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Back in April I purchased a MY85 hasn't been started since 2011. Over the past few weeks we performed numerous maintenance upgrades, TB, cam pullies, water pump and pulley, fuel pump and filter etc. It now starts and ides fine holding steady at 1000 RPMs, but just over 1100 in shutters. We did unplug the MAF and no change in how the car idles or runs. I am getting ready to purchase a vacuum line kit and replace all the lines. Haven't done anything else with the fuel regulator or dampers thus far. Is this a symptoms of a bad LH, MAF or do you have any recommendation on what to test or try next?
As Stan said injectors get clogged from sitting and old gas and that is a symptom (trouble when pushing gas through eg. accelerating). You might try pouring some treatment in and jumper fuel pump and let it circulate for several minutes. Change fuel filter. Refill gas. May help some or a lot, but won’t replace good new or professionally cleaned injectors.
Also check fuel pressure when running. Similar symptoms if low.
I haven't cleaned the injectors as that's on the list of net troubleshooting steps. I do think we may have an under pressured fuel system. We did replace the pump and filter but when we remove the test port on the passenger side fuel rail it just drips out. Are there any ways to test the pressure regulator? I ordered a pressure test gauge for Bosch so that's also on the to do list.
The fuel tank was completely draining when we picked up the car. I did pull to plugs and noticed some varnish. We did add three gallons for new gas but didn't add any injector cleaner to the fuel. I will also add a bottle when we add more gas.
So I was back at troubleshooting my 1985 S3. Just for clarity the previous owner told us the engine is from a 86. This past weekend after receiving a refurbished MAF and some other parts from Roger @ 928RUS and other sources. After we installed the MAF, new fuel regulator, new air temp sensor and reconnected the airbox, etc. She started right up and idled around 700.rpms, previously 1000 rpms. I left it run, reeving the engine consistently past 2000 rpms for the first time without any hesitation. I then proceeded to driving it down the long driveway and back a little over a 1/4 mile without issue. We left it sit for a minutes or two and then attempted to drive it again, This time it hesitated like in the past at 1200+ rpms and when I increased the throttle it backfired once.
So we turned it off and started the process of removing the fuel rails and injectors since I have an injection tester/cleaner. Like I posted in another thread all but three had pretty consistent spray patterns and volume with 2 slightly more and one displaying more of a jet than the spray and 20% more volume.. So now were somewhat back to the drawling board and with all the manifold pieces removed decided to also dive into testing some of the vacuum lines and connections. Replacing a few as we go. While were dissembled I also decided to address a small cam cover leak and removed both of them as well. I decided to send all CAM covers and intake pieces to be blasted and powder coated. Probably looking at too many things at once, but its too late now.
So below I've listed where we're at with a few key parts.
Injectors - I ordered a set of KSM injectors for another forum member. They've been tested so we'll see if that helps our acceleration issue.
Dampers - We tested the rear right, won't hold a vacuum. I need to check the front but since the car sat without fuel for 12 years, I'm assuming both bladders are hard and not doing anything. So I'm replacing them with Radium so save some dollars to put to other parts with Bosch being overpriced.
O2 senor - added to 928RUS cart - replacing that since it's original 38 year old part
Timing check - ordering a Porken timing tool just to be sure timing isn't affecting things during accelerations.
Throttle Position Sensor - I can hear a click when I move the throttle lever slightly. I'd like some opinions on how to troubleshoot that part more thoroughly or should be I just be replaced since I'm in there?
Idle Air Stabilizer - needs tested but if it's idling at 700 rpms can I assume it's fine, and testing suggestions appreciated.
Also looking at replacing a few hoses, oil filter neck gasket, etc. while things are apart.
If anyone has any troubleshooting suggestions or other items I should address while things are apart please let me know.,
John
I've attached a few pictures maybe help with identifying parts that aren't right, etc.. Also the previous owner stated the newer engine (86?) has only around 3K. After removing the CAM covers the cams don't not bad IMO, no sludge, etc. but I highly doubt 3K. Thoughts?
you should remove the water bridge and have it grit blasted,
wipe it with kerosene and put it back on.
NOTE the paint or PC on the WB can cause grounding issues with the temp sensors
replace the TPS short harness and the crank position sensor Roger has them
NOTE both of the connectors on these parts will crumble.
NOTE on the fuel lines that look like metal lines, if they are metal ,
make sure they dont rub on anything as they will quickly saw through any part that they touch.
NOTE in the first picture you should inspect and or replace the white 3 way junction,
as it looks like a generic part.
the factory part has a restriction in it to limit the amount of fuel vapors that can be sent to the intake.
you cant tell unless you look inside the lines.
Also consider replacing the ignition wires
Too late now, but troubleshoot one thing at a time for best results. Laser instead of shotgun. Once you get all of that back together, hopefully correctly, how will you pinpoint what caused the problem(s)?
Thanks MrMerlin for reminding me about the crank position sensor., I do want to swap that out with everything out. I do have a new TPS cable in my cart. I still need to figurer out how to test my current TPS since there are few cheaper option outside of $275 new one from Roger,
Agreed probably not the best way to troubleshoot, but I didn't want to take things back apart 2-3 times especially manifolds, etc. So that's why we decided to go more all in and swap a few more parts for new to rule out any individual part contributing to our power issues above 2000K.
NOTE for the TPS ,you should remove the throttle body and replace the shaft bearings,
the new bearings have 2 O ring seals instead of the original single side,
these single side O rings are now hard as a rock and will leak oil.
NOTE Your current TPS is also full of oil,
so dont replace it ,
unless you replace the bearings.
NOTE for the TPS ,you should remove the throttle body and replace the shaft bearings,
the new bearings have 2 O ring seals instead of the original single side,
these single side O rings are now hard as a rock and will leak oil.
NOTE Your current TPS is also full of oil,
so dont replace it ,
unless you replace the bearings.
MrMerlin, The throttle body did have a little oil residue in it when removed. I'm looking at 928RUS and am not seeing shaft bearing listed as a part available. I'm assuming were talking about this part shown below. Not sure where the shaft bear is, unless inside. I am orders new hoses and will add the TPS to my list. John
depami, thanks for the doc. I'll just order a new senor with the other parts... I'm glad I got the car for under $5K...parts have been adding up quickly.
05-30-2023, 07:53 AM
MY85 Troubleshooting help
