Tbi backfire through intake

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Rustjunky67

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So at the end of the video you can hear my wife mention antifreeze....
This morning I look under the truck and see a little puddle.... crawl under and it appears to have been dripping from bellhousing dust cover.....I look further up and yep wet at back of block....
Get my little borescope out and wouldn't you know it, my phone is telling me no USB camera found (borescope isn't being seen when plugged into phone).....
But best I can tell is maybe it's leaking from China wall/ head intersection area....
BIG QUESTION.....
could that leak be the source of enough vacuum loss to cause my problems??
Seems to me this may have been my problem all along‍♂️♂️
Thoughts, previous experience, advice?
 

someotherguy

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On a TBI, coolant leaking near top rear of engine #1 suspect is the heater hose quick connect fitting. Notorious. Look closely at it before you suspect anything else. The original pot metal part corrodes and can break off if you just look at it wrong, then you're carefully trying to remove the remnants of it from the intake.

Richard
 

Schurkey

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Fix known problems.

You know the ESC module needs to be replaced.

You know the injector dripping needs to be fixed. Wild Guess: the dripping is constant without regard to RPM. At low speed, the mixture is too rich, floods the engine, engine stalls. At higher speed, the dripping is a smaller proportion of the total fuel delivered, the engine can swallow the extra fuel with less effect on the operation.

The coolant problem is not something that will cause engine stalling, and the Dorman quick-connect piece is ten times as good as Genuine GM, one of Dorman's unusually-good items.
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Rustjunky67

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No quick connect José
On a TBI, coolant leaking near top rear of engine #1 suspect is the heater hose quick connect fitting. Notorious. Look closely at it before you suspect anything else. The original pot metal part corrodes and can break off if you just look at it wrong, then you're carefully trying to remove the remnants of it from the intake.

Richard
No quick connect hose anywhere on my truck.....
This is what I have and it's solid and not leaking a drop but yeah that was my first suspect lol....
Thanks for the info though.....I wish that I would have been so lucky..... looks like I get to take all this pretty work I did back off and try again.... or give up and replace the transmission front pump seal in my 2000 Isuzu trooper and get it back in the road, though I can't get to the good gold spots with it like I can this nv4500 tranny in my truck
 

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Rustjunky67

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The coolant problem is not something that will cause engine stalling, and the Dorman quick-connect piece is ten times as good as Genuine GM, one of Dorman's unusually-good items.
See above re: quick connects....
My leak appears to be coming from intake/ head junction..... but with my borescope being suddenly inoperable when I need it most, I can't get a good look or picture...... being blind in one eye don't help none either it always seems to be in a location where I would be able to easily see if it were the other eye....‍♂️♂️♂️♂️♂️♂️
But yeah I agree on the fixing what needs to be fixed but seeing as I'm about to have to pull this son-of-a-mother apart again, that esc module and injectors just moved way down the list of imperatives.....I don't even know what to say at this point but damn lol.... and I had it looking so pretty
 

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thinger2

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You are a badass dude.
You are the very guy who keeps this **** going brother.
I think its awesome.
You will never make it run with dribbly injecters.
If you have 15 psi at the forward end of the filter you have a healthy fuel pump.
I assume that you found the drips by looking at it with a timing light?
Like most things in life, if its dripping when it shouldnt its probably funky.
The next thing is bad factory battery cables.
They are known to look great on the outside and be rotted crud green on the inside
Cut the ends open and take a look.
I bet they look like fuzzy green poo.
A cold start uncontrolled high rev that settles down very slowly is quite often a bad TBI base gasket.
And, though ive never had a TBI do this to me.
A bad knock sensor on a Nissan Or a Jag or a BMW or a bunch of other cars will cause the exact same throttle problems you are describing.
And even on an OBD11 car a bad knock sensor will not trigger the check engine light.
The knock sensor on your truck is screwed into the side of the block just a little above and slighltly behind the starter.
It threads into a water jacket so it will pee on you when you pull it.
If it doesnt, its full if crud.
So, just like everything else us cars are going to do.
Poke it with a stick until it leaks.
Buy the replacement pigtail harness for it too.
It might not solve your problem but you need it anyway.
You can clean and reuse your egr valve if you are very carefull about how you do it.
If it will hold 12 pounds of vacuum for 2 minutes its a good candidate for cleaning.
If it doesnt budge at all.
put it in a bucket of kerosene for a couple of days and see if ypu can get the diapragm to move.
If you can pull the diaphram back while it holds vacuum
All you need to do is scrape the carbon ring off of the inside of the EGR valve.
I am running the original 1994 EGR.
I pull it twice every year.
On the same day service the G80 diff I service the EGR.
Do the dirty nasty **** while you are already dirted up.
Do the clean interior **** when you are clean.
They will both get done,
Its all about not mind ******* yourself when you do it.
You really do need to take a break for yourself.
This is just works for me.
After every ball busting major project?
Get 6 of whatever and and clean the seats, or the dash or just polish a few spots to see how it will turn out.
Every time you feel beat down remember that you are in charge of this whole ******** operation so go out and wash the truck or clean the windows or whatever.
The more time you spend cleaning it, the more you want to fix it,
And that is how you get the motivation to finish the job.
You got this brother.
You are a persistant no giving up dedicated man.
Thats awesome
 

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The knock sensor on your truck is screwed into the side of the block just a little above and slighltly behind the starter.
I'd have said "...slightly ahead of the starter".

It threads into a water jacket so it will pee on you when you pull it.
If it doesnt, its full if crud.
So, just like everything else us cars are going to do.
Poke it with a stick until it leaks.
Yup.
 

Rustjunky67

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How badly does it leak? Consider making it run properly as you top-off the coolant now 'n' then. Fix the coolant leak later.
If it was enough for my wife to smell it that quick, it's too much...... but seriously from the few seconds it's run here and there, it's way too much... I would be adding coolant every time I stop..... it has to be at the China wall I will confirm today
 

thinger2

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I'd have said "...slightly ahead of the starter".


Yup.
I hope I didnt send this guy in the wrong direction.
I described it rearward because Im too lazy to jack the truck up when I pull a starter so I crawl under it from the front.
That way if I drop the starter on my head, I know that it cant do any real damage.
If I go in the other way and drop it on my nuts, I may loose the ability to keep making really really smart life decisions.
Safety first.
 
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