NO VIN told so>?
C2500 or K2500, Sierra is trim.
a PICKUP truck>?
Not a Suburban right?
most cars made have starter relay so the super expensive ignition switch does not burn up ST contacts.
and cars GAS have ignition module, only location changes (if a Distributor it's there) if not Dizzy it's in the ECU or on some cars fire wall to COP coils.
1991
C2500 guess a Pickup is it?
4.3L engine, sorry not doing all 5 engines and diesel
shows distributor and ICM and 1 coil.
and no relay starter see schem.
try here>?
https://eautorepair.net/Marketing/Default.asp
4.3L
It can be difficult to determine the source of an oil leak, especially if the valve cover has already been replaced. Here are some common causes of oil leaks in vehicles:
Engine gasket leaks: Engine gaskets can leak oil, causing oil to seep out onto the engine and surrounding components.
Engine oil seals: Engine oil seals can become worn or damaged, causing oil to leak from the engine.
Engine oil cooler: Engine oil coolers can develop leaks, causing oil to leak out of the engine and onto the manifold.
Engine oil pan: Engine oil pans can develop leaks, causing oil to leak out of the engine and onto the ground.
Engine oil filter: Engine oil filters can develop leaks, causing oil to leak out of the engine and onto the manifold.
If you are unable to locate the source of the oil leak, it is recommended to have a professional mechanic inspect the vehicle
ever see the truck run perfect before, or not in 10 years?
C2500 right not k2500 ,pickup.
NO ENGINE told ,4 engines 3 gas 1diesel.
but is gas so 4 engine not told (no fun there, blind)
4.7 to 5.7L and 5.4L gas.
crankshaft and cam
forgot to say sensor?
CAB means distrib CAP .
rotor sure.
why not new SPARK PLUGS first and for sure those ratty old HV spark wire, useless, I run NGK mag wires.
battery good, cranks fast and engine spins fast and does not start.
and engine compression is good
and we test that spark is good on all 8 cylinders not just one,all 8 are test
and also tested for spark timing. for sure if distributor was removed, or set loose at base and timing lost.
if all that is good the engine now runs on spray test fuel in a can. for 3 seconds, even with fuel pump fuse pulled.
if you get this far,
we check fuel pressure next and even for bad fuel.
no history of car told
bad fuel ,old rusty tanks wreck injectors.
26 year old truck,.
things bad that old are, all fluids and belts
fuel filter packed in gunk and rust.
thermostat bad.
spark parts bad, cap/rotor wire sets x8 and spark plugs. (or timed wrong or put back wrong firing order)
injectors clogged, bad fuel or rust in the tank
bad FPR, bad map sensor.(or only clogged)
or bad fuel pump if pressure is low and FPR not bad.
most of my tests all take tools and meters
a tech can not fix cars lacking his tools.
and skills to use them./
even a timing light is needed on all distrb cars
and all EFI cars a fuel pressure gauge.
and compression gauge
and vacuum gauge.
Your system is pretty basic and easy to troubleshoot. The coil only has 2 connectors. Battery + and the ground signal that comes from the distributor. The + lead should have 12v battery power when the key is turned on and the other wire should get a pulsing ground signal when the engine is turned over. You can test the system with a 12v test light. If you ground the clip end and probe the + wire the light should light bright anytime the key is on and if you clip the light to 12v + and probe the signal wire while the engine is cranking, the light should pulse.
C1500 pickup/
that was done backward, pump first? and bath in fuel.
the order is,
engine , spark and last fuel
are those spark plugs 27 years old,?
can not burn fuel with spark dead. test them all we do. spark tests
same goes on dead engines (mech)
we check engine compression first, 150PSI up and equal x8
then spark x8
IMMO fitted cars the IMMO lamp must not be glowing wrong.
then fuel tests
and air tests (you said added air is no cure , good test that)
means ISC dead , no air to start.
thanks that make any engine seem bad and is not really .
EGR stuck open
huge vacuum leaks (if maf based EFI)
CATS melted blocking exhaust and engine can not pump air
a vacuum test (cracking levels) proves cats not melted.
ISC valve stuck closed no idle air.
use the scan told more correctly?
1; connect up tool.
2: key on scan (nothing you said)
3:crank for 5 seconds.
4: release key (NOT OFF)
5: scan again, give a few minutes to roll out DTC'S if not push the pending DTC button, see them. roll out. using a real scan tool.
not a $13 lame code only reader.
ok still dead
remove fuel pump fuse or relay. (we are expecting flooded engine)
crank for 5 seconds to clear the flood at WOT wide open throttle.
then try in this state now, spray starter fluid, to induction.
3 seconds spray ,get 3seonds run time. repeat 3 times listen for engine damage. Noise.
last and not the least
cap and rotor and wires sets are no good, 27 years old ever
assuming me above battery charger keeps it charged
assumes Distributor not lost time. pulled and put back wrong. as vast folks do, all the time.
not told when it last ran perfectly (never seen it or?)
known for torque converter failure also the sun gear known failure -----------https://www.transmissionrepaircostguide.com/gmc-envoy-transmission-problems/ ----------------https://www.reference.com/world-view/common-gmc-envoy-transmission-problems-594b656e4536f7a3
Based on the symptoms you've described, it sounds like there may be an issue with the fuel delivery system. Here are a few things to check:
Check the fuel pressure using a gauge. The pressure should be around 60 PSI when the key is on and around 30 PSI when cranking. If the pressure is low, check the fuel filter and make sure it's not clogged.
