust, Magnaflow muffler
MSD 6a ignition and Mallory Super Coil
Edelbrock 440 Performer intake manifold
Comp Cams cam chosen for good torque. (mild cam)
727 transmission, shift kit installed.

Previous mileage averaged between 5.75 and 6.5mpg Usually towing something ranging from a motorcycle trailer with 2-4 bikes on it to a Mercedes Benz ML430 SUV (5,500lbs)

Kit installed: Professional Products EFI [size=78%]http://www.professional-products.com/EFI_Main.php[/size]

Things that needed to be overcome that differed from their "Bolt on" claim:
-Needed to source a fuel tank selector valve that also switched return lines from a Ford F150 Truck
-Needed to install T's into filler necks of fuel tanks for return lines
-Needed to purchase 6AN fittings and push lock hosing for high pressure side
-Needed to run dual electric fuel pumps. Low pressure pump to feed high pressure pump as I could not mount below level of bottom of fuel tank, and considering the distance from the tanks to where the HP pump was located.
-Needed to machine down the choke mounting riser cast into intake manifold to clear fuel plumbing on new injection system
-Needed to lengthen wiring for temperature probe installed into water pump housing
-Needed to tap into manifold for manifold vacuum as port on throttle body was ported vacuum and I use manifold vacuum for distributor vacuum advance
-Needed to modify Mopar linkage removed from Edelbrock carb to fit new throttle body. Should have just ordered the right linkage, but I have a machine shop....

First start up. Turn key, let fuel pump pressurize system. Crank, instant start up. High idle at about 1200rpm and slowly watch rpms drop to 900 as engine warms up. Watched their computer "dashboard" plugged into ECM. Watched the learning process change the maps as the engine warmed and it learned it's environment. Blipping the throttle responded with instant rev responses. Much quicker than the carb.

Just a note. I had the calibration jet kit with the carb and installed an O2 sensor in the exhaust so it was jetted really close. But with all carbs, when the temperature or altitude changed, so did the jetting. PITA

Once I was convinced there were no leaks and the motor had run a while I went through a few shut off and start cycles. Talk about easy starting. No throttle needed. Just twist key and boom, running and idling perfect.

First drive:
Took it for about a 50 mile run from Eagle (my shop) to Emmett, Idaho. Nice country highway with 55-65 mph speed limits. A few stop lights. Before I even left my parking lot I noticed how seamless smooth the motor was running. And I thought my carb ran good... Power? WOW. Again, I thought my carb pulled well, but this thing is AMAZING. 1/4 to 1/3 throttle from a stop and it pulled right up to 55-60 mph keeping up with traffic. Granted, I had no tow car, but I was fairly loaded as I had just came back from a trip. Black and grey tanks at 50% Water at 75%.

Cruising at 65mph, cruise control on, semi flat land my vacuum gauge was reading 15-16 inches of vacuum. With the carb I would normally be running 10-11 inches. I watch it like a hawk as I am always trying to maximize mileage. It so effortlessly kept the coach at 65mph that the throttle was barely open.

I turned around in Emmett and headed back. There is a 6% hill that lasts for about 1.5 miles leading into Emmett. Waiting for clear traffic, I came to a complete stop at the base of the hill. Using only 1/2 throttle, it effortlessly accelerated to 55mph going up the grade in a short distance. Using full throttle I topped the hill at 78mph. On the flat ground again I slowed to 40 mph and gave her the beans to simulate a passing situation (not that I pass much in an RV). 40-70 was fantastic.

85 degree day and my engine temps stayed at 175 while cruising and warmed up to 188 while sitting in traffic. I had previously removed the fan clutch and mechanical fan in favor of an electric fan from a Lincoln Mark 8. Fan never needed to kick in. One area I have always been impressed with is how well Executive Industries designed the radiator intake cowl to ram air through the overly large radiator. I have never had an overheating issue, no matter how hot, how loaded or how big the mountain I needed to climb.

I have personally owned this coach for 16 years, my father a good 12 years before me, and my grandfather was the original owner. I have a couple of build threads in this forum where I completely rebuilt the chassis/engine 2 years ago, and a complete interior remodel this last winter.

I will update this thread next week with real world driving and MPG numbers. So far I am more than pleased.

Wantawinnie · June 13, 2012, 09:59 AM

I will be anxious to see how your trip turns out. From your test run it sounds like power and, likely mileage, are much improved. Have you considered an overdrive of some sort to take advantage of lower cruising rpm? I found a rebuilt 727 with a gear vendors attached for cheap on Craigslist last fall that will be going in my rig soon.

Sasquatch · June 13, 2012, 10:10 AM

I would love to have an overdrive. Gear Vendors is on my short list, but the price has me cringing. I keep watching for a used or discounted unit.

Wantawinnie · June 13, 2012, 10:17 AM

They are pricey and I never figured to have one either until this one showed up on Craigslist. I couldn't pass up the deal as my tranny needed a rebuild anyway. It should drop cruising rpm's about 700rpm.

I will be watching your posts to see how your setup performs. Sounds like an excellent upgrade so far.

