bwebb77

First, I've checked the relays all seem to be find. Pump seems to be ok, smell gas so I believe I'm getting fuel but haven't check flow rate or pressure yet. Pull and cleaned all plugs but haven't tested for spark.

I wanted to make sure all vacuum hose were ok first. There in lies the rub. I removed air box and found two vacuum lines staring at me. One comes from the Throttle housing and the other one looks to be going to the pressure damper, although not 100% sure. But from looking at the WSM that looks to be correct. Could this be the reason for the no start?

Question on the 3 way vacuum adapter/connector, Does Autozone or any other like place have these or is it something I must order from 928 Specialists?

Also, in the WSM there looks to be an unnecessary y adapter connection between the lines coming from throttle housing and joining up with y adapter for the lines coming from the pressure regulators.

Any and all help would be greatly appreciated.

PorKen

Check the three pin plug for the CPS (crank position aka reference sensor) under the airbox connected through a metal bracket. It is likely crumbling, a sign that the sensor needs replacing. If the sensor looks original then it is a good idea to replace it prophylactically. There is a BMW part number (0261210002) which is a more reasonably priced alternative.

Vacuum lines may make it run poorly, but shouldn't stop it from starting. Stock, there is a 7-way adapter to connect all of the manifold vacuum lines, fuel pressure regulator/dampers, vacuum modulator (automatic), ignition brain (EZF), etc.

Mike Frye

Fuel, air, spark, compression, all at the right time.

The CPS being bad (if it is) would stop two of these IIRC (no CPS signal would kill the fuel injectors and spark).

Need to verify spark and fuel (noid light and possibly fuel rail pressure gauge).

Another thing to possibly check is ground for your injectors (and all other grounds). Since these cars are 'batch fired' it means all injectors fire with every pulse and all are grounded together. One short or open and they're all dead.

Maybe a little more history will help us help you. Has the car been sitting? When did it run last? ?s it a 'crank but no start' or is the problem that it doesn't even crank? What was the last thing you did? That kind of thing.

There is a test plan for the EZF in the WSM and on the CDs you can get from Jim Morehouse. If you work through that you're guaranteed to find the problem.

bwebb77

Mike, I'm getting around to checking the rest of it. I read through all the "no start" 928 threads. Going through all the Fuel, air and spark test. Just had a question about the y adapter/connector. Figure while I was there I would fix it.

Car turns over strong, just won't catch. Has been sitting for about 9 months, battery disconnected. I drained the fuel and added 5 gallons of new "non ethanol" premium. It did have premium ethanol before. I added sea foam and ran it through and let sit over night, but no luck on starting this morning.

Now, I'm starting the elimination processes.

bwebb77

Fuel pressure seems to be fine, getting spark according to noid test. What might be the next easy test? Not sure about the CPS, can't seem to find it, but since I'm getting spark and fuel I guess it's ok.

WICruiser

Slightly confused - I believe the noid test confirms that the injectors are firing - not the spark plugs.

If you have fuel pressure as indicated and injectors are firing what is the condition of the spark plugs - wet with fuel indicating no spark, or dry indicating that regardless of the above there is no fuel getting into the combustion chambers.

For some reason these cars respond well to using jumper wires to bypass the 3 cricial relays. In my case once I bypassed them the engine started and it seemed that regardless of which relay I put back it continued to start/run.

Landseer

^^ Agree. Kind of like chest paddles.

SteveG

I don't see that you had anything on the fuel rail or delivery disconnected. You shouldn't smell gas. Could be a safety issue. Asside from that, if I thought it was flooding (check plugs for wet) I would hold accel to floor while cranking.

backnblack

Did you try what Ken suggested ? I had this problem, I had spark and had fuel and it was the crank sensor.
I hope this helps.

Cheers
Matt

Richter12x2

It ran yesterday, then doesn't run after Seafoam? Either pull the connector for the LH plug, or pull the Relay for the fuel pump, whichever is easier for you, and crank it for 20seconds or so, wait a few minutes, then again, wait a few minutes and a third time, see if it tries to catch.

Seafoam is awesome at cleaning valves and stuff, but I've found it's really easy to flood the car with it, too. Also, be careful where you feed it - I had it collect in the the end chambers on my '85, backfired (my fault) and blew both those end chambers off, shooting a 5 foot burst of flame in my face. No harm no foul, but my wife was already at the front door ready to call 911 before I realized I wasn't dead or on fire.