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Installing a Holley Sniper and Fuel Injection initial impressions
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woodlandfarms
Posted 2020-09-02 1:18 AM (#7569)
Subject: Installing a Holley Sniper and Fuel Injection initial impressions


Regular

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So to start this, I wanted to explain how I ended up with the Holley. My old Thermoquad was so bad I found parts of the choke connection lodged in its secondaries. While I have restored a number of cars, I am no mechanic, and carburetors and transmissions have always let me down on my restorations. In looking at what our plans are with #86 I decided it would make more sense to get fuel injection, primarily for reliability, but also for altitude as we live at sea level but plan many trips into the mountains above 9000 ft. So with the blessing of the wife, I pulled up the Summit catalogue and found 4 systems, the Holley, FiTech, Summit, and Edelbrock. The first three are basically carburetor with fuel injection pumps replacing the jets. The Edelbrock is the intake manifold with injectors for each cylinder which is a more efficient and potentially more reliable system than the others. The prices (in 2020) were Summits at 750 followed by the Fitech at 1000 (which also included pump and filter). The Holley I ended up with was 1300 and included pumps and filters. The Edelbrock was around 2200 but included a new distributor and ignition system. Another FMC Owner had installed the Edelbrock, and to get it in he had to loose his AC System (which was not working) as well as modify his water neck on the water pump. In the end, the dollars were looming so I had planned on the Summit but the wife intervened and wanted what she saw as more reliability with the Holley. In the end I don't think Holley is more reliable, but the execution and controls are much cleaner. I want to warn you that with this installation I have spent at least an additional $200 on odds and ends I never planned on. I will say Holley is not a big fan of Chrysler and you will find support really lacking. I also did not get any ignition gear. If I was to put on a computer ignition system I would definitely use ONLY the holley Sniper ignition. Getting others to work requires a level of mechanics that I am not up for.

So, to the installation. There are plenty of youtube videos that will guide you through most of it, so I will address only the FMC related issues. First installing the carb. On my bus I had an Edelbrock Performer intake. No reason to change. The carb bolted right up with no issues. But the linkage proved to be two lost days. First, I followed the advice of my first tech support call and ordered Holley Throttle Extension 20-7 and after bending it and twisting it, I got it to what I thought was a working position. But after attaching everything I found I could not open the carb up more than 63%. Well, that doesn't work. So my next tech support call was to get another part (and a far more costly part for something truly small) and that was a holly 20-67 (so now I have $55 into linkage). This worked, but at the cost of my bracket that holds my throttle cable. So I had to take the bracket off, and weld an extension on to it, drill another hole and move the throttle cable back half an inch or so. There are cable brackets but with the FMC's weird geometry I could not say if any would work. So after getting the carb on and linkage squared away I moved on to Fuel. On my FMC ( and I have only ever seen my FMC so...) the fuel lines come out by the generator. Likewise there is an access cover over top of the fuel sender as well as an access port over the carb. If you don't have either of these it is going to be a long journey. So the first thing about FI is that the fuel pump sucks fuel out of the tank and pressurises it to 60PSI in the lines. So leaks can happen in this kind of environment so you need to just be cautious. Second is that your FI Carb doesn't use all the fuel so it sends it back to the gas tank. Thankfully the fuel sender on your FMC gas tank has a return line port so this turns out to not be such an issue. So I laid out my basic plan for the hoses, pre filter, pump and post filter to have easy access for service and started drilling the hole in the firewall to provide a return line. Make sure that you drill a hole that you can put a grommet in, you do not want fuel lines rubbing on sharp metal. Oh, I also had to buy two 90 degree AN-6 to 3/8 Barbed fuel connectors as the ones that come with the Holley are only straight and put the fuel lines into a bit of a kink. But pretty quickly I got it all buttoned up. THen came the Water Temp Sensor, on my machine there is a second port on top of the water pump above the other temp sensor that I could put the sensor into. I did get a free Gycol bath with that operation. Second, I had to drill a hole for the Oxygen Sensor in the muffler. I chose to put this on the drivers side exhaust. After removing the fuel pump from the engine and putting in a cover plate, I found I had much more room to work than on the other side. Finally I went to wiring. Wiring is pretty straight forward. I did not get a fancy ignition, and decided to use what I have (which is a magnetic pick up distributor and a MOPAR electronic ignition). The wiring is simple to get the basics going. One wire to the negative side of your coil, two wires directly to your battery and then a wire to a keyed power source (that does NOT shut off when the engine is turning over), and a wire to the fuel pump. Also you need to connect the water temp and the oxy sensor. Now the big complaint I have is Holleys harness is pretty short. I am not sure why they do what they do, but someone is thinking about flexibility when it comes to wiring. So be prepared for some extensions depending on your situation (I did not, but I did mess with the wiring for a while). Now the cool thing is that holley has a bunch of extra wires that you can control electric relays with. One goes to your AC and will increase the RPM at idle when the AC is on, two other will operate relays for your electric cooling fans and will go on and off at specific temperatures. BUT, and this is a BIG BUT, the wires are all NEGATIVE in polarity. So this means if you are hooking up a fan relay, on the acuator side you need to hook up a hot wire to the relay, and the wire from the holley to the ground side. This gets complicated and really becomes somehting with your AC System which as mine does not work I did not hook up at the moment. But now it is done.

