94 4.3 v6 w lopes then stalls
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94 4.3 v6 w lopes then stalls - 8/21/2008 4:37:41 AM
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Co.45
Posts: 15
Joined: 8/21/2008
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To start i bought this truck about two weeks agao since then i''ve yanked the egr and put in a tomco clean screen
then i yanked the upper plenum and noticed the nut kit was leaking and the fpr was real bad had a puddle on the passenger side.
when i first bought the truck the gentlemen told me he thought and was told by numerous people tho check the cap
becasue it was driving ok until he had a new cap and plugs put in.
well upon the very first diagnosis the main vac line coming off the back (inches away from cap) was split in half so we replaced and check alot more with issues and fixed them! cant find anymore broken vac lines in the engine compartment i have yet to follow the ones going over top of my tranny and back to the fuel tank. im also grabbing a vac gauge today to see if this is the issue!
but after the nut kit and fpr im kinda at a loss? i really thought this was the issue? it still lopes for about a minute and stalls out in neutral and def stalls out in drive whether im stopping or not!
i read this could be the sensors on the plenum? (i forget all the initials) im wondering if the cap could have been put on wrong?
it also hesitates while driving at 40mph any other speed it is mostly smooth?
im all out of ideas? Any help would be a fantabulous
http://www.techsupportforum.com/automotive-center/automotive-support/279402-94-chevy-s10-4-3-v6-problems.html
(i was also directed here by a friendly fellow from another forum here is the post with a little bit more detail)
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RE: 94 4.3 v6 w lopes then stalls - 8/21/2008 5:39:36 AM
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swartlkk
Posts: 14308
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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I see that you have cleaned the EGR, but as was asked in the thread you linked to above, did you clean the pintle area of the EGR valve. It is possible that a chunk of carbon is holding the pintle open, causing your idle problem.
An easy way to find vacuum leaks is with an unlit propane torch. Trace along all intake gasket surfaces and vacuum lines with the unlit torch and the engine running. If the engine speed increases, then you have found a leak.
Also, you may want to remove and clean the idle air control (IAC) valve. It is located near the throttle body (if you can call it that) on the upper half of the intake plenum. That valve controls the air that is allowed into the engine at idle. If it is stuck, you could experience these same symptoms.
At this point, I do not know if the two problems (idle and hesitation) are linked to the same cause. Try the stuff above and let us know how it goes. We will work from there.
_____________________________
Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: 94 4.3 v6 w lopes then stalls - 8/21/2008 12:32:50 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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just tried the vac test you recomended.. nothing happened
i also got under it and found the three lines going back to i think the transfer case
right on the front side of the driveshaft?
anyways one of those lines has vacum the other two dont?
are they supposed to?
and the iac was checked prior to the cpi work. it was actually really clean even though it was never replaced!
also below the iac/throttle body there is a vac line i pulled it off under the air box and it didnt have vacum at all
so i pulled it off right below the iac and ran the engine and that didnt have any vacum unless i turned the throttle
also the EGR i made sure it was really clean.
< Message edited by Co.45 -- 8/21/2008 2:22:52 PM >
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RE: 94 4.3 v6 w lopes then stalls - 8/21/2008 4:30:22 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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I was also told that this could be the cam lobes being worn down?
but wouldn''t that create problems the whole time? it drives good except when its at idle then it stalls
im at a loss dont know what else to check except the the cap being put on wrong? testing that this weekend
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RE: 94 4.3 v6 w lopes then stalls - 8/22/2008 4:44:51 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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update i just hooked up the vac gauge i had 20 off the ball looking thingy and when i went to uplug the vac line coming off the back off the plenum it ran ok???
im assuming this is becasue i have a pinched line somewhere unless one of those line goes to my evap canister but i could have sworn the line off the front of the plenum under the thorttle went to the evap canister?? could it be one of the lines going back to the transfer case? and would that be causing the problem of it sputtering while driving at constant speed?
anyone have any ideas!!!???
