msteiner805

Hi Constantine,

Thanks for your input and you're right on all accounts. My decision was partially influenced by my restoration costs thus far. I'm in this 928 for a good chunk of change so far - I've done quite a bit to get this car up to snuff so far and more needs to get done. Not counting my time & labor, I'm still well below market value, but, I have electrical gremlins, a timing belt/WP and some cosmetic stuff that will all need sorting. This latest TT replacement was a bit of an unexpected hit to the budget. That said, I'm not in this project for resale, but, I do want to keep a budget.

The engineering issue you bring up is an interesting one - per folks like me and other engineers potentially taking the Loctite route given the better Super Clamp solution. Personally, I tend to classify solutions into the following:

- necessary for safety : cost is not the driving factor - effectiveness trumps all.
- necessary for better performance or cosmetics : if its not original I don't bother (a 1000 HP car is frivolous IMO)
- necessary for reliability and durability : this is where things get subjective and where solutions like the Super Clamp reside

I think for a lot of people, having a really nice 928/Merc/Chevelle/whatever means going "all out" on all of the above. These are the beautiful cars - turbo charged, pristine paint, perfect mechanical condition, lots of amazing upgrades. I think that to these folks, going "all-out" is satisfying on its own merit. Frankly, if I ever make boatloads of money, I might do the same. But, by nature I, and potentially a lot of engineers, are frugal and usually take a utilitarian approach to solving a problem. In reality, who knows though. My day job consists of managing engineers and providing technical direction, and, I do spend quite a bit of time trying to reign in costs of proposed solutions, so maybe its just my nature (or, maybe its the fact that our engineers are not spending their own money but rather the company's money LOL).

Regards,
Mike

msteiner805

Docmirror (and anyone else who can advise on this),

First of, thank you for your help and info thus far - very much appreciated. I'm writing this to ask for more info about something you write earlier:

"Having said that, here we go. When the battery is disconnected, and then reconnected the LH and EZK are flashed with default values for the fuel and ign maps. Upon startup, this may cause some modest issues with not being able to start and run smoothly, and the monitoring circuit did it's job and shut down one bank(yes I know it's not a bank) as a precaution. Once you turned it off and started again, the characterization of the brains began and it smoothed out. Completely normal."

I'm having some difficulty accepting that my ICM throws that green LED when I disconnected the battery - is this really a modest issue? Does this means the engine is having a harder than normal time "figuring things out" for the first time? It would seem to me that turning off a bank means we're pretty far off initially but I don't know.

Electrically here is what's been done so far:

-Charged battery.
-All ground points cleaned.
-New spark plug wires.
-Coil resistances good.
-Cleaned 14 pin connector.
-Full intake refresh (new knock sensors, Crank Position Sensor, TPS, cleaned injectors, new fuel lines, holds very good vacuum, new FPRs etc etc). Did not replace the Hall Sensor though...

The last time I started the car was 2 weeks ago when I noticed the first startup was rough and the ICM LED went green. The next startup was better, no LED, and then the engine started smoothing out quite a bit as I drove for a few minutes until me driveshaft ate it...

My reason for bringing this issue back up is that I'm reading that having the engine with one bank off places a lot of stress on the driveline. Since I'm rebuilding the driveline, I'd like to see zero stress on it...

Mike

Adk46

This is a very interesting thread. The approach engineers use for their cars has been mentioned, which got me thinking....

An engineer's job is to find the least expensive means of meeting requirements. Truly bad engineering is the failure to achieve those requirements. What often seems to be bad engineering is the result of setting inadequate requirements, which is the realm of the marketing department specifically, and of management generally. That's a simplistic view, but that's the paradigm.

It means engineers cannot do what they want. But car owners can; of course, that freedom has a wide range of results. The instinct of an engineer car owner will be to devise an explicit set of requirements for himself, and endeavor to meet them. He might wish to indulge in setting higher requirements than permitted at work, but since he will be bearing the costs of those requirements himself, he might look for clever ways to couple lower requirements with an inspection program, and other tricks. That's the real game of engineering.

msteiner805

Back on the road as of the other day! All good - no vibrations, good shifting. Nice to be done with this TT/trans job. I'll post some pics later tonight.

Some notes about the work:

-Two weekends ago I had a friend help install the TT/Trans as a unit. All went well and not so bad with 2 sets of hands doing the jacking/alignment. Last Friday, I received the new drain plugs from Roger (back story here is when I was just about ready to screw the transmission pan drain plug in so as to fill with ATF, I realized that the hex socket was stripped and that I had forgotten to order a replacement). So I ordered a new one and put the project on hold for a few days. $4.50 held me up LOL.

