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Just Some Dude in Jersey
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13,821 Posts
Discussion Starter #521
Don't be fooled by the shiny stuff, Jeff's FI is much better and he's had it for 10+ years, I'm just playing catch up. Lots of guys already have better systems. I never spent one second thinking about how fuel injection works in my entire life until 6 months ago. I had virtually no understanding of any of the prior discussions on the subject and therefore never paid any attention to them. This system is a great way to learn FI at the most basic level. I sort of understand that now and can now start to ponder and school up on higher level FI systems and devices.
 

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Just Some Dude in Jersey
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13,821 Posts
Discussion Starter #522
I wonder how often he pinches himself when he walks in there to make sure he's not dreaming LOL
Ha! I do admit that some embarrassment flows over me from time to time about how over the top the whole car is. I can't really just drive around in it and park it in parking lots and such. It's like a one-car car show 24/7/365. Small crowds gather when I park it, people try to drive and take a picture of it. I constantly have people zooming up to catch me, then suddenly slow down next to or behind me and then just hover there. Y'know what's the MOST annoying? When I'm stopped first at a roll-through stop sign in the middle of nowhere having a great country drive and going a little fast. And a guy at the cross street sloooooooooowly enters the intersection all the while staring out his side window at me. A maneuver that should take 2 seconds takes the guy 10 or more seconds to do. "C'mon mutha fluffa! Get the frock out of the dang way! Stop looking at my car! I'm tryin' ta drive 'ova 'ere!" I holler in my car. This happens on almost every drive I do.
 

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Just Some Dude in Jersey
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13,821 Posts
Discussion Starter #523
I do believe this is a Motronic system.. based on the title! Is that still the case Gordo? (I have not followed every twist and turn of the lot here....)
Yes, still Motronic. It's the car show thing. That darn AFM is totally out of place and scale for a GT engine compartment. This recent discussion is about how to position it better, replace it with a smaller MAF, or Jeff's idea about Speed Density Fuel Control, which apparently doesn't require an AFM or a MAF. The latter two choices would best be achieved with an aftermarket FI control system.
 

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Opel Rallier since 1977
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1,095 Posts
Right.. the SD system uses air temp, manifold pressure, RPM and often aided by a throttle position sensor in production cars. It is what many/most modern production cars use.

There are other MAF's; heated wire MAF's are sensitive and have no significant pressure drop like the swinging door AFM like you have. But the issues of integrating another AFM/MAF into your Motronic system take detailed electronics knowledge to figure out from scratch, if it can be done at all. Maybe someone out there in the auto hobby world has figured it out.
 

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Just Some Dude in Jersey
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Discussion Starter #525
But the issues of integrating another AFM/MAF into your Motronic system take detailed electronics knowledge to figure out from scratch, if it can be done at all. Maybe someone out there in the auto hobby world has figured it out.
Correct. That's why I said that it would be better to go with an aftermarket control system, rather than trying to jury rig the Motronic to accept signals from a MAF or SD device. Charlie has looked into using the AFM's from 6cyl BMW's. Instead of a 2.5" square exit to the AFM, the 6cyl ones have a 3" square. I think it's a half-ass solution. I figure that if V6Opel's Sniper system can mostly self adapt and learn to run our engines, then I should be able to find an operating system-only that can be adapted and connected to the FI hardware I have.

It may not be reasonably possible. This would be a long term can-I-do-it project. If I can't do it somewhat easily, then I won't do it. I don't care about peak performance, my car just needs to run reliably and look good.
 

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Just Some Dude in Jersey
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13,821 Posts
Discussion Starter #527
Interesting! We will have to look into that. Based on your post I just did a quick look for info that I might find useful down the road.
Some quotes from the Web:

<<< Motronic 2.1
The ML 2.1 system integrates an advanced engine management with 2 knock sensors provision for adaptive fuel & timing adjustment, purge canister control, precision sequential fuel control & diagnostics (pre OBD-1). Fuel enrichment during cold-start is achieved by altering the timing of the main injectors based on engine temperature. The idle speed is also fully controlled by the digital Motronic unit, including fast-idle during warm-up. Updated variants ML 2.10.1 thru 2.5 add MAF Mass Air Flow sensor logic and direct fire ignition coils per cylinder. Motronic 2.1 is used in the Porsche 4 cyl 16V 944S/S2/968 and the 6 cyl Boxer Carrera 964 & 993, Opel/Vauxhall, FIAT & Alfa Romeo engines. >>>

A link to a posting by Charles:
<<< Modernizing the L-Jet or Motronic Fuel Injection - Version 1.0 >>>
Motronic M4.1 Wiring Info 20SEH



#165867 by Robsey
Sun May 06, 2018 4:02 pm




This is the 1989 and 1990 Motronic ML4.1 pin-out.
It is very different to the later versions of the SEH set up.
That is the 1991 onward version which uses Motronic ML1.5

As yours is registered in January 1991, I would hope that it was still manufactured in late 1990 and therefore this pin-out should be correct.