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RE: 94 4.3 v6 w lopes then stalls - 8/22/2008 4:52:14 PM
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swartlkk
Posts: 14308
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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So you removed the IAC valve and cleaned it? Sounds like you have an idle speed problem since it idles better with a large scale vacuum leak. You may need a new IAC valve.
_____________________________
Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: 94 4.3 v6 w lopes then stalls - 8/22/2008 5:04:15 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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I was thinking that, there was something wrong when i pulled the iac off it was spic and span which seemed odd to me?
but it also wouldnt move but im not even sure if its supposed to?
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RE: 94 4.3 v6 w lopes then stalls - 8/22/2008 5:05:37 PM
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swartlkk
Posts: 14308
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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They''ll move, but they require some force to get them going. The fact that a vacuum leak makes it idle better tells me that the IAC isn''t doing its job.
_____________________________
Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: 94 4.3 v6 w lopes then stalls - 8/23/2008 8:33:58 AM
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Co.45
Posts: 15
Joined: 8/21/2008
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Thank you so much!
ill give it a try im going to check to see if i can test it with volt meter first if not ill just replace it!
let ya know how it works out for me!
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RE: 94 4.3 v6 w lopes then stalls - 8/24/2008 12:16:23 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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Update!
i just put the new IAC in didnt change anything?? i really thought that was it! I put it in started it up and it ran alittle better for a couple seconds then went back to its usual self? so i went and returned it
gonna get under it today and see if one of those lines going back above the tranny are piched along the way?
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RE: 94 4.3 v6 w lopes then stalls - 8/24/2008 12:25:46 PM
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swartlkk
Posts: 14308
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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Does your fuel pressure hold steady after you pressurize the system, then turn the key off? I am starting to wonder if there is a slight drip from something that is causing a rich condition...
There is definitely something that is causing it to choke down...
_____________________________
Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: 94 4.3 v6 w lopes then stalls - 8/24/2008 3:29:43 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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to me its bad news but im sure it might give you something else to work with.
I went and bought another iac becasue the first one i bought looked like someone bought and tried and took back
so with the new one in i took it for a drive becasue on the first one i failed to read my haynes book fully to see my car had to get to temp first (duh) so with that acting the same way with the new one in i decided to check all electrical connects from the IAC to the relay and it was terrible all this black greasy stuff gooked on in three ports on both relays so i cleaned out the plastic connectors with some contact cleaner and plugged both of them back in and started it up.
to my surprise it stareted up and ran perfect for about ten minutes! then it shot a service engine soon light at me so i turned it off and jumped the ground and diagnostic on my connector and it said it was the IAC so i decided to clear the code and run it again to see if it would shoot the code at me again? did that started it up and it was back to its normal self almost choking out like you said then i put the new IAC on and tried it same thing i even pulled the relays out and shot cleaned those out good. i used the contact spray again (not sure if that could ruin them) but took it for a drive and im still in the same boat but it confuses me alot on why it ran so good for so long till i cleared it?
also i went to start it back up and i accidently had the jumper still in and i pulled it out and turned the key off then started it before it went back to normal lopeing and stalling... and sometimes when i let it stall out real bad like it slows down alot and stumbles a couple times and stalls out, i start it up it revs really high then drops down to regular idel speed
ohh and the vacum kit i bought also tests feul pressure but i dont think i have the right connector to plug in on the bleeder vavle on the nut kit coming out the back of the plenum should a type of thing like that be carried at a local auto parts store? it also came with a t connector and a couple of other fitting but i dont see how it could be used to test pressure outside of that specific fitting to go on the bleeder vavle?
< Message edited by Co.45 -- 8/24/2008 3:35:05 PM >
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RE: 94 4.3 v6 w lopes then stalls - 8/24/2008 5:50:10 PM
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swartlkk
Posts: 14308
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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If it is a combination vac/pressure gauge, then it probably doesn''t go high enough for the fuel pressure that your engine requires (50+psi).
Have you determined where all of that "grease" came from? Sounds like something cooked itself at the relays.
