Update on my Chevy v-6 tbi

Fritz Maurer · Jun 11, 2023

It turns out the injector wires disappear into the loom ; I found it was easier just to spend a little time carving a block out of a piece of mud flap and drilling holes for the wires, rather than try to figure out how to make it run with the injectors unplugged. Thank you to all who contributed.

Hobo,NC · Jun 11, 2023

You said TBI, I can not comprehend how the injector harness could affect manifold vacuum. Now if it were Multi-port injected YES.

This post was edited by Hobo,NC on 06/11/2023 at 06:09 am.

Fritz Maurer · Jun 11, 2023

Nobody said that it did. But since you brought it up,
how does the presence of multi-port injectors
change manifold vacuum?

RBnSC · Jun 11, 2023

Did it look like this one.

NDIHC · Jun 11, 2023

Am I right to assume that it was sucking air through the little notch in the throttle body where the wires run through? And this would be a place for intake air to bypass the air filter.

Fritz Maurer · Jun 11, 2023

Correct. When I first met that thing, I was always curious as to how you could hold your hand over the air cleaner inlet and not affect the engine idle in the slightest. There was so much dirt on the throttle plates that you could not see the screws. That poor motor. Cant believe it runs as good as it does.

Hobo,NC · Jun 11, 2023

(quoted from post at 20:55:43 06/11/23) Correct. When I first met that thing, I was always curious as to how you could hold your hand over the air cleaner inlet and not affect the engine idle in the slightest. There was so much dirt on the throttle plates that you could not see the screws. That poor motor. Cant believe it runs as good as it does.

Again the confusion its in the title

my Chevy v-6 tbi.

Not being there I would ask for clarification TBI are ?.

The confusion "the engine cannot build enough vacuum"

For diagnostic's when " the engine cannot build enough vacuum" its not normal to think that statement is above the throttle plate
( Atmosphere)

Engine Vacuum is measured below the throttle plate.

You ask

how does the presence of multi-port injectors
change manifold vacuum?

On this application The injector harness feeds thru the intake manifold, any leak at the injector pass thru will affect measured engine vacuum.

My apologies for asking you to make that clear, I should have just assumed and blown a WAG out of my $$$.

This post was edited by Hobo,NC on 06/11/2023 at 10:18 am.

Fritz Maurer · Jun 11, 2023

The little black plug at the edge of the gasket
surface. With that gone it will not build enough
vacuum to start. It is apparently not an un-
pluggable, replaceable part without cutting and
splicing, must have to replace the entire harness to
get that part.... still have not found any factory
repair that fits in there. One guy wanted me to buy
the whole tb and splice it into my harness.

used red MN · Jun 11, 2023

Hobo, is the info in his post 100 percent perfectly
clear? No, but the percentage of post on forums like
this that are perfectly clear is very low. The main part I
feel that should have been added but was not that the
engine is running on propane. If everyone had a steel
trap memory and could remember what everyone on
here had posted simply referring to this post as an
update to a previous post all would be fine. The
problem is ..steel trap.. memories especially in older
folks are few and far between, so I give you the link to
the previous post. I am no propane expert but I have
worked on a FEW. This being a dual fuel engine the
propane is sort of an ..add on.. It sounds like the
propane system relies on sensing air flow being drawn
into the engine to initiate mixing in the propane fuel.
Since the propane system is upstream of the TBI
..Throttle Body Injector.. the fact that the ..grommet..
for the wiring to the fuel injectors of the TBI was
missing the air flow valve in the propane unit could not
sense the flow properly.
Previous post

used red MN · Jun 11, 2023

You have added a lot of confusion to this post by not stating that the machine is dual fuel and you are mainly just trying to get it to run on propane properly. A multi-port fuel injector is placed right in the intake manifold and vacuum is acting right against what I believe is called its pintle valve. Obviously if the injector is MIA you will have a big vacuum leak. If Hobo just likes to wind your clock spring I am sorry if I am getting in the middle of that.

Fritz Maurer · Jun 11, 2023

Sorry, Teacher, youre wrong on this one. I stated at the outset that it is not set up for gasoline, thats the way it came from Hyster, and that I was seeking opinions on whether it would run with the injector wires disconnected which would simplify plugging the hole. I got a couple good ideas, but it turned out it wasnt such a big a deal as I thought to make a new grommet. As far as causing confusion, thats you not me. Nobody said anything about multi fuel but you, in fact just the opposite was stated. I seem to remember you reaming someone elses adz over some wiring on a Farmall M a couple years back...turns out you were f. o. s. on that topic because you misunderstood the material. Next time read the text instead of just looking at the pictures.

Hobo,NC · Jun 11, 2023

(quoted from post at 00:33:34 06/12/23) Hobo, is the info in his post 100 percent perfectly
clear? No, but the percentage of post on forums like
this that are perfectly clear is very low. The main part I
feel that should have been added but was not that the
engine is running on propane. If everyone had a steel
trap memory and could remember what everyone on
here had posted simply referring to this post as an
update to a previous post all would be fine. The
problem is ..steel trap.. memories especially in older
folks are few and far between, so I give you the link to
the previous post. I am no propane expert but I have
worked on a FEW. This being a dual fuel engine the
propane is sort of an ..add on.. It sounds like the
propane system relies on sensing air flow being drawn
into the engine to initiate mixing in the propane fuel.
Since the propane system is upstream of the TBI
..Throttle Body Injector.. the fact that the ..grommet..
for the wiring to the fuel injectors of the TBI was
missing the air flow valve in the propane unit could not
sense the flow properly.
Previous post

Fritz day must not be going well. I wanted to understand his issue more in dept more so out of curiosity. Like you I have kept a few running without a complete understanding of the propane system. Not to bother him thru the day I have rationalized why they use airflow above the air horn to pull the propane diagram open.

I have seen this set up but it did not click : (

Update on my Chevy v-6 tbi

Fritz Maurer

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Hobo,NC

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Fritz Maurer

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RBnSC

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NDIHC

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Fritz Maurer

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Hobo,NC

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Fritz Maurer

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used red MN

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used red MN

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Fritz Maurer

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Hobo,NC

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