84 us porsche 928 no start
#1
84 us porsche 928 no start
hey guys having some weird issues with my 928 lately I had it running a few months back but between moving I have not driven it in a while. the car will crank fine fuel pump and pressure checks out (have not checked injectors) but now there's this odd popping noise coming from out the exhaust when it tries to start. first thing I did was check the green wire for continuity between both ends and got good readings. not really sure whats going on here so if anybody can point me in the right direction to check id really appreciate it
#2
Race Car
When it ran prior, did it run well?
Try cheap fixes first. Try replacing the fuel injection relay (#16). If it goes bad, the car won't start, or in my case, will shut off instantly when driving.
PS. congrats on owning the best MY of 928 they ever made!
Try cheap fixes first. Try replacing the fuel injection relay (#16). If it goes bad, the car won't start, or in my case, will shut off instantly when driving.
PS. congrats on owning the best MY of 928 they ever made!
#3
it ran perfectly before never missed a beat I think I do have a spare ezk relay somewhere if not I can try the bridge but the popping noise is whats throwing me off its almost like mini backfires
#4
Addict
Rennlist Member
Rennlist Member
You didn't mention if there is spark. With no spark there is no RPM signal to the L-Jetronic fuel injection box and there is no fuel injection. Check for spark and repair if needed.
The fuel injection (AFC) relay XVI is suspect. To do a jumper test, remove the relay. First check to confirm that there is 12V at relay socket position 30. If yes, go to the next step. If no, check the positive battery cable where the cable attaches. Next, create a Y shaped jumper wire and connect 30 to 87 and 87a socket positions. Crank the engine. If it starts, the relay needs to be replaced. It is a special relay part number 928.615.119.00.
Another problem could be a large vacuum leak. My 1983 928 had a leak at the throttle body. Cars with auto transmissions have two large plugs on the passenger side of the throttle body (look between the intake spider legs). If they crack or fall off the engine will not start.
On cars with manual transmissions, the throttle body connects to a deceleration dampener with two short hoses. A vacuum leak at the hoses or decel dampener will cause a no-start.
Rich
928 Owners Club Membership Chairman
1993 928 GTS cover girl
1987 928 S4
1979 928 5-speed rescue cover girl
1979 928 Euro track beast
The fuel injection (AFC) relay XVI is suspect. To do a jumper test, remove the relay. First check to confirm that there is 12V at relay socket position 30. If yes, go to the next step. If no, check the positive battery cable where the cable attaches. Next, create a Y shaped jumper wire and connect 30 to 87 and 87a socket positions. Crank the engine. If it starts, the relay needs to be replaced. It is a special relay part number 928.615.119.00.
Another problem could be a large vacuum leak. My 1983 928 had a leak at the throttle body. Cars with auto transmissions have two large plugs on the passenger side of the throttle body (look between the intake spider legs). If they crack or fall off the engine will not start.
On cars with manual transmissions, the throttle body connects to a deceleration dampener with two short hoses. A vacuum leak at the hoses or decel dampener will cause a no-start.
Rich
928 Owners Club Membership Chairman
1993 928 GTS cover girl
1987 928 S4
1979 928 5-speed rescue cover girl
1979 928 Euro track beast
#5
thanks for the advice guys unfortunately my battery is dead and oreilleys won't honor their warranty because my phone number wasn't entered on it so I can't check much but I did take a look and actually found my #6 injector plug was cracked and not making connections. just ordered a repair connection from 928srus so ill fix that and let yall know