924Board.org

[rksmotorsports]

Okay folks, here's the prob...........
Won't maintain an idle. Sometimes I can start it (cold) with the ol'reach in and turn the key, but most of the time now, I have to hold the pedal to the floor and crank. (I hate doing that because of cold start/0 oil presure/high revs. I want to install an Accumulator, but that's for another topic.) Then, maybe it will and maybe it won't idle. I can hold it at about 1500 w/foot, but let off and it acts like only 1 or 2 plugs are firing and even then, they're off.......it's wierd, to say the least. If I let it "cough and hick-up", eventually it'll die and/or, back-fire and rotate backwards for about 1-2 turns. Or, I can put the full throttle to it and maybe it'll rev back to all 4 hitting right. Sometimes I can turn it off after either it "coughing" or reving, and it'll start right up and idle............until I move the throttle and then it's back to sh@#! again.
I bought the car used and have had it for about 3 months. It's had it's good days and bad days...lately more bad.......
Approx 13K on fresh motor and head.

Here's what I have replaced:
New- Battery, battery connectors, alternator, coil, rotorcap/button, plugs-Bosch(not wires, probably could use a set),fuel filter (nasty crap out of old one!),O2 sensor and a couple of other things I can't remember right now.

What I have done:
reset crank/cam timing, set ign timing, cleaned fuel system from tank (what a pain......and a pot full of rust too!) through to the fuel filter, removed all A/C components except the through the firewall plumbing (solved overheat prob and lightened it up a tad too), and a couple of other things I don't recall (must be the alzheimer's catching up w/me.

A couple of other notes:
I have one of those little red/amber/green LED air/fuel meters and it will register just a tad rich when it's running right, but will go from rich, to max rich, to not even lit when I'm using the gas (as opposed to cruising at an even rpm).
Also, my fuel guage seems to indicate a lower fuel level when it's pulling the "cough" stunt.
All of this makes me think that the prob is electrical/tronic in nature. I don't have jack for diagnostic tools, so here I am. I throw myself upon the mercy and wisdom of you all for help. I've tried to describe this accuratly, but it's almost like the phone call of "my car is sounding like clunk, grrrrr,bang. What's wrong with it?"

If I had the $$$$ I'd say the hell with it and go with a couple of Webers and a MSD type of ignition, but, that's for another dream
Thanks all.
Kevin

[John Brown]

If I were a betting man, I'd bet you have dirt in the fuel distributor, line, injectors, etc. With that much crud having been found in the fuel system I'd be very suspicious about the remainder; even though the filter should have caught it.

Second suspect would be the 'frequency' valve.

Have you checked the injector function/patterns?

And, always, like a broken record, like it or not, one needs to check these systems with a fuel pressure guage before expending time and money chasing faults.

Good luck
_________________
John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

[gohim]

You can't set the idle speed or mixture on the late model cars until you have dealt with any vacuum leaks, and the engine has been warmed up.

Otherwise, when you play with the adjustments, you will actually be fouling the adjustments up.

Before you started twittling the dials.... Did you replace the vacuum hoses, and make sure that they were all installed in the right places? You did say that the engine has been worked on, maybe the PO (previous owner didn't get everything installed back in the right places).

Also, the 81 and 82 cars have electronic idle stabilization. Did you bypass it, before you started to tried to "tune" the engine? If you didn;t you will always be fighting it.

The electronic idle stabilization unit is the little plastic black box located on top of the "ignition igniter" module on the front of the left inner fender. You can disable it by either disconnecting the spade connector on the top of the left inner fender or by disconnecting the two round plastic plugs on the idle stabilized and plugging them into each other.

