Big Al's Revenge: an OEM+, MTech1 325e restoration

[agent]

This is such a great thread. Looking forward to seeing you and the car in May!

[mike.bmw]

Well done! Will there be a photo shoot to commemorate stage 1?

Looking forward to stage 2!

[Secniv]

Well done on sorting idle.. strangely I was having same problem and after unplugging and re-plugging icv a few times to try figure if was working or not (had already cleaned it once) idle sorted itself!

Like you I need to figure out how to make sure it stays connected?


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[Albie325]

Good news and bad news:

Good news: I figured out the idle issue.

I started the afternoon by taking off the throttle body and readjusting the TPS. I had done it by feel the last time I installed it (basically had it so that I could feel the sensor click on just after opening the throttle). The harness was giving the appropriate voltage (5V) and the continuity between pins on the sensor was intact. I adjusted it the correct way according to the Bentley (continuity should stop with the throttle open between 0.2-0.6mm for pin 2 and at 10 degrees before WOT for pin 3). Didn't seem to be very different than where I had it, but I digress.

Checked a few more hoses, got the throttle body and air box back on, and bled the coolant system since maybe there was air in it messing with the sensors.

Started the car and still had the same idle as before. Unplugged and replugged the ICV harness a couple times, initially no change. Then I got pissed and really jammed the harness on as far as it would go and... she purred like a kitten. Well actually more like a sewing machine but you get the picture. I'll be damned. The ICV harness was just a little loose, I'll have to find a way to tighten it up so it doesn't wiggle it's way back off from engine vibration.

My nemesis:



The other good news: I learned a little more about the car and how to test some of the electrical components. Also, I took the car for a long spin around the neighborhood. The brakes felt much better without the car pulling under high idle, and the steering and suspension felt nice and tight (I was a little more liberal with the "wheeeee" factor now that I knew the engine was running right). I'm really liking the new steering with the ZHP rack, and the Bilstein B8/H&R Sports are more than comfortable enough for daily driving but handled well in some tighter turns.

The 3.25lsd definitely seems to have given acceleration some pep without keeping the rev's too high at speed. Ends up keeping the revs in a more responsive range, for sure one of the best upgrades for an Eta. Thanks again Agent, everything feels nice and smooth. Can't wait to see how it does with a 5 speed and the Conforti chip. And without the engine revving crazily I was better able to hear the exhaust note, nice and throaty with some feed back burbles when revving it up. Haven't noticed any drone at all but haven't been on the highway yet. Plan to take it to work tomorrow so we shall find out.

The bad news: I spent about $400 in likely needless money fixing a loose connector. At least now I know the ICV is brand new, and that the ICM solders are all also fresh.

Stage 1 of Big Al's revenge is officially complete!

Now that I have the car up and running for the first time in almost a year, I want to drive it around a bit and enjoy it again.

What I hope to accomplish for Stage 2 soon (hopefully by the end of the spring):

• Remove the comfort seats, carpet, and essentially all interior bits to check for any rust
• 5-speed swap and associated maintenance while the interior is already out
• Timing belt/water pump, camshaft seal replacement, and a new manual radiator and new hoses while the coolant system is drained
• Clean and redye the carpet and rear parcel tray
• Swap in my crack-free dash
• Clean out the IHKS and likely replace the heater core while the dash is out
• A/C system overhaul
• Fix a few of the black vinyl trim pieces where the vinyl has started to separate
• Reupholster the sport seats and swap them in
• Install my Continental head unit as well as the Premium Sound setup
• Install some houndstooth door cards
• Have a few other goodies, but don't wanna give it all away...

Stay tuned, and thanks for your comments and advice!

[rzerob]

rzerob Thanks for the help, will do.

Will hopefully have an update soon.

No problem. It is hard to diagnose a vehicle that you don't have in front of you. So take everybody's advice with a grain of salt. But everybody is just trying to help. I never mentioned the whole story with the bad coolant temp sensor. So here goes.

This guy comes into the shop with a complaint that his truck is accelerating on it's own some times other than that he says the truck is perfect. So I get this truck and take it for a test drive. It took a while before it started to do it but eventually it started acting up. And when I came to a stop I had to really hold the brakes down to keep it from going.

I didn't have much to go on but I noticed that the coolant gauge never really came up to temp. So I started there. Sure enough it was bad so I replaced that. Then I ran it to make sure it was working. While I was waiting for it to warm up I heard a light hiss coming from the engine. So I did a smoke test and found a tiny crack on one of the vacuum lines. It took a day to get the line but I replaced that too. And that is the story.

