1997 S-10 SS Vortec 4.3 Cranks, But 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?

[Raylo]

Check fuel pressure. Pump may run and sound OK but fuel pressure may be low due to bad reg or weak pump. Pressure below a certain value will get you a no start.

[azpyroguy]

Quote: Originally Posted by Raylo

Check fuel pressure. Pump may run and sound OK but fuel pressure may be low due to bad reg or weak pump. Pressure below a certain value will get you a no start.

We did check that pressure at the check valve right behind the throttle body, and its a solid 62psi.

Is there another place I should be looking for fuel pressure at?

[Bill Wheats]

Well, you have done a lot.
Do you smell gas at the tail pipe after trying to start it for a while?

Double check the plug wire order. You say that it wanted to start when 2 wires were wrong, does it still want to start?

Double check all the wires going to the dizzy and coil...

Does it seem that it almost fires when you let off the starter?

[azpyroguy]

Quote: Originally Posted by Bill Wheats

Well, you have done a lot.
Do you smell gas at the tail pipe after trying to start it for a while?

Double check the plug wire order. You say that it wanted to start when 2 wires were wrong, does it still want to start?

Double check all the wires going to the dizzy and coil...

Does it seem that it almost fires when you let off the starter?

I know while trying to start it yesterday I did get a whiff of gas, it had to off been the tail pipe, becuase we could not smell anything up near the throttle body.

The coil wires and distributor are all correct.

No, it never does not try or attempt to fire.

[Bill Wheats]

We used to take the rotor out as a joke....
You should smell gas if the fuel system is working. Open the air filter and see if it smells strong of gass after trying to start.
Re check the plug wire order at the cap. I think you said that you had good spark.
You need good continous spark. You should watch for more than one spark when testing. Check for spark again.

[MikDee]

On a note here, both piston #1, & piston #4, are on TDC when the crankshaft pulley is stationary at TDC,,, Each revolution of the crank, will set the engine up for one, or the other to fire, (your cam actually moves only 1/2 a turn per each full crank rev) so make sure you're valves are closed, and, You are on TDC for #1,,,, Or, take out your distributor, give the rotor 1/2 a turn, so it's facing #4, and try it then!

[MikeInCtown]

Spray starting fluid while trying to crank. If you are getting a strong spark as you say, the engine should fire when you are spraying the starting fluid. If it fires and runs, and since you have good fuel pressure I'd say the injector assembly is toasted.

[azpyroguy]

Quote: Originally Posted by MikDee

On a note here, both piston #1, & piston #4, are on TDC when the crankshaft pulley is stationary at TDC,,, Each revolution of the crank, will set the engine up for one, or the other to fire, (your cam actually moves only 1/2 a turn per each full crank rev) so make sure you're valves are closed, and, You are on TDC for #1,,,, Or, take out your distributor, give the rotor 1/2 a turn, so it's facing #4, and try it then!

Do you mean just take the dist cap on, and turn the rotor a half turn, and bolt it back on?

[azpyroguy]

Quote: Originally Posted by MikeInCtown

Spray starting fluid while trying to crank. If you are getting a strong spark as you say, the engine should fire when you are spraying the starting fluid. If it fires and runs, and since you have good fuel pressure I'd say the injector assembly is toasted.

I have been reading around that the injector assembly on these can be a problem... I will try the starter fluid, and see what happens...

[Yogi]

If you really have a strong spark at all plugs, and you have 62 psi at the fuel rail, the only things left are the spider (fuel injectors) or the pcm (powertrain control module: engine computer). Are you positive that you have a strong spark at all cylinders?

And please don't pull the distributor, unless it has been disturbed for some reason.

[azpyroguy]

Quote: Originally Posted by Yogi

If you really have a strong spark at all plugs, and you have 62 psi at the fuel rail, the only things left are the spider (fuel injectors) or the pcm (powertrain control module: engine computer). Are you positive that you have a strong spark at all cylinders?

And please don't pull the distributor, unless it has been disturbed for some reason.

