No Spark mystery? 98 Neon 2.0 SOHC

eatsleepfish · Post by **eatsleepfish** » Thu Jan 27, 2011 8:39 pm

Put a headgasket in a 98 neon with a SOHC 2.0. Ran fine for a few minutes and then quit just like shutting the key off. No spark. Has power to the center pin on the coil pack when cranking, so the cam and crank sensors are triggering the ASD relay. The two ground wires from the coil to the PCM have continuity to the PCM and are not shorted to ground. Have replaced the coil, crank sensor and tried a used PCM. PCM powers and grounds are good. I used alldata test procedures to test the circuits, so I am sure my test are valid. Ideas?

1genRTturbo · Post by **1genRTturbo** » Fri Jan 28, 2011 7:51 am

did you bother to see if your coil was acctually firing? check that, and see if the neg on the coil is good. power to it is only half the circuit.

eatsleepfish · Post by **eatsleepfish** » Mon Jan 31, 2011 9:58 am

Has spark if I manually ground and unground the coil. It is something common to both the injectors and the coil as the injectors are not actuating either. Seems likd PCM, but tried that.

Boostedpdx · Post by **Boostedpdx** » Mon Jan 31, 2011 2:04 pm

I really wish people would get over the PCM as being a failure. It is very unlikely that your PCM has failed. Most likely the ground for your coilpack/injectors is fubard. Have you inspected the wire harness? If you are able to ground the coil pack and get spark it is obviously a ground issue.

eatsleepfish · Post by **eatsleepfish** » Mon Jan 31, 2011 2:10 pm

The 2 ground returns to the PCM from the coil have continuity and are not shorted to ground. The PCM grounds and ungrounds the coils and injectors. There are 4 PCM grounds and they are good. I think it is something to do with removing the head, but cannot figure it out.

Boostedpdx · Post by **Boostedpdx** » Mon Jan 31, 2011 3:06 pm

Not sure if they can affect it, but what about the engine ground straps?

eatsleepfish · Post by **eatsleepfish** » Mon Jan 31, 2011 3:15 pm

Yeah, I figured it was a ground right away, but can't find any problem. Engine grounds are good that I can see. Main ground cable is tight etc. Engine cranks good. There are a few small grounds to the body and they are ok as far as I can see. Makes sense that a ground burnt up or is loose as it ran good for a few minutes after I put the head gasket in. Of course it is hard to see anything on this engine. It appears that the PCM is grounding the coil circuits but not ungrounding them to release the spark.

Boostedpdx · Post by **Boostedpdx** » Mon Jan 31, 2011 5:03 pm

Just curious if you checked your fuel pump fuse. Id check that out if i were you!

eatsleepfish · Post by **eatsleepfish** » Mon Jan 31, 2011 5:05 pm

Fuel pump is coming on as soon as you crank the starter. I did check all the fuses though.

BaLLisTiK · Post by **BaLLisTiK** » Tue Feb 01, 2011 12:42 am

eatsleepfish wrote:The 2 ground returns to the PCM from the coil have continuity and are not shorted to ground. The PCM grounds and ungrounds the coils and injectors. There are 4 PCM grounds and they are good. I think it is something to do with removing the head, but cannot figure it out.

Actually I have had one "fail". My factory ECU failed, took me 2 weeks to figure it out.

Boostedpdx · Post by **Boostedpdx** » Tue Feb 01, 2011 3:49 am

BaLLisTiK wrote:
eatsleepfish wrote:The 2 ground returns to the PCM from the coil have continuity and are not shorted to ground. The PCM grounds and ungrounds the coils and injectors. There are 4 PCM grounds and they are good. I think it is something to do with removing the head, but cannot figure it out.
Actually I have had one "fail". My factory ECU failed, took me 2 weeks to figure it out.

I agree that they can fail, but it is highly un likely. And normally when they fail it all goes. Not just one thing. And the only time i have seen one fail was due to a bad jump/bad ground.

BaLLisTiK · Post by **BaLLisTiK** » Tue Feb 01, 2011 11:15 pm

No clue what caused mine to fail, but they guy who finally helped me figure it out, has been around neons since 1998 when he bought his R/T brand new and he's modded neons ever since.... He had never heard of one failing until mine.

As far as I know, it was the only thing that failed. The plugs were full with an orange-ish colored oil so our guess is that it got hot and shorted out something. My car would start, idle and rev perfectly fine but as soon as you go to drive it would sputter, choke and die and then would not start again until the battery was disconnected and reconnected. We replaced IAC, MAP, you name it - nothing worked until he put his R/T ECU in my car and it ran perfect.

I doubt that the ECU is the problem here though.

BaLLisTiK · Post by **BaLLisTiK** » Tue Feb 01, 2011 11:16 pm

BaLLisTiK wrote:No clue what caused mine to fail, but they guy who finally helped me figure it out, has been around neons since 1998 when he bought his R/T brand new and he's modded neons ever since.... He had never heard of one failing until mine.

As far as I know, it was the only thing that failed. The wiring plugs on the ECU were full with an orange-ish colored oil so our guess is that it got hot and shorted out something. My car would start, idle and rev perfectly fine but as soon as you go to drive it would sputter, choke and die and then would not start again until the battery was disconnected and reconnected. We replaced IAC, MAP, you name it - nothing worked until he put his R/T ECU in my car and it ran perfect.

I doubt that the ECU is the problem here though.