Megasquirt2 Install AMC360 TBI 83' Cherokee

[tgreese]

Can't address your pickup issue.

Re the accumulator etc. I have read reports that mounting the fuel pump on the body will be noisy. You may be able to hear the thump-thump-thump of the fuel pump, resonating with the body. Frame mounting should be quieter. I would think that you could mount the pump on the frame rail below the accumulator. Same general location but more isolation of the pump noise.

[myk]

Found all the parts locally to make the accumulator and LP pump setup. Tim, are you talking about the Carter LP pump being noisy or the Walbro HP pump? I had heard also that the Carter pump is quite loud, however it will be mounted down aft of the tank. I don't think the Walbro HP pump is too loud, I'll have to see if there is a spot on the frame rail for it, my intention was to keep it well away from the headers and just a short run of HP hose to the TBI.

As for the pick-up, I'm just going to run the 3/8" hardline down to within ~1/4" or so of the bottom of the sump in the tank and see how it works, it's pretty easy to remove the pickup through the access hole in the floor so if I need to change it later it won't require dropping the tank. The accumulator holds a quart of fuel so it will run quite a while on that if the pickup gets air temporarily.

Glad you guys suggested the above ideas, I think this will be a better solution.

Mike

[tgreese]

Found all the parts locally to make the accumulator and LP pump setup. Tim, are you talking about the Carter LP pump being noisy or the Walbro HP pump? I had heard also that the Carter pump is quite loud, however it will be mounted down aft of the tank. I don't think the Walbro HP pump is too loud, I'll have to see if there is a spot on the frame rail for it, my intention was to keep it well away from the headers and just a short run of HP hose to the TBI.

As for the pick-up, I'm just going to run the 3/8" hardline down to within ~1/4" or so of the bottom of the sump in the tank and see how it works, it's pretty easy to remove the pickup through the access hole in the floor so if I need to change it later it won't require dropping the tank. The accumulator holds a quart of fuel so it will run quite a while on that if the pickup gets air temporarily.

Glad you guys suggested the above ideas, I think this will be a better solution.

Mike

Mostly thinking about the Walbro. Will Marsh at BinderPlanet http://www.binderplanet.com/forums/s...ad.php?t=53524 used a similar setup to what you propose, and complains about the noise from the HP fuel pump, mounted on the inner fender. He uses a NAPA replacement part for a E100, which should be an Airtex. Maybe the Walbro is quieter ...

[myk]

Was able to get all the fuel system parts today, looking like the only spot in the engine bay for the accumulator is on the driver side of the radiator support below the overflow tank, should work just fine though. I was surprised how big the filter/accumulator is. Was able to get the spin on filter base from Shucks/O'reilly it's a Fram HPK2. Picked up the LP pump a Carter P4070, and the accumulator filter a NAPA 3281 both from the local NAPA store. Just need to add an extension tube and a return port on the filter base.



Also snapped a pic of the Innovate LC1 WBO2 sensor in the exhaust, I put it in the Y after the headers and before the muffler.



Mike

[myk]

Finished adding the 3/8" lines to the tank pick-up, unsoldered the old ones oversized the holes and soldered the new one back in, also soldered two little brass rings on the upper ends so the hoses can't slip off. I ran the pick-up line straight down to the bottom of the sump in the tank with 1/4" clearance to the bottom I left the flared end on there so it wasn't a sharp edge, the return line I faced to the front of the tank and a little higher attempting to aim it away from the pick-up as much as possible. Also added the return port on the accumulator. Getting close to putting the tank back in and getting things plumbed.

[myk]

Here's the accumulator finished up, the main inlet and outlet are 90deg 3/8" barbed hose to 1/2" npt brass fittings (had to shorten these a bit so they would spin around without hitting each other), the tank return that I added is a 1.5" x 1/8" npt brass pipe fitting to a 90deg to 3/8" barbed hose, the extension tube to feed the HP pump is a piece of copper tubing silver soldered to the inside of the threaded filter attachment. The filter is a NAPA 3281 and the housing is a remote oil filter housing made by Fram p/n HPK2.

[myk]

Back on the project now, took a break from it for a while. I have the tank back in temporarily to check the clearances for running the new fuel lines. Planning on running the new 3/8" steel lines in place of the originals between the tank and frame rail, appears to be just enough room. I installed the low pressure carter pump right behind the tank on the upper crossmember. Also mounted the megasquirt on the top side of the drivers side inner fender. Mounted the accumulated to the radiator support and the HP pump and filter to the inner fender as well...hopefully it won't be too loud there, we'll see.

[myk]

Major progress the last two days...I've got all the fuel lines installed and the fuel tank back in, glad that part is over, big job. The fuel lines are 3/8 steel which is tough to work with but should last a while. Here's a bunch of pics of the installation, the tee fitting in one of the pics is where the two return lines (one from the TBI and the other from the accumulator) come together and head back to the tank. Next up is the wiring which is easy in comparison, should be ready to fire it up in the next week or two...















Mike

[myk]

Completely finished plumbing the fuel system and tested the pumps out this weekend, everything works as it should, set the FPR at 15psi to start with. I also checked the pressure on the return line with both pumps running wide open and there was no pressure building so that is a good sign that the return system is more than adequate. I was worried about the noise of the Walbro HP pump on the inner fenderwell but the funny thing is that the Carter LP pump in the back is the louder one of the two, the Walbro just hums along nicely in the engine bay noise isn't bad at all, I don't think I'll be able to hear either one with the engine running though. Yesterday I started in on the wiring harness, shouldn't be much longer now...will post some pics when I get a chance.