Make sure that all of the vacuum hoses are good, and plugged into the right places (you're lucky because the later engines have fewer hoses than the earlier ones). Check the fuel injector o-ring seals (fuel injectors are held in place by friction between the o-rings, and fuel injector inserts which are screwed in). The o-rings should be smooth, and firm, not cracked or hard. If the o-rings are bad, you will have bad vacuum leaks, and will not be able to set the odle properly. The o-rings are a common parts used on VWs, Audis, BMWs, and should be easy to find at any decent auto parts store. If the fuel injector inserts are not ORANGE Color (are your whitetish color?) you need to replace them with the new PLASTIC ORANGE COLOR parts. Use Permatex non-hardening teflon based thread sealer when you screw in the inserts to seal them (on the threads, not the o-rings).

The idle speed screw on the throttle body, and the idle mixture screw on the airflow sensor should be reset to a preliminary/starting setup of 2.5 turns out.

The timing should be about 0 degrees on a late car, not 10 ATDC as set in very early 77 cars. Engine must be running and warm to set this so leave til later.

Check the distributor to make sure that it is set to the lower mounting position. Use BOSCH distributor cap and rotor, not the cheap Asian made parts.

Have you replaced the fuel filter?

Remove air cleaner cover, remove fuel injectors and place each in a deep clear bottle (2L soda bottles work). Remove coil wire. Turn ignition switch to "ON". Reach in to the airflow sensor plate through the aior cleaner, and lift plate gently. You should be able to see all four injectors spray an even "fan shaped" pattern. Replace all injectors that do not spray the even fan pattern, or leak after releasing the airflow sensor plate.

Now, you are ready to try spinning the engine to warm it up. If the engine will start and run now, you can warm it up and set the idle speed, idle mixture, and ignition timing. When you are done, reconnect the electronic idle speed stabilizer. If the engine starting running badly, then, the stabilizer may be defective.

[rksmotorsports]

Thanks guys. Pulled the injectors and cranked the engine a turn or 2 (coil wire pulled.....of course!) and 1 of the 4 sprayed, the other 3 didn't even leak or dribble.

My next step is to pull the lines and flush, etc, but before I do that, I want to have my copper 'crush' washers for the banjo bolts, for reinstallation. (I like to have all my stuff ready to go when I start a project. Makes life easier.)

What are the specs on the 'crush' washers for the banjo bolts on the fuel distrib? The fuel/feed lines, as well as the injector bolts. Also, where do you get them? I found out quick that Auto Zone and Advance Auto aren't going to be much help.

[augidog]

Metric copper sealing washers and O rings.
CIS Fuel system hardware.

http://www.specialtauto.com./porsche-parts/index.html
_________________
1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.

[John Brown]

FWIW, if it's the injectors (swap them around to see) you most likely will have little success cleaning. They're about $30 each I think.
_________________
John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

[rksmotorsports]

Thanks John, all.
I picked up the washers today, from a local shop that specializes in Euro cars.
I've a line on replacement injectors, just in case. I'll know more once I get into the distrib and get the lines flushed. One thing is certain.....once I finish, the fuel system --from the tank to the head--will be as clean as the day it left the showroom.
I'll keep y'all posted as the weekend gets here and I get into the system.

[rksmotorsports]

Will Audi 4000 injectors work? I know it's an Audi motor, but I'm still figuring out what swaps and what doesn't. I can get a good deal on a set for the 4000.
_________________
'82 924 N/A: Daily Driver/Project car/Auto-X/Spectator Racer
'84 C4 Corvette: Driver/Auto-X
'95 Isuzu Rodeo:For when it rains

[BillA]

FWIW I just spent the past few weeks (spare time) troubleshooting my 78 with the exact same problem, if what everyone has recommended works: great! I ended up with a bad warmup regulator (they are not cheap!) but it works and it's been about three years since I've been behind the wheel with it, I forgot how much fun it is to drive!!!!

[John Brown]

[BillA]

Absolutely John, I agree, It sounds like he's headed in the right direction. I just wanted to add a "just in case." In my case, I bought this car at the beginning of June, with absolutley no history on what was done to it. To make matters worse they installed a Crane ignition system in it, I should say they attempted, what a mess! You and I talked about this years ago, if people are going to work on cars they should invest a little time and educate themselves on the basics. Don't mean to get off on a tangent! It's frustrating at times!