Yes, we tested at the fuel rail and got 62psi.

Yes, we tested for spark at all plugs, and got a good strong spark on each. Same thing at the coil, a good strong continous spark.

We have been thinking that it might be the PCM, but dont know how to test it... can the Chevy dealer do that?

Since I dont smell fuel in the throttle body, I am leaning towards it being the spider....

And no the distributor has not been disturbed, we just replaced the cap and rotor.

[Bill Wheats]

Quote: Originally Posted by MikDee

On a note here, both piston #1, & piston #4, are on TDC when the crankshaft pulley is stationary at TDC,,, Each revolution of the crank, will set the engine up for one, or the other to fire, (your cam actually moves only 1/2 a turn per each full crank rev) so make sure you're valves are closed, and, You are on TDC for #1,,,, Or, take out your distributor, give the rotor 1/2 a turn, so it's facing #4, and try it then!

They didn't pull the dizzy, or timing chain, so the distributor should still be correct.

[Yogi]

Quote: Originally Posted by azpyroguy

Yes, we tested at the fuel rail and got 62psi.

Yes, we tested for spark at all plugs, and got a good strong spark on each. Same thing at the coil, a good strong continous spark.

We have been thinking that it might be the PCM, but dont know how to test it... can the Chevy dealer do that?

Since I dont smell fuel in the throttle body, I am leaning towards it being the spider....

And no the distributor has not been disturbed, we just replaced the cap and rotor.

Yes, the dealer can test the pcm, but you can probably get a used one from the j/y for less than what the dealer would charge just to test it. I'm thinking a used one would cost about $75, but that is just a guess. I know for sure that you can buy a used one that has been tested and reprogrammed for better performance for $159 plus shipping from Wait4MePerformance.com. A new spider installation kit is about $280 shipped from GMPartsDirect.com. I wouldn't trust a used spider unless you can get one from an '03+. Even then you should study the pictures to be able to identify the late model spider.

There is a way to test the pcm for injector pulse with a test light, but I don't know how to do it. Maybe someone else will chime in here.

[MikDee]

Quote: Originally Posted by Bill Wheats

They didn't pull the dizzy, or timing chain, so the distributor should still be correct.

You said, you messed with the wiring order? You've got fuel pressure, you've got spark, and you smell gas at the tailpipe, unless you're plugs are soaking wet with gas?, it should start. If the engine ran pretty good before, it still should! If your wiring order is screwed up, you'll never get it to start! I meant the engine might be set to fire on #4 TDC, and you have the dist set for #1 TDC, if thats the case take out the dist, turn the rotor to face #4, and put the dist back in.

I'm not a newbie, been workin on engines for 50yrs, mostly chevys, if you doubt it look at my signature.

[MikeInCtown]

Now that I think about it he did say that it had an SES light but that the code scanner couldn't pull any codes. Wouldn't that mean that the PCM wasn't storing codes or working properly?

[Bill Wheats]

Take a look at the PCM. Look for loose connections, corrosion, and verify that it has a good ground.
*Tan/white wire at C17 and the black/white wire at A23 go to ground at the same spot.

The Pink wire going to the fuel injectors is hot (+12V) when the key is on RUN or Start. The PCM pulses a neg to each of the injectors. They each have their own wire run to them.
Testing for pulsing neg at the pcm might be easier.


If you don't get the pulsing neg, then go to your ignition control module in the dizzy. Look for corrosion and take a good look at the white wire for any possible shorting out issues. That is what sends the PCM the signal to neg pulse the injectors.

[Yogi]

Quote: Originally Posted by MikeInCtown

Now that I think about it he did say that it had an SES light but that the code scanner couldn't pull any codes. Wouldn't that mean that the PCM wasn't storing codes or working properly?

Not necessarily. They could be "soft" codes - ones that go away when the light goes out.

Again, please do not pull the distributor. Just make sure that the wires are on in the correct order.

[Yogi]

Quote: Originally Posted by Bill Wheats

Take a look at the PCM. Look for loose connections, corrosion, and verify that it has a good ground.
*Tan/white wire at C17 and the black/white wire at A23 go to ground at the same spot.

