924Board.org

[ThomasJoseph315]

Weak starting issues, but once running she has amazing power!

http://www.youtube.com/watch?v=F4IAPT2NSUE&feature=youtu.be

The Drive

http://www.youtube.com/watch?v=QiIgdB_k1ck&feature=youtu.be

At the end of the second video you will see the starting issues. I think I have bad battery cables.

[ThomasJoseph315]

Where are the stock negative and positive wires from the battery to the engine block?

I'm looking into that starting issue and trying to see if these 40 year old wires are sufficient. What gauge wire would anyone suggest using to re-wire the wire systems?

I'm trying to find a role of 2 gauge wire.

Tomorrow night I will run a resistance test on the wires to check for faults.

[fiat22turbo]

Negative runs to the battery tray. I added a line from there to the engine block on one of the bellhousing bolts.

Positive runs behind the exhaust to the starter solenoid and then to the alternator. They are known for failing due to heat and age. Check the smaller solenoid and alternator wires while you're in there.

Also the alternator ground is a common issue as well.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[ThomasJoseph315]

yea the only ground I see besides the tiny ground wire going to the body right off the battery to the engine is the ground wire the size of a pic pen coming off the alternator.

[ThomasJoseph315]

Edit: I did find the main ground strap from the body to the cylinder head. But I still am going to rewire them anyway. I tested for continuity for ground and I get like .1ish voltage drops. I got to get the car on the ramps to test the starter, I'll try to get to that on my next day off.

Is it possible to have a weak starter tho and good lines? I mean the solenoid is connecting solid, but as soon as the engine begins to fire I get this weak turn over and it can't spin fast enough to start. But once it does, if it does, it's a monster now.

[924RACR]

It is; you will definitely (while in there) want to clean off the connection to the starter.

That said - you may also do well to replace outright the main positive starter cable. Those heavy-gauge cables, with battery terminals, are readily available pre-made at most auto parts stores. Just figure out the length needed and correct connection type. Well worth it, as is replacing both the battery and engine ground cables.

Did you get the timing issue sorted? I've had that happen numerous times; very annoying. Usually it's because I'm a tooth or two off on the alignment of the distributor, so it's wrapped back around and is firing at a position indexed one off the correct cylinder. Can run fine, but kinda hard to set the timing right! LOL
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[larchie]

Just a quick follow-up to Vaughn's knowledgeable post ... I remember many years ago Porsche/VW Magazine recommended installing an over-sized ground cable running to the engine block instead of the body as is stock on some 924s. It still might be worth doing so even though copper prices make them expensive.

The Haynes Manual implies the starter motor and solenoid cannot be tested w/o a AVR tester, but it's not too expensive to have it done at many auto parts stores. http://www.porsche924-944.nl/manual/Haynes/05_Ignition.htm#_05_007

At a minimum, you could do a starter ground-side starter circuit voltage drop test fairly easily if you have an automotive multimeter. One youtube video is http://www.youtube.com/watch?v=Hv8bnmX8TDs There might be better videos online elsewhere.

[ThomasJoseph315]

[scm924s]

[quote="ThomasJoseph315"]At 4:30 you can hear the weak starting, it never fired back up cause it gets stuck on the compression stroke. If I keep trying to crank the ground wire to the body heats up.


Had the same trouble with the Martini, recon starter was the only answer.
_________________
1984 n/a Ruby Red Metallic
1988 924S Guards red- sold
1986 924S Guards Red - sold
1984 n/a Black - sold
1980 n/a Le Mans#1 - sold
1980 n/a Le Mans#2- sold
1977 Martini - sold

[ThomasJoseph315]

[quote="scm924s"]

[larchie]

In the video, the car sounds beautiful -- attempt to re-start was helpful in understanding the problem.

If the engine cranks slowly only after the car is warmed up, the problem is most likely the starter -- so would agree with ThomasJoseph315 and scm925s.

If this is not the case, that is if there's always a slow crank, then some of the things that might cause the slow turn over have already been covered and solved but it might be worth checking the following (starting with the obvious):

Battery might not be fully charged or there's internal resistance in the battery -- have the battery load-tested at a local parts store.

Hot wires almost always indicate a poor connection somewhere. Re-check the ground connection to the engine and engine to the body by adding a temporary jumper between the battery cathode and car body to see if cranking is faster. If cranking is better, then check for continuity again and it goes without saying when resistances are found, re-clean the relevant connection and ground in that circuit (e.g., battery terminals, solenoid, and starter and alternator).

If the positive cable from battery to solenoid on the starter is loose from body clip or firewall clip, check for worn insulation and possible shorting on engine. This might not show up with a continuity test when the car's not running.

When you crank, check to see if the headlight dim excessively, if so, there might be a poor ground elsewhere causing extra resistance at that point and thus cause the battery cathode/ground cable to overheat. (E.g., burned alternator diodes, alternator grounded to engine)

If you are satisfied with the circuits, then I guess the only alternative left is to have the battery load-tested and starter tested.

[ThomasJoseph315]

Now that you mention it,,..

I've noticed the headlights are always pretty dim, I just thought they where old and dirty. Also, whenever I turn them on my A/F gauge reads differently.

[larchie]

[ThomasJoseph315]

[ThomasJoseph315]

Soooo,..

Not only is she alive, she is now in time, and omg is fast! I highly recommend anyone that owns one install a super coil, the throttle responds is amazing.

The reason why it wouldn't start is because the super coil was so strong it was jumping over and pre-igniting the next cylinder stopping the engine rotation. I advanced the dizzy 1/4" and all is well.

So she runs beautifully now, but she failed smog again today. After completely replacing the ignition system and half the fuel system. Getting the timing working correctly she had the same exact read out as before.

The smog guy said the only thing left is the converter. I don't think the one on there is original, but I do think it has been on there for a very long time.

I leaned it out to just under stalling and balanced the A/F mix, but it didn't seem to matter. So Friday I'll be ripping the Cat off and installing a brand new magnaflow cat (cali-friendly)