1987 505 Turbo Revival

[MGR550]

Hello, 

I bought an 84 505 GL(?) a while back and loved it, then managed to find a nice 87 505 turbo. Car has only 110k kms on it and seems to have been stored for the last 30 years or so (tires on it are form 1989!). Also got a whole bunch of the workshop manuals, original sales documentation, brochures, etc. Body and interior are in great shape, but runs rough from sitting so long.

Idle was super low, knock indicator light flashes almost constantly when its warmed up, alternator wasn't working, throttle got stuck if pressed down past half way (that was a little scary), was very unhappy to go on boost, and a bunch of small things on the interior like sunroof, fog lights, and high beam switches not working, hvac fan only turning on at a few positions, front speakers not working, etc. Power steering pump pulley is toast (luckily came with a whole spare pump) and valve cover gasket has a small leak at the front corner. 

What I've already done:

spark plugs, plug wires, coil, fuel pump, fuel filter, wideband O2 sensor (has a controller with narrowband output so it'll play nice, still need to wire this in), and alternator.

Unstuck the wastegate flap (thanks to another forum post where someone else had the issue of ignition cuts at 2750 rpm), set idle speed and fixed sticky throttle (screw was backed all the way out and catching on intake temp (?) sensor). 

Whats next:

vacuum lines, fuel pressure regulator, air filter, check for cracks in VAF-turbo accordion pipe, re-align headlights (pointing way low), going to run some injector cleaner and octane booster through the fuel tank (fuel in tank smelled foul even after flushing it once) - hopefully this solves the knock warning issue, then re-assemble and test it out. 

Electrical issues on the inside I'll have to start probing around. Also going to put LED bulbs in the taillights and marker lights. 

 

Questions:

Anything else I should look at thats prone to failure?

Good way to take apart center console without cracking anything?

Where to route wires through firewall? Removing the firewall insulation plastics?

 

Ill try and add a pic once its back together 

[Bean]

Congratulations!  Sounds like you picked up the white one that was on Kijiji a while back?  Sweet score!

The WB02 will be nice for adding a proper WB02 gauge while also providing output to the ECU - is it heated?  What kind is it?  

Injectors - I'd highly recommend pulling them and either upgrading them to the higher flowing euro units or at least getting them cleaned and tested.  Turbo motors do not abide by poor fueling and you simply can't trust them after sitting so long.  In tank injector cleaners are good for ongoing maintenance on good injectors, but should never be used to "clean" unknown or dirty injectors.  You could do a decent home job with a good injector cleaner and / or an ultrasonic cleaner.  But test spray pattern before using them.

Make sure to do the TPS reset procedure, check timing and make sure it's right at 8 deg or maybe a smidge more, but these engines don't like too much advance over spec.  

Test that wastegate to make sure it holds boost.  That diaphragm in it likely won't last very long as it's been still a very long time and might not last very long so just keep an eye on it.  There is an over boost sensor that will kill ignition on the elbow after the IC so make sure that's wired up as it can save your motor if there's an overboost situation due to wastegate failing.

Pull the knock sensor off and clean both the sensor and the block really well - sitting that long you just want to make sure no corrosion is in between the two.

Center console to pull stereo - there should be two screws that are hidden above stereo - once those are removed the panel that hold the stereo should pull out.  Is that the part of the console you mean?

And yes - Pictures for sure!

Rabin

[MGR550]

Hi Rabin,

This one is a black one, was on FB marketplace in Guelph a month or two ago, I grabbed it quick for a great deal.

WBO2 combo is a PLX Devices controller, which uses a Bosch LSU4.9 sensor. Pretty simple wiring and having the gauge will be a nice diagnostic addition.  

Good point on the injectors, I'll definitely pull them and give them a good clean and inspection. Know of a good source for the higher flowing ones or are they pretty generic?

Trying to avoid taking the whole intake manifold off to get at stuff, so fuel rail off would be good to get at the pressure reg and knock sensor anyways. 

I'll have to look up a how-to on the TPS reset. For timing, is that 8* at idle?

Overboost sensor seems to be working as when the wastegate was stuck closed, it did cut ignition properly. Boost gauge on dash goes up to just below half way mark under load, which I'm hoping is proper level? I'll have to see how it holds up when I get to properly driving it. 

And yes, I need to get in behind the stereo to wire up the O2 gauge, check the speaker wiring (aftermarket Alpine unit), and general electrical debugging stuff. 

Also, manual says 10W40 for gearbox oil, is that right? My other cars its usually like 80W90 or something heavier. 

