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[bigdeath]

Ok I have a 92 suburban that gets fuel pressure all the way to the throttle body and I have rebuilt the whole upper throttle body. The Injectors spray once its running if I start it with fluid or gas in the intake to help it. And it will run as long as I feather the pedal to keep it running, but , it wont idle and when it dies it wont start by itself. Its a 220 tbi system. any ideas?

[Osirus]

have you checked all you injectors? Well 92 isn't that afi? Well you could also be losing spark on one of your cylinders too. there is a number of things that could cause that problem. doe's it do it all the time or just winter time? cuase my camaro used to do that.. Come to think of it hows you timing? that could also affect it.. chevy's are very picky.

And if anyone says a chevy doesn't have a mind of its own is out of there mind.. Some days my camaro started up right away and wanted to run other days it just didn't want to do anything. Ill research it for you.

[bigdeath]

ITs a 350 with a throttle body. IT starts if I feed it and runs fine as long as I keep it runnin. The timmin might be a little fast but its still set the same as when it was running fine. The injectors dont pulse on idle or on start up is the problelm.

[Osirus]

what kinda carb are you running? Sometimes even after you rebuild it doesn't open up right. I went with edelbrock on mine and it was awesome. I can't remeber what one i was using but if i can remeber the carb was opening up right which was cuasing that problem.

[bigdeath]

Its fuel injection.model 220 Throttle body injection to be exact

[Osirus]

ok so its no carbed I was thinking those were carbed still With the throttle body on the side. When did it start doing this? And how long? I am trying to ask some of the guys i work with about it.

[bigdeath]

it happened 3 days ago and its been driving me crazy all 3. Luckily I bought a new car the day before it went

[Osirus]

ok well couple of things it could be. After extensive research.

1: you might have a mass air flow.
2: you could have a ect problem
3: unmetered air leak
4: leaky injectors

more info to come sorry at work lol

[bigdeath]

Mass air flow? I know injectors dont leak so that eliminates that. Im thinking a sesor and or the pcm is malfunctioning but usually that triggers a check engine light. So ITs got me all jacked up

[Osirus]

ok well our new service manager used to be a tech at ford.. yeah there 2 diff manufactures but he was worked on all types of cars.. Yeah next question was going to be your check engine light.. so its not on ok ill get back with you in a 1/2 hour or so let me talk to him.

[bigdeath]

k man thanks alot for your help and time

[Osirus]

He said you have a vacum leak.. A bad one take some spray while its running and spray it around and see if you can pin point it.. I have had that happen in my camaro .. hmmm why didn't I think of that but yeah vacum leak sounds right.. Well man let me know.

[bigdeath]

You can usually hear a vaccum leak though... I think? Also would that stop the injectors from spraying when its idling?

[Osirus]

Yeah vacum leaks you can not always hear. Its basically called unmetered air. And it will cuase you injectors not to fire. Best thing to do is use a can of b12 or can of propance cuase propane goes down. And spray around while you have someone feather the throttle.

Try this out I am sure its a vacum leak cuase I remeber when i put my edelbrock carb on it was doing the same thing and i had found to vacucm leaks 1 around the carb and another on the brake assist

[Kingsrookie]

vacuum leaks are hard to detect and most you can only hear when it is in the ac or heater. But your injectors have a small leak somewhere. I asked my dad and he saiud that that was what it was not a hard problem to fix

[bigdeath]

all the seals are new in the injectors though

[Osirus]

its a vacum leak man trust me on this just get some b12 and spray around and find it you can not hear all leaks. they spray will bubble where the leak is then you just get a few feet of hose and replace it.

If you have already checked your injectors for the small leak which is what i suggested in the begining and you said they checked out fine. Then its got to be a vacum leak.

[Scrin]

vacuum leaks are hard to detect and most you can only hear when it is in the ac or heater. But your injectors have a small leak somewhere. I asked my dad and he saiud that that was what it was not a hard problem to fix

hmm....

[bigdeath]

k ill try it

[Osirus]

let me know if it works.. I am pretty sure about this almost 100% sure. I have been working on cars since i was 10 lol but there is alot to learn still. I am rebuilding a 350 block right now.