Check for any air leaks in the fuel system. The 6.5 diesel engine is known for having issues with the fuel lines and hoses, so make sure there are no leaks or cracks.
Check the injectors. Make sure they're clean and functioning properly. You can use a diesel injector tester to check for proper spray pattern and volume.
Check the injector pump. Make sure it's working properly and that the timing is correct.
Check the cam sensor, crankshaft sensor, and the PCM. These sensors can also cause issues with the engine starting.
It could also be an issue with the engine's computers and wiring, so you may want to consider taking it to a qualified mechanic to diagnose and fix the problem.
DTC P0651
Do you know what 5volt reference is?
Circuit Description
The powertrain control module (PCM) provides a 5-volt reference to the following sensors:
• The throttle position (TP) sensor 2
• The accelerator pedal position (APP) sensor 1
• The manifold absolute pressure (MAP) sensor
The PCM monitors voltage on the 5-volt reference circuit. If the voltage is higher or lower than required, DTC P0651 will set.
Turn OFF the ignition.
Disconnect the throttle body electrical connector. Refer to Throttle Body Assembly Replacement .
Turn ON the ignition, with the engine OFF.
Measure the voltage from the 5-volt reference circuit of the throttle position (TP) sensor 2 to a good ground with a DMM.
Is the voltage within the specified range?
4.8-5.2 V
Is the voltage more than the specified value?
5.2 V
Go to Step 8
Go to Step 6
5
Connect the throttle body electrical connector.
Disconnect the manifold absolute pressure (MAP) sensor. Refer to Manifold Absolute Pressure Sensor Replacement .
Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM.
Is the voltage within the specified range?
If the 5 volt ref circuit is shorting out this would cause your problem .
Automotive Electrical Diagnosis // 5V Reference circuit - YouTubeTroubleshooting a Shorted 5v Reference Circuit (Chevy Silverado) - YouTube
Circuit Description
The powertrain control module (PCM) provides a 5-volt reference to the following sensors:
• The throttle position (TP) sensor 2
• The accelerator pedal position (APP) sensor 1
• The manifold absolute pressure (MAP) sensor
The PCM monitors voltage on the 5-volt reference circuit. If the voltage is higher or lower than required, DTC P0651 will set.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
• The PCM detects a voltage that is higher or lower than required on the 5-volt reference circuit.
• The above condition is present for longer than 10 seconds.
Action Taken When the DTC Sets
• The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
• The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.
Conditions for Clearing the MIL/DTC
• The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
• A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
• A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
• Clear the MIL and the DTC with a scan tool.
Step
Action
Values
Yes
No
Schematic Reference: Engine Controls Schematics
Connector End View Reference: Powertrain Control Module Connector End Views or Engine Controls Connector End Views
1
Did you perform the Diagnostic System Check-Engine Controls?
--
Go to Step 2
Go to Diagnostic System Check - Engine Controls
2
Important: If the vehicle has a cranks but will not run condition proceed to step 3.
Observe the Freeze Frame/Failure Records for this DTC.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
--
Go to Step 3
Go to Intermittent Conditions
3
Turn OFF the ignition.
Disconnect the throttle body electrical connector. Refer to Throttle Body Assembly Replacement .
Turn ON the ignition, with the engine OFF.
Measure the voltage from the 5-volt reference circuit of the throttle position (TP) sensor 2 to a good ground with a DMM.
Is the voltage within the specified range?
4.8-5.2 V
Go to Step 5
Go to Step 4
4
Is the voltage more than the specified value?
5.2 V
Go to Step 8
Go to Step 6
5
Connect the throttle body electrical connector.
Disconnect the manifold absolute pressure (MAP) sensor. Refer to Manifold Absolute Pressure Sensor Replacement .
Measure the voltage from the 5-volt reference circuit of the MAP sensor to a good ground with a DMM.
Is the voltage within the specified range?
4.8-5.2 V
Go to Intermittent Conditions
Go to Step 9
6
Monitor the DMM while disconnecting all other devices connected to this 5-volt reference circuit one at a time.
If voltage changes when one of the above components are disconnected, replace the component. Refer to the appropriate replacement procedure.
Was a component replaced?
--
Go to Step 12
Go to Step 7
7
Test this 5-volt reference circuit for a short to ground or for any sensor low reference circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct a condition?
--
Go to Step 12
Go to Step 10
8
Turn ON the ignition, with the engine OFF.
Test each 5-volt reference circuit and the MAP sensor signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct a condition?
--
Go to Step 12
Go to Step 10
9
Replace the throttle body assembly. Refer to Throttle Body Assembly Replacement .
Did you complete the replacement?
--
Go to Step 12
--
10
Test this 5-volt reference circuit for a short to the TAC motor control 1 or 2 circuits.
Did you find and correct a condition?
--
Go to Step 12
Go to Step 11
11
Replace the powertrain control module (PCM). Refer to Powertrain Control Module Replacement .
Did you complete the replacement?
--
Go to Step 12
--
12
Clear the DTCs with a scan tool.
Turn OFF the ignition for 30 seconds.
Start the engine.
Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records.
Did the DTC fail this ignition?
--
Go to Step 2
Go to Step 13
13
Observe the Capture Info with a scan tool.
Are there any DTCs that have not been diagnosed?
--
Go to Diagnostic Trouble Code (DTC) List
System OK