Mike

[Bill USN-1]

You did a nice job and it looks good but I feel you made things more complicated and worse off then they should have been.

The lift pump isn't needed and actually adds another fail point in the system.
The main pump works fine if mount at or near the bottom level of the tank and close to the tank.
Pumps push much better then they pull and work less.

You have also mounted the pump in the engine bay which induces heat directly to the pump(headers!) and yes, EFI can and will vapor lock if too much heat is introduced.
With a constant return system, all the heat in the fuel as it passes through the engine bay will be returned to the tank. Over time the heat will continue to build.
Heat is also the #1 killer of the pump. And now you mounted right next to the hottest temp created by the engine. How many factory installs have the EFI pump mounted in the engine bay? Most are in the tank to use the fuel to cool them.

I'm not telling you what to do but I have tried most different installation methods and had to fix many. Just trying to save you some frustration.
Even seen guys use the stock engine pump to feed the efi pump.

The method I documented on BinderPlanet works.

If you do nothing else then at least add heat shields around the pump.

[myk]

The lift pump isn't needed and actually adds another fail point in the system.
The main pump works fine if mount at or near the bottom level of the tank and close to the tank.
Pumps push much better then they pull and work less.

There was no place to mount the HP pump close to the tank and low enough, it was discussed earlier in the thread. Would have also required alot more high pressure tubing/hose. The pump starvation is a major issue with these tanks that are not made to feed EFI pumps, any funny angle or acceleration with 1/4 tank or less and the pump will suck air and EFI don't like that at all. The lift pump/accumulator setup eliminates all these issues. I'll take my chances on the reliability of the Carter pump, seemed to outweigh all the other negatives imho.

You have also mounted the pump in the engine bay which induces heat directly to the pump(headers!) and yes, EFI can and will vapor lock if too much heat is introduced.
With a constant return system, all the heat in the fuel as it passes through the engine bay will be returned to the tank. Over time the heat will continue to build.
Heat is also the #1 killer of the pump. And now you mounted right next to the hottest temp created by the engine. How many factory installs have the EFI pump mounted in the engine bay? Most are in the tank to use the fuel to cool them.

I'm not telling you what to do but I have tried most different installation methods and had to fix many. Just trying to save you some frustration.
Even seen guys use the stock engine pump to feed the efi pump.

The method I documented on BinderPlanet works.

If you do nothing else then at least add heat shields around the pump.

Point well taken, I will definitely watch the temps, and have already thought of adding a shield or moving the pump if necessary. The pic is probably a bit deceiving as the pump is below the headers a good amount. Where do you think the stock pump is located (it's in an even hotter location)....

Mike

[Bill USN-1]

I'm sure you did lots of reading before deciding on this set up.

BTDT
Even made my own surge tank out of some scrap exhaust pipe.
Cheaper then buying one.







But in the end...I find it really isn't needed. Just makes you feel better.

And for dual tanks, Just use a 6 port switch valve so you can switch the feed and returns with the same valve.

[Billygoat]

And for dual tanks, Just use a 6 port switch valve so you can switch the feed and returns with the same valve.

X2 - I started with a 3 port valve on Thumper with a T'd return, but it does not work correct, #1 full will dump fuel out the vent instead of going to empty #2, and #1 under 1/2 tank likes to return to #2 and wil even push it out the vent if #2 is full????? - yes crazy

here is the one I have now

http://www.amazon.com/gp/product/B0016HT92G

IIRC the return in only 5/16" not 3/8" - feed is 3/8"
not sure if that will work for this application

[Bill USN-1]

Where do you think the stock pump is located (it's in an even hotter location)....

HMM guess I could take this as a lack of knowledge or an attempt at humor?
You can't compare a mechanical diaphram 2-5psi carb lift pump to a high pressure EFI vane or gerotor electric pump. One is driven and the other drives and creates it's own heat.

IIRC the return in only 5/16" not 3/8" - feed is 3/8"
not sure if that will work for this application

I use the pollak style. It is motor driven and also has the ability to switch the fuel sender wire with the supplied switch. Plenty listed on ebay under fuel tank switch or valve. but not all come with the connector and switch.

I have ran 3/8" feed and 5/16" return on all my systems without problems.
It's the small diameter brass fittings that may cause a problem.
I use steel brake line for the most of the runs and just make the connections with short pieces of hose.
I also add a small double flare to the end to prevent a hose from popping off.

[myk]

HMM guess I could take this as a lack of knowledge or an attempt at humor?

Neither actually, I was just stating a fact. What data do you have that supports a higher failure rate with a HP efi pump failing in this environment vs. the stock pump? With the amount of cool fuel flowing through the HP pump I have to believe it would stay cooler than the factory setup. The heat produced by the pump itself is minimal as I measured the power consumption of the pump at 3.5A @ 12.5v for ~44watts probably half of that is wasted work turned into heat which is nothing for the surface area of the tank to dissipate. I plan on attaching a thermocouple (since I already have them) to the body of the pump and the filter canister to see the effects.

Mike