1994 Chevy Silverado Startup problems

Tiny
OLDDRUM1
  • MEMBER
  • 1994 CHEVROLET SILVERADO
  • 6 CYL
  • 2WD
  • MANUAL
  • 290,000 MILES
When starting my 4.3 v/6 silverado it seems to run very rich and does not want to start. Holding the gas to the floor gets it started, it runs rough for a few seconds and levels out. I will have white exhaust smoke for a second or two then runs fine. Stop and go into store come out five minutes later and same problem. What up?
Wednesday, May 28th, 2008 AT 2:07 PM

12 Replies

Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
Is this engine the vortec or the 4.3z engine with a throttle body. You can tell by the eighth letter of the vin, it will be z or w. Get back to us
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
OLDDRUM1
  • MEMBER
  • 21 POSTS
It is a Z
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
Throttle body. Remove air cleaner and look at injectors when you turn the key on to see if one drips a little gas. If it does then something is stuck inside. Also unplug the egr valve and lightly tap on it with a hammer to make sure its seated, leave it disconnected and see if problem goes away, it may have been partially open. Also a coolant temp sensor for the computer thats reading lower that it should be can cause this. *** Is it losing coolant? Burning oil?
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
OLDDRUM1
  • MEMBER
  • 21 POSTS
It does not seem to be dripping inside, oils and refrigerant is ok also. It seems like it is spraying alot of gas on the right side.
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
Now were at the point where you need a scan tool to look at the sensors while they are working to see where the problem is.
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
OLDDRUM1
  • MEMBER
  • 21 POSTS
Disconnected plug for egr valve and engine started up a lot betterr. Ran pretty rough but again started right up.
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
OLDDRUM1
  • MEMBER
  • 21 POSTS
Do not have a scan tool. Where would one get an inexpensive(cheap) scam Tool?
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
There isnt one. You are probably best off paying a one hour diagnostic fee and have it diagnosed at your local garage. I dont want to see you spending a bunch of money replacing parts that dont need replacing. Let us know how you make out.
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
OLDDRUM1
  • MEMBER
  • 21 POSTS
Thanks a million. Will have scanned tomorrow.
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
OLDDRUM1
  • MEMBER
  • 21 POSTS
1994 Chevy v-6 4.3 1GCDC14Z6RZ1519160 VIN Running

Codes Present No No
4WD On On
AC Clutch Off Off
Ac Enabled No No
Ac Request Off Off
Baro (V) 4.78 4.78
Baro (HG) 29.65 29.65
Battery Volt 11.7 14
LT Fuel Trim 123 123
Lt Fuel Tr CC 16 16
Lt Fuel Tr En No N0
Brake Swithch Off Off
Evap Duty 0 0
Evap Solenoid Off Off
Collant (Fah) -25 -20
EGR Duty 0 0
EGR Requiared 0 0
EGR VLV Pos 0 0
Engine RPM 0 850
Exhaust O2 Lean Rich
High Battery No No
IAC Direction Rev Rev
IAC Position 145 65
Idle Req RPM 950 850
Ignition Sw Off On
Inj Pw (ms) 238.7 3.5
St Fuel Trim 128 128
Knock Ret (Deg.) 0 0
Loop Status Open Open
Map (HG) 29.65 10.36
MAP (V) 4.78 1.29
IAT (Deg F) -40 -40
O2S (MV) 386 781
O2S crsscnts 62 133
Prom ID 9425 9425
Runtime 0 3:10
Spark Adv 0 21
TCC Applied No No
TCC Solenoid Off Off
Throttle 0 0
TPS Sensor 0.69 0.69
Veh. Speed (MPH) 0 0

Sorry it took so long. Been baling hay and truck took back burner to farm productrion.
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
MASTERTECHTIM
  • MECHANIC
  • 4,750 POSTS
I found your problem. Replace the engine coolant temp sensor and your problems will be gone. Also make sure the wires to the connector are not broken, lightly pull on them and make sure they dont pull out. The sensor costs about 10 bucks and is located right near the thermostat housing.
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Wednesday, September 2nd, 2020 AT 6:17 PM
Tiny
OLDDRUM1
  • MEMBER
  • 21 POSTS
Thanks for the help. When I saw the -40 I thought as much. I will change it out tomorrow and let you know how it goes. I am jealous though. Your tool box is bigger than my shop.

Charlie Burden
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Wednesday, September 2nd, 2020 AT 6:17 PM

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