Ladies and Gentlemen,
I have a 1983 Porsche 944 that will start when the engine is cold, and restart if I cut it off and start it back within a minute or so. If I drive it or let it run, cut the engine off and let it sit for five or so minutes it will not start again for at least 3 or so hours. What gives? I’ve replaced the plugs, plug wires, rotor, rotor cap and coil. When I try to restart with out waiting it won’t hit a lick. Help! I’m pulling what little hair I have out. Thanks
Ladies and Gentlemen,
What type of fuel injection does it have . . . Lambada Sond (spelling?). Rocketman
It’s what came from the factory. This car was purchased new by a friend of mine and has only 52,000 original miles on it. It has always has been garage kept and never abused at all.
I think this is the K-Jetronic version of CIS. Doesn’t the Lambda Sond tag refer to maintaining a perfect air fuel ratio,or it could be a designation as far as 02 sensor use, something in that area. But CIS for sure. Sounds like a typical not maintaining fuel pressure problem.
You need to verify the ignition is working when this trouble happens. You could also try spraying a small amount of starter fluid into the intake to see if that gets the engine to fire when the trouble happens.
I can’t recall oldschool . . . I had a late 70’s SAAB with that type of fuel injection . . . it was quirky, but you could fix it. I had a similar problem as the OP . . . wouldn’t start if warm. I rigged a button to activate the cold start valve, which was like a fifth fuel injector, pushed the button while cranking it (when warm) and it started right away. My thoughts are if the ignition and engine are running OK when cold and if you let it run after warm-up, without shutting it down . . . you have a fuel delivery problem. Rocketman
I have some starter fluid and will give it a try asap. Before I put the new coil on, some times it would start and sometimes it would not start. While working on it with the old coil in place, my father took a flat screwdriver and grounded it to the ground side of the coil and the body. The car started right up. After I put the new coil on the car started perfectly the very first time. Cut it off and it will start up again. It’s just when it sets for a short while after running that it won’t start back up. After about 3 or so hours it will start again. Thanks for everyone’s help.
If the coil needs a ground through the mounting bracket then be sure it is making a good clean connection to ground.
You may also want to post this question at a 944-specific forum like this: http://www.944online.com/cgi-bin/forum/forum.cgi
I have an '87 924S that has a similar problem (same engine as yours). The connector for one of the crankshaft position sensors gets flaky. i have to wiggle it to get it to start most of the time.
There is a ground wire that goes from the coil to the groud post on the battery which seems to be working okay. Where is the crankshaft position sensor located?
The connectors are between the cam cover and the firewall. The are two identical connectors mounted in a metal bracket attached to the engine. Try wiggling the top one (I think it’s the top one; I haven’t driven the car in several years).
Okay, this is frustrating. I opened the garage door today, started the car and let it run until the cooling fans kicked on. Cut it off and started it right back up. Waited for 5, 10, 20, 30, and 50 minutes in between each of the start and cutting the engine off and it started back up each time. After the 50 minute period it kinda acted like it was “flooded” but it did start after cranking the engine for about 3 to 4 seconds. I had the air filter out just in case the engine would not start so I could hit it with a little starter fluid. Coil seems to be working fine. Plugs not missing a lick. Got fire everywhere. There has to be something in the fuel delivery system don’t you think?
Thanks again to all,
You might consider the possibility of a failing fuel pump relay; not unheard of on this era of European cars and also including VW, Volvo, etc.
The pumps draw quite a bit of current as compared to other pumps and over time the current draw (which increases as the pump wears due to age/miles) can burn the contact points in the relay.
You might pop the relay out, pry the cover off, and inspect those points for burning. If they’re burnt you can try gently filing them down with a fingernail file.
This kind of thing also occurs with other relays and just about anything else that uses points. My wife has an electric frier that was acting up the other day and eventually quit. After disassembling the thermostat assembly I discovered the points in that were burnt white across the entire surface. This burning was caused by scale developing over the plug in connector (bad connection = high resistance = high current). Filed the points, steel wooled the plug, and good as new.