Car too weak to redline in 1st, but idles fine. Wtf?

[Earendil]

Pulled the voltage regulator tonight. I'm really not sure how it was operational with that regulator... It was so shot.
New one comes Friday, along with the vacuum gauge. More to come Friday!

[Earendil]

There are different alternators. There's the Bosch with the voltage regulator right there on the back, easy as pie. Then there's the Valeo that you have to open up to get the regulator out, which may be what's on there.

Thanks! I looked up pictures of the Valeo unit and I'm positive that's what's in his car. We'll end up replacing the regulator, even if it isn't the root cause, there really is no point in risking losing an alternator in the kinds of places the ix gets its self into this time of year ;)

Sorry to bring up the possibility of the cam again, but did you feel the cam lobes when you checked it out? Also did you very closely inspect the nose of the lobes? The nose is the smaller (a.k.a. lift) side of the lobe. I ask because in the case I saw that has the exact same symptoms you describe (minus the voltage stuff) the nose of the cam was worn down enough to cause the valves to not open as far as they should. They were also open for less duration. His car would not rev past about 4k in any gear.

No problem bring it up again. I did not check think to check how worn the lobes were when I had the valve cover off, I was mostly looking for broken pieces, or out of place pieces. The car was running fine one day, and the next the power curve tanked. Without knowing from experience how lobes fail, sudden changes in the power do not seem likely with lobe wear? Also, wouldn't basically all 6 or close to all 6 cylinders have to wear down quickly all at the same time? Even if two cylinder was experiencing a problem it wouldn't prevent the car from reaching red line, right?

[603Racing]

There are different alternators. There's the Bosch with the voltage regulator right there on the back, easy as pie. Then there's the Valeo that you have to open up to get the regulator out, which may be what's on there.

Sorry to bring up the possibility of the cam again, but did you feel the cam lobes when you checked it out? Also did you very closely inspect the nose of the lobes? The nose is the smaller (a.k.a. lift) side of the lobe. I ask because in the case I saw that has the exact same symptoms you describe (minus the voltage stuff) the nose of the cam was worn down enough to cause the valves to not open as far as they should. They were also open for less duration. His car would not rev past about 4k in any gear.

I hope it's just the voltage regulator! Keep on keepin' on, you have to be close to the solution!

[Earendil]

^That would work just fine.

It'd kill me to see you give up at this point dude! You're doing it right.

Thanks for the vote of confidence. I went ahead and ordered that gauge. It's cheap enough that if it's a throw away gauge, I'll just have some rather expensive rubber tubing.

I've managed to find hidden vacuum leaks quickly and cheaply by taking a car to my local DIY car wash using the water wand to mist the engine with low (low!) pressure.

The last time I sprayed an engine compartment I was like 12, and when cleaning my Dad's car by myself I decided his engine compartment was dirty too. Now ask me how I know what an M20 running on 2 cylinders sounds like ;-)

Oh, and when you did the compression test did the plugs look like you have a lean running condition?

The plugs all looked very similar, and looked somewhere between lean and normal. The dramatic power loss has only been in affect for 30 miles if that.

New clue, that I had suspected:
Last night my friend decided to try and get it from his work (where I've been working on it) to his house. I followed him to keep an eye on it. I watched as he floored 2nd gear trying to make it up a hill, and I tailed him at varying distances. No smell of gas. No smell of anything. No water/oil vapor/smoke. I'm leaning more and more towards vacuum leak or injector malfunction of some kind. The plugs don't look rich, and there is fuel coming out the exhaust.

After making my posts last night, I got too excited and drove out to the car to see about the voltage regulator. I had half a mind to toss the regulator from my car into his just to see what would happen, since I can pull my regulator in probably 2 minutes. I take a look at his Alternator and it has a back cover and no exposed regulator. @#$%. The only thing I can read on it says "Made in France". I couldn't see a brand. Looks like I may have to remove the entire alternator just to figure out what I'm up against here.

I took it for a test drive with the help of my brother. The voltage at idle was 15v, and while driving it varied from 14.55 to 14.9. No as dramatic and mind blowing as I was hoping.

I also checked out his very good looking engine ground strap. I cleaned it up anyway, but that had no effect.

I'd be so very happy if the Vacuum gauge shows me something conclusive one way or the other...

[Ryann]

While on the subject of vacuum gauges, what are the chances that a gauge like this would give me any kind of useful results?

^That would work just fine.

It'd kill me to see you give up at this point dude! You're doing it right.

I've managed to find hidden vacuum leaks quickly and cheaply by taking a car to my local DIY car wash using the water wand to mist the engine with low (low!) pressure.

Oh, and when you did the compression test did the plugs look like you have a lean running condition?

[Earendil]

I sort of assumed it was "Gremlins", but I've spent the last 15 minutes reading up on voltage regulator problems, and high voltage (not just low) is a symptom! Now there is a repair I know how to do! :)

Now about "checking the timing". The only way I know how to do this is to check the TDC marks on the crank and cam shafts, and that isn't a half hour job if I recall. Is there an alternate way?

And smoke tests... That'll be purely in the realm of a mechanic with the equipment.

[jlevie]

The system voltage at idle (way too high) and the flickering lights suggest a bad voltage regulator.

Several small intake leaks scattered around the engine can add up to a major leak. Small leaks, especially those distant from the head, may escape detection by a visual check or by spraying carb cleaner around. But a smoke test of the intake & crank case will find them every time.

It takes maybe a half hour, at most, to check cam timing. That and the smoke test should be the number two and three priorities with the alternator being number one. Excessively high system voltage can damage the car's electronics.

[Earendil]

For my own sanity and for those that don't want to read through my long posts, here is the short list of good components. If someone wants to know how I know it's good, they can read above.

