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Damn Gordon I thought you were right there. Sorry to hear of the troubles (damned if you do damned if you don't) You'll get it sooner than later I'm sure just keep trying and head scratching I guess.
Pause for a beer and breather scratch again and dive back in
 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #782
I think I have all my problems licked on my chromed out install of Opel Motronic fuel injection on my 1970 Opel GT, but it was giving me all sorts of trouble transitioning from idle to run. A big dead spot would occur as I left idle and if I gave it more pedal the engine would stall. I'm pretty sure that everything is working properly and there aren't any vacuum leaks or fuel pressure issues, which leaves the aftermarket Nissan throttle body as the possible culprit. I think it's letting in more air at tip-in from idle than the FI computer is programmed for and can compensate for. I acquired a variety of Opel FI throttle bodies: A 2.0 Jetronic, several 2.4 and a 3.0 Motronic ones, and my present Nissan aftermarket one. The 2.0 and 2.4 TB's have 2.125" throttle plates, the 3.0 one has a 2.375" one, and my aftermarket one has a 2.625" throttle plate. We discovered that there appear to be thick "restricters" mounted to the throttle plates on the 2.4 and 3.0 TB's. We think these are meant to reduce the amount of air that can get into the engine by HALF during the first 1/4 of the throttles' rotation from idle. The Nissan throttle body I was using was about 20-25% larger in diameter than the stock 2.4 one, did not have a restricter, and the barrel of the TB is straight and not narrowed at the throttle plate. I'm hoping that the install this weekend of the stock 2.4 TB on the stock 2.4 FI assemblage will cure my problems and I'll be able to drive my GT for the first time(decently) in a year. Fingers crossed.


 

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Opeler
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2,995 Posts
I am not a fuel injection person, but the plate screwed to the throttle appears logical.
Nice that somebody has assorted parts to ship. One of them should work.
 

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RunOpel
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1,204 Posts
Nice video and explanation Gordo :) I'm thinking I have a lot less headaches with my 1.9 and Weber carb, but yours is certainly faster and prettier :p
 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #786
After a year of engine trouble, replacement of the engine, and the install of the stock Motronic fuel injection system on my Opel 2.4 CIH engine in my 1970 Opel GT, I finally got it all working properly. I'm burned out and exhausted from the ordeal. I just finished installing the stock 2.4 throttle body and got things good enough for a test start and it worked PERFECTLY. I just have to shorten my throttle cable and tidy a few things up tomorrow and I'm ready for a test drive. :)

 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #787 (Edited)
Here's some pics of the throttle body after I cleaned it up, chopped off the throttle body heater hose fittings, and gave it a lick of silver paint.
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This is the Lokar throttle cable end I chose to use on it. This location on the throttle linkage had a ball post on it for a ball and socket linkage rod that went to another pivoting lever that the cable attached to. I deleted the pivoting lever, chopped off the ball post, which left me with a perfect size hole, and just went straight to that hole in the linkage with the cable. Piece of cake.

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I don't know what the function of this port on the throttle body is for. It's on the engine side of the throttle, so it's a high vacuum port. I plugged it off.

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #789
I readjusted the throttle cable for the stock 2.4 throttle body, tightened and tidied up all my work, and went for a 20 minute drive through my local towns. The engine and car performed flawlessly in my area's backed up traffic, red lights, stop signs, and every-freakin'-body walking and jogging in the street like they're afraid of getting the virus on their shoes if they walk on the sidewalk. Incredibly smooth low speed drivability and steady engine running. Power didn't kick in until half-throttle. I didn't do any high speed stuff on this test run, I just wanted to see that it handled all the stop and go driving conditions I have near my house. Here's way too many pictures of my engine. The first 5 were taken outside in the sunlight, the rest in the garage.
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Awesome Gordon! Really happy for you!
 

