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1.6 36MPG
by
Sawbones
on 21 Mar, 2025 04:45
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87 Jetta, 5 spd, 1.6 NA.
Starts and runs great. I don't know how to explain here but the clatter sounds a little sharp or harsh on startup. I have a decent set of injectors. All popping at 1800PSI, negligible leakage, decent spray pattern, nice chatter.
I don't notice huge amounts of smoke going up hills. I'm thinking to verify timing and if that checks out I think I'd like to retard the injection pump a bit. If my timing is off I'll take care of it and maybe that'll do it. If my timing seems to check out I believe I'd be rolling the top of the injection pump away from the engine to retard it, is that correct? I think it sounds the slightest bit advanced. I think my total adjustment might be 2mm at the most. It's very close but something isn't right. Just a hair and see what it sounds like and get another read on MPG.
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#1
by
ORCoaster
on 21 Mar, 2025 18:07
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2mm on a non-turbo setup is about twice what I used to run. I tried 1.05 for a while and I didn't like it. Sounded marble-like.
Yes, loosen the pump and bump it a fraction of an inch towards the radiator. Mark a line at the indicator at the top of the pump between the pulley. There is a nice place there to do that. Then move the pump a pencil or two width distance from that mark. Since you are at 2 mm you might need a bit more but try a few times at the initial setting and go more in incremental steps.
No giant steps in this part of the game, Mother May I?
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#2
by
fatmobile
on 21 Mar, 2025 18:09
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I make a mark on the ear where the front top mounting bolt rides.
Where the pump meets the bracket.
At that point 2mm would be a big move.
Width of a pencil line makes a difference.
Just mark where you started so you can get back there.
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#3
by
Sawbones
on 25 Mar, 2025 05:02
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2mm on a non-turbo setup is about twice what I used to run. I tried 1.05 for a while and I didn't like it. Sounded marble-like.
Yes, loosen the pump and bump it a fraction of an inch towards the radiator. Mark a line at the indicator at the top of the pump between the pulley. There is a nice place there to do that. Then move the pump a pencil or two width distance from that mark. Since you are at 2 mm you might need a bit more but try a few times at the initial setting and go more in incremental steps.
No giant steps in this part of the game, Mother May I?
I mis spoke there. Right now I have it set as close as I can to factory specs. I was thinking to retard it by 2mm but I guess I'd be shooting for more like 0.5mm yea? Now I'm thinking about some kind of small screw jack between the cylinder head and the top of the pump so I can really move this thing precisely instead of a brass hammer.
I shall tread lightly.
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#4
by
Sawbones
on 25 Mar, 2025 05:06
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I make a mark on the ear where the front top mounting bolt rides.
Where the pump meets the bracket.
At that point 2mm would be a big move.
Width of a pencil line makes a difference.
Just mark where you started so you can get back there.
I used to have 20/20 vision. I'm really missing it. If it's closer than 3' to my face I need glasses... Shoot for something like 0.5mm? Before I do anything I'll be sure to mark it in a way that I can get it back. I have that dial indicator that goes on the pump. Would that be good to use or would it just complicate the whole thing? I REALLY don't want to screw up here.
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#5
by
ORCoaster
on 25 Mar, 2025 20:43
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Now I'm thinking about some kind of small screw jack between the cylinder head and the top of the pump so I can really move this thing precisely instead of a brass hammer
Surely not!
Are you loosening all the bolts? One on the face of the pump, 13mm deep socket works best for me. The same goes for the one under the pump. Then the two on the wings on top, I use one of those racheting box wrenches. I save loosening the front one until I am ready to move the pump. Then, ease it off and move the pump by hand.
I have never needed to hit it with anything. I think you are going about it wrong.
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#6
by
fatmobile
on 26 Mar, 2025 23:08
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I grip a vice grips on the front of the pump.
Where the metal bracket is, in a spot with plenty of aluminum backing it up.
Don't use the nubs on top that hold the adjuster screws,... SNAP.
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#7
by
Sawbones
on 31 Mar, 2025 05:15
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Now I'm thinking about some kind of small screw jack between the cylinder head and the top of the pump so I can really move this thing precisely instead of a brass hammer
Surely not!
Are you loosening all the bolts? One on the face of the pump, 13mm deep socket works best for me. The same goes for the one under the pump. Then the two on the wings on top, I use one of those racheting box wrenches. I save loosening the front one until I am ready to move the pump. Then, ease it off and move the pump by hand.
I have never needed to hit it with anything. I think you are going about it wrong.
I don't mean to put any real force to it or whack it by any means. I was just thinking I could move it more precisely with a small TINY little screw jack like you might use for setting up a piece on a milling machine or something. I'm probably overthinking it...
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#8
by
tbro
on 03 Apr, 2025 08:20
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Have you loosened (not removed) the steel fuel lines at the pump and injectors to allow the pump to move freely without resistance? In my experience, it can make a big difference in adjusting the pump.
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#9
by
Sawbones
on 06 Apr, 2025 06:07
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Have you loosened (not removed) the steel fuel lines at the pump and injectors to allow the pump to move freely without resistance? In my experience, it can make a big difference in adjusting the pump.
I haven't touched it yet. I'd be cracking the lines at the pump before I even tried moving it. I was waiting to see if someone says retarding the pump would have any effect on MPG.
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#10
by
ORCoaster
on 07 Apr, 2025 19:43
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Retarding the pump might get you better miles per gallon. If it is set up way too high then bringing it back down to what is spec or a little over spec is a good thing.
You can adjust it a bit at a time and see how the change makes it run better or worse. If you are only changing the timing by .5 mm I am not sure you will notice it.