Known Good components/passed tests

• Airbox/Filter
• AFM
• Fuel filter & pump (Fuel pressure is great at idle and at speed)
• TPS
• Spark Plugs
• Plug Wires
• Coil
• ECU
• Coolant Temp Sensor
• Compression test good

Good newer components, but unchecked.

• Exhaust system. From exhaust manifold is only 3 years old, including cat.
• New within the last 9 months: Intake boot, Throttle body to intake manifold gasket, Valve cover to TB hose, line to FPR, and valve cover gasket.

Out of all of this, I have only found a couple suspect issues, but I don't think they could cause this issue?

• Operating Voltage at idle is 15v (14.5 is spec). I'll have create a hack to test the operating voltage while driving.
• Looks like a small coolant leak into the TB

Left to check before I give up and have a mechanic do things only they can do, or are willing to do.

• Ground Points
• Harmonic Balancer and toothed gear are okay (I read if they start to separate that they will give bad readings at high RPM to the crank position sensor).
• System Voltage during operation (driving)
• Vacuum test (if people think a cheap gauge is worth anything).

Last but not least, if I were a betting man I suppose I would place money on it being one of the following:

• Giant vacuum leak
• Multiple clogged injectors
• Cap and Rotor (which I can't check, see previous post)
• Electrical Gremlins preventing a good spark
• Timing belt having jumped a tooth

[Earendil]

Try swapping ignition coils

I had similar symptoms and it ended up being the coil

Its worth a try

Sent from my Vortex using Tapatalk

Thanks for the thought. I put his coil AND plugs in my beautifully running E30, and my E30 might have even run a little bit better with his stuff. So I'm ruling those two components out.

[SpecM]

Try swapping ignition coils

I had similar symptoms and it ended up being the coil

Its worth a try

Sent from my Vortex using Tapatalk

[Earendil]

You guys are funny with your, "heavy ass ix," comments.

Aren't I? :)

He has other bits on it that make it a bit heavier still. And my 325i is a stripped out track car, which doesn't help my perception ;-)

I had a plugged cat make the car loose a ton of power. Then it blew a whole in the cat (it actually swelled and exploded while red hot). Difficult to check though (plug the exhaust at the tailpipes and see what happens, but you have a leak already so might not do anything).

Another thing to check is the AFM, mainly the internal sliding mechanism, where it makes contact with the board.

Well, the CAT could be wrecked I suppose. But it's only 3 years old, so if the engine was running okay, it shouldn't have torn its self up in such a short period of time.

Also, the exhaust leak is now fixed.

As for the AFM, I stuck his AFM and airbox in my car and it functions just fine, so I've eliminated the airbox.

Maybe I'll blast the fuel rail where the injectors are with carb cleaner and see if that doesn't make it through the seals. I suppose if every last injector was dumping a bunch of air into each cylinder that could cause this issue, right?

[Axxe]

I had a plugged cat make the car loose a ton of power. Then it blew a whole in the cat (it actually swelled and exploded while red hot). Difficult to check though (plug the exhaust at the tailpipes and see what happens, but you have a leak already so might not do anything).

Another thing to check is the AFM, mainly the internal sliding mechanism, where it makes contact with the board.

[325ix]

You guys are funny with your, "heavy ass ix," comments.

[Earendil]

While on the subject of vacuum gauges, what are the chances that a gauge like this would give me any kind of useful results?

Any reason these cheap gauges say they are for carbureted engines? Isn't a vacuum a vacuum? Seems like anything that'll read 0-25 in/Hg will work just fine for the M20.
(FYI: Bentley says normal is 15-22)

[Earendil]

Update:

1. I put his plug wires and his coil into my car, and my car pulled really strong with them.
   
2. Tossed a spare ECU into his car, and that also didn't return any of the power.
   
3. Pulled each plug wire one at a time with the engine running. With each plug there was a drop in RPM, with a quick recovery. And when plugging it back in there was a small increase in RPM, with a quick recovery. I take this to mean that each cylinder is doing something. No Cylinder was worse than another.

I think I'm down to the following items:

1. Injectors: Extremely plugged? A bank of them haven't failed I don't think, due to the plug pull test.
   
2. Massive vacuum leak. It's not coming from the boot, valve cover, FPR hose, or throttle body. Many other places it could be though.
   
3. Timing belt skipped a tooth... or two.
   
4. Cap and rotor. I wasn't able to visually inspect this one. The bottom bolt has been sunk so deep into the plastic that I can't get a socket to grab it. The Radiator and fan might need to be removed to get at this bolt...
   
5. Electrical gremlins. I don't like that the headlights and trunk lights flicker their light intensity. The flicker rate increase with engine speed, and becomes almost undetectable (by my eyes) at around 2500rpm. At idle it's about 3-4 times a second.
   
6. On the Electrical note, I haven't checked the ground points. I should check the engine ground point (there is just one, right?) and make sure those poor spark plugs are being grounded properly. Wouldn't it be nice if it were this...

I know less about trouble shooting engine internals. But can I eliminate a busted engine with the compression test, clean oil, clean coolant, clean exhaust, and a good looking top end (under the valve cover) ? I'm really hoping so.

I'm just about to give up on this car and tell my Dad to take it to a mechanic. I just hate admitting defeat when I've done so much! I'll check the ground points before giving up, but I don't think there is an easy way to test the injectors, and I don't have a vacuum gauge or smoke machine. I'm also not interested in doing a timing belt change without a roof over my head.

Gah!

Thanks guys for letting me bounce ideas off you, and for all your input. All I need are a few more tools and I'd feel like I can shakedown 90% of an E30 engine in under a day.

Cheers,
Tyler