Cranks but won’t start -DME is good
11-18-2018, 04:59 PM
#1
Rennlist Member
Thread Starter
Cranks but won’t start -DME is good
Folks,
First real problem with my 993 in all these years. I keep two spare DME relays just in case. I swapped a brand new one out of the box and then pulled and checked the fuel pump fuse. I don’t recall hearing the fuel pump buzz when I turned the key before start. I also don’t smell fuel after lots of cranking. Battery is on a tender and cranks the engine with authority. Last long drive or run was in June and followed with a refill with fresh non ethanol fuel. Anyone have a flow for crank/no start diag they can recommend?
Saw some fuel pump info on this thread: https://rennlist.com/forums/993-foru...fuel-pump.html
First real problem with my 993 in all these years. I keep two spare DME relays just in case. I swapped a brand new one out of the box and then pulled and checked the fuel pump fuse. I don’t recall hearing the fuel pump buzz when I turned the key before start. I also don’t smell fuel after lots of cranking. Battery is on a tender and cranks the engine with authority. Last long drive or run was in June and followed with a refill with fresh non ethanol fuel. Anyone have a flow for crank/no start diag they can recommend?
Saw some fuel pump info on this thread: https://rennlist.com/forums/993-foru...fuel-pump.html
Last edited by hkspwrsche; 11-18-2018 at 05:33 PM.
11-18-2018, 05:38 PM
#3
Rennlist Member
Thread Starter
11-18-2018, 07:13 PM
#4
I am embarrassed to admit it but I don't know. I've driven my 993 for 12 years and have never had to diagnose a no-start problem. That said there's a 99% likelihood you have a fuel or spark problem. Probably not immobilizer, or it wouldn't crank. Unlikely both coils died at the same time. I would focus on fuel and computer problems. Are you sure you don't have two bad DME relays? The cheapo DME's are sometimes bad out of the box. I would also jumper the fuel pump relay to hear it run and cross it off the list.
11-18-2018, 07:18 PM
#5
RL Community Team
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11-18-2018, 07:38 PM
#6
Rennlist Member
Thread Starter
11-18-2018, 07:51 PM
#7
Rennlist Member
Thread Starter
I am embarrassed to admit it but I don't know. I've driven my 993 for 12 years and have never had to diagnose a no-start problem. That said there's a 99% likelihood you have a fuel or spark problem. Probably not immobilizer, or it wouldn't crank. Unlikely both coils died at the same time. I would focus on fuel and computer problems. Are you sure you don't have two bad DME relays? The cheapo DME's are sometimes bad out of the box. I would also jumper the fuel pump relay to hear it run and cross it off the list.
First time for everything. This is my first no start that wasn’t solved by a spare DME relay. It’s been 6-7 years since that happened and when I had to replace it I put an X over the bad one and plugged in a brand new one. I need to track down my repair manual. The internet suggestions normally helps narrow down most items. Pretty easy to narrow to fuel or spark and not compression since it’s been well maintained, 61k miles and never had any smoke at start up. No immobilizer remote on this 95.
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11-18-2018, 07:54 PM
#8
+1
I have had DME relays before that do not sit right in the fuse box and can cause you starting issue. I would get a friend or help to crank it while you lean the DME to one side so it is making good contact or wiggle it a bit while cranking. You should also feel it clicking while you holding it but this is not a 100% test. I would crack a fuel line as suggested earlier to see if you have fuel flow ? No fuel flow go back to looking at DME relay again. I was exactly like you had two bad relays one of them started my 964 but would not sit correctly in my 993 and cause a no start fault, I know it sounds crazy how can the same relay that is meant to be good start one car but not another lol. Some times the pins on these aftermarket ones are loose fitting and do not make a good connection.
check fuel lines a must.
I have had DME relays before that do not sit right in the fuse box and can cause you starting issue. I would get a friend or help to crank it while you lean the DME to one side so it is making good contact or wiggle it a bit while cranking. You should also feel it clicking while you holding it but this is not a 100% test. I would crack a fuel line as suggested earlier to see if you have fuel flow ? No fuel flow go back to looking at DME relay again. I was exactly like you had two bad relays one of them started my 964 but would not sit correctly in my 993 and cause a no start fault, I know it sounds crazy how can the same relay that is meant to be good start one car but not another lol. Some times the pins on these aftermarket ones are loose fitting and do not make a good connection.
check fuel lines a must.
