So Does Anyone Have A Definative Answer?

[Jtilden]

I have looked and found numerous post concerning my problem. Although the OP starts off with a bang, I have yet to find a post where they have come back and closed out the post with the fix. So here is my problem: After sitting for a few weeks since the last time being started my 944 just cranks....I have spark in all plugs, there is fuel at the rail, I have done the DME relay jumper, I have re-soldered the relay as well, the tach does jump when being cranked. It seems to me that with spark present at the plugs the reason it wont start is because the injectors are not spraying fuel. Has anyone had this problem ( i am sure you have)? What was the fix? A few weeks ago the car ran fine, now nothing....Thanks in advance for your replies....
btw...My next task is to remove and clean the sensors ( since the tach jumps do you think this would be the cause?)

[Rasta Monsta]

Easy first test. . .hook up a timing light to the ignition cable coming off the coil and see if the coil is firing while you're cranking. If it is, you have a fuel pressure problem.

[Jtilden]

Originally Posted by Rasta Monsta

Easy first test. . .hook up a timing light to the ignition cable coming off the coil and see if the coil is firing while you're cranking. If it is, you have a fuel pressure problem.

There is spark when I crank...what on earth could have happened during the time I last drove the car and now that is causing the fuel problem? And if this exact same problem has happened to someone and you fixed it, what was the exact cause. The fact that I have been cranking and cranking and the spark plugs are dry (I replaced them when I first began this chase) tells me fuel is not being delivered through the injectors. What tells the injectors to squirt? I took the plug off of the fuel rail and fuel poured out into a container when I cranked so I know fuel is making it at
least this far.

[944 Ecology]

Bad brain?

[Slam]

When I had a similar problem it was just after I had replaced my injectors. In my case the fix was to solder in a new connector on the #2 injector. Apparently when the DME detects a wiring fault to any injector it shuts them all off.

Try this test: have your trusty assistant crank the motor while you wiggle/rotate the injector wires/connectors one at a time and see if you have any luck.

I never would have found this if I hadn't done the "what did I fix last?" checklist and started wiggling wires.

[Jtilden]

oh btw...before the car completely stopped running, while it idled it would miss and when I gave it gas it would immediately die...now it just cranks...if that means anything...I was thinking about changing the fuel filter next but before I do that i was hoping someone had a definitive answer to prevent all the parts swapping, that can start to get expensive...

[Pops944]

From your last post, and following the rest of the posts, I would suspect fuel delivery problems. Could be clogged fuel filter or a weak fuel pump. You could be getting fuel to the rail, just not with sufficient pressure to do the job. Just something else to consider.

[Rasta Monsta]

Or bad FPR.

[commdiver]

Bad DME computer the injector driver is toast! Get another computer and away you will go!

You might want to re-place or re-wire you injectors wiring as 30 years is a killer for all of us and they are old, brittle, cracked, corroded and cause a big draw on the computers injector driver!

[Jtilden]

Originally Posted by commdiver

Bad DME computer the injector driver is toast! Get another computer and away you will go!

You might want to re-place or re-wire you injectors wiring as 30 years is a killer for all of us and they are old, brittle, cracked, corroded and cause a big draw on the computers injector driver!

OUCH!...i am going to change the filter first...if that does not fix it then i will move on the the fuel pressure test...THEN i will check into the DME computer...man i hope the filter fixes it ...thanks for the input

[Hellraiser]

Does it run if you spray start pilot in the air filter box?

[Stephen03]

vaccum leak?

[Born2bwild1191]

Could be fuel pressure regulator....I just replaced this, it would start, then die within 2 seconds, then just crank and crank. Try unplugging an injector and starting it. If it starts and continues to run (It will be ridiculously rough, but it will idle on 3 cylinders) then it is more than likely your FPR. Relatively cheap, 5 minute install.

[ac83na944]

If you're going to replace all of these parts i know a good Porsche only Salvage yard in Emeryville, CA that has good used parts, knowledgeable staff and GREAT pricing. EASY(European auto salvage yard ) Talk to john he's a 944 Whiz and could probably pinpoint whats going on and what parts you need, and they'll ship them to you.

[924Sman]

Read up on the AFM. You obviously have spark and fuel all that is missing is air to create combustion. But to rule out some, crank and pull the plugs and smell them and the hole for gas, if they smell of gas, pressure is not an issue, if not then either pressure or non working injectors may be the culprit(both rather doubtful IMHO). A blown headgasket can cause this as well by not allowing a clean fuel to burn( water in the cylinder ). Check all vacuum lines for obvious cracking/damage especially the "J boot" with attention directed to the connection under the boot( metal pipe that goes upwards into the bottom of the boot ).

Dal

[Cocacolakidd]

Many of these repairs can be checked to narrow them down - There is a multitude of things to check and a good list can be found at Clark's Garage Home Page

There is also a possibility of the speed and reference sensors are out/wire off/broken etc.

The definitive final answer will be with you when the problem is finally fixed.

Keep posting if necessary as we would all love to help...we also learn with all of the answers from every one...

Try also Starting Fluid (Either in a spray can) this can tell you allot about the fuel delivery

[Jtilden]

thanks for all the insight...i am going to first replace the filter which i received today...next will be the FPR...I am starting to lean towards the FPR...I will keep you posted...more to follow

[mitfa911]

You can buy an injector tester from any auto part store and check to see if you have signal to the injectors. If you want to save the money on the tester, you can make your own tester. Use a Christmas tree light bulb and remove it from the sucket. Insert the lightbulb pins into the injector plug and crank the motor. If it lights up you have signal and your DME is fine. My 2 cents

[nynor]

Originally Posted by Jtilden

oh btw...before the car completely stopped running, while it idled it would miss and when I gave it gas it would immediately die...now it just cranks...if that means anything...I was thinking about changing the fuel filter next but before I do that i was hoping someone had a definitive answer to prevent all the parts swapping, that can start to get expensive...

huge vacuum leak. i suspect the hose at the bottom of the intake.

maybe your belt slipped. or broke. check your timing marks. that will only take about five minutes.

d.

[Grandad#3]

Hello, Check out the link below. No Start Check List

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Larry