ClydesdaleKevin · June 15, 2012, 08:13 AM

I'll be very interested in the real world data with fuel economy...so see if such an upgrade would be worth it to us. It would have to make quite an improvement in fuel economy though, with a starting price of over 1800 bucks, and that is just for the throttle body injector style! Keep us posted with the MPG gains!

Kev

DaveVA78Chieftain · June 16, 2012, 11:01 PM

I have done a lot of research into doing a GM 454 TBI conversion to a 440 so I am somewhat familure with this. While I have seen many improved starting and overall smoother running improvements from this sort of conversion, in general they do say there is little if any fuel milage improvements. Additionally, the Professional Products EFI kit is a fuel only conversion while the GM TBI conversions are both fuel and ignition.
I take it you are still using both the mechanical and vacuum advance features of the stock Dodge distributor?
Have you attempted any distributor mechanical advance recurving?
Are you using an adjustable vacuum advance?
Assuming you peformed the other engine modifications before this, did they make any noticeable fuel milage or performance improvements? If so, how much? Trying to understand the progression and what worked well. You said "5.75 and 6.5mpg". Was that before any engine mdifications or was that the base after the previous engine mods prior to doing the EFI mod? Do you have fuel milage progression across the different changes you have made to the engine? The "5.75 and 6.5mpg" sounds like initial stock information or did the other non-EFI engine modifications have no effect on fuel milage?

Dave

Sasquatch · June 20, 2012, 02:46 PM

Ok, an update after my trip and to answer the other questions.

First, fuel mileage. I saw a little gain with the injection, but not near what I had hoped. Pulling from Boise to Enterprise, OR, which is mainly uphill, and had HORRIBLE headwinds I netted 5.75 mpg with the cruise control set at 65 mph. But, power and driveability were GREATLY improved. Even bucking headwinds, the coach did not slow down below 55 on the biggest hills encountered. Watching the dashboard software, the cruise control would not pull past 50% throttle. So while pulling a big hill, sitting about 55mph, I stepped into the throttle fully and the coach started accelerating pretty good again. I was more than impressed.

I had also converted to electric fans on the radiator and the cab was much quieter, and they never needed to kick on while moving, even on a 85 degree day pulling hills the engine temp never got above 188 degrees, and liked to hover at 174-178 degrees.

On the way home, still with heavy winds, but going down hill, I got 7.25 mpg. So, under both situations, I felt the mileage was a tad better, but not more than 1 mpg increase. In terms of percentages, it is significant though. It makes me doubt people who swear they get 9-11 mpg on their rigs with the same motor running at the same speeds. I am just not seeing it. My coach is as new, and in better shape than 95% of rigs from the same era.

Through all the years of modding this coach in reference to mileage I never saw a marked improvement in mileage, but did see marked improvements in power. So, as the power increased, I did not get worse mileage, which is a good thing.

Distributor and advance. I am running the stock distributor, that I recurved, and limited the mechanical advance slots. I am running manifold vacuum, which is the proper way to do it. Lean conditions burn slower, so when you are running high manifold vacuum, as in cruise or idle, the conditions are lean and need more advance. When you step into it and go rich, the mixture burns much quicker, and the vacuum drops, advance is reduced so it does not ping.

I set my distributor so I have 38 degrees of total advance, mechanical only, then hook back up the vacuum and run it. I have a MSD 6a spark box, Accel super coil, Jacobs wires, and am running NGK plugs with a much wider gap in the range of .045 if I remember right.

Chris Reed · June 22, 2012, 02:22 AM

Did you go with a Powerjection II or Powerjection III? I have an 1984 Chieftain and have been debating installing an overdrive transmission and dumping the carb for fuel injection, but I am having trouble justifying to cost versus the benefit. We drive about 3,000 miles a year now and I get 7.5-9 mpg highway depending on the terrain(8.88mpg for our complete trip to Disneyland which was 1400 miles round trip). I have taken two trips with a 2300lb. towed and our mileage drops to 5.5-6.5 mpg. Do you feel that you will recuperate your cost of the system in the fuel that you will save?

ClydesdaleKevin · June 22, 2012, 08:57 AM

Currently, after a carburetor rebuild on the Quadrajet, a complete tune up, and a manual choke installed, our 89 Holiday Rambler, 35 feet long, towing about 6000 lbs and fully loaded compartments since we are fulltimers, we are averaging a solid 7 mpg. Its a 454 P30.

The engine starts immediately even after sitting for 8 weeks, and power is more than adequate up the hills. Average engine temps are around 200, trans temps around 170. There have been few hills lately that we can't take at at least 55 mph.

I mention all this because I was seriously considering the upgrade, but I can't justify the cost, all things considered.

That said, its a very COOL and NEAT upgrade, and I thank you for posting the information, and being honest about the real world data after the install.

With the power gains though, if mated with an overdrive, you might very well get a huge improvement in fuel economy. If you ever install an overdrive, I would be very interested in knowing the overall gains at that point.

Kev

Sasquatch · June 22, 2012, 11:33 AM

I installed the PJ III.

