tbi flooding out, gas in oil, injectors pouring not spraying

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Swims350

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yes this is for my 88 gmt400 but hey you guy sknow alot and most of you know I don't like, nor do I know much about fuel injection.

Ok so first up just put in a new CTS or coolant temp sensor thinking that was it.

Well i guess not.

truck floods out completely, gas in my oil, smells like gas in it, overfilled by an inch on the dipstick. oil is thin as well because of it. It's brand new oil I just put in. No miles, maybe 5-10 mins run time on it, was not overfilled before.

awhile back when I got it back together and running(had sheetmetal off underhod for paint) one time it idled very fast and was unusual, did this after the battery had drained and I charged it up, then after that one time it was back to normal.

Then just out of the blue I go to fire it up, fires for a second and dies, then I have to floor the pedal to fire it and then it doesn't fire right off. It sputs and coughs and trys and trys, puffing smoke out the pipes smelling of raw gas but after maybe 30 seconds or a minute of holding the pedal down and it doing this it fires and runs, trys to smooth out, then when idleing it starts loading up it seems and when I rev it runs horrible. I shut it down, won't refire, same deal have to floor it.

Next day, fires right up, check the injectors, they are pulsing you can feel the spirts of fuel coming out of them, but it's not a nice cone spray it's running like huge drops or pouring like but not solid stream.

I put in the CTS, unhooked the battery, tried it, same spray from them. I did it again letting it stay unhooked for about 10-15 minutes, still the same.

my o2 is new and plugged in, my map and esc is also plugged in and I have no clue what is causing this and why just all of a sudden.

My gas in the tank is old and very low so would it be something got in the system to cause this? I'm thinking of a complete tbi clean and rebuild, drop tank, clean, flush the lines and new filter. I don't want to do it and it not cure this though, I already wasted $30, 15 in oil and 15 in a new CTS. Right now money is very tight.
 

bucket

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From what I've seen, only two things can cause a crappy spray pattern with TBI injectors. Well, three things.

1. Low fuel pressure

2. Bad injectors

3. Bad o-rings that seal the injector to the injector pod.



If you do have bad injectors, they probably didn't crap out at the same time. One of them probably had a bad spray pattern for a while and you didn't notice it because it still ran OK. But then when the second injectors fails, it can run like absolute poo.
 

Swims350

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both had good spray patterns before. I checked them awhile back when they seemed to not be firing at all, it's only been a few months ago too.

now both do the same thing.
 

HotRodPC

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I say a POS could have gotten hung up in an injector too and holding it open, not allowing it to close.
 

Swims350

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I was thinking that, but they do seem to pulse, when you stick a finger under them to feel the gas it comes in spurts not like solid stream.

wasn't sure if they'd pulse if they were stuck open or just run straight all the time.
 

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I was thinking that, but they do seem to pulse, when you stick a finger under them to feel the gas it comes in spurts not like solid stream.

wasn't sure if they'd pulse if they were stuck open or just run straight all the time.

Have somebody cycle the key off and on while you look at the injectors, see if any fuel comes out...the lower injector O rings dont fail too often, but when they do, its without notice.
 
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Swims350

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I was reading online about checking for drips, gonna have to do it for sure to find out more info.
 

Jims86

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HotRodPC

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towman

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check all your grounds as you have had everything torn apart
 

crazy4offroad

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In WV if anything's going wrong right now you can usually blame a tree :lol: Hope you get it figured out. I like towman's suggestion too, you did have everything torn apart for paint.
 
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Swims350

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all the grounds are hooked up, none were left unhooked.

not only that but it ran after I hooked it all back upwithout flooding out as it's doing now.
 
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89Suburban

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I never heard this problem before, you sure like to be the guinea pig don't ya bud? :roflbow:

Sucks about the new oil wasted.
 

Swims350

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injectors are not leaking when the engine isn't running. I cycled them on and off thru the key no cranking and had no drips at all.

yea I'm always the one with bad luck on crap.
 

Jims86

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injectors are not leaking when the engine isn't running. I cycled them on and off thru the key no cranking and had no drips at all.

yea I'm always the one with bad luck on crap.
If you have a Digital volt meter, unplug the injectors, and do an ohm test, they should be very low at 1.2 ohms each. To check them measure the lead resistance of the DVM leads (short them together). Then subtract that from the readings from the injectors.
I know its a long shot, but we need to eliminate bad injector windings.

Also, I notice that you have not mentioned the MAP sensor in the things that you have checked.
If ANYTHING is wrong with the vac connections, or the electrical connections, the truck will run pig rich. If you still have the original vac line going to it, make sure its in good shape. A low vac reading from the MAP, tells the ECM to richen her up.
 

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