*!!! HELP !!!* M20 Cranks but wont start..running out of ideas...

[e30onBBSs]

Any update?

[e30onBBSs]

^ Bam! That's a smart response.

Thanks Kershaw :D

If I sniped that I'm going to be stoked!

[Kershaw]

^ Bam! That's a smart response.

[e30onBBSs]

*!!! HELP !!!* M20 Cranks but wont start..running out of ideas...

Check your c191 connector and listen for injector pulse while cranking with a screwdriver on the injectors. I had the same issue as you. Checked fuel like you did, but the problem was that the injectors had no power. So I thought I had fuel but I had no i jector pulse, so obviously no fuel was getting into the combustion chamber. Definitely a place to check as that connector is known to become corroded. It's the small one under the manifold near the starter.

Chances are good the new harness you got is corroded on the harness side.

https://www.youtube.com/watch?v=GDJoKIoSd-w

If you don't hear this sound ^ They aren't opening, and fuel is going in and out of the rail but skipping the injectors, so no start.

[packratbimmer]

CPS plugged into the right connector? It is easier to get them crossed when swapping in a new harness.

[Kershaw]

It's not possible to retension the belt and have the motor out 180*. You'd have to take the belt off, rotate the block once, and then put the belt back on. I'm not sure that's even possible without taking the head off.

I'd suggest putting the old harness back on to check, since you know it started then, even if it was sporadic. But dnguyen has a good suggestion, verify the firing order.

[dnguyen1963]

When you crank the engine for a bit, did you remove the spark plugs to see if they are wet? If they are completely dry then there is no fuel coming into the cylinder. Did you verify that the engine is firing in the correct order?

[MPLFoster]

bump for no luck yet... :(

[MPLFoster]

Yes the car was able to start before replacing the harness but it was not consistently starting every time. And when it did fire it would not hold an idle. it would die right away.

i had a good working harness laying around so after i found the frayed wires on the diag plug i swapped it out. I was meticulous in labeling connectors/grounds/signal wires so everything went back where it should go.

When i was in there i taking apart the distributor i decided to take apart the timing covers as well and noticed the belt was just a bit loose so i re-adjusted the tensioner as per the Bentley guidelines. my friends says i may have put the timing 180 degrees out. not sure how i would have done that. is there an easy way to see if the timing is off? i checked the timing marks, again using the bentley, and the marks are bang on...

[Kershaw]

People like say things are ok without checking them a lot. Not to mention there are lots of different diagnostic tests, if you list the ones you've done, people can chime in with other tests. Diagnosing cars over the internet is tricky as it is, so specificity is absolutely necessary. And something is obviously not ok or the car would start. If you have fuel and spark, the car should start.

So the car did start before replacing the engine harness though?

[MPLFoster]

Why did you replace the engine harness?

You said the ignition system checked out, you didn't mention physically looking at the plug while cranking to check for spark. Does it spark?

Same with the fuel, you say it's ok but you don't mention pulling off the fuel in hose, sticking it in a plastic bottle, cranking the car over and see if it's spitting out fuel.

Don't just say things are ok, list the things you've done to verify that things are ok so we can start ruling things out.

i replaced the harness because the section with the diagnostic port had frayed wiring and was giving me stumbling issues/no start. Now with the new harness it will crank but not fire at all. Checked all my connections/grounds and they're all making solid contact/in the correct position. No frayed wiring.

Pulled each plug wire and saw spark on each. Pulled the fuel line, pit it in a bottle and it sprays like hell. When i said they're ok its because it checked them. don't know why i would say they're OK otherwise. i will be more specific in the future.

[crappycoco]

I'd check what Kershaw said above. See if the sparks are firing and if the gas is coming to the injectors.

[MPLFoster]

CPS is a new OEM unit. DME pin test says CPS is good. its not mixed up with the plug ignition wire pulse sensor plug either.

[Kershaw]

Why did you replace the engine harness?

You said the ignition system checked out, you didn't mention physically looking at the plug while cranking to check for spark. Does it spark?

Same with the fuel, you say it's ok but you don't mention pulling off the fuel in hose, sticking it in a plastic bottle, cranking the car over and see if it's spitting out fuel.

Don't just say things are ok, list the things you've done to verify that things are ok so we can start ruling things out.

[dnguyen1963]

Did you check the CPS? If there is no signal from the DME then the engine will never fire.