928NOOBIE

Why are they green.

Chucks928

Not sure 928 ! It must mean its important...

GT6ixer

^ Yep. MacGyver never cut the green wire.

Chucks928

So Sunday I decided its time to check the cold start valve.I removed the air filter housing and air flow sensor to get to it. Checked the resistance and it was 4.3 ohms ( wsm has it at 4 ohms). Then,hooked up my test lite to the connector and had my wife crank it over briefly. I told her not to worry as it wouldnt fire since it never fires when cold and the air flow sensor was removed. Lo and behold it fires right up! She barely turned the key and it fired...shocked the hell out of me honestly. I didnt realize it would run without the airflow sensor connected!? But it did,and it ran at 1000 rpm for a minute and then settled in at a nice 750 rpms. So.....I think this shows that my cold start valve was/is bad. Later when the temps dropped off it was back to not starting when cold but when I did get it fired up,it ran a little better with the cold start valve unplugged and idled right down.
I also got underneath it today and found some crappy wiring around the alternator and removed and cleaned the main ground wire from the block to the frame. The 928 is slowly coming back to life!

Chucks928

Next project...cleaning the fuel injectors! If you havent done this ,its really a fairly easy project,at least on an 82. I pulled 4 injectors at a time,leaving them connected to the fuel rails. Basically the 4 hold down bolts,4 plugs and the 2 rail compression fittings. I took off the passenger side first, then the drivers side... a dremel tool works wonders on cutting the hose clamps. All of the rubber seals were rock hard and cracked badly! Just about all had to be cut off. The filters were a bear to remove,but using a fine threaded bolt they were eventually removed. 2 injectors were missing their pintle caps ( appeared to have not even been installed somewhere prior). 2 fuel filters were also missing. All injectors were soaked over night in acetone, lots of junk came off. Then using my homemade flushing rig all injectors were flushed with injector cleaner while activating the solenoid with a12 volt battery. 7of them flushed nicely with a nice,strong pattern.The 8th injector had an erratic pattern and would slowly bleed off when the solenoid was deactivated.Definitely leaking by.
So I have to ask....should the questionable one be sent to Witchhunters for cleaning? Or replaced? I see that most part stores can supply aftermarket ones for 30-50$,but are they worth it or should I try to save the original? Any thoughts? Thanks ahead of time!

1st pic..the one with a cap broken off somewhere in the past.
2nd pic..my flushing setup...its crude but did a great job at pressure flushing.
3rd...most looked like this
4th.. a couple injectors post cleaning..

dr bob

Chuck --

Consider sending all of them to your favorite service. That will net you the new caps and they will all flow the same. Obviates the filters you already swapped though.

I'm all for DIY stuff, and often jump through some big hoops just so I can do stuff myself. Like building an injector cleaning fixture, and also a kit for cleaning them on the car with BG. After all that fun, the car still ran very noticeably better after I replaced the injectors with new. Yours are only 35 years old, they should still be perfect...

Chucks928

Out they go! The cost really isnt bad compared to the piece of mind that will come knowing they are 100%. Lots more stuff to DIY on it anyways.

Chucks928

Hello,due to the usual summer family plans and trying to get the 69 Plymouth engine back together,well,the 928 has been on the backburner somewhat. I did replace a few items and repair a few things though..Anyways,heres an update. The car still has the cold start issue and when running has a nice stumble...sounds like its not firing on all cylinders..lack of any power and seems to be running very rich.
ok...heres what I,ve done since purchasing this 82 928s

1. replaced the following
battery
alternator
fuel filter
rotor and cap
green wire
temp 2 sensor
temp gauge sensor
almost all of the Bosche style connections,including fuel injectors,sensors,cold start valve,etc
fuel pump relay and fuel injection relay
spark plugs

2.I,ve checked the following
AFM...in spec as per WSM
Thermo time switch. Out of spec as per WSM but I,ve read on the forums that the WSM may be wrong
Sent out injectors to witchhunter along with the cold start valve...all are in good working order
found and cleaned as many grounds as possible.I think I got them all.
replaced all of the vacuum lines I could find..think I got them all.
Set timing as per WSM
checked fuel pressure and flow..in spec

I think thats about it!