_____________________________
Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: 94 4.3 v6 w lopes then stalls - 8/24/2008 7:51:25 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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No i havnt yet we checked what seemed to be the o2 sensor connections and iac im planning to follow all of them tomorrow.
is there a simple way to test them without actually pulling apart harnesses?
also i went and messed witht he relays again and got it to idle normal so once this happened i went for a drive pulled out of the drive way and hit the gas and it stumbled real bad hesitated more than the usual did this for a good bit and now its stalling out as soon as i stop like a two three second delay from full stop to stall also there is a weird noise im getting from the rear and off the relay
sounds like the feul pump running after the engine stalls for about four sec then a click noise from the pump and the relay?
I have 4 videos here for you i want to get one of the noise so i figured getting the idle would be good to
Driving Stall Fuel pump noise Starting stall Idle and stall
< Message edited by Co.45 -- 8/24/2008 8:18:51 PM >
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RE: 94 4.3 v6 w lopes then stalls - 8/25/2008 9:25:58 AM
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swartlkk
Posts: 14308
Joined: 5/1/2005
From: Waterloo, NY
Status: online
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Fuel pump sounds normal.
It definitely seems like an electrical problem and seeing as how messing with the relays caused things to work, I think that is where you need to focus your attention.
_____________________________
Kyle-
2004 Rainier
1970 Chevelle - Resto
1974 K5 Blazer - Resto
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RE: 94 4.3 v6 w lopes then stalls - 8/25/2008 1:55:39 PM
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Co.45
Posts: 15
Joined: 8/21/2008
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Just got back from first day of school with the kids.
im about to check all the electrical as soon as it cools down.
let ya know what i find!
i hope i find it
< Message edited by Co.45 -- 8/25/2008 3:29:16 PM >
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RE: 94 4.3 v6 w lopes then stalls - 8/26/2008 4:48:18 AM
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Co.45
Posts: 15
Joined: 8/21/2008
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would a bad alt cause my stalling problem becasue my bat does drops down as soon as the engine stalls out
and drains pretty quickly there after?
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RE: 94 4.3 v6 w lopes then stalls - 8/27/2008 12:54:33 PM
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Leeann_Bravada
Posts: 72
Joined: 8/27/2008
Status: online
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I just joined because I''m having the same issue with my ''93 Bravada vin W....and I have just found this TSB:
No Start, Hard Start, Rough Idle After Start (Clean CPI Poppet Valve) #99-06-01-022 - (12/21/1999)
No Start, Hard Start, Or Rough Idle After Start (Clean CPI Poppet Valves)
1992-1995 Chevrolet and GMC M/L, S/T Models
1992-1995 Oldsmobile Bravada
with 4.3 L Engine (VIN W RPO L35)
Condition
Some customers may comment on no start, hard start, rough idle after start, surge, or other driveability concerns related to the fuel system (clean CPI Poppet nozzles).
Cause
Under certain conditions, fuel elements may deposit on the poppet balls, seats, or pintles, which can cause the poppet balls to stick in either an open or closed position.
Correction
Follow the Strategy-Based diagnostics for your customer''s specific driveability concern. If diagnosis leads to sticking poppet nozzles, this cleaning procedure should be performed prior to replacement of the CPI injector.
CPI Injector Cleaning Procedure
Loosen the fuel filler cap to relieve vapor pressure in the fuel tank.
Raise the vehicle on a hoist.
Locate the underbody fuel line (1) junction point:
For S/T and L-van, it is along the left frame rail at approximately mid-vehicle.
For M-van, it is behind the left-front wheel housing.
Caution
Considerable fuel leakage may occur. Make sure that protective eyewear is worn, and that suitable fuel containment measures are taken.
Loosen and disconnect both the pressure and return lines at their junction points. The fittings towards the front of the vehicle (both pressure and return) have "male" fittings, and the fittings towards the rear of the vehicle have "female" fittings.
