Won't Start - PART II
 

Ok so I got a new DME relay, new coil and a fresh new battery and then I finally got some time today to put them in ....got all finished and turned the key....turned over like a bandit....it ran for about 4 seconds and died.....I had previously checked the old coil ( per a procedure I saw on rennlist) to check coil and DME signal....but figured while I was there it did not hurt to replace...so it seems like a fuel problem ( I appear to have good spark from the coil although I did not pop the dist. cap to check it and the rotor)....

Thing thats got me concerned is that the connectors on the old DME relay ( looked like it may have been an original) were slightly blackened!

Also ( may just be coincedental bad luck.....) I noticed today that the clutch pedal drops to the floor with no resistance and stays there ( slave cylinder????).....could this be related?

For those who do not rememder my previous post, the car went from running like a champ one morning about 4 weeks ago...to not starting that same afternoon!

HELP! If I can't figure it out it goes on the flat bed to the mechaninc ( $$)!

thanks!:confused:

ok, lemme just put this in perspective:

--> before it was like totally dead, and now it turned over for a few seconds and then died?

what happens if you wait a few seconds and then try again?

let's look at this, because it sounds like a "cold start" problem:

1) have you tested the cold start valve, the thermo time switch?

2) is the fuel pump working? when the car is in the "acc" position... do you hear the fuel pump running for a second to pressurize the fuel lines?

3) do you have any moisture in the fuel lines? pour two or three cans of "drygas" in there to take ALL the moisture out of the fuel. mosture in fuel lines can do just this sort of thing.

4) have you checked the connections to the airflow meter? a loose wire, or a bad connection will do it.

5) is anything blocking the fuel lines? clogged injectors? clogged filter?

6) this may seem obvious, but did you replace the battery negative cable? i paid about $5 for one at an Advance Auto when i had a similar problem and the problem went away. corrosion on those cables will cause starting problems. replace the cable and the problems go away.

7) check ALL your ignition components to make sure there isn't a loose connection.

good luck!

obin

Obin

How do I test the cold start valve/thermo time switch?

I did wait a few seconds.....spins but still won't start ( does not even try now)

I do hear the fuel pump when I turn the key to the on position.

As far as moisture....that's a good question...yesterday...out of the same concern I did throw a can of drygas in the tank, and this AM I got a fresh gallon of gas and put in the tank as well
( because wouldn't I have felt stupid if the fuel sender was saying 1/2tank when it was really empty!)

I also pulled & cleaned the K&N filter ( was a mess) and while I was there I wiggled all the connectors I could see.

The neg. battery cable???? It's a fairly heavy bare line that seems to be in great shape....I also checked for continuity between the neg post and the block just to see if I had good ground.....it's fine! How would the neg cable cause this if there's obviously a good connection??

Where should I start with the cold start valve and the other ignition parts?

thanks



:(

waaaaaaaaait a second... before we go any further, i just thought of something:

have you checked your ignition switch? those can go dead all-of-a-sudden. the car will seem just like yours. it cranks, then after that it's dead when you try to start it. everything dies like you cut the power. is that what's happening now?

ignition switches are cheap (like $10 or so). and not too hard to replace. i've done it twice before.

obin

Obin

It still spins fine.... ( as a matter of fact faster than ever ....I am very glad I got the new battery.....a Die-hard)....it just won't start!

Would it do that if it was the switch??

:(

hmm, ok let's break this down into two parts. what happens when you crank the key to the "ignition" position from the "accessories" position? when you put it over to "ignition", does the starter motor work? or is it that the car is cranking, and the starter motor is going, but the motor won't "catch".

three posssibilities:

1) a vacuum leak (check all your vacuum hoses for leaks, or clogs for that matter)

2) if the car shuts OFF like there's no power when you try to start it... then that's an electrical issue. it's probably the ignition switch. in other words, no starter, no fuel pump, everything is DEAD.