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Fantastic Gordon! Hot Damn you did it and it looks awesome. Your steady persistent approach has paid off 10 fold. Only wish I were closer to see and hear it in person Bet it is indeed something special. congrats bub
 

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RunOpel
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1,204 Posts
Nice job Gordo :) what a sweet feeling you must of had. There is nothing like driving the Opel after it's been idle for awhile. I have said before though, you need sunglasses on before you crack open that hood :p
 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #795
I only have 3 glitches (that I know of):

1) My radio doesn't turn on and the fuse for it at the box isn't blown. It has a red LED that I think flashes every 5 seconds when the engine is off. I think this is normal. But it doesn't turn on with the ignition. So I figure that I have live battery power to it, but switched power isn't getting to it. I'm hoping for a dislodged ground or a blown fuse at the unit.

2) I've got engine vibration in the car. But it's not a metal on metal sound/vibration. Because I have shortened motor mounts, but the tranny is not lowered, I figured that the engine was tilting down in the front and forcing the exhaust to angle upwards and contact the frame rail. I just checked that when I got home from work and there's plenty of exhaust clearance. Buuuut, I see that my crank position sensor is sitting tight down on the front suspension cross member. I can't slide a piece of paper between them. I've know about the close proximity, but I didn't know it was hard pressing there. This situation is also due to the shortened mounts. I just need 3/16"-1/4" of clearance there for piece of mind. It's towards the right side of the car, so I'm going to try to loosen the passenger side motor mount nut, lift the engine on the passenger side, and slip in a 1/4" shim between the mount and the mounting ear.

3) My alternator vibrates and shakes. You may recall that I had to mod pulleys and alternator positioning. I may attempt to create a 3rd brace for the alternator at the back of it running from the block to the alt. Has anyone done such a thing?
 

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Opeler
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2,995 Posts
Here's some pics of the throttle body after I cleaned it up, chopped off the throttle body heater hose fittings, and gave it a lick of silver paint.
Understand that your GT is a warm weather Opel.
Presume that HEATED throttle body (mostly?) helps during cold weather operation.
 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #797
Correct, I don't drive my GT in cold weather and, therefore, do not have a need heat my throttle body.

I fixed the vibrating alternator! I looked around in the alt vicinity and saw that one of the mounting bolts for the lower alternator bracket was in a good place to mount one end of an L-bracket. And I was already aware of an 8mm bolt hole in the back of the alt. I first went to my shelf of used or useless chrome and stainless steel stuff and found a barely used alternator F-bracket that seemed about right. A test fit showed it and it's bolt holes were just the right length. I chopped off the leg in the middle and that left me with an L-bracket. I bent and tweaked it it my vice to get it just right. It was a tad short, so I needed to add 3 shim washers. I bolted it in and started the car and no more wiggling alternator.

It was too tight in there to take a good pic, these were the best I could do:

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Senior Contributor
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4,961 Posts
Does that added bracket make it so you can't adjust the belt tension?
 

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RunOpel
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1,204 Posts
Oh that’s a good question Jeff. If it does, that will suck. Gordo you do need a radio, so I hope you find and fix that issue. But it’s looking a lot better and closer to completion :)
 

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Just Some Dude in Jersey
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14,123 Posts
Discussion Starter #800
The holes are elongated on the bracket to make it fit an Opel engine. But I still needed to add washers to shim it outwards to be able to get the bolt in the alternator in.

It's really just a proof of concept. That big hunky brace is massive overkill. I just lucked out with finding a piece of metal in my chromy stash that turned out to be the right size and shape. I could have cut the bolt hole at the alternator end of the bracket and made it an open slot. I could have done it in a minute. I'll probably do that at a later date. But I wanted to try it out to see if the concept worked. It works REALLY good. It was sort of a late night, just before bedtime, thing. I had merely gone out to the garage to take a look at things, so that could ponder possible ideas and distances over night. Next thing you know I'm slicing and dicing up a chromed aftermarket F-bracket with an angle grinder and cursing at my car and giving it the finger as I kept dropping washers and bolts. I was in bed a 1/2 hour after I was done.

Ahhhhh, the good old days are back!
 
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