When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello 👋 community. So I picked up this 1981 5spd. These pics do it justice as its not this clean in person . But I am happy with the purchase and plan on keeping the classic. 928 has been a dream car of mine since my best friends dad owned 1978 when we where in elementary school. I have a deep passion for the 928's.
Original color was guards red and painted this blue by the previous owner.
Got a great deal on this running 5spd and didn't want to pass the opportunity. Now, knowing what I know now I realize it's pretty much the bottom of the barrel in performance. Bummer as I'm a mod/speed freak and not the best setup to start dumping money in for any back breaking performance. However, I'll be taking delivery of a 91 S4 in about two weeks so ill leave the land speed records for that. That's about 1yr away so for now ill make this lightweight as fun as a driver as possible. Looking for about 350-400whp, boosted. Not a lot for today's modern crazy standards, but that should be plenty to keep a smile on my face.
But before that phase, I need to get her running right! Currently having issues with a super lean condition, a sticking starter (keeps cranking so maybe ignition). Also discovered some disconnected vacuums among other shotty work.
Welcome to Rennlist and the 928 Forum! And congrats on getting a pretty car, and a running 5-speed(!!) to boot. You are among friends here.
Take the time to go through the "new visitors" thread in the sticky section at the top. A pile of basic stuff will get covered in there. I'll start the browbeating on some essentials like new fuel lines and power steering hoses too. Save yourself the disappointment of burning the car down. I bundle brake and -all- the coolant hoses, the heater control valve, -all- the fluids, battery ground strap, and undoubtedly more into my "do these before you drive the car" recommendations list. Since your wife (nice smile...) is willing to ride in the car, the least you can do is not strand her for stupid stuff or catch her on fire.
Thank you for the tips dr. Bob! Yes this looks like a great community. My car came with a workshop manual but it's missing all the important sections! Go figure. Thanks for pointing me to the owners manual and stickies.
Yes I agree not driving it until it's been through.
I did fail to mention what I've found done under the hood. There is new rubber from the injectors to rails, mostly new vacuum lines but a couple disconnected and cancelled with electrical tape, new CAT in 2016. Looks like a replaced MAF (another one was in the trunk). MAF just fell into my hand when I removed the air box.
A few more pics.
Interior looks like its been thru. Blower, stereo heater etc non of it turns on. Some dash buttons are not connected to the harness so they just put the interior back in and didn't reconnect it all.
It was having a hard time with cold starts when I purchased but bought a new starter relay and starts cold nicely now.
From that I know. Shouldn't the pos/neg from the harness be consistently connected the same to all injectors? Notice on these two one has red harness going to pos injector and the other its opposite. Overall there are 5 pos going to neg and 3 flipped.
This upper micro switch has totally malfunctioned. The pin is broke. Also the cable is completely dissattached with the upper throttle cable snipped. Could this be why it runs so sluggish up top?
Here the top arrow is poiting to the snipped cable and the lower arrow where i assume it should be attached to.
Not sure about injector polarity.
I think the snipped cable is for cruise control, attaches on top.
The lower ball end would be for a transmission cable, only used on automatic transmissions.
Don't forget to buy a new air filter, and make sure it's installed with the hump up. Air intake tubes would also be helpful.
It's possible to get an entirely new wiring harness, which I'm planning to do when I do an intake refresh. That, along with cleaning up the fuse box, would go a long way. Others may disagree, but electrical issues seem to be a common issue on older cars. I'm still reading through the electrical threads, but there are some top-notch experts in here that can handle any issue.
Welcome to the community!! The Ljet cars tend to be extremely reliable and probably have the lowest maintenance of any year 928, especially when it comes to the fuel injection system.
Having said that, it’s not encouraging that someone let the harnesses rot, did an ugly grafting of new connectors, clipped off a bowden cable, and who knows what else. But it’s running and everything can definitely be brought back to spec.
If it were my car, the first thing I’d do is a complete intake refresh and replace the injection harness (and almost certainly the front of engine harness as well). And do an entire electrical system check, ground cleaning, and central board cleaning. And engine cleaning... Lol!! The original harnesses are way past any reasonable lifespan at this point. And an intake refresh means replacing all the plastic lines and rubber bits in and around the intake that are responsible for holding vacuum. Those high NO values could well be coming from an intake leak, or multiple leaks. I see a big grease smudge under the AFM o-ring which could indicate a leak so replace that o-ring for sure. And you can replace those two microswitches while you’re at it (one is for idle, one is for full throttle). Might want to do a compression test to evaluate the state of the engine too before dumping a lot of time and $.
Another nice-to-have is having the injectors professionally cleaned, which would be perfect to have done while you’re working on that other stuff.
And as you’ll see from the new owner thread mentioned by Dr Bob, there are a few must-do essential items dealing with the timing belt, fuel hoses and lines, and lower ball joints (if the original aluminum ones haven’t been upgraded to steel).
Get a new o2 sensor when you’re done unless you can verify the existing one is very recent.
You’ll be able to source everything you need and get a ton of great advice from Roger and 928sRUs, aka ROG100 here on Rennlist.
PS polarity doesn’t matter on the injectors. But that harness needs to be replaced so it’s a moot point.
Also PS there’s no MAF but there is an AFM. Also are those S4 8 inch rear wheels on the front (all the way round it appears)? Wrong offset for the front.
Sounds like you have a lot of vacuum leaks from the way the PO terminated the lines. Look at the diagram on the hood and retrace every line to make sure they are going to the right places.
I would also do an ignition tune up (cap, rotor, wires, and plugs) along with an intake refresh (replacing all the seals and hoses on the top end) to get it running at its best.
My 81 always passed SMOG with flying colors after I did that. It's fairly easy to do on an 81 and will probably take you a weekend if you take your time. Hardest part is getting the fuel lines off.
The 81s also didn't have an EGR system so you don't need to worry about that.
As stated above they are hands down the easiest 928 to keep up as they are the simplest by far.
It looks like the PO did the ignition as the cap wires and plugs look new.
I do have the intake tubes.
Yes there are a few open vacuums. The diagram under the hood is a bit tricky to follow. Looking for a better visual diagram that might be easier to understand. But I guess if I stare at the hood diagram long enough it will start to make more sense
Yes there are a few open vacuums. The diagram under the hood is a bit tricky to follow. Looking for a better visual diagram that might be easier to understand. But I guess if I stare at the hood diagram long enough it will start to make more sense
What do the half circles mean?
If you're talking about the ones where the lines intersect, that is to show that the drawn lines are just crossing, but the hoses they represent are not connected.
If you're talking about the ones where the lines intersect, that is to show that the drawn lines are just crossing, but the hoses they represent are not connected.
11-14-2020, 11:27 PM
1981 928 5spd fixing and modding
. But I am happy with the purchase and plan on keeping the classic. 928 has been a dream car of mine since my best friends dad owned 1978 when we where in elementary school. I have a deep passion for the 928's.
