924Board.org

Aplaja · Joined: 25 May 2016 Posts: 7 Location: Finland

Hi! I'm an 924 owner from Finland (which can be seen in my English skills) and I have a problem. At the start I want to say that the car have been my dad's from 1985 so it has been ours 31 years now. The car worked well before my dad put it to the garage for the next 15 years. Now, 2 years ago, I got the car for myself and started to repair it. The major problem on car is that it lags (I don't know how you say it). Idle is rough and there are no all the power in the engine. These problems dissappears sometimes but come back eventually. I have changed almost everything on the car: spark plugs and wires, ICU, fuel distributor, distributor cap and rotor, fuel filter, ignition coil etc. I also checked groundings and cleaned WUR and it made the cold starting much better. One of the biggest thing that wonder me is that when all the marks are lined (camshaft, flywheel, crankshaft and distributor) car won't even start. The ignition it too early. I have to twist the distributor about 30-45 degrees clockwise and then it runs better. I tested this also flywheel mark +10 and -10 and it wasn't any better. It runs so poorly that it kicks my back very hard whole time when driving that it makes it annoying to even drive it. Now it has gone so bad that the car won't even start and if it starts you can't drive it because it dies when it idles or when pressing gas pedal a little bit. I have to press the gas pedal so deep as I can to start moving and prevent car to die.

Ozzie · Posted: Thu May 26, 2016 8:12 am Post subject:

Has the flywheel ever been removed?
These can be refitted out of alignment which will throw all the timing out.

The easiest way to check is put the flywheel on TDC and see if the belt pulley lines up with the pointer on the oil pump.

Another thing, if the cam pulley has been removed they can go on backwards.
then all the valve timing will be out.
_________________
Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance

pmcaya2 · Joined: 24 Nov 2005 Posts: 191 Location: Scio, NY USA

Welcome to the board. Since the car was running well when it was put away, I'd start with the following steps:

- read the section on "Timing Belt Alignment" in the "How To" section of this forum. Double check your timing alignment, especially having #1 cylinder at Top Dead Center (TDC) and the distributor pointing at the wire that fires the #1 cylinder.
- since you changed the plugs, make sure you have the wires connected to the correct plugs (correct firing order)
- check all vacuum lines and make sure there are no leaks in the air intake boot.
It sounds like the car wants to run. Look at the basic things first. Good luck - Peter

Aplaja · Joined: 25 May 2016 Posts: 7 Location: Finland

Thank you!

But I forgot to mention that I have written 12 pages to Finnish Porsche forums about this malfunction and I have checked all these basic things that could have been broken.

Flywheel hasn't been removed. All the marks (flywheel, cam and crankshafts) are aligned and I habe checked timing like 10 times. I also checked the cam pulley by opening the cylinder head cover and checking that when 1. cylinder is in TDC both 1. cylinders valves are closed.

Leaks and wires have been checked many times.

Could it be the fuel pump which is broken? I tested the pump and here is how it worked: https://youtu.be/vcghOLFdFFE Are pressures too low or why the spray pattern isn't good?

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

pmcaya2 · Joined: 24 Nov 2005 Posts: 191 Location: Scio, NY USA

From your video it looks like your injectors and fuel pressure are OK. You could check the relative volume by putting the injectors in 500ml plastic drink bottles, but it looks uniform on the video

Anyway,you said that "These problems dissappears sometimes but come back eventually." Makes me think that the problem is electrical. I've seen one situation where a bad coil wire produced similar problems that were hard to diagnose. If the coil or coil wire are working intermittently, everything down-stream will be affected. I'd swap the coil wire or check the coil at this point. Sounds like you're doing all the right things. I hope that this helps. - Peter

Aplaja · Joined: 25 May 2016 Posts: 7 Location: Finland

I will set it on fire next time.

I have changed coil wire. I think that the problem could be the fuel pump. In my opinion the pattern of injectors are very lousy and this could be because of low fuel pressure?

JjyKs · Joined: 05 Oct 2015 Posts: 114 Location: Finland

The 2nd injector seems a bit odd, but that shouldn't be the reason for what you described. Just like the pmcaya2 said, the problem going away sometimes makes it sound electrical.

I would start by replacing the coil. Also, what year your car is? If it has transistorized ignition i would also try another ignition control box. (I have one extra one lying around here @ Kerava if you happen to be close. No idea if it works since there was water inside the connector whole winter but doesn't hurt to try). Also these guys said that Motonet actually has it in stock:
http://www.9xxfin.com/forum/viewtopic.php?f=2&t=25808

If it doesn't get fixed I would make some mark to the belt and check with timing light when the car works and when it doesn't to see if there's any difference. It could also be possible that your distributors advance systems are stuck (there's centrifugal and vacuum advances)

Also, it could help to attach a Wideband lambda to the car. They're pretty cheap on ebay, and that way you could actually see if it's because of fuel or ignition.

Aplaja · Joined: 25 May 2016 Posts: 7 Location: Finland

I live in Rovaniemi so there is some distance between us.

I'm that Aplaja who wrote to that 9xxfin topic you linked.

So, I bought a new control unit last summer and there wasn't any difference on the car between the boxes so I don't think it's about that. It could help if someone could confirm that 928 box fits in 924 (two rows, 6 connectors).

To JjyKs: here is a topic where I have described the problems in Finnish and more clearly. http://www.9xxfin.com/forum/viewtopic.php?f=1&t=22759

Paul · Posted: Sat May 28, 2016 8:22 am Post subject:

Check the centrifugal advance in the ignition distributor, make sure the weights are not frozen.

Also obtain a CIS tester and check your pressures.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Aplaja · Joined: 25 May 2016 Posts: 7 Location: Finland

How do I check these advances?

Paul · Posted: Mon May 30, 2016 1:49 am Post subject:

Remove any vacuum hoses connected to the distributor and rev the engine while watching the timing marks with a timing light.
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.