 

Thanks,

Matt

[Jayden M]

As Rabin said getting the injectors ultrasonic cleaned would probably help. I'v gone through a similar situation, and i'v seen the engine go from running rough/shaky to smooth just by ultrasonic clean on the injectors. I'd clean the cold start injector if you do clean the other 4 as i'v seen them leak fuel while not powered.

That accordion hose to the Turbo cracks very easy, it is very likely to crack just from you taking it off.

If the car sat for awhile with gasoline from 2005+, then I would check if the primer pump in the tank works - They commonly fail from sitting and can actually block/restrict fuel flow if they are not working(main fuel pump will probably make weird noises if so).  However 1987 may have been the year with no primer pump... cant remember.

[Bean]

Ah yes - I think I reached out to the owner of that one as well, but he didn’t answer any of my questions and wouldn’t send me any detailed pics I asked for…. Hope it checked out in person!

TPS reset should come up if you search site, or in the tech resources.

It’s a little bit of a dance to make sure idle is at proper rpm, tps is in spec, and timing at idle is at 8 degrees, but critical for them to run nice.

Injectors - Probably best to clean the stock ones and get it running perfect in stock configuration first.  Stock ECU is ancient tech, so if you like the car the first thing I’d do is plan for an aftermarket ECU, and then you can run properly sized injectors with a proper boost controller.  I would recommend highly that you don’t mod it very much with stock ecu.

Motor oil is the correct spec, but I run Redline 75W90NS oil in my manual trans and diffs.  Works great.

Make sure to lube the torque tube Center bearing as well - should find a grease zerk in the middle of it.  10-15 pumps of grease minimum.

Fuel rail should come out without removing the intake manifold as well.  I’ve done it….

Rabin

[MGR550]

Good news; despite my lack of indoor work space and the snow this weekend I got a good bit done!

4x injectors removed, ultrasonic cleaned, and verified spray patterns are neat and identical, new pressure reg fitted, new vacuum/pressure lines on (old ones snapped like uncooked spaghetti), headlights leveled (the little adjustment post had fallen off the nut, which I'm assuming is a little more broken than it should be), got the old O2 sensor out and new one in, wiring for the WBO2 controller through the firewall but not wired in yet, and some LED bulbs all around. 

Still lots to do and I'll have to get at the other stuff from the bottom side whenever I free up some driveway/garage space to lift it up and get at from underneath. Also figured I'd leave the accordion pipe alone. Left the input to the fuel rail off so I can purge what's left in the tank and verify the pump isn't too starved by an upstream blockage or primer pump fault. 

Photos incoming as soon as its back together presentably and I get that WBO2 gauge installed; thinking in that little cubby right above the cigarette lighter on the center console, though the thought of cutting into the console panel has got me worried to crack it, worst case I have access to a 3D printer.

How do you get into the rear window brake light to change the bulb? Also what is that diaphragm on top of the valve cover connected to the throttle for?

Thanks,

Matt

[Bean]

The rear light is screwed to parcel shelf from inside trunk I believe?  Last one removed was many years ago so foggy on that one!

Diaphragm is for cruise control. 

I like the idea of relocating the switches to the cubby, and then gauges where the switches (and clock) were.  Pretty sure @d00zer did that in his car…

Rabin
 

[MGR550]

So I got it mostly back together and running again, very happy about that!

Main issue now is WBO2 gauge is showing super lean around idle ~19+, but shows a normal 13-ish at about 2500 rpm, so trying to figure that out now... I haven't done the TPS reset yet, but I'm trying to think of other areas that might cause the lean idle (or erroneous lean reading). Weak fuel supply? Air leak somewhere? 

Also knock light is flashing once its warmed up a bit, but I'm assuming the two issues are likely related.

Getting closer to it being back on the road and drivable again.

Matt

[MGR550]

Did some more testing and stuff this morning and got more diagnostic info:

WBO2 output to the gauge seems accurate with how the engine sounds and exhaust smells and stuff, so I think I can trust it's reading.

Narrowband output from the controller to the old NBO2 lead seems accurate as well (0V at very lean, 0.5 V-ish around gauge AFR of 14)

Idle starts off ok at AFR 14-ish, but gradually increases to very lean values over about a minute or so and the engine misfires every now and then.

Increasing the rpms slowly to 1000-1200 makes it run much nicer; WBO2 reading around 14. Any higher than that and it gets super rich (black smoke, stumbling, etc).

I had the aux air valve out and it had a rectangular-ish thru hole in the plate at rest (should this be closed fully without any power to it?), and I could swing the spring loaded plate out of the way without sticking. Electrical connector had 30 ohm across.

