Won't start/backfires

emcee · 07-08-2003, 05:16 AM

I originally posted this on the turbo side by accident. Here's the story: I was driving 84 944 under normal conditions. Pulled up to a stop light after traveling highway miles and the car went dead. I tried to crank the car and it experienced backfiring in the motor. The car will NOT START. The motor turns over normally, but backfires and does not attempt to engage. This problem came on with no indication whatsoever. There was no loss of power, no sputtering, no missing, no overheating, NOTHING. Lawrence Coppari on the turbo side has been very helpful so far but suggested I post this on the NA side. Here's what I do know: I can see the cam turning through the hole and I can feel the gasoline pressured at the pump. Any help, wisdom or comments would be greatly appreciated. Thank you.

highboost951 · 07-08-2003, 05:31 AM

any strong smells of fuel from the exhaust when cranking it over? or fuel in the vacuum lines? could be a bad fuel pressure dampner or regulator. You also need to check your cap and rotor, any more details?

emcee · 07-08-2003, 05:49 AM

thanks for the re. Cap and rotor are new (less than a year) along with plugs, wires,& o2.At first I couldnt smell anything but there is a smell of fuel after trying to start it. I havent tried the smell at the exaust. What I smell under the hood I wouldnt consider strong. Havent checked the vaccum lines. thank you for your help.

emcee · 07-08-2003, 06:00 AM

When you asked me about any more details it reminded me that when Im cranking the car the small miles per gallon guage stays over on the right side (60mpg) until the first backfire then it drops down to the left side (0 mpg)and does not return.I have never noticed what the operational procedure of this guage is before this happened.hope that helps some. Thank You for time

FLA944 · 07-08-2003, 02:31 PM

Bring the flywheel up to TDC and see if the cam mark aligns (probably doesn't)

If the marks align, check the connectors for the sensors on the flywheel. They are located on a bracket mounted to the firewall.

Rick

Lawrence Coppari · 07-09-2003, 03:35 AM

There may be male/female connections for the flywheel sensors about a foot away from where the sensors mount on the flywheel. That is where they are located on my '86. The connectors could be dirty or corroded.
Mine did that to me once. Open them up and clean them and retry. This pertains to what FLA944 said about flywheel sensors.

Porsche944 · 07-09-2003, 06:28 AM

Backfiring is a sign that the timing is off. The only time my '84 ever backfired was after a belt change. I failed to use thread lock on the rotor hold down screw. The screw backed out and the rotor turned on the cam shaft which caused the ignition timing to be WAY off.

emcee · 07-09-2003, 07:49 AM

Thanks guys for your help. The car is now safely now back in my garage. I will be troubleshooting all weekend.