1997 S-10 SS, 4.3 Vortec, Cranks, No Start.

[azpyroguy]

Hi All;
I have been helping my father troubleshoot a issue with his S-10.

Model: 97 S-10 SS, with 4.3l W VIN Engine Code, 2 Wheel Drive.
Issue: Cranks, No Start.

History: Prior to the truck only just cranking with no start, it would occasionally cut out while driving, drop back about 200 rpm, throw a SES, but return to normal less than a second later, never actually dying.

We did not have a code scanner until recently, but we were able to scan for codes before it actually quit running, and none were found.

Were using a Innova 3110 Scanner.

We even scanned for codes after it died, and not were found.

We have since:

- Replaced the cap and rotor.
- Checked fuel pressure, at check valve, and its at 62psi
- Strong spark at coil, and all plugs.
- Fuel pump primes, and sounds strong.
- Cranks strong.
- Replaced the cam position sensor
- Replaced the crank position sensor
- Replaced the throttle position sensor
- Checked continuity on all fuses.
- Checked voltages at Ignition control module, and coil.
- Cleaned the contacts on the conectors at the Crank Position, TPS, Coil, and ICM.
- Oil is clean, and has no signs of a blown head gasket.
- All of dash, accessories, and gauges, work fine.

The only thing that we did notice, was that when we put it all back together we accidently got the plug wires in the wrong order, and it wanted to fire.. but just stumbled...

We are down to it maybe being the distributor..... dunno what else it could be... anyone else have any ideas? Injector pulses?

 

[stick]

it is a chevy,,,,,,just give up while you are ahead

 

[SrtBrad]

Start with a compression test with all the spark plugs out when doing the compression test.

 

[azpyroguy]

Start with a compression test with all the spark plugs out when doing the compression test.

That is on the next list of things... but it never seemed to lose power like you would expect it to do if a ring(s) were going bad, and god forbid if it threw a rod... no funny noises, banging etc...

Even with low compression, it should at least try and fire.

 

[azpyroguy]

it is a chevy,,,,,,just give up while you are ahead

Well.. he does like our SRTs, but just does not have the extra cash to buy one...

 

[SrtBrad]

Fuel, air, compression and spark is what you need to verify first. Make sure the compression is within 15 psi of each cylinder. Make sure your fuel filter is not clogged as well. A clogged fuel filter with a good fuel pump will still deliver enough fuel at idle but will starve under acceleration. Verify the injectors are not clogged. etc etc...

I will walk you thru this if you like. Just start off with the compression test.

 

[azpyroguy]

I failed to mention, we did install a new fuel filter.

We also checked fuel pressure at the check valve on the fuel rail.

Since it never does start, I can only check fuel pressure as it primes the system...

I will go an get a compression checker and see if we have good compresssion... he has one.. but its a cheapy, and does not work well.

 

[FastRam]

I called a freind of mine who is mechanic at a local Chevy dealer. At first thought, he had no reason to believe why it wouldn't start given all the checks and diagnostics you performed. The only other thing maybe an injector issue. It is doubtful the distributor is the problem if you have spark at each plug when it is cranked. Unfortunately, you may have to connect up a TECH 2 (GM scan tool) to figure out if the injectors are working as they should.

 

[azpyroguy]

I called a freind of mine who is mechanic at a local Chevy dealer. At first thought, he had no reason to believe why it wouldn't start given all the checks and diagnostics you performed. The only other thing maybe an injector issue. It is doubtful the distributor is the problem if you have spark at each plug when it is cranked. Unfortunately, you may have to connect up a TECH 2 (GM scan tool) to figure out if the injectors are working as they should.

I am leaning towards its being the injector system.. which on this truck is a complete assembly called the spider, and from what I have been finding out is prone to failing... it has 116,000 miles it...

 

[FastRam]

Yep, they use a crappy spider assembly with el'cheapo poppet valves they call injectors. My '96 with a 350 vortec uses a similar setup, installed underneath the upper intake plenum. It consists of a central distribution block with 8 "injectors" that distributes fuel via 8 plastic hoses to each intake port. Crappy setup and tends to leak, clog, throw codes, poor driveability, etc. In my case, I purchased an upgraded GM fuel injection setup that rids the fuel block thingy and uses 8 real injectors.

Another thing you can check is the fuel pressure when trying to crank. The pressure should be between 56 and 66 psi when cranking. Also, after cranking, assuming the pressure builds, check to make sure the pressure does not bleed off too quickly. You may have a faulty regulator or a bad pump, even though it shows a positive pressure, it can be faulty when trying to crank. Also you can try to pour some fuel directly into the TBI and try starting it. If it starts and runs after fuel is poured into the TBI, your fuel pump is history (too low pressure when cranking).

 

[76574srt10]

He said he checked the fuel pressure and it was 62psi. Does it sound like it is timed correctly? Is it not trying to back fire at all? I would also check the crank position in reference to the rotor in the distributor, making sure it is on #1 cylinder and plug as it should be. I'm wondering if the timing chain has jumped or the plastic gear gave out. A compression test is really needed.

 

[FastRam]

He said he checked the fuel pressure and it was 62psi. Does it sound like it is timed correctly? Is it not trying to back fire at all? I would also check the crank position in reference to the rotor in the distributor, making sure it is on #1 cylinder and plug as it should be. I'm wondering if the timing chain has jumped or the plastic gear gave out. A compression test is really needed.

