others reading this (my comments) DOES not apply to 1989/90, G16a engines, these 2 years have a very unique Throttle body, (no duty cycle air bleeds on any of these engine)
your very welcome,wow what great questions, all !!!
and there are lots of gaskets to fall off working here, the side wider has 2 sst gaskets that love to fall off, in the dark.
1: what rpm? RPMs matter, big time. need hard number, before and after RPM. in every case.
the key to understanding this is my graphic, drawing,with marks a,b,c,d. ?
those are the legal (not leaks) air paths. there are only 4, so if you block all 4, on a new car, the engine must stall with zero air inducted it can not run.
this sets a base line, zero air. car will not ever start again. with zero air.
on a hot engine, the iAC is 100% closed. leaving only 3 paths, if the IAC is bad, all other RPM errors are not important, the engine will scream with this thing leaking and the ISC goes nuts.
ISC means IT and its magic software. (called the ISC servo system.)
so if that is known for a fact to be closed, then Id pinch the ISC hose.
and rpm goes from where.? 1000? and goes to 400 or stalls.
usually it would stall. but if not, i screw the bleed in 100% gently do not damage its seat, just gently close it. CW, screw.
now IAC is closed,
now bleed is closes
and you pinch the iSC hose,(air) all air is gone. now. it must stall and never start again.
see this?
these checks (RPM facts) will disclose to me what is wrong, or if there are un-metered air leaks.
all hoses must not cause RPM changes, except do not pinch these
PFREG (this foods engine if pinched)
the MAP hose (you dont have it)
the PCV, do not pinch it or seals in the engine can leak, for this 1 hose, eyeball ispections only workl
the Brake booster hose can be blocked , pinching it is near impossible but it must be tested, to be 100% sure. un do it and block it , with my kit of corks.
there are not all that many lines, see them ,at end.?
hose 45 is ISC metered air line, if you block it , the engine will stall, or run very very slow. (if the bleed is wide open the engine might run real slow.) i can not predict bleed , setting.
on one car it was missing on this forum. ouch.
post
Thanks Fixkick! Idle was working normal prior to me doing the service on the valves.
During that service I took off the throttle body, sidewinder tube and air intake hose. So, those are my prime suspects.
(missing gaskets or the main tube rubber ring, was folded over, and now leaks like sieve.?
I need some remedial troubleshooting here as I've never tried to solve a vacuum leak.
1. When I pinched the ISC air line, I saw the rpm drop. Hot engine rpm before and after, i need real numbers, only.???
Is this good or bad? its bad, if it didnt stall, but no numbers no guessing by me.
What should I expect on a car with no leaks? i it will idle at 800rpm at any electrical load. if A/T in DRIVE TOO.
How do I tell if this line has an air leak?
If that valve is at aprox 50% at hot idle, I would expect it to drop the rpm. So, while I saw rpm drop, I wasn't sure if this is good or bad. (no tacho, no joy)
2. If I pinch other hoses and the rpm drops does that mean that hose is leaking? yes and no. depends on hose function.
There's a little one that goes into the top of the throttle body (EGR ported vacuum) and one that goes from the main air line into the valve cover. PCV
3. The only screw I turned is the one under the rubber cap on top back of the TB. good we can fix that easy.
4. If I run propane around the hoses, I wasn't sure how high it should be set.(set what?)
Should you have a lot of propane flowing out or just a slight hiss if fine? Should it be coming out strong enough as if you were going to light it?
let it rip, do so out doors with gloves and goggles, in case it flashes over, propane is forgiving unlike any liquid fuels.
5. Is it possible that someone set the idle higher and higher as the throttle body was getting full of carbon? sure, but you had the throttle off
and im sure you checked that the VALVE is 99.99% closed, or at .0005" (smallest feeler gauge on earth, mostly)
That pathway of the fuel air screw under the rubber cap was full of carbon as well as the entire TB. yes, it was very dirty.
we can not guess the actions of any PO. but i assume he did it all wrong, and in most cases, they did. over and over..
that is because they never read the FSM. its all there. (not the .0005 check that is mine, they tell you buy a new TB< for 1K buck.
1:TV closed 99.99%
2: IAC closed hot, if not closed, all bets off. for 1 and 2. what is RPM now hot? 800, 500, 1000s or 1500 or what, i cant guess these, it must be stated.
3: bleed, can be set last and should but we can fiddle it all we want to aid diagnosis. close it. what happens? CW. set it.
4: pinch the ISC air hose and then engine stalls, there is no air to run car now. zero air, zero run, zero starts.
thanks,
John
here they all are, sans booster.
