I have a 93 gmc jimmy with the 4.3l vortec engine code w i have a fuel problem and can't really pin point it

Question

When i start the car cold if i put the throttle quarter down it fires right up first time but other wise it takes anywhere from 3-5 times cranking it and giving it gas to start so i thought it was the fuel pump, but then after a while of being hot it smells horrible inside and out but then for no reason it will smell fine again and when its hot when i give it gas it sputters and falls completely apart until about 22-25 mph then it drives fine and all highway driving is fine no matter how im driving but horrible in the city and for the first time last night when i shut it off it almost startin dieseling and tried to start back up when i shut the key off but then it shut off and i havent had a problem with that yet so far and i get horrible gas mileage i put in 45$ of 87 when it was 2.97 a gallon and only took me 215 miles so im thinking its either the fuel pump or maybe the pressure regulator is sticking but if anybody has any ideas im open thanks

Answer 1

I own a shop, and have seen this one many times. What you have is this; The engine idle speed is controlled by the amount of air entering the engine, and when you turn it off this air supply must be shut down completely, or it will try to keep running. What I have found this to be is a sticking EGR valve. You have the one that has the EGR that is very popular to do this very thing. You can test this by using a piece of pipe, or something you can tap at the base of the EGR valve while its running, and it will either go to running good, or go all to pieces like it does at times. This smell is from the cat converter getting hot due to the over excessive amount of air entering the engine. You could even have a plugged up cat converter. If it is, you can look at it at night after the vehicle has been ran for a while, and it will get cherry red if its plugged up. Look for any type of vacuum leak on the engine. You can do this with a propane torch. Don't light it, but just open it enough to put gas out, and move it around the engine while its running, and if you find a vacuum leak it will pull the gas into the engine, and it will change the idle speed as soon as you find the leaking culprit.
Part 2:
I own a 94 S-10 Blazer code W engine, and mine did the very same thing. What it turned out to be was the fuel pressure regulator was leaking fuel at a steady drip. Once I removed the upper plenium, I discovered about an inch of fuel that had leaked down from it. To replace the regulator, you must replace the whole spider assembly, as its not servicable, and must be replaced as an assembly. All that excess fuel will cause other problems such as the EGR to start sticking, and the O-2 sensor to stop working properly too. Dieseling is normally caused by an engine that keeps getting air into it even though the butterfly in the throttle body is closed, it somehow could be still getting air from some source. The old carbureted engines had a solenoid that deactivated and closed the butterflies completely off just for this reason. I don't care how much fuel is in an engine, if the air supply is cut off, it can't continue to burn. Is the butteryfly in the throttle body sticking in an open postion, and in severe need of cleaning? The (IAC Solenoid) Idle Air Control solenoid is supposed to close completely off once the igniton switch is turned off, and it may have build up in it, and its not closing completely off allowing air to continue to enter the engine. The EGR Valve will sometimes stick in the open position, and let air into the engine. Once you press the gas pedal enough to send that much fuel into the engine to make up for the extra air, then it would smooth out an run pretty good. The Throttle position sensor controls the amount of fuel the engine gets, and the IAC (sensor) Solenoid controls the amount of air at idle speed, but the butterfly is the manual control for air only to enter the engine. If the fuel pump is running more than you would normally hear it run, then its probably the spider assembly has to be replaced, but if its an air problem, then the engine has a bad vacuum leak such as the EGR staying open, or the butterfly (sticking) not closing off all the way. This engine is famous for the spider assembly to do this exact thing. They are not cheap, and you can only get it from the dealer. It is possibe the computer doesn't know what temprature the engine really is (bad temprature sensor), and it will do this. See if you smell the strong odor of fuel at the top of the engine after it has sit for about 10-15 minutes, if so then you can bet the spider assembly has problems.
Glad to help out, Good Luck!!!

Answer 2

This Site Might Help You.

RE:
I have a 93 gmc jimmy with the 4.3l vortec engine code w i have a fuel problem and can't really pin point it
When i start the car cold if i put the throttle quarter down it fires right up first time but other wise it takes anywhere from 3-5 times cranking it and giving it gas to start so i thought it was the fuel pump, but then after a while of being hot it smells horrible inside and out but then for no...

Answer 3

You will have to do some checking to be sure. Make sure all of the secondary ignition wiring is in good shape. This means pulling wires off the cap and plugs to inspect for corrosion or carbon tracking. Check the coil wire as well. If you find something, replace everything that has corrosion on it and the complete set of spark plug wires. If it's all good, make sure the coil can produce strong and consistent spark output. Then check the fuel pressure, you need to have around 45 psi while running. I suspect what you have is an internal fuel leak inside the intake plenum. With the fuel pressue guage connected, turn the ignition on but don't start the motor. Check for fuel pressure coming up to spec and then the pressure leaking down quickly. If it does this you most likely have a CPI leak under the intake plenum and will have to replace the whole thing. If you lift the plenum off and the intake is really clean inside or there is puddles of gas inside, you've found your problem. With you saying it smells and poor gas mileage, I would suspect this.

Answer 4

93 Gmc Jimmy

Answer 5

Those CPI motors have an "fuel spider assembly" under the intake. It consists of 6 plastic fuel line to feed the cylinders and the fuel pressure regulator. It is best to replace the supply lines in the back of the plenum too. Not hard to do, time consuming. One of those will make the truck run like that. I'd also suggest replacing EGR Valve too as it will be carboned up from too much fuel.And get the gasket with screen in it (Tomco # 2-1357) to prevent new EGR Valve getting screwed up!

Answer 6

hi i have a question i have a 93 gmc jimmy 4x4 6 cyl vertech engine fuel injection.the truck keeps bogging out when i give it gas ,is hard to start sometimes. what can be the problem i think its the fuel presure regulater..whats your thought ..thanks

Answer 7

--->> Tips---> https://trimurl.im/g16/i-have-a-93-gmc-jimmy-with-the-4-3l-vortec-engine-code-w-i-have-a-fuel-problem-and-can-39-t-really-pin-point-it

Answer 8

Haven't thought about it

Answer 9

Michael Lee and Cole Williams asked the same question. You should read their answers side by side.

Answer 10

ive seen to of these chevys withe cat partially plugged causing hesitation and odd power surges now i dont know for sure but have some exhaust shop check this out just have them listen to it.