The Pink wire going to the fuel injectors is hot (+12V) when the key is on RUN or Start. The PCM pulses a neg to each of the injectors. They each have their own wire run to them.
Testing for pulsing neg at the pcm might be easier.


If that checks out then go to your ignition control module in the dizzy. Look for corrosion and take a good look at the white wire for any possible shorting out issues. That is what sends the PCM the signal to neg pulse the injectors.

The camshaft position sensor is in the dizzy. The ignition control module is on a bracket next to the ignition coil.

[Bill Wheats]

Quote: Originally Posted by MikDee

You said, you messed with the wiring order? You've got fuel pressure, you've got spark, and you smell gas at the tailpipe, unless you're plugs are soaking wet with gas?, it should start. If the engine ran pretty good before, it still should! If your wiring order is screwed up, you'll never get it to start! I meant the engine might be set to fire on #4 TDC, and you have the dist set for #1 TDC, if thats the case take out the dist, turn the rotor to face #4, and put the dist back in.

I'm not a newbie, been workin on engines for 50yrs, mostly chevys, if you doubt it look at my signature.

Don't pull your dizzy yet!
You can't turn the dizzy on the 4.3 It is fixed and the timing is advance electronically. These dzzies can't be reinstalled 180` out because they have 13 teeth.
If their dizzy and timing chain haven't been pulled than that can't be the problem.....
However the firing order could be wrong because of the placement of the cables.
P.S. If you swap #4 and #2 the 4.3 will run. Couldn't believe it my self, but.. or Maybe that was #4 & #6??? whatever.

[MikDee]

Quote: Originally Posted by Bill Wheats

Don't pull your dizzy yet!
You can't turn the dizzy on the 4.3 It is fixed and the timing is advance electronically. These dzzies can't be reinstalled 180` out because they have 13 teeth.
If their dizzy and timing chain haven't been pulled than that can't be the problem.....
However the firing order could be wrong because of the placement of the cables.
P.S. If you swap #4 and #2 the 4.3 will run. Couldn't believe it my self, but.. or Maybe that was #4 & #6??? whatever.

You Don't Turn The Dizzy! You turn the Rotor, 1/2 a turn, the Dizzy stays where it is!! If you have no spark at the plugs, it could be the ignition module in the dist, they go bad occasionally, they start acting up when hot by cutting out, then cool off, & run ok for awhile.

P.S. It doesn't matter how many teeth are on the dist gear, you pull the dist out, you turn the rotor till it lines up with #1, or #4, on the dist cap, depending on if the engine is set to fire on #1, or #4, then put the dist back in place where it belongs. Also, by the way, those wires start, & end, on the cap only in one particular place, (see the shop manual) you can't put them willy, nilly, anywhere on the cap! Plus they hafta go in a clockwise circle in the proper firing order.

[MikeInCtown]

The rotor only goes on one way. It won't seat if you try to turn it 180*

[Bill Wheats]

Quote: Originally Posted by MikDee

You Don't Turn The Dizzy! You turn the Rotor, 1/2 a turn, the Dizzy stays where it is!! If you have no spark at the plugs, it could be the ignition module in the dist, they go bad occasionally, they start acting up when hot by cutting out, then cool off, & run ok for awhile.

P.S. It doesn't matter how many teeth are on the dist gear, you pull the dist out, you turn the rotor till it lines up with #1, or #4, on the dist cap, depending on if the engine is set to fire on #1, or #4, then put the dist back in place where it belongs. Also, by the way, those wires start, & end, on the cap only in one particular place, (see the shop manual) you can't put them willy, nilly, anywhere on the cap! Plus they hafta go in a clockwise circle in the proper firing order.

You do understand that we are talking about a 4.3 here? And the OP didn't remove the dizzy or timing chain since it last ran right. I could believe that the chain slipped but we are still trying to prove whether the injectors are pumping fuel or not.

