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I was an old member, I have a TBI Problem

chevyguybc

chevyguybc

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hey all, going to renew my subscription anyday now, waiting for mom to get home with the CC number for paypal! anyhoo!

picked up a 87 k2500, 8 lug, complealty stock.

4 speed, 208

dont know gear ratio, but thats all besides the point, i have done a ton of searching and am now asking

my pump and tank work and are like new... it gushes fuel out the line..

I bypassed the sleector valve on the return , still same problem.

It trys to start on the huge amounts of drips coming from the injectors...

what would cause this dripping, and not a misting

Im going to a wrecker after I write this to grab anything and everything I can

If i dont get it working, its getting a edelbrock intake and quadrajet carb:doah:
 
If this truck sat for a long period of time the injectors could be clogged up from bad fuel and that's why they drip and won't spray properly.
 
I would say dirty/clogged injector. Also switching from FI to Carb is not as quick and easy as you think. You have to deal with the High pressure fuel system of FI and go with a low pressure for carb and Then youve got the tranny and dizzy all get involved as well. Do some research b4 going this route.
 
Fixing the FI will be a lot less work than swapping to a carb. Plus FI has lots of advantages. Don't forget about all of the carb tuning issues you will get, which will probably be as much work as your existing FI problem.

When working on FI, connect a fuel pressure gauge. I think you have to disconnect a line to add in a "T" on TBI. Then you know what you are dealing with. You might want to find somebody with the same setup who will let you trade injectors for a few minutes for troubleshooting.

So how does it run? Won't start at all or some other problem?
 
The great thing about 1987's is that they are EFI. Fix it, don't put a carb on there, you would regret it later.

Martin
 
I agree keep the TBI. Theres a good reason so many people, myself included, are swapping TBI or even newer types of fuel injection onto these older carbed rigs
 
yes, the tbi will be nice if i ever figure it out

I put new injectors on it today and all sensors, coil,

from a junkyard i got it all for 50 bucks canadian, major deal

anyways, i can tell the injectors are working properly, BUT, same problem!

I am pulling the tank I think the pump is not working correctly, or the sock is gummed up( ive seen this before from a sitting TBI)

also, when i crank the truck, a few seconds after the crank, the fuel pump relay makes a noise,

also the TBI doesnt prime when the key is turned on

I was showing code 12 over and over again
 
First point of attention. DONT GO BACKWARDS!!!! FI to carb is a terrible terrible idea. Theres guys out there that shed a tear and busted their ass to go from carb to FI.

Now that thats off my chest. Are you trying to crank the truck immediately after your turn the key on? It takes 3-4 secs for the lines to get proper fuel pressure. Remember they are 13-17psi now 55psi.

Secondly have you checked the simplistics like fuel filter, fuel condition, and pos at the injector? Before jumping and spending money theres some simple things you can do. One would be to put an actual pressure guage on the line. Two would be to put a test light on the injector and make sure your getting a good signal, and three would be to make sure that filter isnt gummed up.
 
thanks for all the posts!

I can hear the injectors clicking!

The fuel is old and has been drained!

I am pretty sure it is the fuel pump sock, its gummed up and not allowing fuel to enter.

how can i test the fuel pump while its dry and out..
 
Its getting fuel, but dripping it, thats why I think its a fuel pressure thing

Why is it only dripping it, and not spraying it, well due to lack of fuel pressure
 
chevyguybc said:
Its getting fuel, but dripping it, thats why I think its a fuel pressure thing

Why is it only dripping it, and not spraying it, well due to lack of fuel pressure
Click to expand...

There still is the possibility that it might be pumping fine from the tank and getting gummed up at the filter. It could be a 20min 12 dollar fix rather than an all day diagnostic.

Put a pressure gauge on it before and after the filter and see if theres a difference.

You could also try smacking the bottom of your tank. You might move that sediment around and wahlah. Definitely a pickup issue then. Which reminds me, purhaps that plastic baffle that the tbi tanks came with has broken (like they do) and maybe wedged itself under the pickup.
 
i have bypassed the frame pickup already with some fuel hose, also bypassed the tank selector valve, because only one tank is active


technically I need to drop both tanks, which I will, and replace the selector valve, or get it working and install a new pump in the other tank

Im fine with one tank working

I will be droppin the tank tommaro

hopefully a gummed up filter sock explain the dripping of fuel.
 
Did you clean out the injector pod passages when you swapped the injectors out? If you have fuel gushing out of the supply line when you crack it open and hit the key, it is probably alright. Do you have any fuel coming out of the return side?
 
i had the same type of issue it was the pressure regulater was bad right on top of the tbi mine only run foot on the floor wfo would not idle put new regulater on all better can even buy a kit from napa to put new springs and stuff
 
i stucka complete injector pod on from a 94 350. didnt have to mess with the injector, just some stubborn lines on the back

it was looking alot better,

i dropped both the tanks this morning after trying all my new sensors( well new to me) and the what look to be rebuilt injectors. the spray pattern looked good, but it was still a heavy drip

how can i check my return line to see if its clean

the rubber inbetween the fuel pump and the tube is rotted away, athough still looks like fluid would pass threw it.. although Im thinking it would close shut under pressure and that along with the very old filter sock would stop the fuel.

when I turn the key on it did not drip or squirt, only did it drip when cranking
 
Is this causing a problem other than the fact that you noticed it and it bother you? I've honestly never looking at my injector spray pattern, just rebuilt the TBI and went.
 
chevyguybc said:
the rubber inbetween the fuel pump and the tube is rotted away
Click to expand...

This is definately your problem. You aren't getting fuel pressure becasue the pump is picking up fuel and then losing pressure at the bad hose. I have a friend with an S-10 blazer that this just happened to him, he replaced the hose and all is good now.
 
yes, i just got back from replacing the tank strainer, and that little pickup filler of hose.

IT had a hole, and was leaking thru there...

the tank is dry now, and back installed with all new rubber hose everywhere, I had to cut down this perfect rad hose my parts guy found

its a radiatior hose, it should be fine for filling the tank right? fuel doesnt sit on it permanently....


also, is this normal, turn the key on and it primes, then when u crank it primes but doesnt stay on until vehicle is running? im waiting for my gas to get here , hopefully Ive fixed it and another chevy is back on the road, with one tank out of two, haha
 
Fuel pump primes, and does not run again (assuming the key is not turned to "off") until the ECM sees that the coil is firing as the engine rotates.
 
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