RaveDisc

Hi people,

I put a new start in the 964, the engine is now turning over very rapidly, but can't start. It will only start when the battery get's weaker after trying to start it for a long time. So I can run the car only with a weak battery, not when the battery is fully charged. What kind of problem is this ?? I am confused!

Thank you for your help!

Steve Weiner-Rennsport Systems

The very first questions I have are:

1) Got a new DME relay in there?

2) Did you test for spark while cranking at the plugs?

3) Is the engine getting fuel??

RaveDisc

Hello,

No I don't have a new DME unit, I replaced the spark plugs with new ones, but it didn't change anything. There is no spark at the plugs while cranking. However the car do turn on when the battery gets weak. So at that point, the engine is getting fuel and the spark plugs are probably doing their job as normally.

In the fuse box, there are some modifications that have been done (I am pretty sure this isn't from factory, but done by the previous owner), I think this is the jumper solution done to the DME.

Steve Weiner-Rennsport Systems

You may simply have a bad DME relay. Don't forget, that controls the DME (ignition) and fuel pump (fuel supply).

RaveDisc

I think the DME relay was the source of the problem, but my mechanic says there was something else... Thank you, the problem is solved

ian89C4

What did he say it was???

RaveDisc

"Lots of other things" or something like that was the answer... but I told him since the beginning that it could be the DME relay. However, since he never had such a problem on a car (he's a good mechanic but never worked on older Porsches than 996), he was searching for other possibilities, like hall sensor, crankshaft sensor etc...
Now that I wanted to finally install my FVD chip and MAF (I've got them since my first day of ownership but never installed them on the car) he called me to say that the chip makes the car running fine at idle, but it struggles and turn off when the gas pedal is pressed. So impossible to drive the car... he says we have to put the original chip back. He says he tried to make the chip work with the AFM and the MAF, but it would change anything... Do you think my chip is useless ? Because I'd really like to chip the car.

elbeee964

(Don't have an answer, but an interesting list of symptoms.)

gchristofi

Do you trust a mechanic that missed the DME problem to install your MAF and Chip?

Jim Richards

My thoughts exactly. I would find someone experienced to help you with these mods. Don't pay him to learn on the job. By the way, does your car have a lightweight flywheel? Any other mods?

RaveDisc

@Gchristofi,
I understand what you mean, but he managed to solve the problem, the thing is he didn't believe this was the cause.
It is always complicated when you can not explain to someone how those cars work, ie. how to check oil... he always tells me "you have no oil" and I say, "you have to check it when the car is warmed correctly, not when cold!", but now I think he got it, because we changed oil and he saw how things work. lol.

I did open the DME unit myself to insert the chip, but the mechanic said he couldn't take the chip off the motherboard (because it is soldered, and he doesn't have the tools for that), but a friend of mine knows how to do it. They installed everything but the car would only work at idle, but when pressing gas (in neutral or when engaging a gear) it turns off.
However, I heard that when installing the FVD chip, there is a wire you should solder on the board to make the chip work.
So I will see if we can find the wire in question and correct the problem.

I would have gone to a Porsche specialist, but here there aren't any real one, I live in Serbia.

@Jim Richards,
Yes I have a lightweight flywheel/Sachs clutch. I've read that it makes our 964 stall too easily, maybe mine has that problem but I got used to it quite quickly, and I can drive it without wearing the clutch too much IMO. However, maybe I don't even have that problem, I am not sure, because I bought the car like that.
Other mods : BMC air intake and I am not sure how you call this mod, maybe a bipass exhaust with 964 turbo catalitic converter (in fact it's a second exhaust pipe that is linked to the first one) so the car has 2 mufflers, one left, and one right (the original one).
All these mods (except the lightweight flywheel and clutch) come from the LB2 kit from FVD : chip, MAF, exhaust and air intake. That's why I try to install the chip and MAF together. They claim a 50hp increase and around 65NM more. When everything put together I'd like to go for a dyno test and see what it means in the real world :-)

RaveDisc

Hmm... the MAF is dead, because we tried to run the car without doing some modification to the DME unit. I wasn't sure wether the MAF was from a 964 turbo or a 993 turbo, and 993 needs 5V power supply, not 12V... so the car was running on 12V and the MAF died. If I don't want to buy an other MAF, I can stay with the AFM and take a unit on the chip that controls the MAF settings, but then I shouldn't get as much power as it should.
Those MAF are pretty pricey, I have to find one in Europe or as near as possible.

rarebear

A word of advice on chipping (my experience). It is not worth all the hassle, it gives marginal more power, if you have a turbo car however the gain is immense...
You also have to use ron97 fuel at least ! The stalling with a LWF wil not be solved, you need the RS ecu and sensors.
Any pictures of your 964 ?

RaveDisc

I understand, however I'd like to see how it performs with the whole LB2 kit (from FVD). And I have to say I feel better when I give my best to make the car work after lots of hassle :-)

My brother has an Audi S4 B5, chipped, we have it since 5 or 6 years now, and it worked top notch when we bought it, but rapidly stopped to perform well because of failing MAF and other things. I replaced all the hoses, bought a new MAF and the car still didn't go as it should... I lost my time and money with lots of mechanics, but only the person that is now working on my 964 found a solution and it was a problem with vacuums, nobody else could fix it.

So I'm used to this sort of things... :-)

Here we have 95 octane fuel, but I can add octane booster and it'll make it fine.

About the pictures, here are some, but I didn't take time to make much of them, since I drove the car very little in my 2 years of ownership...









It has a non factory WB, looks very nice, but unfortunately I will have to fix some things, I don't know how you call it in english, like some clips that hold the plastic body kit with the metal part of the car. They started to be visible soon because it hasn't been done as it should. So it will go for a respray...
Also, I'd like to put some 17" wheels on it, it would look a lot better since it's wider. 18" would be nice too, but our roads are horrible and it's not easy to avoid all the holes, lol.