From what I can gather, order of operations is: adjust air bypass screw (not sure which direction), then main throttle plate idle adjustment, microswitch, TPS, ignition timing

[MGR550]

Found (at least one of) the source(s) of my problems! Leaky intake manifold gasket! #4 cyl right in the back corner, I thought it was just some noise from hvac fan or cruise control diaphragm, but sprayed a bit of fuel in the area and the idle picked right up and sounded way better. Wiggled a finger in there and voila, intake leak confirmed.

Now the question: is the gasket available or do I just buy some raw material and cut it out myself? Anything specific on the material?

[Bean]

It’s just a paper gasket - not really that complex to cut out so I’d just use hood gasket material and cut it yourself.

The running rich at higher RPM’s doesn’t sound related to that however - you might want to put a fuel pressure gauge on it as it seems odd that it would be running rich unless the FPR wasn’t working properly maybe?

There won’t be much boost at all without load, so not sure what would be up with that…. Maybe VAF is out of spec?

Rabin

[MGR550]

Hello again and happy holidays! I got a nice Peugeot pepper grinder for christmas 

Good news and bad news as usual on the car front lol. Intake manifold is off and back on again with a new gasket, 5th injector is cleaned, and mating faces for knock sensor cleaned; all is back together and it starts! Woohoo! 

Bad news time is it really doesn't run nice.. super rich all over, doesn't respond to throttle input pretty much at all. Only way I can get it to respond and run decent is if I move the throttle plate by hand and keep the little idle microswitch closed (as if the throttle were closed). I suspect I may have bumped the tps on the throttle body when removing and cleaning the manifold. Any other ideas?

Matt

[MGR550]

So when I disconnect the main 4 injector electrical plug and start it, it starts for about a second then dies, so I'm assuming thats the cold start injector doing its thing and all is good there. Probed the test lead by the airbox and got 7.4V at its current low & lumpy idle rpm. Backed out the air bypass screw on the throttle body and that seemed to help the idle a tiny bit but not much. 

Is there a temperature control feedback that would make it run rich and maybe one of the thermocouple probes is dead?

Other than that all I can think of points to TPS, but I never loosened off the bolts any. Same with ignition timing potentially but I haven't touched that yet either and both seemed to be ok before taking the manifold off. 

[Bean]

The TPS adjustment procedure is critical.  And you have to make sure no one used the throttle stop switch screw as the idle adjuster - that screw is only meant to close the switch and that’s it.

I wouldn’t take of the before settings as valid as they may have been messed with to compensate for vacuum leak.  Recheck and verify everything would be my advice.

[MGR550]

Bit of a long one haha so apologies in advance. I'm tempted to just get an aftermarket ecu at this point and avoid the headache but I'm going to chip at it a while longer first because I'm stubborn.

Did the TPS reset, still the same. Tried biasing the TPS to be more lean, no benefit, which seemed odd. TPS reset specifies with 'closed throttle', meaning as if it were at idle, or idle screw backed out all the way so the throttle plate is actually all the way shut?

Then changed the spark plug wires back to the old ones, gained back some throttle response, but still super rich and unhappy. Does it require anything specific for plug wires?

Turbo boost gauge on dash cluster doesn't go all the way to the bottom, so maybe a vacuum leak in that circuit? I see in the manual reference to a 'full load enrichment switch' and similar pneumatic operated switches which raised red flags given the symptoms, but can't seem to find them as pictured.  My 2 vacuum ports on the top of the manifold go to fuel pressure reg and the other tee-s off going to a hockey-puck-esque cylinder beside the charcoal(?) canister, and to a little mystery pod below the air filter box. 

Also re-soldered some frayed wiring on the injector resistor bundle and to the coolant temp sensor. 

Still revs up nice and sounds fine if I open the throttle but hold closed the little idle switch, so I don't think its ignition related based on that. Quite confused but feels like I'm slowly narrowing in on the solution. 

[MGR550]

Alrighty, back with more weird symptoms lol, this one seems to tie some stuff together. 

I could fully remove 2 of the spark plug wires from the distributor cap and there is no difference to how the engine runs. The other 2 clearly make it barely run if I remove them singly, especially so considering it seems its only on 2 cylinders anyways. Tried swapping the 2 dud cylinder wires on the cap thinking I had the firing order wrong but no difference. Holding the wires near, but not plugged in to, the nubs on the cap still allows the spark to jump the gap, so its at least trying to fire. This also explains the poor throttle response, super rich exhaust (as long as the 2 dud cylinder's injectors are firing, which it makes sense that they would be). Theres no way I have more than 2 of the wires wrong with how it runs when testing those.

