Landseer

Guys, to many 85-only starting / stalling / no start issues.

Seriously, I think Porsche did something funky in that firewall engine harness Similar to 98 Jeep wrangler, maybe, a crimp weld that corroded over the years.

Ten re-dos with the long needlenose and my problem went away / grounds were previously polished clean and resoldered twice.

I think its in the harness.

tomcat

Hey guys, still no joy.

I replaced the CPS and no change. I still have not checked fuel pressure or the injectors, but...

I sprayed staring fluid into the MAF and still nothing. I also checked spark on two wires during cranking and seemed to be ok.

I assume starting fluid should have did something as long as there is spark?

WICruiser

Spraying starting fluid into the intake can be a bit tricky, especially if you are a one man show. That being said you need to get the very basics: spark (sounds like you have), fuel (may or may not have), and compression. Assume for the moment that you have compression. Are you sure you have spark at the right time? Typically it is not off so far the it isn't obvious by combustion happening in the intake or exhaust side of things but I have been there although not on a 928. If you have a timing light you should be able to confirm #1 spark plug is firing near "0" degrees on the crank damper indicator.

Get a fuel pressure gauge installed temporarily in the end cap location of the fuel rail. that way you can confirm that the fuel pump is actually building the required pressure in the fuel rails.

Get a noid light to confirm that the injectors are firing.

Let us know what you find.

tomcat

On the same page, thanks Roger. Need to check the injectors and check fuel pressure.

But was is confusing is not so much the hard starting, but more the way the engine failed while driving. Wasn't like running out of gas. Engine was still on, just would not accelerate and slowly decelled to a stop. Like the accelerator broke.

tomcat

I tried starting this morning and got a pop (i.e., I think there was some fuel burned). The curious thing is it seems to only happen the first time I try to start the car. Each subsequent attempt will not fire until I let the car sit over night. Almost like it floods immediately after the first spark. Have seem wet plugs and smell gas from the tailpipe.

I think the LH, EZK, MAF, CPS are all ok. Got spark. Could it be the spark is not strong enough? If so, my guess check the coil, wires, and plugs? How do I check the coils?

Checking the injectors tonight.

WICruiser

It doesn't seem likely that both coils would be weak at the same time. From the description of the original it sounds like it basically ran out of gas just because you had enough fuel to run at idle but not enough to generate any power. It is sounding more and more like a fuel pump, or blocked fuel filter. You get enough fuel pressure before you use any fuel to fire the injectors once but then the fuel supply and pressure go away. You may get anough of a dribble out of the injectors at very low pressure to smell some fuel and run into the open intake valves and wet the plugs but not really enough to do anything else.

Landseer

John, did you find the grounds for the computers yet? Don't go further until this is taken care of.

As Mike said, remove air cleaner assy, the grounds are located on each side of the back of valley, near the bell housing. When those grounds are bad or loose you can get symptoms similar to those you posted. And I'm dead serious about the 85 cars probably having an endemic bad spot in the harness that those grounds disappear into. Just manipulating mine would cause the car to stop.

Also, I'd advise you check the small red wire on battery positive - ensure its clean and tight.

Also, I'd replace the negative battery ground wire with a temporary ground wire from Advance Auto. (buy a longer black ground cable for a normal car battery and use it).

Do you have a noid light yet? Lisle, stocked by some of the remaining independent parts sellers, makes a very good one. Order it online if you have to.

I'd disconnect battery and remove fuse panel from passenger footwell. You want to ensure the wires on the backside of the panel are completely intact --- that they haven't subtly melted into each other. There is a defroster wire or fan wire that I've seen melt into the other wires on two different cars, screwing up the relay for the LH.

Is your 14 pin connector complete, intact, and fully cleaned, including beneath the backing covers that retain the male and female electrodes?

tomcat

Checked the red wire on the positive previously and tried jumper cables for a ground strap, but...

I went and purchased the noid lights. And while I was in there, I got a set of spark plugs. While changing the plugs I found one of my wires with a one inch gash. I taped up the wire and checked for spark. Spark looked ok and no arching. Tries to start, but still wouldn't start. I'm going to try in the morning.

The description of the fuel rail being primed at start up and then not pressurizing afterwards is interesting. I believe the fuel pump is ok. Filter is kinda old so is suspect. Haven't checked the regulators either.

Regardless of whether I get it started tomorrow, I definitely need to have to start doing some regular maintenance.

Landseer

Time for some work. I wouldn't even bother trying to start it until the maintenance is done.

Really doesn't matter what order you take it in, either.

tomcat

Checked the fuel pressure - 38psi with the pump relay jumped. Did not try to crank yet.

When checking the pressure gauge, I notice a hissing somewhere around the intake. Not from the regulator or dampers though. Does anyone know where is leak is coming from? Had a really hard time locating it. Not sure where the source of air would becoming from without the engine turning.

WICruiser

Unless the engine had been running recently there should not be any air sources to produce a hiss. Are you sure that it is not one of the fuel regulators or dampers reacting to the fuel pressure you were testing?

It would be interesting to know if the pressure holds when you crank the engine or if it drops.

It is possible that the problem is a regulator or damper that is sucking fuel into the intake flooding the engine resulting in the no-start condition.

tomcat

The hissing is the fuel going through the hose. Thought it was pretty weird also.

Fuel pressure is good during starting also.

Finally found the ground I was looking for and cleaned it - covered by the harness. Also checked vacuum on the regulator and dampers - ok. Also checked several injectors - clicking during start up. Got the noids, but couldn't get the connectors off. Also checked the power to the LH and EZK - ok.

Thinking caps/rotors/wires/coils, timing, or injectors. I assume a vacuum leak wouldn't cause a no start? I know the hose coming off the cam tower cover is trashed, but driving for over a year that way. And assume bad TPS wouldn't cause a no start?

tomcat

I just wanted to add...

I.was alittle frustrated when I ordered a fuel pressure gauge and found out the fitting was a male plus coming off the rail. Sat all weekend looking for a female adapter - none. 944 forum had a guy who suggested connecting male to male with fuel hose and clamps. Gauge offered with a 1/8 female to m12 male before I realized I needed a female. Worked great.

tomcat

Finally getting a little frustrated that everything was checking out. I guess really seeing the inevitable. Starting tearing into the front end of the engine.

Water pump pulley tilted out about in inch. I am hoping the timing is "ok" because the belt was still riding on the edge of the pulley. So far just a timing belt change. We'll see.

Mike Frye

Ugh!

That's ugly. John, you know where was the last time I saw that, you were there. It was John V's race car and he had bent some valves.

If the only damage you have is at the WP you should play a lottery ticket.

I'm crossing my fingers for you. Time to start at square 1...