Cranks but won’t start -DME is good
11-19-2018, 10:00 AM
#16
Rennlist Member
I had this condition develop about six years into my owning my 993. After doing all of the "standard" RL recommended diagnostics, and somewhat in desperation, I pulled the cover off the fuel pump and gave it two sharp raps with a small ball peen hammer. The car cranked right up and ran another five years without a hiccup.
11-19-2018, 11:31 AM
#17
Rennlist Member
Thread Starter
11-19-2018, 12:47 PM
#19
Let the fuel pressure bleed down for a few hours. Then turn the key to the "ON" position (Just before cranking) and see if the fuel pump runs.
You could have a failed fuel pump.
You could have a failed fuel pump.
11-19-2018, 02:46 PM
#21
Rennlist Member
Thread Starter
Actually impossible since the place I go has special ethanol free 87 and 93 pumps. Diesel is on the other side of the facility as well as race fuel is separate.
Plus, Ive never done that in my life. I only run ethanol free 93.
Last edited by hkspwrsche; 02-06-2019 at 01:02 AM.
11-19-2018, 02:51 PM
#22
Rennlist Member
Thread Starter
I don’t mind stocking some common failure items so I ordered a crank sensor in case it leads me there but, if not I can keep it on the shelf for some other day.
Is there an easy way to check the pump? Easy way to put 12v to it maybe?
11-20-2018, 01:36 AM
#24
Or spray carb cleaner or starting fluid into the air cleaner? If it runs, then DEFINITELY a fuel problem, right?
11-20-2018, 02:04 AM
#25
Drifting
I had this condition develop about six years into my owning my 993. After doing all of the "standard" RL recommended diagnostics, and somewhat in desperation, I pulled the cover off the fuel pump and gave it two sharp raps with a small ball peen hammer. The car cranked right up and ran another five years without a hiccup.
i have seen this work before too on a clogged or failing fuel pump. There is also a check valve that tends to fail as well.
No harm in giving it a hit
11-20-2018, 03:48 AM
#26
SJW, a Carin' kinda guy
Rennlist Member
Rennlist Member
Even on injected cars, you will smell fuel if you have fuel but no spark.
If you do not hear the fuel pump, that is your issue (whether it is fuel pump itself or something related to power to it). Easy enough to check power with a multimeter.
And yes, sitting for 5 months would make me think fuel pump is stuck. Hitting them does work IME (but not IME on a 993). Sometimes even rocking the car works. How much fuel is in the tank now?
If you do not hear the fuel pump, that is your issue (whether it is fuel pump itself or something related to power to it). Easy enough to check power with a multimeter.
And yes, sitting for 5 months would make me think fuel pump is stuck. Hitting them does work IME (but not IME on a 993). Sometimes even rocking the car works. How much fuel is in the tank now?
11-20-2018, 09:02 AM
#27
RL Community Team
Rennlist Member
Rennlist Member
Just a thought, if one has a good fuel pump relay one should hear the pump run for a few moments when turning on the ignition after sitting overnight before starting the engine. No sound and the pump is not working. No pump no fuel. If you hear the pump, I would think fuel supply is not your issue. I would then check for spark. If no spark from either coil, I would think you have a rotational sensor issue.
Andy
Andy
11-20-2018, 09:23 PM
#28
Rennlist Member
Thread Starter
Can’t seem to get spark. Checked from a plug wire and then right off the coil wires.
Had ordered a CPS. May gamble before fiddling much more. Found a thread with the more affordable Bosch part number so it’s wasnt much of a gamble.
Hopefully I’ll have that and be able to also check fuel pressure this weekend if that’s not it.
Not sure I can smell fuel on the 993 but, I have a 356 in the garage and I’ve been pulling the Solex carbs on and off. That’s probably made me numb to the lean injection system.
Had ordered a CPS. May gamble before fiddling much more. Found a thread with the more affordable Bosch part number so it’s wasnt much of a gamble.
Hopefully I’ll have that and be able to also check fuel pressure this weekend if that’s not it.
Not sure I can smell fuel on the 993 but, I have a 356 in the garage and I’ve been pulling the Solex carbs on and off. That’s probably made me numb to the lean injection system.
11-20-2018, 09:58 PM
#29
RL Technical Advisor
FWIW,....Many times such faults lie with oxidation in the CPS (or any other) connectors and this is fixed using Deoxit inside both the male & female sides of these things.
Environmental conditions can cause what I call "connectoritis" where oxidation and/or corrosion block the tiny voltages that pass through various connections in the car. Any & all electrical connections must be "bright, shiny, and clean" in order to maintain proper conductivity.
I'd sure try that before shelling out $$$ for new parts.
Environmental conditions can cause what I call "connectoritis" where oxidation and/or corrosion block the tiny voltages that pass through various connections in the car. Any & all electrical connections must be "bright, shiny, and clean" in order to maintain proper conductivity.
I'd sure try that before shelling out $$$ for new parts.
11-21-2018, 12:11 AM
#30
Rennlist Member
Thread Starter
FWIW,....Many times such faults lie with oxidation in the CPS (or any other) connectors and this is fixed using Deoxit inside both the male & female sides of these things.
Environmental conditions can cause what I call "connectoritis" where oxidation and/or corrosion block the tiny voltages that pass through various connections in the car. Any & all electrical connections must be "bright, shiny, and clean" in order to maintain proper conductivity.
I'd sure try that before shelling out $$$ for new parts.
Environmental conditions can cause what I call "connectoritis" where oxidation and/or corrosion block the tiny voltages that pass through various connections in the car. Any & all electrical connections must be "bright, shiny, and clean" in order to maintain proper conductivity.
I'd sure try that before shelling out $$$ for new parts.
I guess I’m thinking in terms of 356 preparedness. Those guys advise keeping belts, tools, a complete tune up kit, clutch cables, or even whole distributors as spares! From that perspective, I thought I could use a spare sensor either way.