Journal for my M491

[oh snap]

I bought my car in 2011 in California and brought it up to Canada. Highlights in the post I made here Introduction: 1985 Iris Blue M491 911

Shortly after buying the car I changed jobs, started a family and then moved to Japan. The car remained in Canada for 2 years after I left, driven a couple of times a year when I returned home. I didn't like the idea of letting the car sit and while selling it crossed my mind, I knew I would regret it. So, we finally decided to bring the car to Japan.

The car at port.



It took me a couple of months to get organized and get it to pass emissions and registration processes. Finally back on the road when early this year.


The car now has 102,000 miles and a good list of things that need attention. My plan is to whittle away at them as time and money permit, do it myself whenever possible and keep track of what I’ve done and need to do with this thread. It will give me a place to think out loud and ask stupid questions. Suggestions, feedback and criticism are all welcome.

I picked off the low hanging fruit with a change of transmission fluid, engine oil, valve adjustment and oil/air filters. Then I fixed the grinding sound coming from the steering wheel by cleaning and greasing the horn button contact, and deleted the disintegrating engine sound deadening pad. Still need to clean it up a bit. Soon I should have some re-manufactured injectors arriving which I hope will fix my hunting idle. The CHT, O2 and ICV are all new so if the injectors don’t do it I’ll try to find a vacuum leak. I also have a small hole in one CV Boot and 4 replacements so the plan is to clean and grease all joints as soon as new Schnorr washers arrive.

[oh snap]

My most immediate problem is an intermittent hot start issue which is sometimes causing my starter to grind against the ring gear.


When the car is hot it will often not start right away. It doesn't sit cranking but it will click once like a dead battery. I wait for 10 or seconds and try again, sometimes it will start right up, and sometimes it will take 2 or 3 tries. Half the time when it hot starts it will make a grinding noise which others have said is probably the starter grinding on the ring gear. I dont want to have to replace the ring gear so this is my priority.


When the car was in Canada it was getting weak to start. I attributed this to an aging battery in a car that was sitting. When it arrived here my mechanic said both the starter and the battery should be replaced. I replaced the starter with a Bosch sr68x and bought was a smaller 35ah 12v battery. I used post shims as the posts are the smaller round size and replaced the short negative cable with a slightly longer OEM Mercedes-Benz cable. I cleaned all the terminals with sand paper and applied dielectric grease. I thought the shims might be a problem but I get 0.1mv drop on the negative. I tested the positive as well but I did it from the terminal and not the post so I will check it again properly later.

Last weekend I got under the car and thoroughly cleaned transmission to body ground cable. Then I inspected the starter and I found that the yellow wire was extended ~3 cm and the connection at the starter isn't all that snug. Hopefully this is the problem. I want to test this wire for continuity but I couldn't get the ignition switch out. I read a post describing a way to twist them out with a sharp pick so I will give that a try tonight. What else should I be testing here? Positive battery post to yellow wire at starter when cranking? It looks like the wire is extended with a crimp connector. Do you think its worth soldering a new wire in instead? I imagine replacing the entire wire is best be not doable without tearing a lot of stuff apart.

The basic readings from my multimeter:
12.6v at the battery with everything off.
When starting the car voltage at the battery drops somewhere into 9V. Everything I read says it should not go below 10. Does this indicate a bad battery or could it be from a loose connection?
When I turn the key to the last position before it starts the engine the Volts drop off about 0.1v per 20-30 seconds. Then around 12.35 it starts the drop starts to slow down and it holds.
with the car running i get 14.6 @ 2000 rpm. Around 14.35 at idle.

Thanks for any suggestions, will update again later tonight.

[Chuck.H]

Why are you using a smaller battery? Seems like a good place to lose weight if you're at the track, not so much if you want rock-solid reliability in a daily driver.

Nice looking car!
Chuck.H
'89 TurboLookTarga, 392k miles and often thousands of miles from home

[javadog]

Sounds like a a bad battery.

JR

[oh snap]

When I was looking for a battery I thought save some money and save some weight. Guess I got caught up in the Poorman's lightweight battery thread... So, if its dipping below 10v at start up is there 100% a battery problem or would another factor cause it to do that? I only ask because it seems to have the most problems when the car is up to temp and then stopped for a few minutes. ie fill up for gas, pop into a convenience store etc.

Here is a picture of the extended wire.


It was quite loose. Maybe the female terminal is too large for the male end on the starter. I crimped it down with some pliers a little and it is more snug now, Ill see how that goes. My test drive went well but its an intermittent problem so it might pop back up.

If <10V when cranked = buy a new battery I will order one tomorrow.

[oh snap]

I put the battery on a charger yesterday afternoon and then this morning it started fine with no noise. I drove it about 10-15min to a Japanese lesson. It sat for ~1.5h and made that grinding noise when starting. Drove it another 10-15 min to lunch and let it sit for about 30 min and it started right up with no noise. Drove it another 10min to pop into an electrical store (5min) and it started right up with no noise.

Its possible that its neither battery or heat related, though I wont rule out either. Sticky solenoid? Needs a shim? Has a shim and doesn't need it? I bought the Bosch because I read high torque starters sometimes have fitment problems, now I read a lot of people saying QC for reman Bosch is not great. I still have the original starter maybe I should try to rebuild that...

Tonight Ill swap the good battery from our other car and see if anything changes. Seems strange that it could not start once and then start normally after 30 seconds if it were because the battery though. But then I know very little about this stuff...

[oh snap]

I got the new injectors late last week and put them in after work on Friday night. I removed the AC Compressor when I did the valve adjust so the right side was easy. Left side is a pain but overall not such a hard job. Outlined nicely in this thread:Removing Fuel Injectors, 3.2
The o-rings didn’t want to press right in so I used a little motor oil on them, fit well after that.


Old ones were definitely a little ripe.

The injectors are from ebay and sold as “Standard FJ11 injectors.” The ebay auction calls them “new out of the box” but they are remanufactured. I expected as much as they were only $20 each. They are listed as compatible with the the Buick/Chrysler/BMW injectors as discussed in this thread: Alternative Fuel Injectors. Runs great but I will check the tune in the near future. It didn’t cure my hunting idle but I the car is much much smoother especially at low speeds. no more jerkiness or hesitation in parking lots.


The battery in our other car ended up being a different type so I never did swap it over. Ill try to find another to borrow temporarily. Going to remove the alternator and clean up the connections just to be safe. Any other grounds/connections to check?

This weekend is Porsche South Meet 2015. They expect about 100 cars. Ill take a bunch of pictures.