Install the J 44466-2 (1) (this hose has two 90 degree male fittings and no service port) to the "fuel tank" side of the fuel pressure and return lines. Installation of this hose eliminates the need to electrically disable the fuel pump and allows fuel to recirculate to the fuel tank.
Important
This cleaning procedure and service tools separate the fuel tank and pump from the cleaning process. Do not allow the Top Engine Cleaner solution to reach the fuel tank and/or pump. Top Engine Cleaner solution may cause a failure of the fuel pump.
Install the J 44466-1 (3) (this hose has two female fittings and a service port) to the "engine side" of the fuel pressure and return lines. Installation of this hose creates a "loop" through the hose and the engine side of the fuel system.
Obtain the J 35800-A (2). Make sure the valve at the bottom of the canister (3) is closed.
Remove the canister top and add 24 ml (0.8 fl.oz.) Top Engine Cleaner, GM P/N 1050002 (Canada P/N 992872), to the canister.
Fill the remainder of the canister with regular unleaded gasoline and install the canister top.
Suspend J 35800-A from a convenient location under the vehicle.
Connect the hose from J 35800-A to the service port on the J 44466-1.
Open the valve (3) at the bottom of J 35800-A.
Connect a "shop air" source to the fitting at the top of J 35800-A and adjust the regulator (1) to 75 psi.
Lower the vehicle to a convenient height and start the vehicle. It may be necessary to re-adjust the J 35800-A pressure regulator to maintain 75 psi.
Let the vehicle run at idle until the canister is empty and the vehicle stalls.
Turn OFF the vehicle ignition switch.
Raise the vehicle.
Remove the shop air supply from J 35800-A.
Depressurize J 35800-A.
Disconnect J 35800-A from J 44466-1.
Remove J 44466-1 and J 44466-2 from the vehicle fuel lines.
Re-connect the vehicle fuel lines.
Lower the vehicle.
Add one (1) ounce of Port Fuel Injector Cleaner, GM P/N 12345104 (Canada GM P/N 10953467), to the vehicle''s fuel tank for each gallon of gasoline estimated to be in the tank. Instruct the customer to add the remainder of the bottle of Port Fuel Injector Cleaner to the vehicle''s fuel tank at the next fill-up.
Tighten the fuel tank filler cap.
Start the engine and check for fuel leaks.
Clear any Powertrain DTC codes as required.
Advise the customer to change brands of fuel.
Parts Information
Part Number
Description
1050002
Top Engine Cleaner (U.S.)
992872
Top Engine Cleaner (Canada)
12345104
Port Fuel Injector Cleaner
10953467
Port Fuel Injector Cleaner (Canada)
Parts are currently available from GMSPO.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation
Description
Labor Time
J5645
Injector, Fuel - Clean
0.8
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
Images available only to Customers.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
© Copyright General Motors Corporation. All Rights Reserved.
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93 Bravada vin W
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RE: 94 4.3 v6 w lopes then stalls - 8/27/2008 1:07:02 PM
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Co.45
Posts: 15
Joined: 8/21/2008
Status: offline
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I actually did my whole replacement of fpr and nut kit without cleaning those i will make sure to check the condition of them when i have the plenum off the check the cap and plugs!
thanks for the tip
i dont think its that though it ran good when i started messing twith the electrical so im bettin on it being electrical!
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RE: 94 4.3 v6 w lopes then stalls - 8/27/2008 1:28:36 PM
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Leeann_Bravada
Posts: 72
Joined: 8/27/2008
Status: online
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Mine improves when I do anything with the EGR - until it warms up.
I did replace the FPR because mine had started leaking, but I didn''t check the poppets either.
There''s another TSB about using GMs top engine cleaner to clean out the carbon in the upper engine passages - something about letting it suck into a vacuum hose, etc. Supposedly there are instructions on the can. I''m going to check that out, too, since my EGR seems to cause issues and get better briefly after I mess with it. Perhaps chunks of carbon are getting loose and clogging it again, right after I''ve cleaned it.
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93 Bravada vin W
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