- The car needs an alignment - I think the eccentrics are not aligned (yes, I forgot to mark them). This is OK since I have a freshly rebuilt steering rack in there so an alignment needs to happen regardless.

- When I had everything assembled, I started the car and heard a rattle! Crap. I started to listen and couldn't hear it coming from anywhere in the drive line. After the test drive, I remembered that when I was removing the exhaust, the exhaust tips felt loose. Sure enough, I took off the exhaust tips and *rattle gone*. Super happy about this as I thought it was going to be another drive line issue.

- Does anyone know the torque value for the 19mm bolt/plug on the transmission return line from the trans cooler (I'm not sure if its the return line or not - its the hollow bolt connecting an ATF line of the passenger's side of the trans). Sorry for a lack of pics here - will update soon.

Mike

docmirror

I'd like to say I know but I'd be lying. Without some hands on, there's about 45 things that could cause the IMS to fault one bank and set it to limp home mode. (I know it's not one bank, and I know it's not 'limp home' mode)

It requires some diagnosis that just can't be done on the internet. The IMS(Ign monitoring system) senses the firing of one set of ignition group and cuts the fuel if there is an imbalance in the resulting temp of the two thermocouples mounted in the exhaust stream. So, we're looking at the injection wiring harness, the injectors, LH, EZK, plugs, wires, rotors, caps, MAF, and even compression comes into play.

Plenty of people defeat the IMS and just run the car without it. If you haven't replaced the spark plugs yet, do those and inspect the plug holes for oil fouling. While you have the plugs out, do a compression test and record the numbers. If it's aways been green LED, you can investigate the IMS thermocouple voltages and see if one of them is faulty.

This is the short list, so I'll stop here.

msteiner805

Thanks Doc,

The plugs are new, compression is good. MAF is still suspect...

Some more info : I pulled and cleaned the thermocouples in the exhaust manifold on each side of the block prior to installing the transmission back in last week. This was prior to filling the car with ATF. The thermocouples had a bunch of black crud on them.

While filling the ATF, I started the engine for 5-10 seconds, shut down, added ATF. I repeated this filling process several times until the fluid was at level. I then took the car on a short test drive - no ICM LEDs and smooth running the whole drive. This was maybe after about 5-6 start-up/shutdown ignition cycles.

Today, I started the car again, drove it about 5 miles and I couldn't feel anything, like the engine isn't even there! The car is so smooth - smoother than the day before. I feel nothing at all - not even the slightest vibration or roughness. Honestly I'm pretty freakin' amazed at this point. Either it took about a dozen starts for the computer to "figure it out" or, cleaning the thermocouples was the magic bullet.

Then, if you account for
- exhaust thermocouple cleaning
- ground point cleaning
- Installing an actual battery ground cable
- Rebuilt torque tube
- New flex plate
- Intake refresh (new sensors)
- ATF + diff service
- rebuilt steering rack + ball joints
- New motor mounts
- New plugs, wire, caps etc etc LOL

Then this 928 should be like new haha!!

I'm not declaring victory just yet ... but so far, this 928 is feeling like a new car. I'm working on a list of items left to do . But I finally feel like I'm getting there.

Mike

docmirror

OK, you've been where I was going so it's all good. I"m guessing you had a cascaded failure mode, and it just finally overwhelmed the IMS. Cleaning the TCs and getting the MAF used to the new parameters might have done the trick.

I'm sorry I don't know the characterization schedule but I'm pretty sure that several starts, and stops need to be done so that the enrichment values when cold are set properly. This is all part of the Temp II and O2 sensor calibrations. Which is another area you might need to visit some day. Glad it's running well, lets hope it stays that way for a while.

FredR

Mike,

"Chance favours the prepare mind"!

In a matter of weeks you have already done what most top notch owners do over many years and [sad to say] many never do at all [unless and until they have to].

Doubtless there will still many "regular ticket" items to do [it never ends] but at least I reckon you now have a great chance to have many years of relatively trouble free motoring. Doubtless the LH unit will fail if it has not been rebuilt already] and if you can secure an additional spare unit or preemptively have yours rebuilt [when funds available!] so much the better.

So many of these cars do not run at full potential and personally I fail to see the point in having one if it does not run as intended.

Just keep it between the hedges and enjoy!

Rgds

Fred

Schocki

Just a quick update. I´m working on a bigger WYAIT project right now and found the time to check the TB play. 10 years and about 45 kmiles later and there is still no change.
0,27 mm tolerance in the TB, looks like Loctite 290 did the job.
BTW I applied Loctite because there was no other cost effective solution available in 2005.

msteiner805

Hi All,

Just wanted to give a general update - its been a few months since I updated this thread and I wanted to let everyone know what has been happening. Aside from starting a new job several months ago, and, spending time with my family, my car time has been fairly limited.