[img] http://www.fixkick.com/sensors/EGR/92-95-EGR-16v.jpg[/img]
your very welcome,wow what great questions, all !!!
and there are lots of gaskets to fall off working here, the side wider has 2 sst gaskets that love to fall off, in the dark.
1: what rpm? RPMs matter, big time. need hard number, before and after RPM. in every case.
the key to understanding this is my graphic, drawing,with marks a,b,c,d. ?
those are the legal (not leaks) air paths. there are only 4, so if you block all 4, on a new car, the engine must stall with zero air inducted it can not run.
this sets a base line, zero air. car will not ever start again. with zero air.
on a hot engine, the iAC is 100% closed. leaving only 3 paths, if the IAC is bad, all other RPM errors are not important, the engine will scream with this thing leaking and the ISC goes nuts.
ISC means IT and its magic software. (called the ISC servo system.)
so if that is known for a fact to be closed, then Id pinch the ISC hose.
and rpm goes from where.? 1000? and goes to 400 or stalls.
usually it would stall. but if not, i screw the bleed in 100% gently do not damage its seat, just gently close it. CW, screw.
now IAC is closed,
now bleed is closes
and you pinch the iSC hose,(air) all air is gone. now. it must stall and never start again.
see this?
these checks (RPM facts) will disclose to me what is wrong, or if there are un-metered air leaks.
all hoses must not cause RPM changes, except do not pinch these
PFREG (this foods engine if pinched)
the MAP hose (you dont have it)
the PCV, do not pinch it or seals in the engine can leak, for this 1 hose, eyeball ispections only workl
the Brake booster hose can be blocked , pinching it is near impossible but it must be tested, to be 100% sure. un do it and block it , with my kit of corks.
there are not all that many lines, see them ,at end.?
hose 45 is ISC metered air line, if you block it , the engine will stall, or run very very slow. (if the bleed is wide open the engine might run real slow.) i can not predict bleed , setting.
on one car it was missing on this forum. ouch.
post
Thanks Fixkick! Idle was working normal prior to me doing the service on the valves.
During that service I took off the throttle body, sidewinder tube and air intake hose. So, those are my prime suspects.
(missing gaskets or the main tube rubber ring, was folded over, and now leaks like sieve.?
I need some remedial troubleshooting here as I've never tried to solve a vacuum leak.
1. When I pinched the ISC air line, I saw the rpm drop. Hot engine rpm before and after, i need real numbers, only.???
Is this good or bad? its bad, if it didnt stall, but no numbers no guessing by me.
What should I expect on a car with no leaks? i it will idle at 800rpm at any electrical load. if A/T in DRIVE TOO.
How do I tell if this line has an air leak?
If that valve is at aprox 50% at hot idle, I would expect it to drop the rpm. So, while I saw rpm drop, I wasn't sure if this is good or bad. (no tacho, no joy)
2. If I pinch other hoses and the rpm drops does that mean that hose is leaking? yes and no. depends on hose function.
There's a little one that goes into the top of the throttle body (EGR ported vacuum) and one that goes from the main air line into the valve cover. PCV
3. The only screw I turned is the one under the rubber cap on top back of the TB. good we can fix that easy.
4. If I run propane around the hoses, I wasn't sure how high it should be set.(set what?)
Should you have a lot of propane flowing out or just a slight hiss if fine? Should it be coming out strong enough as if you were going to light it?
let it rip, do so out doors with gloves and goggles, in case it flashes over, propane is forgiving unlike any liquid fuels.
5. Is it possible that someone set the idle higher and higher as the throttle body was getting full of carbon? sure, but you had the throttle off
and im sure you checked that the VALVE is 99.99% closed, or at .0005" (smallest feeler gauge on earth, mostly)
That pathway of the fuel air screw under the rubber cap was full of carbon as well as the entire TB. yes, it was very dirty.
we can not guess the actions of any PO. but i assume he did it all wrong, and in most cases, they did. over and over..
that is because they never read the FSM. its all there. (not the .0005 check that is mine, they tell you buy a new TB< for 1K buck.
1:TV closed 99.99%
2: IAC closed hot, if not closed, all bets off. for 1 and 2. what is RPM now hot? 800, 500, 1000s or 1500 or what, i cant guess these, it must be stated.
3: bleed, can be set last and should but we can fiddle it all we want to aid diagnosis. close it. what happens? CW. set it.
4: pinch the ISC air hose and then engine stalls, there is no air to run car now. zero air, zero run, zero starts.
thanks,
John
here they all are, sans booster.
[img] http://www.fixkick.com/sensors/EGR/92-95-EGR-16v.jpg[/img]
http://www.fixkick.com