So I went through the startup procedure and had my first issue. I had hooked up my 3/8 fuel lines directly to the fuel sender and there was a drip and clearly air being drawn in. I decided to get a small piece of 5/16 Fuel injection gas hose, and found a 3/8 to 5/16 barbed connector. Make sure you use Fuel Injected rated clamps, they are different than hose clamps. This of course took a day to source. But in under a half hour I was completely buttoned up. so back to the ignition, turned it on, no leaks and cranked over. The engine started up immediatley. At this point you let the engine warm up and hten you start dialing in your idle, and a few other odds and ends and once you feel good you hit the road. The engine takes about 200 miles or so to completely learn, so driving it is a must. I have had a minor issue in balancing a few of the guages, but I think this will just work itself out. I also need to find a happy idle speed. Probably greater than 850 but we will see.

Here is the link to some pictures. http://www.fmcowners.com/mbbs22/photos/photo-thumbnails.asp?albumid...

I will come back and give updates.
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B. Sitton
Posted 2020-09-02 8:08 AM (#7570 - in reply to #7569)
Subject: Re: Installing a Holley Sniper and Fuel Injection initial impressions


Extreme Veteran

100100100252525
Location: Ignacio Colorado
Check the adjustment on the transmission kick down. After moving things it is very important to get it adjusted so it will downshift when floored at lower speed. No kickdown will result in a transmission failure real soon.
Bill
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BigRabbitMan
Posted 2020-09-02 9:43 AM (#7571 - in reply to #7569)
Subject: Re: Installing a Holley Sniper and Fuel Injection initial impressions



Elite Veteran

10001002525
Location: Cottage Grove, OR
This is a great write up. I will see it at the Oregon rally. You will have some road miles on it by then.
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woodlandfarms
Posted 2020-09-02 10:24 AM (#7572 - in reply to #7569)
Subject: Re: Installing a Holley Sniper and Fuel Injection initial impressions


Regular

252525
Thanks bill. I matched the previous adjustment to the new pin position. Doesnt mean it is right as the other carb was such a mess but it is a good jumping off point
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FrothyShank
Posted 2020-09-10 6:33 AM (#7575 - in reply to #7572)
Subject: Re: Installing a Holley Sniper and Fuel Injection initial impressions



Contributor


Location: Bend, OR
Very helpful. Nice phots as well. I recently rebuilt the Thermoquad, and if that doesn’t “go” I’ll be considering following in your footsteps. Thanks.
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