Compression check wouldn't hurt but ... the fuel pump even though it delivers 62psi at no load, aka no crank, may diminish significantly if cranked. If the pump doesn't deliver, when cranked, a minimum pressure, the truck will never start, that is unless you help it out, :marchmellow: The other alternative is to say F it, you tried your best, haul it to the dealer.

 

[Roz]

I am leaning towards its being the injector system.. which on this truck is a complete assembly called the spider, and from what I have been finding out is prone to failing... it has 116,000 miles it...

I used to have 99 Sonoma and the spider injector took a dump on mine. It did the exact thing you're describing. . .

That's a "common" problem on the 4.3L vortec.

 

[azpyroguy]

- Starting Fluid, not work.

- Can't really smell gas from the tail pipe while cranking, but can smell starting fluid.

- Fuel Pressure under cranking is 63-65psi, and settles back to 59-60 when not cranking, slowly going to 54-55 and stopping there.

- Good grounds on C17 and A23

- Tried swapping dizzy plugs for 1 and 3 (the ones that got it to pop last time), this time, it did nothing, even with starting fluid.

- Checked and cleaned the EGR pintle, and connector.

We ran out of light (it stuck in driveway), and we are going to test for pulsing grounds on Thursday at PCM to check for injector drivers.

Will post our findings.

 

[76574srt10]

If starting fluid doesn't work then I doubt it's a fuel delivery issue. Still sounds like ignition. I can't see where compression would drop across all cylinders to the point it wouldn't start. try to bring it up to top dead center on #1 and see where the rotor is pointing.

Have you ever replaced the ignition switch in the column? They were really a POS and would fail. 116,500 is a lot of miles to not have replaced one yet on those trucks. are all the gauges working?

 

[azpyroguy]

If starting fluid doesn't work then I doubt it's a fuel delivery issue. Still sounds like ignition. I can't see where compression would drop across all cylinders to the point it wouldn't start. try to bring it up to top dead center on #1 and see where the rotor is pointing.

Have you ever replaced the ignition switch in the column? They were really a POS and would fail. 116,500 is a lot of miles to not have replaced one yet on those trucks. are all the gauges working?

That was my thoughts as well.. very unlikey that all cylinders would loose compression to point of not starting.

Yes, all gauges, accessories, blower, lights, radio, etc.. all work great.

 

[76574srt10]

I had an intake manifold warp on me one time and it acted like this and was booger to find. It was warped so that it wouldn't provide a vacuum and acted like a total lose of compression.

 

[bigike]

Pull a spark plug put a screwdriver in the boot, get near a ground and crank the engine................... no spark check power to the coil.............

Remember the fire triangle fuel/air/heat without any of these the engine will not run. Diagnose your fire triangle.

are you getting fuel
are you getting air
are you getting spark if youve got spark pull the plug and put your finger over the hole it should pop......... compression is heat.

good luck.........4.3 great engine!

 

[MR ED's SRT10]

IT'S THE SPYDER ASSY!

:rock: It's the spider assy, I had this happen on an Astro van i had it happened twice to me replace the spider assy. and all will be fine . Good luck!:marchmellow: :congrats:

 

[FastRam]

- Starting Fluid, not work.

- Can't really smell gas from the tail pipe while cranking, but can smell starting fluid.

- Fuel Pressure under cranking is 63-65psi, and settles back to 59-60 when not cranking, slowly going to 54-55 and stopping there.

- Good grounds on C17 and A23

- Tried swapping dizzy plugs for 1 and 3 (the ones that got it to pop last time), this time, it did nothing, even with starting fluid.

- Checked and cleaned the EGR pintle, and connector.

We ran out of light (it stuck in driveway), and we are going to test for pulsing grounds on Thursday at PCM to check for injector drivers.

Will post our findings.

You got good pressure under cranking, fuel pump OK. For the injectors you can check 3 things, resistance, power to the injectors and PCM signal. To check all this, you'll need to disconnect the wiring harness connector at the fuel metering body, located behind the TB on top of the intake. There should be a retaining clip that needs to be removed and then the harness should lift off. Resistance values for each injector should measure between 1.37 to 1.77ohms. To check voltage to the injector wiring harness pins, turn the ignition switch to on and measure the voltage for each injector (see wiring color coding below). To test the PCM signal to each injector, you'll need a test or "noid" light. I am not sure how the light will connect to the harness pins -- you may need to fab up some jumper wiring/terminals. Connect the light to each injector wiring pin, and crank over the engine. The light should flash evenly for each injector. If the light doesn't flash evenly, you may have an issue with the ECM/PCM. Below are the wiring color codes for each injector. Sorry, I don't have the pin ID/connector numbers.

Injector 1: Pink, Black
Injector 2: Pink, Light Green/Black
Injector 3: Pink, Pink/Black
Injector 4: Pink, Light Blue/Black
Injector 5: Pink, Black/White
Injector 6: Pink, Yellow/Black

FYI: all Pink wires are connected together at a common point in the harness/connector and are the dedicated power supply wires from the ECM-1 20A fuse circuit located in the under hood fuse box.

Yes these assemblies are famous for failure and replacing them is a PITA as you have to pull the upper intake in order to gain access to the spider assembly. I hope this helps and good luck.