3) if the car cranks and cranks and cranks but just doesn't want to START... then that's a fuel injection issue most likely (though it can still be ignition).

so when the key is in the "start" position... is the starter motor spinning? or is the car trying to start but it just won't "catch". i have a 1984 944 so chances are that i'd be able to figure it out by the sounds the car is making as you try to start it. worst case, just e-mail me your phone # and i can see if i can hear what the engine is doing.

good luck!

obin

Obin

Number 3!

The starter is fine ...engine cranks fine....but won't "catch"!

I was initially of the impression that it was the SPARK part of the combustion process, but now I don't know! Would vaccum problems also result in what I am seeing with the clutch pedal ( see original post) or is that un-related?

thanks for the input/advice!

:confused:

I'd say the clutch pedal on the floor is unrelated.

drew1

ok, now i got it! i was thinking that it would not "start" as in the starter position was "dead".

ok, now here's what can do it:

electrical possibilites:
1) bad battery (but that doesn't apply to you as the battery is new). so eliminate that one

2) bad battery cable (don't eliminate that, the cable can LOOK fine but corrosion will prevent your car from starting. cables are cheap so go ahead and replace it anyways when you do a new battery. the corrosion in the cables can make it harder for a current to get through, and make your new battery act like an old one to the car).

3) worn, or bad spark plugs (when was the last time you put new plugs in? i suggest NGK for the 944. this is a $6.00 fix that MIGHT just do it).

4) bad ignition coil (but that doesn't apply because you replaced yours).

5) bad ignition WIRES (in other words, how is the center tap wire that comes out of the coil? was it damaged when the coil was replaced? check that, and check the spark plug wires for continuity and correct resistance).

6) bad electrical connections going to ignition components (check ALL the wires in the ignition system by sight, WATCH OUT FOR THE IGNITION SYSTEM AS IT IS LETHAL IF YOU TOUCH IT WHILE THE CAR IS TRYING TO START!!!! wiggle all the wires to make sure none are loose.

7) check ALL of your fuses, and make sure that none of them have corroded connectors on the ends.

fuel injection possibilites:

starting problems can result when the engine is not getting enough fuel to keep it running. this can be caused by:

1) bad, leaky, or clogged fuel injectors

2) a bad DME (you replaced the relay, but is the car computer itself ok? check all the wires going into the DME to make sure none are broken, corroded, or not connected at all).

3) bad fuel pump not giving engine enough fuel to start.

4) clogged fuel filter not letting enough fuel by to start car.

5) bad fuel pressure regulator, throttle switch, or auxiliary air regulator.

6) bad fuel itself (you'd be surprised at how HARD it is to diagnose bad gasoline, and how EASY it is to put drygas in and save yourself a $300 fee).

check off the stuff that you KNOW it isn't, and report back in a bit. i should be around later :). worst case, send me your number and i want to listen to what the car is doing (like i said, i have an 84 944 also and i know what they are supposed to sound like when starting ;) )

good luck!

obin

Ive seen many similar posts so forgive me I have yours confused with someone else. I had a similar problem with my 81 924. The Haynes manual covers this in more detail. I highly recomend following the trouble shooting procedures. It takes some time but at the least it will eliminate alot of possibilites.

Here are some short cuts though. Repalce the plugs. Get at spark tester at your local auto parts store $2.00. The one I bought clips to any part of the engine and attach a spark plug wire. The gap is adustable you can see how strong the spark is. Repeat this on each plug wire and the coil wire.

If the spark is strong then its not the igntion.

Pull the ruber boot off and spray some starting fluid directly into the throtle valve housing and try to start the car.

If it starts but does not run then its a fuel problem.

Pull the injectors you can do this with just a pair of pliers. place the injector in a coke bottle and crank the engine. You will be able to see the injector spray.

If there is no gas comming out of the injector check the fuel relay first.

remove the fuel relay from under the dash and take a peice of wire an connect the slots labeled 30 and 87. Try to start the car.

If the car starts replace the fuel pump relay.

This solved my problem.

