we own a 95 4 dr 4 wheel drive, vortec 4.3 cpi blazer.. blew the head gasket on it, took the heads in had them checked, there are no cracks, nothing wrong at all with the heads, thank god!! anyways, got all new gaskets, new oil filters, etc put it all back together and now it wont start, my husband is about to screw him self into the ground trying to figure this out, it will turn over but wont engage and start running.. any help would be greatly appreciated....
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something with the fuel system would be my guess if you put everything back together right... same thing happened to mine and i had to get a new fuel pump... kinda pricey though

 

i just bought a ignition control modual for it, put that in, and still nothing,,, having the old one checked just to make sure,, fuel pump.. swore i heard that working.. thanks tho

 

Do you get any fire at the plugs at all? Like will it spark etc, but just not catch and run. Is it possible the ditributor got 180 out or someting else with the firing order? Check this out and see if it leads you anywhere. If you get to a point that it will not let you go any farther, tell me where at what point and I will try to follow up on it and give you direction from that point with more of a flow chart type check list as this one.
Forgot to add,.... is it throwing a DTC and if so what is it or if more than one, them?


Document ID# 1370930
1995 Chevrolet/Geo Blazer - 4WD


--------------------------------------------------------------------------------

Engine Cranks but Does Not Run
Circuit Description
The diagnosis for an engine that cranks but does not run must have three elements present before proceeding with the diagnostic table. The following conditions must exist:

The battery must be adequately charged.
The engine cranking speed must be sufficient.
There must be an adequate amount of fuel in the fuel tank.
Diagnostic Aids
If no trouble is found in the fuel pump circuit or the ignition system and the cause of an Engine Cranks But Will Not Run has not been found, check for the following conditions:

Fouled spark plugs
An EGR valve stuck open
Low fuel pressure-Refer to Fuel System Diagnosis .
Water or foreign material in the fuel system
A grounded Ignition Control (IC) signal circuit may cause a No Start or a Start then Stall condition
Basic engine problem
The VCM has integrated IC circuits that are fault protected; therefore, if a circuit has failed, the failure may not damage the integrated IC. If that is the case, the IC will keep the circuit open until the fault in the circuit has been corrected.

When the fault has been corrected, reinstall the VCM. Check the circuit. Replace the VCM only if the circuit is still inoperative.

Test Description
The numbers below refer to the step numbers on the diagnostic tables.

If the signal is over 2.5 volts, the engine may be in the clear flood mode which will cause starting problems.

If the engine coolant sensor is below -30° C, the VCM provides fuel for this extremely cold temperature which will severely flood the engine.

This step checks the ignition feed circuit to the injectors.

Voltage at the spark plug is checked using the spark plug tester tool J 26792 . No spark indicates a basic ignition problem.

This test determines if there is fuel pressure at the fuel injection unit and holding steady.

Step
Action
Value(s)
Yes
No

Schematic Reference: Engine Controls Schematics

1
Was the Powertrain On-Board Diagnostic (OBD) System Check performed?
--
Go to Step 2
Go to Powertrain On Board Diagnostic (OBD) System Check

2
Install the scan tool.
Monitor the TP sensor on the scan tool.
With the throttle closed is the TP sensor over the specified value?
2.5 Volts
Go to DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage
Go to Step 3

3
Monitor the ECT sensor on the scan tool.

Is the ECT sensor below the specified value?
-30° C
Go to DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage
Go to Step 4

4
Turn off the ignition for 10 seconds.
Turn ON the ignition.
Does the fuel pump operate for 2 seconds?
--
Go to Step 5
Go to Fuel Pump Electrical Circuit Diagnosis

5
Disconnect the injector connector at the intake manifold.
Connect a test light to ground.
Probe the injector ignition feed circuit.
Is the test light ON?
--
Go to Step 6
Go to Step 8

6
Disconnect one spark plug wire.
Install the spark tester J 26792 .
Crank the engine.
Is the spark present?
--
Go to Step 7
Go to Enhanced Ignition System Diagnosis

7
Reconnect the one spark plug wire.
Turn off the igniti

 

i reread my intial post and noticed that i stated that our blazer was a tbi.. wrong hubbys truck is a tbi the blazer is a cpi. sorry about that..
ok, checked the fuel pump... works
no spark at the coil,
dont believe that the injectors are working.
battery charged? yes
engine cranking speed sufficent? yes
over half a tank of gas
OBD system check.. No
so will continue going thru the rest of the list that you gave me.
we were told unless the blazer is running there will be no codes to get seeing as the battery was disconnected for so long?

will be doing more testing tommrow

thanks for the help so far!

 

blazer still wont start,
starting to think that it is the ignition modual...but cant test them to see if they are good or not.
does anybody know if there is a way to test them?
or any other ideas?

 

checked wires, no pulse at all getting to the coil,
no pulse getting to the injectors.
coil checked out fine.
so thats where we are at now..

 

I don't know if the 95's have the same problem that the 92's did, but the fuel lines under the plenium going to the fuel injectors were my problem. ugh, and what a problem it turned out to be. Every time the Blazer would shut down, fuel would spill from the cracked fuel lines into the air intake, causing the engine to flood. I could still start my Blazer though, keeping the gas pedal floored, and continuously starting it for about a minute, it would eventually chug to life. I couldn't tell it was flooded though, couldn't ever smell raw gas until I pulled the air filter out.

Although, this issue should have shown it's ugly face before the blown gasket (rough idle, raw egg smelling exhaust). I dunno, I'm shooting in the dark, but who knows, it may help...

 

the eggy smell could be a long gone dead catylitic converter.

 

madjeygirl,
Most autoparts stores can test the ICM, ignition control module. Even if the ignition control module is bad you should still get spark. Just the timing of the spark will be off.

Check to make sure your hubby reconnected the crank position sensor on his truck.