924Board.org

TurboBullet · Joined: 08 Feb 2009 Posts: 64 Location: Southern NJ

went to work and it started up and drove perfectly, came out and the car cranks but wont start. what are the possible problems with these cars? I come from more modern fuel injection systems that tell you via OBD what is wrong with them... some info i put in a new fuel pump and filter, and an entirely new ignition system a few months ago. i also checked all the fuses and found no blown ones. any HELP is appreciated!

!tom · Posted: Sat May 23, 2009 9:52 am Post subject:

Does the fuel pump run when you're trying to start?

Depending on the car (who's vital information is missing in your post -- it is encouraged to put it in your signature so others can help easily) the pump should prime the system when you turn the key, or will operate when the air metering plate is deflected due to the induction when cranking.

I'd assume from your handle that you've got the type that primes when you turn the key.

This is the first place to look, and a likely culprit is either a failed fuel pump relay, or poor contacts between the relay and its socket.
_________________
78 924 NA
5-lug

TurboBullet · Joined: 08 Feb 2009 Posts: 64 Location: Southern NJ

michi924 · Joined: 22 May 2007 Posts: 163 Location: Pontevedra, Spain

I would check the DME relay and the crankshaft sensors.
_________________
Porsche 924 NA Euro.

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Can I ask how you expect to sucessfully add a turbo to a Porsche 2.5L engine, when you don't know how it works?

What do you expect to accomplish, and how do you plan to install the turbo without destroying the engine if you don't have any knowledge of how the engine, fuel system or ignition work?

TurboBullet · Joined: 08 Feb 2009 Posts: 64 Location: Southern NJ

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Well...

You got that right. The Hayness 944 Service Manual is not a service manual at all. It's a $20 book telling the owner to take the car to a mechanic or dealer for service.

And by the way. DO NOT TRUST THE HAYNES MANUAL FOR ANY TORQUE SPECS.

There are numerous errors which will drive you crazy with fasteners that strip or break off long before to arrive at spec.

You need the Porsche Spec Books for the 924S, 944, and 951 for quick reference to fluids, flows, torque, clearances, etc...

You need a current (6 volume) Porsche 944 Factory Workshop Service Manual WITH 951 Volume to get the rest of the information you may need.

OLD SCHOOL cars are easier to build, rebuild, maintain, and troubleshoot, than "Newer" designs with heavy electronics. Engines are engines, if you understand how a basic engine works, you can fix any engine, regardless of the level of electronics present. People who depend on OBD electronics for diagnosis to repair are Parts Changers, Not Mechanics.

That being said, Good Luck with your project. Looks like you are already moving in the right direction by using 951 core motor. I was going to suggest starting with a 951 engine, since altering a 944 engine for a turbo would cost more than buying a 951 core motor to base a project on.

Be aware that there are a ton of other parts that Porsche changed when they built the 951. While you may choose to go aftermarket for upgrade parts, looking at what Porsche did will give you an idea of what you need to do.

The DME relay is the one that I suspect you had to repair. Most all experienced 2.5L Porsche engine owners carry a known good spare DME relay in the glove box to help prevent getting stranded, and when your engine does not start, is a good place to begin looking.

wasapyt · Joined: 17 May 2009 Posts: 26 Location: Lemoore California

DAmm turbobullet u totally owned gohim lol i laughed after the secound paragraph sorry gohim but .. YOU JUSS GOT PWNED
_________________
1978 924 n/a

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

Wow, another new guy feels the need to compare appendage length after being dressed down by Gohim, we've never seen this before.

This seems like a good opportunity to remind everyone how important I am. Here is a Formula 1 engine I developed:

_________________
1987 951 - M193 Version for Japan

rkn · Joined: 01 Apr 2007 Posts: 176 Location: Copenhagen

well played chrenan

_________________
1980 924NA ROW

TurboBullet · Joined: 08 Feb 2009 Posts: 64 Location: Southern NJ

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Chrenan

When will we see the 924 conversion kit?

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

I'm working on it right now. I don't want to call it a "conversion kit" until all the development work is done. But, needless to say, once it is ready the members here will be able to get a very strong home-grown kit for a reasonable price. I'm working off board at the moment with a few former members who know the world of big power engines better than anyone. Luckily for us, they don't hold a grudge for being chased off. Trust me, this can't go wrong.
_________________
1987 951 - M193 Version for Japan

gohim · Joined: 02 Nov 2002 Posts: 4459 Location: Rialto, CA

Do you have someone from Automobile Atlanta working with you?

AA seems to be the master at getting people to pay for products that don't exisit. Maybe they can be a consulant?

Will it be OBDII, or CAN?

Chrenan · Joined: 15 Jan 2003 Posts: 3903 Location: Canada

Automobile Atlanta and Motor Meister will be key players in distribution and installation.

For my money, OBDII is the only way to go. If it ain't in a code, it ain't happening.
_________________
1987 951 - M193 Version for Japan