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'94 5.7 TBI wont start, engine flooded?

This is a discussion on '94 5.7 TBI wont start, engine flooded? within the Technical / Maintenance forums, part of the General Discussion category; Hey guys, This is my first time owning a truck, and first time on a forum, so please bear with ...

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    '94 5.7 TBI wont start, engine flooded?


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    Hey guys,

    This is my first time owning a truck, and first time on a forum, so please bear with me. I have a '92 K1500 4x4 with a '94 5.7 TBI motor(154k). I noticed that most of the times I tried to accelerate, the engine "bucks" or falls on its face. Sometimes if I push hard on the pedal, she'll respond strong, but usually you have to feather the gas just right. Biggest time she falls, is on the hwy. So, I pulled it in my garage to take a look at it, and went to start it up..nothing. Just cranks, wont start

    Checked the fuel filter- Ok.
    Checked 4 spark plugs- One was COVERED in gas, the others had a light coating, but still present.
    Checked for spark- Ok.
    Checked ECT sensor- Bad. Post was worn down one one side. Replaced.

    Heres where im currently stuck. If my engine is flooded, I cant check if the sensor was my original problem
    Ive been told that holding down the pedal while starting, sends the engine into flood mode, which makes the air/fuel ratio leaner, but all that did was kill my battery, and I suspect, flood the engine more.

    Someone also said to take all the plugs out and let it dry, but it is about 30 degrees here, and from what I thought, it would take warmer temp air to evaporate the gas. And while they're out to try cranking it to force out the gas, but that seems flammable (potentially), and the more I try cranking over, kills my battery more.

    I'm lost!! Im a college student who just started my ASE major as of this month. Ive only tinkered with Honda's, and one '87 Chrysler Conquest TSI, so trucks are a new learning experience. I am def. on a budget but not scared to get in there and do it myself. Any help would be extremely awesome.

    Thanks!
    Mike D.

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    Re: '94 5.7 TBI wont start, engine flooded?

    How did you check for spark?

    Are you sure it's getting fuel? If you remove the air cleaner, you can see the injectors. You can also see if fuel is spraying from them if you get someone else to crank the engine.

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    Re: '94 5.7 TBI wont start, engine flooded?

    OK a couple of things here. First off welcome to the forums and you did right by buying a Chevy!!

    Now... On some GM vehicles putting the petal at WOT will put the computer in diagnostics mode which should shut off both the injectors and spark. This is used for crank testing and compression testing plus a few other things in the factory service manuals.

    To clear flooding there is no really easy way to do this but here is a trick I learned a while back. For really flooded engines (like yours) unplug both injectors, crank the engine and then open the trottle about 75% or so but not WOT. Crank until the engine seems to want to fire. (it may actually start for a few seconds) Now plug 1 (yes only 1) injector back in and try to start the engine again. If it starts great! but it will not idle so keep your foot on it and keep it running for a few minutes to clear out the fuel and warm up the engine. If it will stay running (sometimes they will once warm) then plug the second injector back in while running if not then just shut it off and plug the injector in.

    OK now about the battery... take it to your local O'Reilly's or Advance auto and have them charge it up for you if you dont have a charger. DO NOT rely on the alternator to charge your battery for you or you will be buying a new alternator soon. They are made to maintain a charge, and not to do the charging. Also DO NOT remove the battery cables while the engine is running... this does not test the alternator it frys them, Some old school testing methods were fine in the old days but not so much today.

    The ECT sensor will not keep you from starting, not with an OBD I engine. It will however mess with your fuel trims once the engine is warm. Check your injector spray pattern. It should be a nice fine misty cone not a windex bottle spray or a squirt gun. If you turn the key to on there will be a 1 second pulse from the injectors to give the engine some starting fuel. DO NOT turn the key on and off to give the engine more starting fuel... it will flood. TBI engines have the same manifold characteristics as a carb engine, meaning that they will puddle fuel in less turbulant areas and they are greatly effected by vacuum and air velocity. TBI was not much of an inprovement over a carb.

    I hope this helps get you going.

    Massey
    idriveafastcar and MvdNY82 like this.

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    1998 Silverado 1500 5.7L
    1999 Camaro RS
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    Is there life after death? F**K with my truck and you will find out!

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    Re: '94 5.7 TBI wont start, engine flooded?

    And to add on to what Massey has provided, while at the parts store, have them test your battery. BTW they also sell small manuals.
    00 k-1500 ECSB 5.3 4l60e, Z71, 231,500 miles. TRADED 5-2013
    03 2500HD ECSB 6.0 4l80e, 145,000 miles.
    05 K2500HD ECLB 6.6l LLY, 5speed Allison, 270,700 miles (Got 5-2013)

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    Re: '94 5.7 TBI wont start, engine flooded?

    I had the same bucking issue at full throttle. After I accidentally reversed the one of the injectors when I put new seals and filters on them. Also check and make sure the little baby filters on the tips of the injectors are decently clean.

