560SEL M117 Megasquirt - Page 5 - PeachParts Mercedes-Benz Forum

Frank Reiner · #61 10-27-2015, 04:03 PM

Quote:

Originally Posted by 300SD81

I do seem to be having knocking? and a lean out if I completely let off the gas at high rpm though, does the EZL do something special for high vacuum/high rpm? It only happens during engine braking, I tried reducing the advance there but it didn't seem to effect it.

In the situation above, (closed throttle, high RPM deceleration), there can be no combustion noise, "knock, ping, etc.", as there is no combustion; CIS has cut off the fuel!!

Mike D · #62 10-27-2015, 04:09 PM

Not completely Frank. You still have enough fuel entering the system to maintain idle.

97 SL320 · #63 10-27-2015, 04:52 PM

Quote:

Originally Posted by Mike D

When you apply the brakes your vacuum should drop so high vacuum shouldn't be a factor in the ignition. Maybe bump the fuel table at those registers?

A couple of fine points for this and a prior post. Few cars use screw on spark plug ends, the best source will be a lawn mower / chain saw plug.

For vacuum power brakes, engine vacuum will drop when you release the pedal and not on the apply.

With the brakes released, there is engine vacuum on the master cyl side of the booster diaphragm and the pedal side.

As the brakes are applied, the first bit of travel closes a valve located on the pedal side. This prevents additional vacuum from reaching the pedal side.

As the pedal is pushed farther, the pedal side of the diaphragm is opened to atmosphere, this is what pushes the master cylinder piston stopping the car. The vacuum / air valve self balances the booster so the brakes don't slam on. ( RE: as the diaphragm catches up to the pedal, the atmosphere valve closes preventing more pressure build up. )

When the brakes are released, the valve allows vacuum to enter the pedal side and at this time engine vacuum will drop momentarily. If you are doing a track event where you are on and off the throttle / brakes, this could lead to a slight / short term lean condition that may be hard to find through regular driving. I don't have direct experience with programming EFI however.

I know on a cold start with my old carbed Bronco , if I let off the brakes immediately after a cold start, the idle will drop.

Frank Reiner · #64 10-27-2015, 05:36 PM

Quote:

Originally Posted by Mike D

Not completely Frank. You still have enough fuel entering the system to maintain idle.

Inasmuch as the system in question is KE (CIS-E), it is necessary to know that EHA current is reversed in the situation of high RPM, closed throttle, resulting in the complete cutoff of fuel. [Reversal of current is also used in some KE engines for RPM limitation.] As falling engine speed approaches idle speed, the fuel flow is restored.

300SD81 · #65 10-27-2015, 06:02 PM

Quote:

Originally Posted by Mike D

You've got me confused now. Are you using the MS to control the ignition timing? If so, then you need to adjust the spark advance to match or at least correspond to the original spark table you posted if you are still using the CIS.

You have to match the CIS's fuel supply characteristics and NOT a regular EFI controlled type.

From the looks of the original map it seems to have a large drop at about 2800. Can't really read the numbers but the plots seem to show a plateau before another increase at the upper end.

The CIS system will do a sudden "lean" when you release the pedal due to decreased air flow. The original vacuum system compensated for this by retarding the timing immediately by 10-14 degrees.

Yup, you're gonna have fun.

I should have said timing WAS controlled by the EZL. It's now the MS. There's not really a vacuum system though, the only connection is MAP to the EZL. The spark table was generated from stock values in the FSM. I'll try more retard in the 30 kpa bins though. The "fun" is only temporary though, it's getting fuel rails installed within the next month or 2, I just need it drivable until then.

Quote:

Originally Posted by Frank Reiner

In the situation above, (closed throttle, high RPM deceleration), there can be no combustion noise, "knock, ping, etc.", as there is no combustion; CIS has cut off the fuel!!

That would explain the lean condition. Maybe I'm just hearing things

I never listened to it this closely with the heat/ac and stereo off before. I'll have to try reconnecting the coil and distributor and see...

duxthe1 · #66 10-27-2015, 11:12 PM

Quote:

Originally Posted by Frank Reiner

In the situation above, (closed throttle, high RPM deceleration), there can be no combustion noise, "knock, ping, etc.", as there is no combustion; CIS has cut off the fuel!!

