944 Engine Cut-Out / Lag

Dakota Kid · 06-03-2002, 10:12 AM

Hi All,

I have an 85-1/2 944 (non-turbo) with about 103,000 miles that recently started cutting-out on me. Here's what I've been able to notice...

1. cut-out happens at all speeds, idle through highway,
2. no cylinders appear to fire during the cut-out,
3. cut-out lasts about a second and is intermittent,
4. seems to be worse when it's warmer outside
5. runs great when isn't acting up

I've checked the sensors according to the Mitchell and Haynes manual and seem to function ok. It may run fine for a day and then cut-out several times minutes apart.

The DME relay was replaced, plugs/wires replaced, changed the fuel filter, checked the fuel pressure during a cut-out (fine), checked the sensor connections, ignition key for loose connections (seem ok).

The timing retards about 5 degrees (moves away 1/2" from sight hole) but am not sure if this is the cause or an effect.

What are your ideas and experiences?

Thanks in advance.

Obin Robinson · 06-03-2002, 10:27 AM

i know it sounds rediculous... but check your battery cables. i had a VERY similar problem to you and after i replaced the battery ground, and cleaned up the positive cable... the problem never came back.

good luck!

obin

Andre · Andre's Garage

if your battery wires are loose the car shouldn't cut out. If its running it would be running off the alternator and not the battery. You can disconnect your battery completely after starting the car and go drive around. i think...

RaF944 · 06-03-2002, 12:34 PM

How about the injectors?

SoCal Driver · SoCal Driver's Garage

Think your "brain" (DME) is going.

Had the first one on my 83 just die going down the road then come back on like you mention. Then really die requiring me to reach under the steering collumn, disconnect the plug part way then reconnect it while the engine was still in gear with the key on.

Would take off and run - for a while.

Used brain fixed it.

Still have the old one if anyone is interested.

rbt944 · 06-03-2002, 11:03 PM

Quote:

How about the injectors?

You should really check this Dakota Kid. My 944 kept turning off and would suddenly turn on again. Then it was driving good for a while. But on the way from school, it kept happening on and off until I got home. I removed the injectors and sent them off to get cleaned. It turns out that 3 of them were bad. They were leaking fuel. I can't wait to get the new ones on. I've been kept from driving my 944 for too long.

Lawrence Coppari · 06-04-2002, 04:26 AM

Don't unhook battery while engine is running. See thread entitled 'Question About Alternator'.

NickZaimis · 05:54 AM

I had similar problem ...Turn out to be the fuel presure regulator was bad.
It start like your car and with time got worst/
A good way to check it is when cut off have a 19mm open wrench and release the pressure on the releave valve on the top of the rail and retied again.
The car sould start right away.
(If the car is warm when you do that i suggest have a gallon of water handy to wash-dilute the excess gas from around your engine)
Good luck

hoover · 06-04-2002, 11:37 AM

A similar problem on my car was traced (eventually) to a broken wire at the fuel pump, the outer insulation was ok but the wire inside had parted, but made contact some of the time. A long shot, but you never know!

Dakota Kid · 07-16-2002, 06:10 PM

Hello again all,

Finally found the problem, make that problems.

Was messing around seeing what changed the performance if anything when sensors were disconnected while the motor was running.

Turned out to be an intermittent water temp sensor (blue one). Once that was changed out, I noticed the timing was off (i.e. the mark wasn't lined up with the timing hole). Then I replaced the mark sensor which changed the timing back to normal.

Thanks for all the ideas.

Dakota Kid