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    Re: '94 5.7 TBI wont start, engine flooded?

    Thanks for all the responses guys! Ill be trying those ideas after class today and this weekend. Hope it does the trick, and I will post back with any updates.

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    Re: '94 5.7 TBI wont start, engine flooded?

    Well any updates?

    Massey

    Click below for pics

    1998 Silverado 1500 5.7L
    1999 Camaro RS
    2000 Camaro Z28

    Is there life after death? F**K with my truck and you will find out!

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    Re: '94 5.7 TBI wont start, engine flooded?

    Sorry, not yet Massey. Got caught up with school and got class 8-5 Sat. Might not have any progress till Sun. But thank you for the diligence, and i will post the moment i hear this baby purr again ;)

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    Re: '94 5.7 TBI wont start, engine flooded?

    Ok,

    I tried to start it today, and it killed my battery again! There has to be something draining it, because im only holding the key on for about 2 or 3 seconds at a time. I will attempt to borrow a multimeter from someone and see where the draw is. Its gotta be en route to my alt, or starter, although I looked at the starter orig., everything looked ok, wires tight. We'll see. Also, someone suggested using choke cleaner, or ether to help start it up. Any comments on that?

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    Re: '94 5.7 TBI wont start, engine flooded?

    How long did it take for your battery to die? How many times did you crank the starter for "2-3 seconds at a time?"

    Get a helper. Remove the air cleaner and the collar beneath the air cleaner so you can see the injectors. Have your helper crank the engine while you observe the injectors. Are they spraying fuel? If you can't see them spraying, stick your finger in and see if gas gets on it. You need to verify the presence of fuel at the injectors.

    How did you check for spark? The safest way is with a timing light. There are other methods, but I always use a timing light.

    You need to be absolutely certain fuel is getting to the engine, and you need to be certain there is ignition.

    If it won't sputter, cough, or act like it at least wants to start with ether, then I'd say you've got an ignition problem. With that said, ether is very hard on engines. Try what I suggested above.

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    Re: '94 5.7 TBI wont start, engine flooded?

    Hey jhowell,
    Thanks for the advice. Its a brand new battery, and it killed it on the 4th try of "2-3 seconds", my dad always told me not to hold it too long or you could ruin more than just the starter. It did the same with the orig. battery that came with the truck, but that battery was already in bad shape, so didnt think much of it. I have my roommate helping me, and yes im getting fuel to the engine. We did exactly what you are suggesting before i joined this forum. I checked fuel filter, fuel pours out with half a push of the pedal. Wiped off spark plugs till dry, put them back in and tried starting again and after a couple failed starts, they're covered again. Took off air filter housing off the TBI and had roomate look at injectors, injectors have a "misty cone" not spraying all over the place. Placed a paper towel under them. Towel is soaked. So, fuel is not my issue. (Except the lake of it sitting not evaporating in my engine due to it being only 20+ degrees here in Kansas). As far as spark goes, its there. I know because I was holding the wire with the plug in it when my buddy turned the ignition without warning me! Not only did i see 2 of the plugs spark outside the engine...i was holding one. Not the safest way, but i assure you, with the charge i got, it works. I have since checked with a light i got from a professor of mine, and again, we have spark. So,with that said, im thinking the engine IS flooded, but theres an underlying electrical problem. When my ECT sensor failed, i think it could have shorted out something else or vice-versa, like a 2 for 1 special. Now that i replaced the sensor, the engine wont realize the change till it Actually starts and changes my air/fuel ratio, since it is dumping way too much gas Everytime i turn the key. But i cant get it to start before my batt dies, it wants to go (its not sputtering, or choking yet) but i can tell just from the type of sound the engine makes, and with every rotation you hear it get weaker. I tried jumping it from my roomates k1500 (same exact truck), but wasnt enough current to work. Im def gonna run some tests on the elec. system tomorrow after class and see whats up. I just dont have the money right now to buy batt. after batt. without trying to find the problem first. Let me know if you think of anything else. Thank you all for the support.
    Mike D

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    Re: '94 5.7 TBI wont start, engine flooded?

    A battery shouldn't go dead after a total of 15-20 seconds of running the starter, especially if it's brand new. A new, fully charged battery should be able to turn the engine for at least a minute or more. The problem isn't the ECT sensor. They don't short out. They tend to fail quietly, with little fanfare.

    Your problem is the starter. The starter draws more amperage than anything else on the vehicle. It's the only thing that can suck enough power out of the battery to kill it in such a short time.

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    Re: '94 5.7 TBI wont start, engine flooded?

    A dead shorted ECT will not hurt anything as the engine reads the resistance of the ECT not a voltage signal. A cold battery does not have the same staying power as a warm battery so having a new battery suffer the cold and drain fast is not uncommon but dont let the battery stay uncharged in the cold as the PH change of the acid can be enough to freeze which will ruin the battery. Oh and the ECT will NOT cause flooding in any case.

