Bryan

This is new information on my previous thread about being stuck at work with a dead 944.

The car is an '88 8-valve, normally aspirated car.

The car cranks strongly but will not even think about catching or starting.

The car drove fine to work, and would not start after work.

The timing belt is fine and the crank and cam are perfectly timed.

Stone cold, and with a squirt of oil into the cylinders, I get about 150psi of compression on #1 cylinder (the rest are similar)

The DME relay is new.

The fuel pump runs when it is supposed to, the fuel pump and filter are about a year old, you can hear fuel moving through the rail when you manually run the pump, the static fuel pressure (engine not cranking) is to spec, and after cranking for a while I can smell raw fuel at the tailpipe.

The signal at the injectors is present and pulses when I crank the engine.

I've tried two sets of spark plugs, they're clean and gapped plugs but not new.

The cap, rotor, coil, wires, and DME computer are all about a year old. The coil checks out electrically both in and out of the car. The coil is powered correctly with the ignition on.

When cranking, plug #1 fires (testing by grounding it against the cam box) rhythmically at about 15 degrees BTDC.

The grounds on the bellhousing and battery box are clean and tight.

Spraying a big burst of starting fluid into the intake manifold and cranking also results in absolutely nothing even resembling kicking over or starting.

How does and engine have compression, correctly timed spark, and fuel being injected (or starting fluid) and not even give the remotest hint of starting?

I don't think Click and Clack could solve this one.

Bryan

MHT

Bryan, what did the plugs look like when you pulled them out? Were they wet with fuel? Try pulling the vacuum hoses from the regulator and damper, see if there is any fuel leaking from the rear of the valves. Check the resistance of the coolant temp sensor. Try cranking the car with the throttle wide open. Good luck Mark T.

MHT

New thought, did you check the physical orientation of the rotor button, is it pointing at #1 when the eng. is at TDC? 15 deg. sounds like too much advance while cranking, but I have never had reason to check it. Mark T.

Bryan

The plugs that were in the car when this happened were Bosch Platinum +4s that I put in a couple months ago. They were gassy smelling and oil fouled when I removed them. I replaced them with the stock Bosch single-electrode plugs that came out of the car when I replaced them with the plats. They were that perfect cocoa brown color, they went back into the car, the no-start condition continued, and they too smelled a little gassy when I removed them to test compression and squirt oil in the bores. They weren't wet with fuel, but they smelled like gas a little.

The distributor rotor was secure on the cam and pointing at the right pole on the cap. The 15 deg btdc is approximate as we checked it while cranking the engine and shooting an adjustable timing light into the timing mark hole in the bellhousing. If the cam and crank are timed and the spark is "somewhere" around tdc, then I'm assuming it's right.

I cranked the car with the throttle closed, partially open, and wide open. With and without an intake manifold full of starting fluid.

I didn't check the regulator and damper for leaking into their vacuum lines, but the static fuel pressure is OK. And the car won't even cough or sputter with starting fluid (I only use starting fluid with the injectors disconnected).

Same deal with the temp sensor. I didn't measure it but I don't see how it could keep the engine from starting. I could see it making the car run a little rough, but this thing cranks and cranks and does absolutely nothing even remotely resembling starting.

However, the temp sensor is listed as something to check during a no-start condition so I will do that.

Thanks and keep the ideas coming, folks!

Bryan

Jason_86_951

Throwing out a guess:
Broken rotor??? Causing no spark to get to plugs?

Tough one!!

Jason_86_951

opps...
I read your post again, and yes you have checked that.

Chris_924s

Bryan, Mine has been exhibiting the same mysterious no start scenario. It was towed to a wrench today, and I'll post what they find.
This is baffling. I have spent dozens of hours working the same diagnosis trail with zero results.

newoldguy

Well, you've certainly ruled out a bunch of potential culprits. So, assuming it isn't one of the above, I'm going to suggest more investigation of the grounds. The one that seemed to fix my car were the ones that are under the fuse/relay box in the passenger compartment. They're hard to get at but you should see two pairs of brown wires going to 10mm bolts. Loosen,clean,tighten. Worth a try. Let us all know if you find it--whatever the cause and cure. These problems are the damnation of us all.

Luis de Prat

Bryan, does your car have a factory alarm? My S2 had identical symptoms and it was the alarm control module.

targa

OK - this may sound weird but check your ignition switch.

I may be totally off here but I had a similar problem. No problem starting when cool but after sitting in the sun all day, my 83 NA would crank but not turn over. Bugged me for a year or so - was very intermittent. I replaced just about everything before taking it to my mechanic. Turns out it was the ignition switch! The heat from the sun actually expanded the internal plastic and caused the contacts to seperate (at least thats what my mechanic told me). Once replaced, I never had a problem with it starting.

Worth a shot huh?

Bryan

No factory or aftermarket alarm in this car. The car sits inside a parking garage all day at work, and on the night it died, it was about 40F out and extremely damp (the parking garage is partially underground). It had been well below zero the few preceeding weeks and the car had no problems. And the preceeding summer had been fine too. The only thing odd was that the garage was extremely damp - like foggy inside.

This problem does seem electrical in nature, I will check the grounds under the fuse/relay box.

The ignition switch could also be a culprit, but I had never heard of one going bad until now. I added this to the list as well.

Keep the ideas coming!

Thanks,

Bryan

Mark Lue

Just throwing out some thaughts: (1) Spark exists but not enought to start the car, check the wire between the coil and the distributor it maybe broken internally or a small crack or burnt opening may have opened, no doubt aided by the overly moist air when you tried to start the car the first time.

(2) Cap is BAD or Rotor screw missing, turning on the distributor shaft.

(3) Check out this post for additional info:

<a href="http://forums.pelicanparts.com/showthread.php?s=&threadid=99154" target="_blank">http://forums.pelicanparts.com/showthread.php?s=&threadid=99154</a>