Anyways...I have done a lot of reading on these forums and was getting the feeling that maybe my AFM was causing the rough running and so I pulled it off this morning to take a look. I figured while I had it off I should check the plugs to see what they were doing.I had just replaced the old ones a few months ago and though its been started quite a few times and idled,it hasnt been run on the road.They should have been fairly clean,but here are the pics I took..

Chucks928

5 of the plugs looked like the pic in the previous post...light gray, good burn.


2 looked like this ...wet and dark

Chucks928

and 1 looked like this...dark and dry.

My first though is ,Damn..I,ve got bad valves or seals on this thing! Any thought on what else could cause such uneven burn on new plugs? The plugs are NGK BPR5EYs and looking through the maintanance logs the plug wires were replaced in 2012 (approx 5k ago). Using my inductive timing light I was getting a firing signal on all wires but didnt pull plugs looking for spark. As a side note..I pulled the plug on the O2 sensor and nothing changes while its running.That was next on my parts replacement list. Any input is appreciated!

soontobered84

Leaky injector?

Chucks928

I dont know...I had the injectors cleaned and they were all good. It seems the more things I fix,the worse it runs!

Chucks928

So, I think I narrowed it down to the "what" as far as the rough running. Long story short I found cylinders # 5 and 6 are not firing. Both are lighting up the noid light and both are getting spark to the plugs,but neither are firing normally. I pulled the plugs and one was dry and looks like it hadnt been firing and the other was very wet.( these are new NGK plugs) I had the injectors sent out for cleaning but I,m wondering if they are really working. If they are, looks like I,ll be digging a little deeper into the engine than I had hoped. A few more tests to run!

Chucks928

Hello... due to another car taking priority,my 1982 928 was,for the most part, parked and set aside this summer. I did poke around a little with it,but as the 69 Plymouth took priority,the 928 saw little progress. It has been tucked away for the winter,though it may get a little attention if the weather turns mild this winter. I thought I would post this to get some ideas on where to go and what to do as I try and get the 928 back up and running properly this coming spring. So..here goes!

A quick summary....1982 928,purchased 2 yrs ago,not running. With a lot of help from Rennlist members it is getting closer to being driveable but its still not there and I need a plan as I move forward.
I,ll start with parts replaced. ( its long! ) Alternator
battery
temp2 sensor
spark plugs
cap and rotor
green wire
temp gauge sensor
fuel pump
fuel filter
temp time switch
o2 sensor
fuel injection relay
ignition switch
all Bosch connectors ( injectors and sensors..plugs were all broken or cracked)
intake boot and o ring
all vacuum hoses and fuel hoses
Fuel injectors were pulled and sent to Witchhunters,along with cold start injector.( they reported injectors as in fair condition)
fuel tank dropped and cleaned.
Compression check... all cylinders were 135-140 psi. local Porsche shop said the readings were not super,but were good for the age of the car.
I think that just about sums up parts replaced and basic maintenance.
I,ve also gone through the car and cleaned all grounds, pulled and cleaned relays and pulled the dash pod and replaced all the bulbs and cleaned all contacts.
I pulled the AFM and tested,it was in spec as per the manual. Most sensors that I did replace were either out of spec or very close to being out of spec. I,m sure there are a few more things that I,ve done,but as stated,the car was bumped down the priority list this year. It was started and run every week this summer and run up and down the road a little just to keep it oiled and lubed somewhat.

so....how does it run? well.. it still has the cold start issue...needs starting fluid to fire on cool days..if its 60 or warmer it will start on its own. Early on it would idle up to 1200 rpms or so and then settle in at 750 rpms once warmed up, but has become less willing to idle nicely as the weather cooled.
It still seems to run as if its only firing on 6-7 plugs.....has a burble,or misfire at idle and when I take it down the road it just doesnt have the power. I have a feeling that I could take it further without it stalling or dying,but it would be struggling with power.
This car was not running when purchased,and as many of us have heard before.." it just needs a little TLC " ! Never having worked on a Porsche I was a little skeptical but also looking forward to the challenge of getting it back on the road. I,m getting there,but need some expert thoughts on which way to go next. Any thoughts or input is always appreciated!
Chuck

Landseer

Replace the thermo time switch, it's the one that is mounted horizontally into the water bridge. That sensor fires the cold start injector on l-jet, essentially a ninth injector. They go bad and car can't start in cooler weather. Just replace it, don't waste time troubleshooting it or second guessing vs manual specifications based on old rennlist posts. True for all Bosch junk on old Porsche resurections, esp this switch.