I bought a 99 s10 4.3 auto 4x4 that was not running. The guy broke the key off in the ignition. He tried drilling it out but found out he just screwed it up. so he bought another steering column just to find out he got the wrong year model.. . this is where I bought it from him. I got it home and started working on it. It would crank but not fire up. I checked the fuel pressure and it was on the low side and fell quickly. I then sprayed fuel in the TB but still no start.. No fire from the plugs. Anyway, I traced it to the coil. It is getting fire to it but not sending any to the dist. I checked the crank sensor and coil but they checked out to be good. Also, the security light stays on all the time, I mean it never goes out. I have to take the battery cable off to keep it from running the batt. down. I am thinking if I can get it to fire and possibly run and go from there. What do you all think I should do first? PS; I have bought a new fuel pump and filter but have not installed it. I am trying to get to fire firstp. Thanks for any hel.

 

1) You will need to diagnose why you cannot maintain fuel pressure and fix that issue. Get the fuel pressure reading at the fuel filter as well as the shrader at the engine.

2) What do you mean that you have fire to the coil but not the distr? Does this mean that you can detect the ignition pulses from the ICM to the coil but there is no secondary ignition output from the top of the coil or there is secondary (high voltage) output from the coil that does not appear at the output from the distr? What are the voltage levels of the ICM pulses?

3) Eventually you will need to clear up the security issues but this disables the fuel pump after a few seconds of running and has nothing to do with ignition problems. A buggered up steering column and ignition assembly might impact ignition however.
George

 

Sorry I have not gotten back for a while but I am working on this alone and have been trying to make a remote starter button from the starter to under the hood. This way I can check the pulse to coil. The fuel pump is weak and is border line on the pressure and does fall quickly. As stated earlier I have a new ac/delco pump and filter. I was just was hoping to get it to fire first.

 

Well I got a remote start and found no pulse going to the coil. Where do I go to find the trouble

 

Attached is the circuit diagram for your ignition system. Lets get started figuring out why you have no spark:

1. Make sure you have 12V on the pink wire to the coil at the connector while connected and key on
2. Make sure you have 12V on the pink wire to the ICM at the connector while connected with key on. Check first with the meter ground wire on battery ground and then check it again using the ICM blk/wht ground wire on terminal C at the connector while connected.
3. Disconnect the ICM connector but leave the coil connected and check to see if you have 12V on the wht/blk wire in the connector at the ICM end with key on

We will go from here after you report back.

George

 

I test the wires you mentioned above and I am getting 12 v to the pink wire. Not being much with electrical i thought I would get the coil and icm off a running 99s10 and try that. Well no fire. So I am going back to the list you told me to check and go at it again. Something has to be broken somewhere, now just to find it. By the way on the connection to the icm it's labeled in the diagram that the four wires are listed ABCD only the pink wire has 12 volts the others have nothing even while cracking. Is that correct?

 

You should in 3) below. There will be activity on the ICM white wire during cranking but it’s not 12v and it’s pulses, not a DC voltage. Depending on the answers to my 3/22 post, then we move on to wiring continuity and the firing pulses to the icm


George

 

It has been awhile since I was last on and if I need to start a new I will. After checking the wires on the coil and module and cps I found the wires to the cps have cut and splice back together but was extended some with different color wires. The wires seem to be connected correctly except one. The black/white wire is connected to a purple looking wire. They are no other black/white wire that is not connected that I can see. Anyway the pink wires have power. With the coil connected the c terminal to the module has power. I am guessing the crank sensor wire may be the trouble. What think you.

 

The crank sensor has three wires: purple, yellow and pink. What are the sensor wire colors and what are the harness wire colors? The pink wire here should also have 12v at key on.

George