Excellent! Even raggedy, you got it running!

 

I got new plugs put in it today and replaced the 4 under hood fuel lines as well as a couple vacuum lines. Currently it seems like it might be idling a little better, but it still seems like it's either running rough or missing if you bring the Rs up at all.

Apparently it doesn't sound much like it in this video, but it still sounds rough off idle like it did in that video yesterday. Any suggestions on where I should start with the rough running? I'm gonna check the distributor caps and rotors tomorrow hopefully. Should I try swapping coil(s) or ignition amps (whatever they are next to the hood latch) from the tan car to this car (not knowing if they are any good on that car)? I do have the two computers I bought for the tan car that I could try in this car also.

(Long cranking due to fuel line replacement.)


None of the old plugs looked bad. I wrote the porsche cylinder numbers on the tops and the chrysler/gm numbering that I'm used to to the right of the porsche number for my own sanity.
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Two of the replaced lines.
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Replace the front ignition computers. They're the things under the plastic cover to the right (driver's side) of the hood latch on the front of the car. When one of the two go bad 4 cylinders fire off-time.

Simplest replacement. Had same problem, engine ran like a clock afterwards. Then vacuum, then fuel lines.

 

Found a set of those for $50 used and tested. The ones on the tan car were one of the things that was rewired at some point by the previous owner, so I'm not sure how trustworthy the ones are on that car, otherwise I'd have tried them first.

Hopefully that's all it is, and then I can move onto the timing belt job and other stuff to make it roadworthy.

 

Last night I tried the ignition amps from the tan car on the blue one and it didn't seem to make a difference. Maybe those ones are no good either (as said, the wiring on them in the tan car was redone at some point, so who knows) and the set that's on the way will work better.

I did order a fuel pressure test gauge that will work with this car since my kit doesn't have the special porsche fitting. So hopefully between those ignition amps and the fuel pressure gauge I can narrow things down and figure out what's going on. It's really weird because it seems like it idles just fine.

Here's it running with a vacuum gauge hooked up.

 

So I'm pretty sure now that I'm having fuel pressure issues. With the motor running I have 28-30psi. With the motor off and the fuel pump relay jumpered I have about 40psi. Some searching makes it seem like I should have 55psi while running, which seems about what I'm used to from other vehicles

https://www.youtube.com/watch?v=wm6hFQTAmlk&feature=youtu.be&ab_channel=IntenseBlue318

The original fuel pump was seized (eventually unseized, but won't pump) so I replaced it with one of these: https://www.ebay.com/itm/83-87-Porsche-928-S-Fuel-Pump-Orig-New-Hayg-Bosch-Walbro/220558255886?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 I also replaced the fuel filter at the same time and drained out all the old gas and put in a few gallons of fresh 93.


Any ideas on what could be the problem here? Regulator? Dampers? Pump?


Original pump
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About to fire this one back up after the timing belt. Found a 5th fuel line (unless it's vacuum) under the hood that I hadn't seen mentioned anywhere. Looked dry rotted so it's replaced too. Just replaced it on the tan 86 too so I don't forget about it.

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your a brave man, you seem to trouble shoot really well...

 

It keeps me off the street.

 

I would think that your problem is that you haven't run your car enough to have the fuel flow clean your injectors. You probably have an injector firing, but it's clogged up with varnish or ethanol residue and hasn't cleared yet.

It might not ever clear on it's own or it might clear the next time you warm up the engine to operating temperature.

You can also have your injectors cleaned at Witch Hunter or Cruzin' Performance or maybe you know someone local to you.

I have used B12 Chemtool in a can, a Mityvac with a vaccum line to the top of the injector drawing a vacuum, and a homemade injector connector jig with a switch, and a power supply to get that stuff out of my injectors. It worked well

 

I did let it warm up today after getting the timing belt job wrapped up. Still a bit choppy, so maybe I can try some seafoam in the tank to clear out the injectors. Still idles just fine though.

 

Here's the car getting run out of the garage after the timing belt and a bit of a walk around of it (plus me fumbling around).

 

Some pics of the car after the timing belt.

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Found some interesting stuff in the car too. I knew it was a california car, but looks like it spent time in WA as well. Last oil change sticker on the windshield is 2009.

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Wait... Who is letting you park project cars all over their yard?

 

These are currently at my parent's house in SC. I've bribed them with one of the 928s being theirs once they're up and running. Me and my brother have a house and a garage in Pittsburgh (with even more project cars), but I'm currently working in SC.