I spoke with one of the technicians at PP and he said they have some revised maps where they leaned out the cruise some more for better mileage. He has sent me those maps to play with. Unfortunately, I do not have another trip planned in the next few weeks, so it will have to wait to see results.

Cost vs. savings: I could go on and on with this debate. In pure dollars, will I ever recoup my expense? No, not at all. But it is more than just that for me. I am an engineer, mechanic, love to tinker, and am very anal about my rigs. With the carb, I never knew if I was jetted properly until I put in the O2 sensor and air fuel gauge. Then it blew me away how hard it was to keep the carbs jetted properly. I could get them set right here at home at 75 degrees and the temperature would change, or I would start climbing hills or going down to the coast and the jetting would change.

With Injection, my fuel ratios are ALWAYS right. Cold days, hot days, sea level or 10,000 foot passes in Colorado. It does not care, it is always right. The coach always starts with a bump of the key, and I can drive it away smoothly even if the motor is stone cold. I dont do that, but I never could with the carb and 440 combination. Once I have the injection all set and tweaked properly (I am close, real close), then I can literally close the engine cover and forget about it other than service.

I am wondering if you Winne owners that are getting much better mileage on the same chassis is just a factor of weight. Even though my Executive is only 26', it weighs in at almost 13.5k. It is a VERY heavy coach for it's size.

Overdrive. This is something I am looking at. But I will not spend a ton to do it. I am pretty much at the limit I want to spend for mileage and driveability. My only thought is to pull out one of the newer 727 overdrive transmissions from a newer Dodge truck, build it, and use it. But I would have to overcome my parking brake issue and the fact that the newer Dodge overdrive transmissions are not holding up to abuse really well where the old tank 727 is bullet proof.

ibdilbert01 · June 22, 2012, 09:10 PM

Great job on the throttle body install! Turning the key and having her fire right up w/out pumping the hell out of the gas pedal has to feel pretty gosh darn rewarding!!!!!
As for overdrive, you might want think about dropping a 518 in it, they were nothing more than a 727 w/ overdrive.
http://www.transmissioncenter.net/SwapInformation.htm

Sasquatch · June 22, 2012, 11:18 PM

I have thought about the 518. But they are no way near as strong as the 727. Many have come apart in heavy pulling applications such as a 14k lb motorhome pulling a tow car. I need to go speak with a transmission builder about this.

And as a second consideration, the 727 I have has the emergency brake fitted to the output shaft of the transmission on the M500 chassis. I would not know how to deal with that one.

Wantawinnie · June 23, 2012, 08:16 AM

The A518 or any newer Dodge transmission will require an adapter to work behind a 440.

Chris Reed · July 07, 2012, 01:10 PM

I was thinking about what I read in your post following your maiden voyage. Do you think with the dramatic increase in power that you gained that maybe you developed a desire to feel the power? Maybe that is why your fuel economy hasn't improved. As for the weight of my motor home it is 27' and weighs in just below 12,000lbs., so it is considerably lighter. Our fuel economy and weight with our towed is more inline with your just motor homes weight (14,350lbs), crazy how that works itself out. I can't wait to see if your revised maps help at all with the fuel economy.

Neil Carrick · January 11, 2014, 08:35 PM

I kept thinking that the mileage you folks are reporting was quite low, until I realized that our gallon here in Canada is considerably larger. D:oH!
The conversion is IMP x 1.201 = USG. So 5 imp gallons x 1.201 =6 usg. I haven't put a ton of miles on ours yet, but seemed to be around 10 1/2 maybe 11 miles per imperial gallon.

Neil...

Sasquatch · October 26, 2015, 02:21 PM

I wrote this in another thread, but it is a further update to my injection conversion:

I installed a Professional Products active learning 4bbl TBI injection system on my 76 Executive with a M500 chassis and a mildly built 440. I have tracked my mileage for 21 years now and the injection system did more to improve mileage and driving pleasure than any other upgrade (I have done a ton). It now starts, hot or cold with a bump of the key. It runs flawlessly at any RPM, any load, elevation and temperature. I averaged about 6.5mpg over the last 20 years. Every mod I did (headers, exhaust, cam, ignition, etc.) all improved the power, but mileage stayed about the same. I cruise at 65mph out here in the mountain west. Last summer I took a 1600 mile trip to the California redwoods... I saw as high as 8.5mpg on two separate tank fulls, and averaged 7.9 for the trip. So I picked up 1.4 mpg. Power went up, engine smoothness went up, driveability improved dramatically. It may never pay off the $2000 invested in the system, but the driving pleasure is worth every penny.

DRMousseau · October 26, 2015, 05:10 PM

Ya know, I really liked this thread,... wondered about your sparkplugs too, till I read further. And I'm glad you got all ya needed out of this.

Thought I'd note that my 440 mpg was much the same, maybe a tad better.... with 6-7tons too. I WAS HEAVY, in a D20. But my rolling resistance was really, REALLY light!!! I mean,... me, a lightweight old man, could push it and get it rolling on a flat smooth surface if tire pressure was up good!!! But if a 1/2' stone was in the way,... lol!