Hey billywilly, Would you mind catching us up to speed on what you have done and what you haven't done so we have an idea where you stand at (in terms of what you've tried already). All you need for ignition is fuel, spark and air. Obviously your not getting one of them (at least).

 

The fuel injectors were only $20 a piece to rebuild them. We knew the guy who rebuilt them so we're not sure if he gave us a discount or not.

This weekend we put on the cleaned injectors and tried starting it. It almost started. Before it cranked and cranked but this time it fired and was so close to staying running and then it stopped. Pulled the spark plugs out and now it doesn't have spark. So something else must have gone bad that caused it to turn off spark and possibly the fuel injectors, maybe the ASD or CPS. I looked it up online and that is the two sensors I found that could be the problem.
Im going to see if I can borrow a computer from school to see if it has any codes.

 

codes will help....also make sure the spark plug wires arent melted from touching exaust manifold ...I've heard of that doing it ...other likely causes are the coil rotor cap..(most likely the coil)I'd pull it and get it tested at the local autostore.

 

Ok, so you still have not tried unscrewing the pre cat o2 sensor right? LOL And btw,the ASD is a relay, not a sensor.

 

It sounds like there's a gross failure with one or more components. This may be why you have no spark. First, off, I would again check your fuel pressure and pump relay to spec. If it's out of spec or, your pressure is out of whack, it will trip the ECU to shut down the system.

If your CKPS is out: again, the ECU will kill power

If your CPS is out, same thing- all power will be cut.

I knew it wasn't your injectors and, that is dirt cheap to rebuild them for 20 a pop. We charge 40 a pop just to clean and test them never mind rebuild them. A complete rebuild all mechanical and electrical parts is about 350 for a V8. Those are Bosch too- not junk.

Anyway, back to your issues:

First verify the voltage coming out of the battery to the ASD relay is proper and within correct operating range.

Verify the ohms at the ASD Relay and the Fuel Pump Relay while powered and UN-powered. Refer to Haynes manual or a dozen others listed out on the net on the procedure. It's very very simple.

If both of those are good, proceed to checking your CKPS by back-probing it and slowly (very very slowly) rotating the engine by hand at the crank. Check for voltage output hi, and lo. Use an analog meter for this as it's easier to see the voltage swing.

Next, verify your CPS is putting out 5 VDC. This can be done by simply removing the cap and rotating the engine until the rotor is pointing in the middle of the hall sensor / pickup assembly / CPS. You should now see +5V.

You will need to know how to use a DMM or DVM and which wire is hot and which is ground. You will also want to check the input to these sensors to ensure the voltage going in is to spec. Again, there's tons of information on which wire is which, and, when in doubt, you can refer to the schematics or this forum. I believe I had posted this a few times now.

If not, it's time to R&R (remove and replace) either one or both depending on what you see at time of test.

But, those are the most common reasons for all power being cut. When a gross failure is detected at the PCM / ECU, it kills power to the ASD relay thus preventing power from reaching the EFI system components. This means, no power to the coil, no power to your injectors and no power to your fuel pump as well.

Those are the ones I would be looking into first.

Good luck. Let me know how it goes.

CM

 

If your getting no spark, have your ignition coil tested. It could be that it's dead.

 

Good point there. Forgot that. Take the coil off the truck and connect an ohm meter across the primary and measure the ohms. Compare it to spec in the Haynes manual. Toyo made one coil and there was another mfr that made the another coil. Both sets of specs are listed in the Haynes manual. If the ohms are not up to spec- R&R (remove and replace) it.

Check your coil input voltage as well and verify that you have 13-14 volts coming into the coil at the + side with a DVM. Remove the connector from the coil before doing this test or, if using inline, use a test light instead to verify that you have some voltage at least. While it will not tell you what the voltage is, it will at least tell you if it's receiving voltage or not. Best way is to remove the connector and check it with a DMM. This is the feed coming off the ASD relay. If you do not see power, check the resistance of the wire coming off the ASD relay to the Coil. It should be ~1 ohm. If it reads high, there's an issue with the wire and it needs to be replaced.

Also, check the ground from the coil to the ECU. Remove the coil connector, remove the black connector at the ECU and probe for continuity. Should read the same. If it's reading high resistance, you have an issue with the ground wire. R&R. As of course, be sure to disconnect the battery first.

If, at time of cranking the engine, if no voltage is witnessed at the coil, you have a voltage supply issue. If you have voltage to the coil but nothing on the ground side, your ECUs coil driver circuit may be faulty to where it's not switching ground on / off or, it has cut all power from reaching the coil via ASD relay.

In either condition, you need to start working outward from the battery to the ASD relay, to power to the coil, from coil to ECU. If you have power going into the coil and, you have power at the ground being switched on and off, (use a test light for this - do not use a meter on the ground side for risk of sending meter voltage into the ECU coil driver circuit thus damaging the internal components)

You also may not see any voltage at all initially due to the PCM killing all power at the ASD relay. In that case, you will need to reset the ECU in order to clear that out before you start taking any measurements. If and when you clear it out and note voltage now, we now are 100% certain that power is being cut at the ECU due to gross failure.

 

Thats what I just suggested?

 

let me just say that I agree with both sides of the argument here on the behavior and tone... By that I mean, sure ya'll were a bit hard on the guy.. BUT it was mentioned many times to please take it in stride, and the rest of it was frustration, and I can tell the OP really didnt take too much offense, he was mature enough to handle the frustration,and not get riled up by it... all the way around the OP took this all very well..and was mature enough to accept that he wasn't communicating well to the people who were trying to help him, and therefore they got frustrated.. Let me also say that this forum has some of the nicest people I have ever talked to.. I joined the S10 forum since I now own an S10, and they are jerks..

 

Is that a question or a comment? The question mark threw me off.