In short, I have been enjoying this wonderful car . I drive it a few miles every weekend and every time I get in and start her up, a smile comes to my face. The engine has smoothed out *a lot*, there is now virtually no vibration at any rpm. I also love the way the engine smells after a heat cycle, it has that new engine smell now combined with a spotless AC system. All the new rubber in the engine bay LOL.

I have had to service a few items :

- New heater switch to finally fix my magic blower. I cleaned the old switch and it worked much better for a while - and then the magic blower syndrome would start up again (i.e. full blast or no blast). A new part from Roger and voila - 100% working blower 100% of the time.

- Got a new jump post cover!

- Replaced the 14-pin connector under the new jump post cover.

- Cleaned the crash sensor contacts and cleared my air-bag fault! Thank you owner's club for lending me the Hammer to do this. I love seeing the instrument panel without that annoying fault icon

- A couple weeks ago I got a message "Differential Control OFF" so I checked the PSD reservoir and it was very low. So I flushed the system, added brake fluid and all good! So far (1 week) no more message when the car was starting up. I also felt a difference when driving - its like the car is on rails when the system is working versus when it isn't!

- Unfortunately, in the process of checking the PSD reservoir, my rear lining started to deteriorate. I was able to get it back in, but its got some fairly large chunks flaking off. Not sure what to do about this since I don't want to spend $600 on this stuff but I don't think there are any other options.


That's been the progress since I last reported in. The car feels like a new car but I'm sure there will be some more gremlins.

What's left to do:

- I think there's a very faint smell of fuel from near the fuel pump. I'll have to get in there and start the investigation.

- Wheels need to be repainted/coated. I'll have to do some research on this as one of the rear wheels has some solid marks (1/8" chunks missing) from an altercation with a high curb. Any suggestions for refinishing/paint?

- Door and window rubbers need to be replaced.

- Rear suspension is too low. I attempted to adjust the drivers side shock, but, no success. I may need new rear shocks...


Other than that, I'm thoroughly enjoying the car, thank you everyone for you help and I'm lucky to have a 928 that will continue making me smile for the foreseeable future.

AO

Mike,

Great update.

For the wheel liner... not much can be done. I've got the same issue. Just treat them gingerly and hopefully they will last a bit longer. Just some crappy plastic Porsche decided to use.

For the shock height, I would try cleaning the adjuster collar as best you can with a wire brush and the soaking it with some WD40 or other penetrating lube. Then after it has soaked... and I mean really soaked, try working it back and forth a little at a time. See if you can get it free.

Had a similar issue on a previous car. Shock adjusters were fused (corosion) together. Ended up having to get new adjusters. The shock itself may be fine.

Good luck.

mskar

Not sure how fragile the wheel liners are, I've not removed mine yet but I have had excellent luck using epoxy resin and fiberglass cloth to repair deteriorating plastic.

I used this method to repair the guts of my overhead Vanagon A/C ducts, these have held up beautifully, and just got done repairing the broken plastic mounting holes on my 928 door panels. I glass in washers around any mounting holes to reinforce them.

You may be able to get away with doing just the hidden side if you don't want to see your repairs but depending on how much sanding and paintwork you do they could look as good as new.

Also +1 for two-part formable plastic putty. I've used that, a dremel, and small files to repair a good number of expensive/irreplaceable plastic parts.

FredR

Mike,

First of all Happy New Year to you and your family!

I think Andrew has covered most of the bases on the rear shocks. Knowing your attention to detail you might consider pulling the rear coilovers [quite easy really]. These things seize up quite commonly - presumably connected with road salt and galvanic corrosion. Did you try increasing the ride height first or were they seized solid in both directions [probably the case]? No need to suspect the shock absorber because of this but it could well be "tired" by now.

On the subject of ride height did you measure this or is that a subjective assessment? I reckon it is better to be a bit on the low side at the rear rather than high. Remember that when you change the ride height the alignment will change slightly- probably nothing of significance but just be aware.

Rgds

Fred

msteiner805

Hey that's a really good idea - thanks for mentioning this! I occasionally do surfboard repair so I have knowledge of the materials and the process. I'll give it a shot this weekend.

msteiner805

Hi Fred,
Happy new year to you too! I hope your holidays went well.

The big nut screwed onto the bottom of the shock acting as a catch for the spring - this is called the coilover? Yes, that thing will not move even when I use a large c-wrench and put quite a lot of force on it. I soaked it in lube for several days but still no luck.

Per the ride height I'm using the finger test for now, I can fit 2 fingers between the pass. side wheel and the body panel at the apex. At the driver's side - no fingers fit. When the car sits on a flat surface you can see the difference too. I haven't done an alignment yet (pending this issue).

Mike