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I have a friend that brought me a 92 Chevy S10 that when you go to start it the carburator just DUMPS fuel into the engine, if you get it started it smooths out a good deal but will idle high and is running rich.
I don’t have much experience with carburetors as I was born into the fuel injection generation….this doesn’t even look like a pure carburetor either though, it looks like some electronic, mechanical bastard child, it has a bunch of electronic sensors on it that I’m not used to seeing on carburetors.
Where should I start on this problem?
The way maintenance has been done on this vehicle I expect it to have more then a few problems.
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[quote=”Nodak81″ post=174048]Correct me if I’m wrong but I thought all the engine options for a ’92 were TBI in some form, not carburated. Sounds like an injector is stuck open, or an injector wire could be grounded out so it’s staying open soon as the key is cycled. O-ring could be an issue too.[/quote]
This is the correct answer
[quote=”Evil-i” post=174073]Unless someone has re-engineered things, that truck should have throttle body injection.
If I remember correctly, Russian Ladas were the last carburetted vehicles available in North America, and I’m pretty sure even these primitive lumps were fuel injected by ’92. Ironically, GM developed the fuel injection system for Lada.[/quote]
I believe 87 was the introductory year for TBI on the S-10’s
A little more info to help you work on this in the future
Use a paper clip or jumper wire and connect the two terminals on the top right of 16 pin connector on the bottom of the dash looks like the obd II connector.
Turn the key on and count the check engine light flashes for codes you will get 2 digit codes. This is an obi I system so if you have the old Snap on red brick you can use it on this vehicle if you also have the cardsI was thinking the same thing when I seen it was a 92, was figuring that someone dropped a different engine in. But yes those GM injectors like to blow the top seal. Watch for gas to pour out right where the injectors wire connector plugs in
Okay so all the gaskets and such I was to check were good, engine code said it overheated and that was it.
Changed out the plugs and checked for spark. Checked the distributor cap and rotor.
Checked the EGR valve, it was completely clogged so that part is on order.Here’s the weird part though, the injector was spitting out tons of gas when starting, I noticed the red wire (there’s also a blue one) was frayed and kinda broken.
I cut the wire, stripped it and soldered a new piece of wire in. Now the injector doesn’t put out any fuel when starting…I checked the fuel injector and it was working fine, I checked the continuity between both sections of wire and it was fine and the wire goes back into the engine harness off to somewhere….the fuses are fine.
I’m working on getting some wireing diagrams for the truck but could there be something I’m missing? I find it weird that I would go from one extreme to another.
Any thoughts besides the ones that I listed?
Never actually worked on a TBI system myself, I kind of went from carbs then straight to multiport EFI. But I believe the blue wire is the ground wire controlled (pulsed) by the computer, you’ll need a noid light to check the pulsing (while cranking engine over). I assume the red wire must be the positive lead. Do you get +12v from the red wire with the ignition on?
It is positive.
I received power while cranking before I fixed the wire.
Now I don’t. Looking for a diagram to see where this son bitch is supposed to go, I’ll probably end up running a new wire and zip tying it to the existing wire harness.When I did receive power though it was not pulsed by the computer. It was a constant heavy flow, like all it did was open a valve.
[quote=”CrazedAssassin” post=174641]
When I did receive power though it was not pulsed by the computer. It was a constant heavy flow, like all it did was open a valve.[/quote]You mean the red or blue wire? Only the ground side is pulsed by the computer, I think the positive side is just like any normal switched connection, should have 12v anytime the key is on. Depending on what circuit you tap into you might want to throw a fuse in-line since the other end is going to the computer via the injector, don’t want too much juice getting through!
On that particular system the fuel pump is wired in with the oil pressure sending unit. If oil pressure is low it will shut off the pump.
Spray it with a little starting fluid if it starts check the fuel pump relay.Awesome that’ll help a good deal; I’ll be back out there Tuesday or Wednesday shop we’ll see what I find.
Found a wire diagram.
[IMG]http://uploads.tapatalk-cdn.com/20160908/5c1ebc7edecc1d268529f209d803a7fe.jpg[/IMG]
Okay update is that apparently I blew the fuse while soldering the wires and overlooked it because I had just checked the fuses before soldering.
So that was a smart one lol….
So then we tried turning it over and the damn thing caught on fire and I had to put it out.
I was confused for a bit on what it could be before I realized the bolts / studs that hold the throttle body on the engine were snapped and it was just laying on top of the engine…..Bought new studs, drilled, extracted, and tapped the holes and now the housing is on there correctly.
But now that I have repaired these things it doesn’t want to start…..although the owner would have try to crank it for about 30 minutes at a time before to get it to start…..
Looking to borrow a portable air compressor at the moment to do a compression and leak down test. I don’t think the valves are seating down all the way.
Okay so the IAC and the coolant temperature sensor were bad, the injector is now working appropriately.
Still having backfires out the intake though like I mentioned beforeLeak down test showed 96% compression loss on cylinder 4 out of the intake.
Cylinder 3 only had 10% loss.
Cylinder 2 46% out intake.
Cylinder 1 24% pass the piston rings.So…. You can see where this is taking me lol
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