BLK87S4

This was my daily driver for several years (5 speed, 89K). It has been sitting the last 5 years (I took a job overseas for 3 of those years). When I returned I decided to go ahead and make some repairs and replace some wear items. Namely, I pulled the engine and:

1. Replaced the motor mounts (original hydraulic ones had failed, now has the solid rubber mounts)
2. Replaced the TB, WP, and rebuilt the tensioner (I have done this once before)
3. Replaced the clutch, pressure plate, and the rear main seal (old clutch started slipping the last few days I was driving it)
4. Replaced the oil pan gasket (it leaked)
5. Replaced the valve cover and intake gaskets (they leaked)
6. Replaced the timing chain tensioner pads (they had small grooves in them)
7. New plugs (what the hay)
8. New fuel pump & filter (old one froze)
9. Replaced the CPS (noticed my tach wasn't jumping while cranking, it still doesn't)
10. Cleaned the injectors (first fuel through the lines was pretty cruddy, lines are clean now)
11. Replaced the Hall Sensor wire (it literally crumbled to the touch)
12. Replaced the fuel tank screen and pick up (dropped the tank and replaced everything)
13. Replaced the filler tube insert (totally corroded)
14. New battery
15. Cleaned every ground connection I could find from the rear through the engine bay (while engine was out) and I used the wiring diagram to find them all (poor grounds were my nemesis with my first 928)
16. Fixed several wire breaks in the engine harness (honestly about 3 including the CPS wire)
17. I had the ECU rebuilt, it checked out fine, but I was chasing a fuel pump not engaging....to my surprise I put a relay in the wrong connection (AT kick down position) and that kept the fuel pump from energizing. Regardless I had the ECU rebuilt (now I have a 5 yr warranty for it).
18. I forgot to mention I also removed the CEB and cleaned the connections for the fuses, for the relays (which is why one of them was a space off) and the circuit connectors....sprayed the whole thing with moisture barrier when I was finished.
19. I also replaced all of the vacuum lines with silicone lines.

When I try to start the car it cranks fine, it will catch but will not stay running. I have uploaded a video to my FB page (don't know how to post a video here). In the vide I crank it three times. The first time no foot on the gas pedal. It will catch and immediately die. The second time, I put my foot 1/2 way down and it will take a little longer to die. The last time I crank it I feather the throttle a little bit and it will back fire and run a little longer.

I have pulled the plugs and they are firing/sparking well. I am concerned about a few things and am wondering what your (collective) thoughts are about possible causes of it not starting and idling.

I'm thinking there is probably another wire broken in the harness. I've tested the CPS and hall circuits. They test fine. I have tested the O2 sensors circuits (fine). The car is getting spark, timing is correct (double checked it...twice). I'm about at my wits end. I still have a lot to do on the car to get it back on the road, but I would sure like to hear it start and idle before I move on to front end alignment, AC hose replacement, bleeding the brakes and clutch (replacing he fluid, might as well), lowering the ride height ( just a little).

A few things that bother me (besides it starting) are the tach not moving at all when I try to start the car and not having had the MAF tested. Anyway,I'll be quiet and gratefully stand by for your thoughts.


Thanks,
Robert.

NC928S4

Unplug the MAF and see if it goes in run and stumble mode to start the isolation process.

ammonman

Have you checked the diaphragms in the fuel pressure regulator and the two fuel pressure dampers? Remove the vacuum hose from each and smell for fuel. When these diaphragms fail they allow un-metered fuel into the intake manifold causing an over-rich/flooded condition and hard starts. Does the fuel pump run while you are cranking the engine? If so the CPS is likely OK as it has to send a pulsed signal to the EZK to pass over to the LH so it knows the engine is spinning and time to turn on the fuel pump(s).

Mike

Mrmerlin

did you plug in the idle control valve under the intake as well as the TPS?

BLK87S4

I have unplugged the MAF and it sounds about the same. Will it idle with the MAF unplugged?

The fuel pump does run while the engine is being cranked. I have removed the bleeder cap befor to measure the flow (connected a tube to pump fuel into a one liter bottle, also to make sure the fuel lines were truly clean).

The two connections under the intake are both connected. I don't recall which one was broken, but one of them was one of the wires that was brittle and broke when I pulled the intake to replace the gaskets. Maybe another section broke during the reinstall?

NC928S4

It should idle but roughly.

I would check Worf's document link starting at page 22.

If that checks out consult with Stan, who is the 928 man.