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Hi, I have a 89 964 C2 RHD
The car starts as it should sometimes, but when it is hot it tends not to, and sometimes whether it is hot/cold, it won't start at all.
By not starting I mean the engine just turns but doesn't start. I can start it by manually engaging fuel pump by taking cover off DME and pressing buttons on it.
The car has an immobiliser installed and whether or not I use the immobiliser key it doesn't effect my odds of it starting so maybe it is disconnected.
There is a loud humming noise coming from the front left of the car, which I believe is the fuel pump? I've bought a new Bosch pump but don't have a car lift or any instructions on how to install.
I've also just replaced the fuel pump DME relay, which didn't effect anything.
Has anyone any ideas or experience as to why my car doesn't like to start when hot and sometimes when cold? Flywheel sensor? Fuel pump? Immobiliser? Demons?
Hot start problem can be the ignition coils...once it starts does it drive normally, if it runs erratically and "bucks" its probably the old coils.. DO NOT REPLACE WITH THE CURRENTLY AVAILABLE Bosch Coils, they are garbage...do the 993 coil pack swap instead
If the loud humming noise from the fuel pump is constant, I would replace the pump first since you already have it. In my 964 I cannot hear the pump from inside the car.
Hot start problem can be the ignition coils...once it starts does it drive normally, if it runs erratically and "bucks" its probably the old coils.. DO NOT REPLACE WITH THE CURRENTLY AVAILABLE Bosch Coils, they are garbage...do the 993 coil pack swap instead
no it runs and drives perfectly. So not coil packs.
The immobilizer is a notorious culprit. Do you have access to a scan tool to see any error codes?
Electrical issues can be hard to trace.
Do you have fuel in your intakes? If yes, you may be looking at a bad fuel pressure regulator.
Also check if the connector to your MAF has had the tech bulletin modification done.
Any internal combustion engine needs fuel, spark, and air in the right proportions and at the right time. So if your coils are good and your fuel pump is good, the immobilizer is a good candidate.
The immobilizer is a notorious culprit. Do you have access to a scan tool to see any error codes?
Electrical issues can be hard to trace.
Do you have fuel in your intakes? If yes, you may be looking at a bad fuel pressure regulator.
Also check if the connector to your MAF has had the tech bulletin modification done.
Any internal combustion engine needs fuel, spark, and air in the right proportions and at the right time. So if your coils are good and your fuel pump is good, the immobilizer is a good candidate.
Fuel pressure regulator is relatively new in it, can't imagine its the problem.
Will get immobiliser removed.
Anyone know how to change fuel pump?
Do I need a car lift?
Engine Speed sensor at flywheel , Airbag brain jump at center hall location, possibly Alarm.
Ground corrosion under seat, back of fuse panel, back of Fuel gauge.
Could it be the starter? My car exhibited most of the symptoms your car has prior to replacing the starter a couple of weeks ago. On cold starts, the car would usually fire up on first try. I noticed that it was kind of weak, but when I really grew concerned was when it would take several attempts to start when the engine was hot or fully up to temperature. The car is/was running fine without any noticeable hiccups while driving. The only "symptom" replacing the starter can't address is how you're able to start the car by manually manipulating the fuel pump.
If nothing else, it'll eliminate the starter as a source of the issue.
...Anyone know how to change fuel pump?
Do I need a car lift?
I changed my fuel pump a few years ago and it was not that hard to do. If you search here I am sure there are some threads to guide you through it. And yes you need to elevate the car somehow, at least enough so you can get underneath it. I think I did mine by getting the floorpan 16" off the ground. It was tight but doable. There are some good threads here and on Pelican on how to elevate a car.
You need a little space under the car for a fuel pump change. While you are there, I would change the fuel filter in the fuel tank. You will have to drain the tank anyway so you may want to get that done. Also check the flexible fuel line while at it. They are getting old and brittle.
You will have a little fuel spillage - at least I did - and you really don't want to get it on your face. Don't pull a Jay Leno while you are doing this. Mechanically not hard to do but needs a little mindfulness while doing it.
+1 on new lines between pump and tank and a new in-tank filter. The lines are expensive but you will have peace of mind.
Disconnect the battery to make sure there are no sparks possible. Use LED work lights.
This will give you some idea of how high the car has to be to change the fuel pump. That's my legs sticking out. Mind you, I am a pretty skinny guy. I did not have any kind of a lift back then and it was a heck of a job to elevate the car, so this was a bear minimum lift. Good idea to have a fire extinguisher handy also.
The immobilizer is a notorious culprit. Do you have access to a scan tool to see any error codes?
Electrical issues can be hard to trace.
Do you have fuel in your intakes? If yes, you may be looking at a bad fuel pressure regulator.
Also check if the connector to your MAF has had the tech bulletin modification done.
Any internal combustion engine needs fuel, spark, and air in the right proportions and at the right time. So if your coils are good and your fuel pump is good, the immobilizer is a good candidate.
You mean an alarm ECU, right? The use of an OEM immobilizer started with the 993. The alarm ECU is typically very reliable, unless the battery is over-voltaged, e.g. battery charger.
__________________
Loren
Systems Consulting - Automotive Electronics
Specializing in Porsche cars http://www.systemsc.com/
You mean an alarm ECU, right? The use of an OEM immobilizer started with the 993. The alarm ECU is typically very reliable, unless the battery is over-voltaged, e.g. battery charger.
The immobiliser is an aftermarket addition. Its a TOAD immobiliser.
You need a little space under the car for a fuel pump change. While you are there, I would change the fuel filter in the fuel tank. You will have to drain the tank anyway so you may want to get that done. Also check the flexible fuel line while at it. They are getting old and brittle.
You will have a little fuel spillage - at least I did - and you really don't want to get it on your face. Don't pull a Jay Leno while you are doing this. Mechanically not hard to do but needs a little mindfulness while doing it.
Good advice here. I drained the tank and still had several gallons flow out of the fuel pump when disconnected. Plenty of room to work with the car up on Jackpoint jackstands. Here are a few photos Removing the fuel pump
04-02-2023, 05:39 PM
964 expert needed! Not starting
