m20 wont start!!! CPS, battery, and COIL check out fine...

[jlevie]

Do you have spark from the output wire when cranking the engine? No spark could be:

No timing data from the CPS to the DME
No power to the DME (bad main relay, or fusible link) or a bad DME ground
No START signal to the DME
Bad coil or no power to the coil
Bad DME

If you have spark from the coil output but not at the plugs you could have a bad distributor, rotor, or broken timing belt.

If you have spark from the plugs the next check would eb to see what the rail fuel pressure is while cranking the engine. You could have a bad fuel pump relay, blown fuse, bad pump, clogged filter, or bad FPR.

If the rail fuel pressure is normal when cranking, use a noid light to see if the injectors are firing. A bad connection at C191 (underneath the intake) is not uncommon.

[spiDmang]

Do you have spark from the output wire when cranking the engine? No spark could be:

No timing data from the CPS to the DME
No power to the DME (bad main relay, or fusible link) or a bad DME ground
No START signal to the DME
Bad coil or no power to the coil
Bad DME

If you have spark from the coil output but not at the plugs you could have a bad distributor, rotor, or broken timing belt.

If you have spark from the plugs the next check would eb to see what the rail fuel pressure is while cranking the engine. You could have a bad fuel pump relay, blown fuse, bad pump, clogged filter, or bad FPR.

If the rail fuel pressure is normal when cranking, use a noid light to see if the injectors are firing. A bad connection at C191 (underneath the intake) is not uncommon.

jlevie, thanks for posting all that info up.

I jumped the gun, and started trying to diagnose items further down the line (cps). Ill check the spark plugs tomorrow, and check back in. im hoping its an easy fix

[spiDmang]

damn...

so i verified that i DO have spark at the plugs (bought a spare plug, hooked it up to a plug wire, grounded it, and cranked to see if i have spark...which was positive)

i pulled my plugs, and they are getting fuel because they were saturated, and smelt like gasoline (which should mean all fuel components are ok right??)

Jlevie, are you sure a snapped tbelt wouldnt allow a plug to fire??

[jlevie]

A broken belt could allow one cylinder to fire if the rotor was in the right position. But the other cylinders would have no spark. Too much, or too little, fuel could prevent the engine from starting and since it isn't firing the plugs could wind up wet with fuel. So there still could be fuel system problems.

[spiDmang]

hmmmm a buddy of mine said to let the engine and plugs air dry, as well as add a couple of drops of oil into the cylinder to try and build compression...

as for the belt, ill check that as well

[spiDmang]

so i got the car up and running by removing the plugs and cleaning off the carbon deposits on em.

i also replaced the cap and rotor and it fires up first try on cold start ups.

BUT now, im having a hard time with warm start up's.

i assume i gotta replace the FPR, rebuild injectors, or replace the fuel filter....

[spiDmang]

Pulling the vacuum hose of the FPR should have the car raise in RPMs when idling correct?

I pulled the line to the FPR, and my idle didnt budge one bit

[E30_fiend]

main relay seems to be the issue to me.


Taylor

[jlevie]

main relay seems to be the issue to me.

The engine has spark and thus the DME is running, Which means that the main relay is good.

[E30_fiend]

The engine has spark and thus the DME is running, Which means that the main relay is good.

My bad. Fuel pump seems like it could be a likely culprit too, does it not?

[jlevie]

Pulling the vacuum hose of the FPR should have the car raise in RPMs when idling correct?

I pulled the line to the FPR, and my idle didnt budge one bit

Yes, that should have affected idle, since it didn't there are probably intake leaks. Have a shop run a smoke test.

[spiDmang]

Yes, that should have affected idle, since it didn't there are probably intake leaks. Have a shop run a smoke test.

hmm ic. I replaced the intake boot (which was more cracked out then tyrone biggums).

Are there any other major hoses that can leak (like the "mess under the intake mani" mod for the 318i)?

id honestly rather not pay a shop since i like doing the work myself. Is there a way to do it myself?

[jlevie]

The complete list of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hoses, valve, and expansion tank
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

While leaks in some of those can be found by inspection or by spraying carb
cleaner on suspect areas, not finding leaks that way doesn't eliminate the
possibility. Only a smoke test will really work.

[spiDmang]

how much does a smoke test usually run?

[jlevie]

About a half hour's worth of labor.