Replacing Bosch jetronic with MegaSquirt EFI

[gurunutkins]

hi oughtsix
thanks for the referal, hope I can give as much as I get
cheers
barri

[jonwhite99]

Oughtsix,

I am very impressed. Your site is very very imformative, well done.

I have managed to construct a working tps using the mercedes throttle and a ford tps unit and a piece of Aluminium plate it worked well I have some pics I must post. I will send you a predrilled plate in a couple of weeks when I have made a few.

Again well doen on the site

Jon White

[oughtsix]

Welcome Barri! (I came across Barri on the MegaBoard and invited him to join us here. I believe he is converting a ~74 450sl with D-jetronic to MegaSquirt?)

Thank you for the feedback on my site Jon. It helps a lot to know someone finds it useful. My site is still a work in progress and I hope to get up some information on the wiring while it is still fresh in my mind. I have a few pictures of the wiring to share also. My site is located in my garage so please excuse any speed and stability issues (although it should be pretty reliable as far as up time).

I am looking forwards to seeing what you have come up with for a TPS. This is one feature I still have not implemented. I noticed while I was driving today that I did not have much engine braking. When I let off the throttle she seems to want to coast at the same speed forever. I have a strong suspision that this is due to not having a TPS and Megasquirt not leaning out my AFR during coasting. I think this is also going to have some negative affects on my gas mileage.

I am very happy to report that my 450 got me to work for a second day in a row without any glitches. I have a much better feeling about it's reliability now that I have cleaned up the rats nest wiring. I am also not ashamed to pop the hood any more. So far I have only had one problem. A couple of evenings ago I pulled into a gas station and she was totally dead when I tried to start her up. I took me a minute to figure out I hadn't fastened the battery cable tight enough in the trunk and it popped off.

On the down side I can't get any response from my Inovate LC1 Wideband O2 sensor. At least I have a pretty good map that seems to be very driveable! My LC1 is giving an error 8 which means a bad sensor. I am a little frustraited with it right now and I am having a hard time desiding wether to replace the sensor at $79, get a whole new cable at $199 and be updated to the latest DAC or find something different. The LC1 was great when it was working properly but my version has always been a little flakey (supposed to be fixed with their latest revision). I wish the MegaCrew was making a little more headway on their WO2 controller but I am simply amazed with what they have already given away for basically free.

I will try to get my latest map published some where shortly. If anyone is to the point of needing a map let me know and I will prioritize getting it posted.

Mike.

[bluefang]

Hey great work with the MegaSquirt conversion. I know ur prob going to have this up on ur site in a few days Oughtsix but where did u end up placing ur O2 sensor in the exhaust, I have a 1974 450SLC and cant find one on mine to replace so i need to install one, hopefuly before i start ripping everything apart and i cant drive it.

[hbar]

I'm also wondering where to place the O2 sensor on my '78 450 SEL. I've removed the EGR system and that leaves a large hole in the drivers side manifold just off the front cylinder and I think this may be a good place for the sensor..

[oughtsix]

Sorry guys, my 1980 emissions controlled monstrosity had lambda feedback. It was simply a matter of pulling the stock O2 sensor and replacing it with the wideband sensor.

My sensor is located near the transmission tunnel below the shifter.
Mercedes engines and more Benz accessory from Performance Products

I drilled a hole in the lower part of the transmission tunnel right in front of the seat cross member. I put a gromet in and sealed with silicone. I ran the wire to the stock ECU location in the drivers compartment. I like this location because the LC1 electronics are inside the cabin. I would have prefered to have it under the hood though and wired directly to the relay board instead of having to splice into the harness.

I caped the EGR hole in the exhaust manifold with a brass cap. I don't know if there is enough exhaust flow here for the O2 sensor to function properly???? I would also worry about only getting a reading from one cylinder (probabally ok but beyond my knowledge level)? Wiring wise it would be a perfect location.

I hadn't thought of this but it would definitely be a lot easier to have an exhaust shop weld in a bung while your car is still driveable. (Welcome to the discussion bluefang!)

P.S. If you come across any other issues that I have neglected to address please let me know and I will post them on my site. (I just added a preinstall checklist including O2 sensor bung installation) Thanks, Mike.

[hbar]

[I don't know if there is enough exhaust flow here for the O2 sensor to function properly???? I would also worry about only getting a reading from one cylinder (probabally ok but beyond my knowledge level)? Wiring wise it would be a perfect location.]


The two issues of exhaust flow and only reading one cylinder were exactly what I was concerned about. I'm not sure how to find out the answer to these two questions but I'll do some asking around.

[oughtsix]

The MegaBoard has been great about educated speculation on issues like these. I would like to know what you find out.

I have made several updates to my website this evening including some pictures but I still have more documentation to do.

[oughtsix]

Well I did some junk yardding this weekend and came up with a few finds. My major concern was replacing the heater filter material taped over the intake duct with a real air filter system.

There isn't much room for an airfilter box under the hood. The guy at the pick and pull seemed fairly reasonable and didn't want to try to price out a bunch of junk. I pulled 4 TPS's a bunch of intake ducts and hoses and a couple of air boxes for $30. I got air boxes off of a 90 vintage Subaru and a 91 honda accord. The honda accord air box looks like it will fit in front of the passenger side fender and not be too difficult to plumb in but I think this will mean moving the washer fluid tank. The mouth of the old CIS system was 4" so I put a piece of 4" PVC pipe in it's place to hold the IAT. I got a few air hoses off of some mid 90's grandam's that have 4" ID acticulated hoses. These mate up to the PVC quite well. My biggest problem is I don't want the air intake to look junky compared to the rest of the engine.

I have also gotten an RMA number from inovative for my LC1. I look forwards to having wideband O2 capabilties again. I need to pull the LC1 and get it in the mail. I wish I had the time to do that this weekend but other duties around the house took priority.

Has anyone else made any progress on their install? I don't want to put any pressure on you guys but my install has only taken two years to get to this point.

[hbar]

My install is advancing slowly, but slowly.


I just got my injectors back from having grooves machined in the barrel for o rings in order to isolate them from the heat of the heads. I'm expecting the new injector gaskets, filters and spacers to arrive UPS tomorrow, then I can install the fuel rails, regulator and fuel line, and get the upper and lower intake reinstalled along with the miscellaneous parts that go with it. I cut each of the old mechanical injector hold down clamps in half and am using them to hold the new injectors along with a spacer. I'll take pix this week and get them posted hopefully by friday.

I'm really having a lot of fun with this project but it's taking a long time. I think I'm on pace to at least tie your two year mark, ought6, and maybe even beat it.