On an older engine, I would have kept turning the dizzy while someone ran the key until it fired. That isn't an option anymore.

[MikDee]

Quote: Originally Posted by Bill Wheats

You do understand that we are talking about a 4.3 here? And the OP didn't remove the dizzy or timing chain since it last ran right. I could believe that the chain slipped but we are still trying to prove whether the injectors are pumping fuel or not.

On an older engine, I would have kept turning the dizzy while someone ran the key until it fired. That isn't an option anymore.

I Do know that you can pull the Dizzy out, and put the rotor facing anywhere you want, and drop the Dizzy body back into it's "special" spot, do you understand that? The Chevy V6 has 2 cylinders that are at TDC at the same time, as the TDC crank timing mark,,, #1, & #4, The camshaft (which turns at 1/2 the speed of the crank, will determine which cylinder is ready to fire when the timing mark is on TDC) If your looking at Timing mark on the crank, you need to make sure that, the cam is ready to fire on #1, before you set the Dizzy rotor on #1, because if the engine was cranked with the Dizzy out, it could be #4, Do You understand? This pic shows where the wires physically belong on the cap:

[Yogi]

Quote: Originally Posted by azpyroguy

I have been reading around that the injector assembly on these can be a problem... I will try the starter fluid, and see what happens...

Have you tried the starter fluid yet?

[lesterl]

Quote: Originally Posted by MikDee

I Do know that you can pull the Dizzy out, and put the rotor facing anywhere you want, and drop the Dizzy body back into it's "special" spot, do you understand that? The Chevy V6 has 2 cylinders that are at TDC at the same time, as the TDC crank timing mark,,, #1, & #4, The camshaft (which turns at 1/2 the speed of the crank, will determine which cylinder is ready to fire when the timing mark is on TDC) If your looking at Timing mark on the crank, you need to make sure that, the cam is ready to fire on #1, before you set the Dizzy rotor on #1, because if the engine was cranked with the Dizzy out, it could be #4, Do You understand? This pic shows where the wires physically belong on the cap:

OK, do you understand that he DID NOT GET THE MECHANICAL TIMING OF THE DISTRIBUTOR OUT, he got the plugwires on wrong when he replaced them and the cap and rotor, the distributor should be left installed in the engine as he didnt pull it in the first place, he needs to try the starting fluid to see if she fires since it has good spark, if it doesnt fire then he needs to look into compression or timing.

[Bill Wheats]

Quote: Originally Posted by MikDee

I Do know that you can pull the Dizzy out, and put the rotor facing anywhere you want, and drop the Dizzy body back into it's "special" spot, do you understand that? The Chevy V6 has 2 cylinders that are at TDC at the same time, as the TDC crank timing mark,,, #1, & #4, The camshaft (which turns at 1/2 the speed of the crank, will determine which cylinder is ready to fire when the timing mark is on TDC) If your looking at Timing mark on the crank, you need to make sure that, the cam is ready to fire on #1, before you set the Dizzy rotor on #1, because if the engine was cranked with the Dizzy out, it could be #4, Do You understand?

I understand exactly what you are saying. Unfortunately the designers in their wisdom gave the dizzy 13 teeth, not twelve or 6. That means that when you do what you are talking about doing on this engine then the timing will be off and you won't be able to adjust it.

Now getting back to this thread; What would lead you to believe that changing the firing sequence by changing the rotor to a different position then the crank and cam were factor set for is going to solve their issues since nobody has changed the crank to cam alignment?

Am I missing something?
Sorry for the long thread.

[lesterl]

Forgot this is CSFI engine, try the starting fluid to see if she starts that will verify your wiring on the DIZZY is correct and that it should run but you are/arent getting fuel. Unhook the MAF sensor while you are at it, if the intake is off and air is not passing the MAF it wont fire the injectors, unhooking the MAF will put the truck into a mode that ignores the sensor (what I do to get carbon buildup off the throttle plate).

Like Mike Said prior the Rotor bug is keyed to go on one way so it wont be the problem unless it is the wrong one or manufactured backwards.