| View previous topic :: View next topic |
| Author |
Message |
ajw0100
Joined: 14 Jan 2010 Posts: 2 Location: Kansas City
|
Posted: Thu Jan 14, 2010 1:14 pm Post subject: Misfire Problems '77 924 Porsche |
|
|
Hello Everyone, Any help at all would be greatly appreciated.
I am currently working on a 1977 Porsche 924.
Recent new parts include the following: battery, fuel pump, fuel filter, spark plugs, plug wires, cap and rotor, and the coil.
Additionally: the fuel tank was drained and filled with new gas; the fuel distributor, fuel lines and fuel injectors were cleaned.
The problem I am having is first the engine will only start with the cold start valve energized with a remote starter switch ran from the battery. (I understand this is common problem) However, if the injector is pulled out it does spray fuel with 10.5 volts from the harness connector but will not start without unhooking the connector and installing the remote switch. If the cold start valve is de-energized the engine immediately dies.
Next, the engine will start but is only running off of the #2 cylinder. After about 5 seconds of idling fuel starts to pour out of the exhaust. When the spark plugs are all pulled out #2 is clean and #'s 1, 3 and 4 are covered in fuel. Also, the exhaust tube for #2 is hot and #'s 1, 3 and 4 are cold.
Now, if I install an in-line spark tester all four wires will flash while cranking. And if the spark plugs are pulled out one at a time and grounded to the valve cover each will also fire while cranking.
Compression on four cylinders are equal and within specs. Valve timing and ignition timing are correct. Cooling system pressure test was okay. All plug wires are within resistance specs. Resistance on primary and secondary of coil are okay. Rotor and cap look good as well. The first set of new plugs we put in were champion then we tried a new set of NGK (Bosch was not available). The air valve moves freely and all injectors are spraying evenly.
So, I am not sure what is causing the misfires on 3 of the 4 cylinders.
It would be wonderful and anyone has some advice. Again, I would greatly appreciate it.
Joe |
|
| Back to top |
|
 |
mikebola

Joined: 07 Sep 2009 Posts: 361 Location: Parkside, PA
|
Posted: Thu Jan 14, 2010 1:40 pm Post subject: |
|
|
Have you checked the spray pattern of the injectors? they may be leaking or have an obstruction. _________________ proud owner of a 1979 924 Sebring Edition with a 931 trans that looks horrible but somehow runs... |
|
| Back to top |
|
 |
Imafordguy
Joined: 06 Dec 2009 Posts: 189 Location: Eugene Or.
|
Posted: Thu Jan 14, 2010 2:02 pm Post subject: |
|
|
What color spark? Do you have good compression? Are you sure firing order is correct and correct direction or rotation?
With all new gear if your spark is weak... I would suspect wiring issuses. _________________ 81 Porsche 924
84 Porsche 944(parting it)
66 Ford f100
66 AC cobra kit car(major project)
64 ford f100 (429 SCJ)
62 Studebaker golden hawk gt
61 baja bug (with bad opel 1.8, looking at ford 2.3 turbo to flovo) |
|
| Back to top |
|
 |
joejax

Joined: 02 Dec 2009 Posts: 919 Location: Jacksonville,FLA,USA
|
Posted: Fri Jan 15, 2010 1:29 pm Post subject: |
|
|
I would triple check to make sure timing is in line. also, thought I have heard on here that the wrong plug wires can be a problem.
Unsure about that, have not gotten a definate answer yet. Hopefully it's something that easy. _________________ I got nothin'
Uhhh...you got any pics? |
|
| Back to top |
|
 |
datatrain

Joined: 15 Sep 2007 Posts: 441 Location: Osoyoos, British Columbia
|
Posted: Fri Jan 15, 2010 1:35 pm Post subject: |
|
|
I know this sounds simple, but I think your plug wires are on the wrong plugs. _________________ '78 924 NA with Collector plate
33 year old car, with me for 21 yrs
Mint '92 318i BMW
Near mint '98 Buick LeSabre
VE7HFR |
|
| Back to top |
|
 |
ideola

Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI
|
Posted: Fri Jan 15, 2010 10:15 pm Post subject: |
|
|
+1^
Make sure you have the plug wires on in the correct order AND the correct orientation. Order is 1-3-4-2, and the distributor rotates CLOCKWISE. If you installed them 1-3-4-2 counterclockwise, you will only fire on two cylinders.
Also, make sure your distributor is properly indexed. _________________ erstwhile owner of just about every 924 variant ever made |
|
| Back to top |
|
 |
ajw0100
Joined: 14 Jan 2010 Posts: 2 Location: Kansas City
|
Posted: Sat Jan 16, 2010 3:28 am Post subject: |
|
|
Compression is equal and within specs for all cylinders. I do have the firing order set up 1-3-4-2 with the rotor spinning clockwise. To set up the initial timing I put the #1 cylinder on TDC compression and turned the distributor cap so that the #1 spark plug wire is lined up with the rotor. This does get the engine to start but only on the #2 cylinder. Advancing or retarding the timing with it running doesn't make any difference. Also, removing the line to the vacuum advance and plugging the line on the manifold doesn't change anything. I printed off the article on indexing the distributor so I will check out how the marks are lined up and I will also check the color of the spark.
Thanks everyone for you help so far,
Joe |
|
| Back to top |
|
 |
rkn

