Hey guys,

I came out the other day and tried to start my '94 d90, which i drive everyday and it wouldn't start. The engine would turn but it wouldn't fire. There were no codes in the computer. I checked all the fuses, which were good, and I can hear the fuel pump relay but no pump. I installed a new pump and can hear the pump now coming on when i turn the key.

I tried again and it still won't start. I pulled the fuel pressure regulator and have fuel in the rail when i turn the key to on. I also pulled the #8 spark plug and held it against the block and see spark. So I have fuel in the rail and I have spark but it still won't run. What am i missing?

Please help

 

Maybe broken timing chain?

 

Well I doubt its anything obviously mechanical because you would have known that before shutting down the engine when it was running OK!

So something obvious methinks,
So Hola que tal?

A question?
How did you pull the codes since the ECM is CUX14 and that's is best done with something like an Autologic!

Now it seems you somehow diagnosed a fuel pump as being defective and it was replaced BUT did you change the in line fuel filter on the frame. That item may be the reason if its choked up!
Now if you changed it the system must develop 2.2 bar (that's 34/35psi regulated) and hold that pressure for an extended period. If it doesn't develop that pressure it won't start. Pull off the regulator hose vacuum hose and it should rise to 40psi once you get it running.

Staying with fueling for a moment do remember that the oxygen sensors on the CUX 14 system play a big part in controlling fueling since there is not much else; its basically a simple system. If its over fueling, which can be a prominent issue, something may be flooding the engine and throwing a new set of plugs in it might just get it to roar.

Of course about 75% of "no starts" are ignition related and on that 3.9 engine timing is often critical for ease of starts and no long crank times. Things like a worn timing chain that has jumped a tooth, a detached vacuum ADV unit, loose distributor will throw the timing out enough to effect the way it starts.
A strobe lamp on #1 plug wire should give you a cranking indication of base timing to be set at 6 to 8 degrees BTDC at sea level..
Again the ignition module can often be a culprit and even though it was running when it was shut down it might also be the root cause of the problem.
I hope some of these musings might help you run down your problem.
T/V