I took the plugs out to clean them, were very fouled up, cleaned then put them back in, double checked the firing order (1-3-2-4; 1 at the flywheel) and it definitely ran better and had much better throttle response. AFR still showed pretty rich (11-ish) and it started to run worse till it was back running poorly like before. 

Perhaps weak spark (maybe from the old plug wires, or wrong plugs? currently have bosch 6737) combined with slightly too rich (maybe from a air leak which is also causing the boost gauge to not go to the bottom) making the plugs fowl up and making it run even worse then? 

I'm still suspicious of the various load/pressure sensing things in the technical description manual that I can't seem to find in my engine bay. Anyone able to send me a pic of their vacuum line routing and stuff? 

[SRDT]

Try to swap the injectors, bad injectors can flow too little but also too much.

[MGR550]

WOOHOO! Took the fuel system apart again and cleaned EVERYTHING, ran the injectors through the ultrasonic cleaner a handful of times and gave them a thorough clean, put it all pack together and she started right up, nice clean afr, idles amazing, great throttle response, all is well!

I promised a pic once I got it all back together so here she is!

Thanks a bunch for the advice, still some more of the minor polishing I had initially intended, but I'm very excited to drive this again finally! 

[Jayden M]

Congratulations!     Glad to see another turbo driving again.

Its amazing how that old gas can clog up fuel system components.

[MGR550]

Got it warmed up today, still had the knock warning light coming on, esp when coming on boost so I didn't push it. Going to try messing with the plugs/wires/timing again now that the injector problem is solved.

I still can't find the 'advance map selection' and 'full load pressure switch' as shown in the technical description manual, I drew out a little pic of where my vacuum lines go. There is another pneumatic block thing kinda underneath the coolant expansion bottle and the battery tray which has a handful of lines and an electrical connector going to it. One of the two pneumatic line barbs on the bottom is just open to air at the moment. 

I can't see any electrical connectors that aren't plugged in to anything, so they may just be in a different spot? 

[Bean]

Congrats!  Nice to know you have the issue figured. 

Make sure the vacuum advance on distrubutor is working, idle set, timing set, and TPS is setup as well - these are all very important.

If the port that is open to air is pulling a vacuum at idle then plug it, if there's no vacuum then it should be fine open to air.

Rabin

[MGR550]

Maybe a dumb question but how would I check the vacuum advance on the distributor? just unplugging the pressure sensor on the manifold? or the vacuum lines?

TPS is set as per procedure at 'closed throttle' being idle level throttle?

Also for setting timing, I see the marks on the block and the french N9TE manual I found shows it as a 4* per increment gradation, but on the crank pulley its kinda hard to tell what the mark is. Is it just the tiny little square chamfer cutouts on the edge? And should anything be unplugged while setting the timing?

 

also the french manual doesnt show either of the 2 pressure signal sensors that I had circled in the above pic, so maybe just a different version.

[Bean]

The vacuum advance diaphragm should hold a vacuum, and if you have a vacuum source you should be able to change the timing which ensures the advance mechanism is working.

Timing marks - I just put the light on and it’s usually obvious which mark to use.  I believe you want it at 8 degrees.

TPS is set with ignition on but not running I think, throttle closed.

Rabin

[SRDT]

There is more than one ignition setup on the 505 Turbo engine.

I think the first one just had a knock detection module. Later they added fixed advance on the distributor and two advance curves inside another module with a pressure switch to choose between the two.

The last US models had a Bosch EZK ignition ECU like many Volvos and other turbo cars.

[MGR550]

Ahh ok that makes a lot more sense! The French manual I had found is missing a few key pages here and there, but I think I can get most of the info I need from it and the English one with the different ignition setup.  

I did the ignition timing - idle speed - TPS setting roulette and seems to have had a positive effect! Swapped back to the new spark plugs, and to some other electronic ignition plug wires I had from another project. Re-cleaned the knock sensor mating faces and torqued it to spec.

Anyways, I took it out for a test drive today and it went really well overall! good throttle response, idle stability, AFR, gave it the beans a little and it pulled strong. Wasnt much heat form the hvac so I'll probably have to do a bleed on the coolant. 

The knock light issue is still there though... Once its warmed up, it flashes pretty consistently so I still need to chase that down somehow. Other than the knock issue, up next is oil changes/ greasing of the driveline components and finally that new power steering pump.