Need 1st gen Jedi's help... throttle bog & backfire

TOY2G said:
I have not checked the fuel pressure ( i lack the gauge). I replaced the plugs when we did the head (less than 300 miles ago).
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Right. What he's saying is, pull them now and see what they look like. The condition of your plugs can sometimes tell you what's going on in the combustion chamber.

Starting fluid should not have messed up the AFM. It's just a flappy door on a potentiometer, it's not like a MAF where's it's sensitive to different chemicals or gets cranky when it's dirty.

Also, I'm still baffled by your vacuum advance hoses and wonder if you have a 22R distributor on there. The 22RE has an electronic advance setup. If you have vacuum hoses on the dizzy, then I'd like to see pics of where those are coming from on the manifold and/or valve cover, and I'd like to see a pic of your ignition coil on the drivers inner fender if you have a minute?
 
KidVermicious said:
Right. What he's saying is, pull them now and see what they look like. The condition of your plugs can sometimes tell you what's going on in the combustion chamber.

Starting fluid should not have messed up the AFM. It's just a flappy door on a potentiometer, it's not like a MAF where's it's sensitive to different chemicals or gets cranky when it's dirty.

Also, I'm still baffled by your vacuum advance hoses and wonder if you have a 22R distributor on there. The 22RE has an electronic advance setup. If you have vacuum hoses on the dizzy, then I'd like to see pics of where those are coming from on the manifold and/or valve cover, and I'd like to see a pic of your ignition coil on the drivers inner fender if you have a minute?
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here is the picture of the two vacuum lines from from behind the dist to the intake. I read that you have to cap the two lines there to do the timing.

 
TOY2G said:
here is the picture of the two vacuum lines from from behind the dist to the intake. I read that you have to cap the two lines there to do the timing.

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those are from the power steering pump, and have nothing to do with timing.
which also means, capping them wont change anything in regards to what you've been doing either.
 
I had a friend that had the same problem although on a chevy s10...as mentioned above it was a bad catalytic converter that broke apart and clogged the exhaust.
 
Well, I have an update, but no resolution.

I have managed to fix the idle, sitting at about 900 rpm at temperature. I adjusted the AFM to make the mix a little richer, it fixed both my idle problem and 90% of my bogging when hitting the throttle.

you can see in this pick I moved it three teeth, the factory setting was at the tooth you can see the small mark on.




Next I jumped the B and Fp terminal to get constant fuel pressure with key on engine off. I was trying to rule out fuel pump, however I am still thinking that may be part of the cause. It will not start without starting fluid, even with the fuel pump on full time.
Cold start injector is at 3.4ohms and there is fuel getting to it.

I did find this under the throttle body.

when I removed the plastic cap, there was a small screw sitting in it along with a tiny o-ring. I re-installed the screw, but nothing changed. I suspect this is the fuel pressure regulator, however, a search for the part online turns up nothing that looks like mine. Not to mention, this diagram shows it in a different location Part (23280) mine is in the area of part (22210E)

481808804.png~original



SO in the end, I figured out how to make the idle better by compensating for modern fuel with the higher flash point....BUT... the truck will still only start with starting fluid, even if it has been running 20+ min and at full operating temp... if you shut it off, it needs starting fluid to start it.
 
Check key harness in colum, the plastic tumbler contacts inside may be done.Did you check cold start injector while you are it? Often over looked here in texas since it never gets down to ohio temps, although it was nice there for turkey day week while I was there. Good luck
 
[MENTION=49649]KidVermicious[/MENTION] how important is the fuel damper?

Mine had the screw missing out of it when I took that cap off, I ordered a new one, but that would not cause my fuel problem would it?

I got a new cold start injector and if I give it power with my power probe the truck will fire off like a new car. If i do not inject it manually, it will start now, but after about 8-12 seconds of cranking.

The part that blows my mind....I can let it run for 30+min in my warehouse (55 degrees) and even at full operating temp, once you shut it off, its still a hard start.

I ordered a new fuel dampener, and a new pressure regulator (just in case)...I just appreciate your thoughts on the matter since you know these first gens pretty darn well.
 
My understanding is that the damper isn't necessary for the truck to run. If it was bad for a long time the fuel injectors might have been damaged though?

I have two sets of injectors on my shelf, but they've been sitting for a while...
 
Im probably way off here..but what if the pcv valve is stuck open and causing the hard start from too much oil getting in the intake?
 
TOY2G said:
[MENTION=49649]KidVermicious[/MENTION] how important is the fuel damper?

Mine had the screw missing out of it when I took that cap off, I ordered a new one, but that would not cause my fuel problem would it?

I got a new cold start injector and if I give it power with my power probe the truck will fire off like a new car. If i do not inject it manually, it will start now, but after about 8-12 seconds of cranking.

The part that blows my mind....I can let it run for 30+min in my warehouse (55 degrees) and even at full operating temp, once you shut it off, its still a hard start.

I ordered a new fuel dampener, and a new pressure regulator (just in case)...I just appreciate your thoughts on the matter since you know these first gens pretty darn well.
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that sounds like a bad fuel pump.

ive had mine do the same. for me, the cause is running the tank too far down, and overheating the pump. this takes out internal check valve. the fuel drains down, and has a harder time pressurizing the line when you try to start it.

I verified this with a pressure gauge. it would crank all day, and never start, until it hit 38 psi. but never before that. replacing the pump fixed it.



next time crank it for 1-2 seconds then left off. then try cranking again, see if it starts faster.
 
Well.... I am giving up (for now)

Cold start injector is now working properly (FYI CSI gets 9.5 volts from the Temp Time Switch)

I tried to drive it today and as soon as I start giving it throttle, it chokes to death. put it in drive and let it idle...all day long, but any throttle at all and it falls all over itself. I cannot even get it to 4000 rpm now, even in park...

So i backed it into the warehouse and that is wher eit will stay until i feel better about it.
 
KidVermicious said:
My understanding is that the damper isn't necessary for the truck to run. If it was bad for a long time the fuel injectors might have been damaged though?

I have two sets of injectors on my shelf, but they've been sitting for a while...
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How much are you wanting for one of the sets of injectors. I have replaced everything else, so I figured I can get the injectors from you and rebuild them, perhaps that will help.
 
TOY2G said:
How much are you wanting for one of the sets of injectors. I have replaced everything else, so I figured I can get the injectors from you and rebuild them, perhaps that will help.
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PM me your address. If they work then you can paypal me whatever, and if they don't you can pitch 'em. :D
 
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