Joined: 01 Apr 2007 Posts: 176 Location: Copenhagen
|
Posted: Sat Jan 16, 2010 4:13 am Post subject: |
|
|
Are your plugs getting flooded?
Last summer -after my car had been sitting for a while - I fitted new plugs and wires, and I could only get her fired up on 1-2 cyls., despite fuel/spark/timing being OK.
Turned out my A:F mix was way off and the the plugs practically drowned + fuel out the exhaust as you say.
How is your mixture? Perhaps your CSV is spraying non-stop? _________________ 1980 924NA ROW |
|
| Back to top |
|
 |
poorsha924
Joined: 13 Nov 2007 Posts: 143 Location: Kansas City Mo
|
Posted: Sat Jan 16, 2010 4:48 am Post subject: mis fire 77 924 |
|
|
Hi there (been there done that)
It could be several things no or low fuel volume, massive vaccum leak or other issuesThere is a few things you have to check 1st I see you live in KC so do I If you would like to contact me I could explain easier to talk to you then to type out thing you need to check. contact me thru the board via PM or my email address : bernieunlimited@aol.com
poorsha 924  _________________ 79 924S snailshell
audi big bore t-body
16" turbo wheels |
|
| Back to top |
|
 |
Joes924Racer

Joined: 03 Nov 2002 Posts: 11964 Location: Oregon, Denver Colorado native!
|
Posted: Sat Jan 16, 2010 5:23 am Post subject: |
|
|
Are you kidding fuel pours out of the exhaust are you sure its not water.
im thinking warm up regulator. though recheck plug wires. and make sure dizzy is indexed to proper firering order.. for firsts fuel pouring out the exhaust thats bad. _________________ 1979 porsche 924 Na
1980 porsche Turbo 931GT Replica
Have u ever driven a turbo. |
|
| Back to top |
|
 |
Slam
Joined: 07 Jan 2005 Posts: 1690 Location: Wainwright, Alberta, Canada
|
Posted: Sat Jan 16, 2010 5:56 am Post subject: |
|
|
As above re the spray pattern. Maybe three injectors are stuck open. Also control pressure check may give a clue. Keep an eye on your oil if you're flooding the crankcase with fuel. Bearings don't like that very much.
Welcome to the gang! _________________ '88 944 Auto - may or may not resurrect |
|
| Back to top |
|
 |
Ozzie

Joined: 12 Mar 2005 Posts: 4448 Location: Townsville, Qld. Australia
|
Posted: Sun Jan 17, 2010 5:49 pm Post subject: |
|
|
I know you checked your timing off TDC.
Did the cam line up at the same time?
The cam turns at 1/2 the speed of the crank and your timing could be 180 degrees off.
The crank AND cam have to line up at TDC to set the timing position for the rotor on no 1 cylinder. _________________ Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
|
| Back to top |
|
 |
Ozzie

Joined: 12 Mar 2005 Posts: 4448 Location: Townsville, Qld. Australia
|
Posted: Mon Jan 18, 2010 6:36 pm Post subject: |
|
|
how did you go? _________________ Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
|
| Back to top |
|
 |
Ozzie

Joined: 12 Mar 2005 Posts: 4448 Location: Townsville, Qld. Australia
|
Posted: Wed Jan 20, 2010 6:57 am Post subject: |
|
|
bump _________________ Porsche 924 1984 (UK import) NA
Its AUTO and its BLACK
Montego Black on black/red
Engineer of Electro/Mechanical Systems Maintenance |
|
| Back to top |
|
 |
924OZY
Joined: 24 Jan 2010 Posts: 71 Location: Gold Coast Australia
|
Posted: Sun Jan 24, 2010 11:00 pm Post subject: I had the same problem |
|
|
I had the same problem and thought it was running super rich on two cylinders after changing the plugs, and seeing two black ones.
Turns out the Leads were the wrong way around (counter clockwise 1342 by previous owner). Mine was rich on 1 and somethin else:
I Have to remove distibutor cap and check where the rotor button ends up at tdc, then do the leads as desribed above, then try to get a timing light on it and set the timing.
Good luck _________________ 924 N/A snailshell, superpro linkage bushes, 2.5"exhaust
4.0L ef Fairmont, 3000rpm stall, shift-kit, J3 chip, 3" exhaust, self tuned using tunerpro, soon to be boosted,
expecting 350Kw at wheels at 10psi. |
|
| Back to top |
|
 |
|