Christopher Zach

Good point. It's a pretty high pressure system and finding a bubble in the line usually is not good. I assume I have to take off the whole top of the intake to get to the lines? Do any of them run over things like the exhaust manifolds for extra crunch.

Definitely will need shop manuals for this thing, will have to find a set. Lot of screws in the construction.

C

crushingday

Some helpful links

crushingday

http://dwaynesgarage.norcal928.org

Christopher Zach

Interesting. Looking at the electrical wiring documents for the 86 928S I see that there is the two DMEs, and also two ignition control units. I wonder if those can go bad intermittently.

James Bailey

Yes the car can run on 4 cylinders two on each bank....running very long will overheat the catalytic convertor , then the car catches on fire...Fairly common event. So much so that later S-4s got a system to shut of the injection to the 4 none firing cylinders.

Christopher Zach

Interesting. Is the root cause of that a failed ignition module?

James Bailey

sometimes but more often corroded or poorly fitting coil wire..

Christopher Zach

Ok, I'll check the wires and look for the coils. I did find the spark computers, they are on the front of the car, driver's side, left of latch. Two of them, same part number as the 944S, so I may try swapping them over to the S this weekend to see if they both work.

Fired the car up for idle yesterday evening, would idle at 500rpm in Park, normally seemed to do 1,000. Not sure which is the normal idle speed is.

Christopher Zach

So this morning I popped the hood and took a solid look at the engine. Water hoses appear to be surprisingly good, I'm thinking someone did a solid service on this a few years ago and replaced some things. Likewise the fuel lines are pliable, not cracked, look a few years old as opposed to 30.

Very interesting thing I noted was on the front of the car under the hood: I found the spark computers/drivers (will be testing those this weekend) but I also noticed a red cap on the high side AC port. Sure enough it's an R134 fitting, I'm guessing the fill port at the compressor is also switched out. Which means someone converted the gas (good) and if it still has some pressure might be re-chargable/serviceable. I'll take a look at the dryer after work and see if it has been replaced as well; but either way either PAG or POE oil is in the system (PAG is better IMO but POE doesn't require you to purge the lines and compressor of old R12 oil, a pain that I have done). With luck it's still got pressure, if not I'll pull the dryer, drop the compressor, and do a full service to convert it to double-capped PAG. If it does I will leave it very much alone :-)

So that's the morning report. Will work on it some this evening (it's 100 degrees in MD, BLAH!) and some more tomorrow morning.

mj1pate

So, Chris where in Md are you located? I also have an 86.5 (grand prix white) and I'm located in Eldersburg Carroll County.

yes, read the FAQ. That hard shift issue is more likely that the vacuum hose to the auto trans vacuum modulator is perforated. Get the car on a lift and you can see/feel the rubber ends of the hose near the engine and transmission. The main run of the vacuum line is a metal tube running along the torque tube. Replacing the rubber end pieces is an easy win for better shifts.

Christopher Zach

I'm down at the bottom of Baltimore Co, by the airport. I'll PM you my number, come on by this weekend and we can make vroom vroom noises.

Will find a lift, I think I will get a new set of ramps with a lower slope so I can get this thing up. Lower than my other cars, no doubt.

Took a look at the AC; it had a bit of 134a in it, and holds a vacuum which is good. The low side 134a fitting is damaged so I'll replace that first, then try filling it.

Firing it up at lunch today I see the engine idle at 500, then went up to a solid 900 within a minute. Hm. Will fill the AC system and take it out for a little drive this evening, I just realized I threw out my timing light (which could have told me if any of the plugs on a distributor were firing, thus isolating a downed side) when I got rid of my 914. D'OH!

Off to the FLAPS after work.

skpyle

Chris, something to think about. If you are going to the FLAPS to get spark plugs, among other things, 929's are most happy with common-as-dirt Bosch copper core plugs.
No need for high-zoot or trick spark plugs. One of the few cheap things on a 928.

Christopher Zach

FLAPS was fairly useless, should I be saying it's an 87 for brake pads? Think I will buy those online. Did get DOT3 brake fluid to top off the brakes for the moment, and 5 cans of 134a. Currently drawing the final vacuum for 30m to get any remaining water out, then will put in 2 cans of 134a and go from there (I have the dual evaporator system, looks like I will need about 32oz total-ish).

Noted on the plugs, once again I would need to take that whole pipe system off to get to the plugs, correct? Little job or bigger job?

Socal_Tom

Isn't it DOT4 for our cars?

James Bailey

Just the two side plenums by undoing the clamped hoses.