With the tiny bit of air from the vacuum leak and the tiny bit of fuel from the coolant temp reading cold it was enough to make it feel like the accelerator pedal was being pressed slightly. So I hope that helps. You should definitely do a smoke test too. There are some good cheap smoke testers on ebay. Good luck.

[Albie325]

rzerob Thanks for the help, will do.

Will hopefully have an update soon.

[rzerob]

12 is for your gauge. So we can rule that out.

13 is for you computer. If this was bad it could cause rich symptoms.

15 I believe this is your cold start switch. If this was bad and dumping fuel it could cause rich symptoms.

16 I believe this is your timing switch and I am not familiar with it.

Check your Bentley manual for proper way to test these 3 sensors.

[e30RS]

Impressive seriously.

[Albie325]

I had a car come in that was pushing the car when he did not have his foot on the gas. And it wound up being his coolant temp sensor. It was causing it to become rich enough that it was like lightly stepping on the accelerator pedal.

You have two of them on the M20. One for the gauge and one for the computer. If your gauge is reading correct temperature maybe your computer's sensor is bad and reading high. Or the wiring to the sensor is bad.

Hmm interesting. I've previously replaced sensors 12, 13, and 15 in the below pic as they were pretty reasonably priced and looked to be crumbling. Sensor 15 is actually NLA and is a 20Celsius (white top) temperature switch, I replaced it with part #12-63-1-279-719 which is a 0Ceslsius (purple top) switch. As a result, the car typically runs just to the colder side of midline on the temp guage and was running fine before this most recent project. I didn't replace sensor #16 as I had no indication it was bad (and it's expensive, ~$200):




Are these what you're talking about? Also, I did disconnect the coolant overflow tank and hose connected to the top of the radiator, but didn't re-bleed the coolant system, you think that would matter? Might be next on my list.

1. You need to smoke test instead of do the starter fluid method.
2. There is a test you can do on the TPS while on the bench to see if it's operating correctly. I'm unsure if the M1.0 TPS is the same PN as the M1.3 TPS. Additionally, you might have to verify your CPS is at the right distance from the flywheel. You will have slightly different symptoms than 80% of the other users because you have a M20b27, and everyone else has the later model M20b25.
3. When are you putting on those bumpers, I would love a detailed write up to help guide me during my euro bumper installation process.

Yes a smoke test is in my near future, once I can get a free day off work to do it. I'll look into the TPS as well, as for the CPS, I haven't messed with them at all so not sure why the distance would be off.

I probably won't be fitting the euros on until I'm getting ready to paint the car and MTech 1, not sure when that will be. I will definitely do a write up when I do it, until then here's a few links that I'll be referencing:

https://www.r3vlimited.com/board/showthread.php?t=112187&highlight=euro&t=112187&highlight=euro

There's a few threads within a thread as well.

[paynemw]

1. You need to smoke test instead of do the starter fluid method.
2. There is a test you can do on the TPS while on the bench to see if it's operating correctly. I'm unsure if the M1.0 TPS is the same PN as the M1.3 TPS. Additionally, you might have to verify your CPS is at the right distance from the flywheel. You will have slightly different symptoms than 80% of the other users because you have a M20b27, and everyone else has the later model M20b25.
3. When are you putting on those bumpers, I would love a detailed write up to help guide me during my euro bumper installation process.

[rzerob]

[*] While in drive (or reverse), the car seems to want to "pull" harder than usual, and I had to apply the brakes harder than expected to keep the car stopped.

I had a car come in that was pushing the car when he did not have his foot on the gas. And it wound up being his coolant temp sensor. It was causing it to become rich enough that it was like lightly stepping on the accelerator pedal.

You have two of them on the M20. One for the gauge and one for the computer. If your gauge is reading correct temperature maybe your computer's sensor is bad and reading high. Or the wiring to the sensor is bad.

[Albie325]

So I got the car running again last weekend and all the undercarriage stuff was buttoned up. I was having some surging idle between 1k-2k. Also once the car was warm, it wanted to idle right at 3K for awhile upon turning the car off and restarting, pretty high for an ETA. After warming up a bit, I had some smoking from the exhaust manifold that I was initially worried was an exhaust leak but ended up just being the VHT paint baking on. That has since stopped.