Image

As for ease of reading - try reading the schematic in night mode - so much easier to see / read.
 

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RunOpel
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831 Posts
My first thought was sunglasses but now that you mention a welding mask, that would be more suited :)
Gordo I don’t see how anyone is going to be able to compete with your car at any car show you enter. That is truly an amazing engine. I’m not envious nor jealous, just in amazement and would love to see it in person some day. Nice work 👍
 

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She's Beautiful Gordon!
 

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hot diggity dog Gordo that looks fantastic I love it when a plan of a plan of a plan finally comes together
The welders helmet is funny treat it like the sun or eclipse don't look directly at it LOL
Fantastic work my friend
The bad part is I can't stop looking at it
will need it in poster form to hang in my garage
 

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Looking great Gordo!

One thing that may cause a future tuning headaches is the number of 90 degree bends in the air intake between the AFM and Throttle body - I'm no expert, but I think these should be minimized. How one does that in the available space under a GT hood and still maintains the look you're after is anyone's guess. Hopefully this setup works for you since you have already tried a myriad of permutations and combinations.

Good luck with the rest of the project. Looking forward to the "Und Now" video when you fire it up!

Harold.

P.S.: Sorry to hear of Norbert's passing. RIP Norbert.
 

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Just Some Dude in Jersey
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Discussion Starter #536
If you saw how restrictive and cockmamie that air flow meter is inside, you'd surmise that smooth air flow is not of great concern. The 3" ROUND cold air intake duct work can handle almost double the amount of air that the 2.5" SQUARE opening at one end of the meter can pass. Of greater concern is potential leaking of air into the system at the various joints of the duct work. This would theoretically allow more air to get to the throttle than actually passes through the air flow meter, thereby the meter would under report how much air is flowing to the throttle. This can easily be eliminated by simply putting some tape around the various joints before putting the joint clamps on, but I need the duct work to be in it's final position before I tape the joints. I'll have to leave 1-2 joints tapeless for the inevitable times that I'll need to remove the duct work to get at stuff. I could still tape those joints, but I'll have to reapply it when I reassemble. I could, of course, use rubber accordion hose for the whole length of the duct work and not have to worry about any air leaks, but that wouldn't be blingy. We'll see, it's all an experiment and I expect failures or annoyances that will necessitate a redo.
 

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Senior Contributor
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4,894 Posts
My BS flex hose is chrome but I like the smooth bore stuff better. I have wanted to change my intake to smooth bore aluminum for quite some time but I just have not gotten around to it. Is there any such word as gotten?
 

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Just Some Dude in Jersey
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13,821 Posts
Discussion Starter #538
Strange pictures from strange angles
Today I finished up all my hose hook ups and final tightening of things. I rerouted and re-imagined a few things, as compared to my previous pics. There's still some refinement of things, like how my fuel line to the rail comes a little too close to the hood latch lever and stuff, but it should all work as it should. Next I will work on finalizing my throttle cable bracket on the manifold and it's attachment and adjustment to the gas pedal. It needs to anchor the cable housing a bit farther back. Here's pics for you to wonder about.....

Tick...tock...tick.... Boy, it's a good thing I post lots of pics. A guy on the internet spotted that I had forgotten to install the fuel injector retaining clips. Man, he must have REALLY zoomed in to see that.
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Just Some Dude in Jersey
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Discussion Starter #540
@#$%&!!!!!! OMG I HATE MODDING GT's TO USE THROTTLE CABLES! @#$%&!!!!!

8 hours today just working on the throttle cable bracket and various distances. The only mechanical thing left to do. The G-Dang Lokar throttle cable housing is 2"-3" too short and the amount of cable sticking out of the housing is 2"-3" too long for everything to work out nicely. Don't even get me started bitching about the limited number of choices of ends for the cable you have to choose from. I've worked on bicycles since I was 11, I worked in a bicycle shop all 4 years of high school, I worked 4 years of my adult life in bicycle shops, I mountain biked for 30 years, I have installed 1000's of cables on bicycles and custom situations, but I have never had a cable install job fight me like this one.

It's installed and working more or less properly. Full range of throttle movement, full throttle when the pedal hits the floor, pedal returns fully. I FLUCKIN' HATE IT! It's not up to my standards.

I could go into detail about all the aspects that are pissing me off, but that will just piss me off more. If only it was easier to make your own custom cables. But it's NOT easy. Believe me, I've watched dozens of YouTube videos on the plethora of ways to make your own throttle cables and all of them suck. The problem is that your foot can apply enormous force to a cable. You can snap the end off of ANY cable with foot pressure, no matter how good it's ends are attached.

And the G-dang GT gas pedal is not cable friendly at all. I could mod my pedal to make a lot of the problems go away, but it would be a monstrous PIA to try to get my pedal out because of the electric power steering. Access to the pedal mounting bolts is almost impossible.

But, like I said, it's working and I can move on to tackling the wire harness.

I'm going to have to revisit this mod at a later date.......
 
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