If this doesn't work you need to follow the procedures in the manual. Test the parts one by one otherwise it will cost you a lot of money repalcing parts that were not broken.

Orbin:
I didnt think ignition systems were leathal. I may not remember the therory correctly but ignition systems take 12 volts and using the coil convert it to 10,000 volts give or take. Anytime you increase voltage you lower amperage. Its the amperage that kills. A 12 volt system bumped to 10,000 volts has very little amps. It might stop a pacemaker, and it will sting alot but the average person should be safe.

Roger,

i treat all ignition systems like they are lethal. you can never be too certain if a person you're giving advice to has a known (or unknown) medical condition in which a spark from an ignition could kill them. it is current that kills.. but a bad shock from an ignition can stun a person and then they could get hurt by another manner (falling onto something, getting burnt, etc).

i'd just rather play it safe ;)

also, when working on/with ignition components, i usually wear a set of kitchen gloves, or my Mechanix gloves. you can never be too sure!

obin

Ok well I have been out of commision for a few days....food poisoning sucks!!!:mad:

Anyway I think my next course of action will be to take off and inspect the cap and rotor just to make sure they're in working order....then make sure again that I have spark.....

Assuming I do have spark then I will check the fuel pump and fuel filter.......I know that before I purchased the car ( only about 5000 miles ago) It had sat for several years....when I bought it my mechanic was to have flushed the tank...installed a new sender, pump and filter....when I crawl under the car it is apparent that the filter and pump are new...they're too clean to be otherwise....but maybe the filter picked up crap left in the tank......

I'll keep you all posted....

by the way....does anyone know how to check the DME relay itself? I did replace mine ( I guess it's not the problem) but I'd like to test it somehow to be sure the old one is still good!

thanks
:cool:

Any progress Joe?

I have same problem time ago....
 

I have the same problem about year ago, at my old '84 944.

Spend about 3 days to find and fix it.

Problem was in buggy Fuel pump relay (or maybe it's seat, i replace it anyway).

So check it seat and function ("click" after key turn)

Sounds like a problem I had last year. The only additional symptom I had was that the car was very low on fuel when I had last stopped - that should have told me what the problem was.

Even though I added a gallon of fuel, it started then stopped and later wouldn't start at all. In my case it was a fuel blockage. I opened up the fuel rail (don't lose the ball bearing) and tried to flush a few pints via a hose to a bucket to prove the supply was OK - but no flow ! By this point I had taken steps to bypass the Fuel relay which had turned the volts off because the blockage was downstream of the pressure senser. Bypassing the relay forced the pump on and presumably lifted the fuel line pressure above the normal operating level. A dead wasp (just a guess) was ejected into the bucket. I sealed the fuel line again and it started first time.

Steve

Steve Taylor,

Where is fuel pressure sensor?

drew1`

Try holding the gas to rhe floor when cranking it works for my 81 924..

Good job, only 8 years too late....

I'm not a 4 stroke engine expert but I have had some expierence with no start issues. I will give some insight that will help track down what the issue is.

4 strokes need to have compression gas, and ignition. Without anyone of those it will not run. If they are weak it will still start.

1. I would get a coil tester. These are about $10 at the auto parts store and will save a lot of time to see if your coil and ignition system is up to snuff. What I do is take one of the plug wires and plug the coil tester in there and ground it out somewhere.

2. Gas, if you see a spark in the coil tester then it means you may not be getting gas. So I would take one of the plugs out and see if its wet or smells of gas. If it doesn't then you need to figure out if the injectors are pulsing. There is a diode test light you can make for this.

3. If both of those check out then it means you are really down on compression. So I would check that next.

If all of those check out you may have a more serious issue like the DME/Computer has some bad cold solder joints or you aren't getting signals from some sensors.

Does the tach bounce at all? If not then the speed/ref sensors are bad or are not adjusted properly.

You have a lot of good suggestions here. To be honest I would go with my path first then look at the replacing parts route.