The surging idle didn't, however. I have been using these links as well as a bunch of R3V threads to try and root out the problem:

http://www.verrill.com/car/idle/e30_idleproblem.shtml

http://www.verrill.com/car/e30_idlefaq.shtml

Not related, but I had to replace the coolant level sensor since the old one fell apart when I swapped out the overflow tank:





Moving on to the idle problem, everything on the intake side was replaced within the last year, all hoses and gaskets, the injector O-rings, the whole lot. All fuel hoses, the fuel pump, the fuel filter, both in-line dampeners, all new. I've also cleaned the ICV once before and did it again just for good measure.

So moving through the usual suspects, I unplugged the ICV with the car running and surging, and it made no difference whatsoever to how the car ran. So I figure maybe the idle control module or idle control valve was the culprit. I bit the bullet and ordered both figuring they're both 30 years old anyway and will probably go NLA just when I need to order.

New (refurbed) ICM:





From my understanding, only the early model cars have this ICM, later models have the idle control integrated with the DME. The solder points are known for going bad, and it actually wasn't too crazy expensive to replace. It's located above the glove box, there's a plastic cover with 2 half-turn plastic lock nuts and two small Phillips head screws to remove, and there it is:







Only one screw holding it in place, really easy to remove.

To my surprise, it looks like this was already replaced at some point based on the stickers:





Swapping in the new one seemed to help the idle a little, but not a lot. So then I swapped in the new ICV:





Definitely looks cleaner:



Unfortunately, this didn't help either.

Bummed, I took the car out for a drive just to see if maybe that would clear things out a bit. Aside from the idle, it ran pretty good and the suspension, steering, and brakes (after bedding in) all felt great. They were maybe a little soft and I might bleed them once more. I stopped to fill up the gas tank (and put in some LiquiMoly JecTron in the tank) and a guy came running out to ask me about the car. Ol' girl still got it.

I also felt she was worthy of a well-deserved bath, she was FILTHY:



Not the best pic, but here's the new ride height with the Bilstein B8's and H&R sports:





Unfortunately I don't have a great pre- pic for comparison.

Looks great, except it's running like poop.

The car hadn't run in almost a year, but everything had been replaced and was running fine with no idle issues prior to shutting it down. I have triple checked that all the hoses are tightened down. I re-tightened all of the valve cover studs, the gasket was also replaced within the last year. I checked the oil dipstick and the oil filler cap. I have sprayed enough starter fluid around the engine bay to blow the car up several times over. I can't find a leak, but all symptoms seem to point to unmetered air getting in somewhere.

Other symptoms:

• Putting the car in drive steadies the idle and drops it to a steady 1k, however when it's running right it's usually at 700 rpm.
• While in drive (or reverse), the car seems to want to "pull" harder than usual, and I had to apply the brakes harder than expected to keep the car stopped. I thought maybe this had to do with the new 3.25 diff gearing but I think if the idle was normal this wouldn't happen.
• With the car in park, revving the engine elicits a "hyperdynamic" response. The engine rev's way higher and stays up longer than what I would expect for the amount of throttle supplied

Could it be the TPS or crank position sensors? Would an exhaust leak cause this? Or a new O2 sensor? Any other suggestions???? I'm at my wit's end. Would really appreciate some input.

[jeenyus]

great work mah guy. the soldering kit you got was one i was looking at for a while, but decided to purchase another one for about the same cost. Temp control is so crucial for soldering.

[Albie325]

I love the Motive power bleeder man, makes super quick work of it.

I appreciate the wiring write-up, I can begin to diagnose my ABS module with that.

Ya the power bleeder was great, the link I posted has another link in it that goes into way more detail than I did for inquiring minds

The whole bleeding the ABS thing is probably unnecessary especially if you're only changing calipers or doing a fluid flush since there should still technically be residual fluid in the system. Since every component of my brake system (MC, hard and soft lines, calipers) was replaced and I directly compressed air into the pump, I wanted to be sure as much air was out as possible. It was easy enough to do and didn't require much in the way of disassembly or tools so I figured what the hell. I definitely noticed more air getting pushed through once I got the ABS pump to run.

[Melon]

I didn't cycle the ABS module and my brakes bled fine.
(Admittedly it has never worked since I got the car, and am working on that.)
I love the Motive power bleeder man, makes super quick work of it.

I appreciate the wiring write-up, I can begin to diagnose my ABS module with that.