Before I went to MS I built a controller that dispayed O2 voltage and allowed me to modify the signal. It was quite surprising to see just how often the CIS-E would go into overrun fuel cut.

300SD81 · #67 11-02-2015, 05:36 PM

Little under 1000 miles round trip this weekend, flawless with 4 people and 600lbs of beer and tailgate gear in the car.

greazzer · #68 11-02-2015, 05:49 PM

Watching this thread and I was thinking of going over to the dark side ... getting a gasser as a side line beater. I have two questions, and sorry if this sounds like high-jacking

1. Is there a COTs kit (complete) Commercial-off-the-shelf which has everything ready to go?

2. Can this be done to the 6.9 (M100, W116) monster engine? I saw a YouTube video of a guy who I think did the same thing, but it looks like he had Jay Leno's budget. Can this type of concept be done on a tinkerer's budget?

And, most importantly, very impressive work !

300SD81 · #69 11-02-2015, 06:10 PM

Quote:

Originally Posted by greazzer

Watching this thread and I was thinking of going over to the dark side ... getting a gasser as a side line beater. I have two questions, and sorry if this sounds like high-jacking

Do it, the power level is quite addictive

Hence why it's taking so long to rebuild the 300. Big power 617 is still in my future some day though.

Quote:

Originally Posted by greazzer

1. Is there a COTs kit (complete) Commercial-off-the-shelf which has everything ready to go?

EFI kit | Elbe Engineering

Quote:

Originally Posted by greazzer

2. Can this be done to the 6.9 (M100, W116) monster engine? I saw a YouTube video of a guy who I think did the same thing, but it looks like he had Jay Leno's budget. Can this type of concept be done on a tinkerer's budget?

I see no reason why not, not sure how the fuel system is set up on one so you might be in for finding a way to put injectors in the intake manifold.

Quote:

Originally Posted by greazzer

And, most importantly, very impressive work !

Thanks

greazzer · #70 11-02-2015, 07:28 PM

Since you have been tooling around in the ol' girl, how would you describe the power and response? Is it on par with throwing you back in your seat, wowza ... ?

300SD81 · #71 11-02-2015, 08:22 PM

Quote:

Originally Posted by greazzer

Since you have been tooling around in the ol' girl, how would you describe the power and response? Is it on par with throwing you back in your seat, wowza ... ?

At first

, not so much anymore, hence the upgrades.

greazzer · #72 11-02-2015, 08:56 PM

Well, against my better judgement, I went ahead and emailed Estonia about any kits for the 6.9. I have partially thrown in the towel with my W123 Diesel, and had it towed off for the pro's to finish the interior. As such, the project will be moving along a lot faster. So ..., I am looking for a beater and 6.9s are all over CL on the cheaps and I already have a bunch of parts for them, so once my wife attempts to remove a part of my anatomy if I get one early next year, I can blame you ... lol

300SD81 · #73 11-03-2015, 03:26 PM

Still haven't learned my lesson. If there's any operation requiring the use of a part-off blade, make extras because I cannot figure out how to make it work right. Don't even have any extra aluminum here unless I feel like turning down a piece of 3in round...

Edit: Went ahead and made another one from the 3in. such a waste of aluminum.

Das Benz · #74 11-03-2015, 06:30 PM

Quote:

Originally Posted by 300SD81

Still haven't learned my lesson. If there's any operation requiring the use of a part-off blade, make extras because I cannot figure out how to make it work right. Don't even have any extra aluminum here unless I feel like turning down a piece of 3in round...

Edit: Went ahead and made another one from the 3in. such a waste of aluminum.

Just a note, I don't know if you have test fit them yet, but my only recommendation as an improvement over my initial design drawings is to increase the outside oring gland depth a bit. This will vary depending on the diameter of the oring that you end up using.

300SD81 · #75 11-03-2015, 06:42 PM

Quote:

Originally Posted by Das Benz

Just a note, I don't know if you have test fit them yet, but my only recommendation as an improvement over my initial design drawings is to increase the outside oring gland depth a bit. This will vary depending on the diameter of the oring that you end up using.

The drawing you sent didn't have the o-ring gland. I measured the original injector holder and used that dimension, and the same o-rings. Got spares so I can pull the ones on the car and test fit later.

Any updates on your build? or CNC conversion? 3 hours to make one of these is not fun.