11-18-2018, 08:18 PM
#9
Rennlist Member
Thread Starter
,
Thanks worth a try to wiggle the relay around and check the pins to see if they are in the fuse/relay block.
+1
I have had DME relays before that do not sit right in the fuse box and can cause you starting issue. I would get a friend or help to crank it while you lean the DME to one side so it is making good contact or wiggle it a bit while cranking. You should also feel it clicking while you holding it but this is not a 100% test. I would crack a fuel line as suggested earlier to see if you have fuel flow ? No fuel flow go back to looking at DME relay again. I was exactly like you had two bad relays one of them started my 964 but would not sit correctly in my 993 and cause a no start fault, I know it sounds crazy how can the same relay that is meant to be good start one car but not another lol. Some times the pins on these aftermarket ones are loose fitting and do not make a good connection.
check fuel lines a must.
I have had DME relays before that do not sit right in the fuse box and can cause you starting issue. I would get a friend or help to crank it while you lean the DME to one side so it is making good contact or wiggle it a bit while cranking. You should also feel it clicking while you holding it but this is not a 100% test. I would crack a fuel line as suggested earlier to see if you have fuel flow ? No fuel flow go back to looking at DME relay again. I was exactly like you had two bad relays one of them started my 964 but would not sit correctly in my 993 and cause a no start fault, I know it sounds crazy how can the same relay that is meant to be good start one car but not another lol. Some times the pins on these aftermarket ones are loose fitting and do not make a good connection.
check fuel lines a must.
Thanks worth a try to wiggle the relay around and check the pins to see if they are in the fuse/relay block.
11-18-2018, 08:44 PM
#10
Rennlist Member
Thread Starter
+1
I have had DME relays before that do not sit right in the fuse box and can cause you starting issue. I would get a friend or help to crank it while you lean the DME to one side so it is making good contact or wiggle it a bit while cranking. You should also feel it clicking while you holding it but this is not a 100% test. I would crack a fuel line as suggested earlier to see if you have fuel flow ? No fuel flow go back to looking at DME relay again. I was exactly like you had two bad relays one of them started my 964 but would not sit correctly in my 993 and cause a no start fault, I know it sounds crazy how can the same relay that is meant to be good start one car but not another lol. Some times the pins on these aftermarket ones are loose fitting and do not make a good connection.
check fuel lines a must.
I have had DME relays before that do not sit right in the fuse box and can cause you starting issue. I would get a friend or help to crank it while you lean the DME to one side so it is making good contact or wiggle it a bit while cranking. You should also feel it clicking while you holding it but this is not a 100% test. I would crack a fuel line as suggested earlier to see if you have fuel flow ? No fuel flow go back to looking at DME relay again. I was exactly like you had two bad relays one of them started my 964 but would not sit correctly in my 993 and cause a no start fault, I know it sounds crazy how can the same relay that is meant to be good start one car but not another lol. Some times the pins on these aftermarket ones are loose fitting and do not make a good connection.
check fuel lines a must.
Seems like this rules out the DME. Both sides click closed but still no start.
11-19-2018, 12:20 AM
#11
11-19-2018, 07:15 AM
#13
I am embarrassed to admit it but I don't know. I've driven my 993 for 12 years and have never had to diagnose a no-start problem. That said there's a 99% likelihood you have a fuel or spark problem. Probably not immobilizer, or it wouldn't crank. Unlikely both coils died at the same time. I would focus on fuel and computer problems. Are you sure you don't have two bad DME relays? The cheapo DME's are sometimes bad out of the box. I would also jumper the fuel pump relay to hear it run and cross it off the list.
Re the case above, my vote goes to the flywheel crank sensor.
11-19-2018, 09:43 AM
#15
Common problem is failed crank sensor, mine and a friend within weeks of each other. Then an abs wheel sensor died. Seems they are getting to the end of their useful life after 20yrs.