    One thing that has not been mentioned but should be is the plugs. Fuel fouled plugs may be the cause of the engine not wanting to start as well. They may look clean but they do not conduct as well as they should which could cause a weak spark and that may be enough to keep the engine from starting.

    Have you tried my write up on clearing a flooded TBI engine? IF it is the battery that is keeping you from getting it done then have some one bring you to the local part store and get your battery charged and tested. Bring the Alternator too to make sure the alternator was not the cause of the old battery going bad and a bad alternator will make a good battery bad really fast.

    Massey

    Click below for pics

    1998 Silverado 1500 5.7L
    1999 Camaro RS
    2000 Camaro Z28

    Is there life after death? F**K with my truck and you will find out!

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    Re: '94 5.7 TBI wont start, engine flooded?

    So, i pulled the starter as jhowell suggested and had it tested. Starters fine and so is the alt. No burn marks or anything on power wires. So im not sure whats causing the draw on the batt that quickly. @Massey, i didnt think about the spark plugs. I did wipe them off and let them air dry before reinstalling them, they seemed to visually look ok but im going to purchase all 8 new ones and see if that does the trick. Sorry for the long wait for a reply but doing this and my school work is a tough battle;). I'll update asap

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    Re: '94 5.7 TBI wont start, engine flooded?

    Ok, we have life...sorta. I put the starter back in, replaced all 8 plugs. Sprayed some starter fluid in the intake, and she started up for a sec. My roommate sprayed more while i was starting it and it kept running as long as he sprayed the fluid in. I tried taking one injector at a time as massey suggested, but as soon as the fluids removed she dies. I will say this, when she kicks over the engine sounds really strong. I def think i got all of the extra fuel out. Would this be a timing issue? Might also be the reason she falls on her face when accelerating hard? any ideas?
    Mike

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    Re: '94 5.7 TBI wont start, engine flooded?

    Ok, this isnt working. Im outta here.

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    Re: '94 5.7 TBI wont start, engine flooded?

    If it sort of runs when constantly dumping ether into it, then you're probably not having a flooding issue at all. Sounds like you have a weak fuel pump.

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    Re: '94 5.7 TBI wont start, engine flooded?

    You have the same symptoms I did when barely had any fuel pressure. You say the injectors gave a misty cone...mine was more like a downpour cone. Replace your fuel pump with:

    http://www.summitracing.com/parts/ACF-EP381/

    http://www.summitracing.com/parts/ATX-WH3000/

    http://www.summitracing.com/parts/ATX-FS22/

    If that's not the fix at least you'll have an upgraded fuel pump, and from there I would check all your battery connections.
    '95 C1500, LT's, 3200 stall, and some PCM tweaking


    Quote Originally Posted by Chevy4life11 View Post
    ive got 8 inches and i still wish i had 6 more

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    Re: '94 5.7 TBI wont start, engine flooded?

    Quote Originally Posted by silverado_lover View Post
    You have the same symptoms I did when barely had any fuel pressure. You say the injectors gave a misty cone...mine was more like a downpour cone. Replace your fuel pump with:

    http://www.summitracing.com/parts/ACF-EP381/

    http://www.summitracing.com/parts/ATX-WH3000/

    http://www.summitracing.com/parts/ATX-FS22/

    If that's not the fix at least you'll have an upgraded fuel pump, and from there I would check all your battery connections.
    That's not really an upgraded pump, it's just a replacement. FWIW, just because some comes in a Delco box, does not mean it is a factory original part. Delphi is the maker of factory original pumps and as a standalone item, they can be had for about $30 less than the Delco. If the truck is still on its original pump/sender assembly, he's probably better off replacing the sender unit as well which comes with new wiring and strainer. Delphi sells the pump by itself, or as part of the complete pump/sender assembly. I bought a Delphi pump, and then a sender from Advance Auto Parts as it was far cheaper than the complete assembly from Delphi.

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    Re: '94 5.7 TBI wont start, engine flooded?

    For his truck it's an upgrade, his TBI pump probably maxes out at 15 PSI in it's functioning state. The pump I listed pumps enough fuel for a Gen III/IV engine. I see no point in replacing the whole sending unit for at least $200 when you can just replace the wiring, strainer, and pump for at least half the cost of the whole sending unit.

    OP if you do indeed get the EP-381 pump when you replace the pump be sure to replace the little black rubber piece coming off the outlet of the fuel pump with the rubber piece that comes with the new pump. I can promise that the rubber piece that came with the truck will split and you'll have to pull out your sending unit all over again to replace that tiny rubber piece.

    Ask me how I know
    '95 C1500, LT's, 3200 stall, and some PCM tweaking


    Quote Originally Posted by Chevy4life11 View Post
    ive got 8 inches and i still wish i had 6 more

 

 
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