Barn door left open, ponies escaped

[Leftlane]

Or...

You thought you're stock ETA was slow

Or...

I converted to a manual and all I got was this lousy 63hp.


Okay, sorry - I'll stop. Here's the deal, I've got a totally stock 1985 325e that I recently went through the trouble to convert to a manual transmission. See this thread that you guys helped me with (and for which I'm grateful).

Now that I've got a manual 325e on my hands, I wanted to go down that fun road of performing little tweaks here and there to see what I could do to spice it up a bit - and maybe even get it to a point where I could take it to the odd track day or autox for giggles (I've done a lot of that sort of thing with Miatas and Mustangs, but never an E30).

To start, I wanted a baseline dyno run. I've got a Turner Motorsports 325e chip still in the box that I wasn't going to install until I made sure the car was making as close to its factory 121hp as possible. I finally made it to the dyno last Friday.

I won't be installing that chip too soon. 62whp. Yup. I sensed it was slow, but always sort of banked that as "well, it's got a 2.79:1 rear gear." Given enough time, it'll zoom down the highway as near triple digits speeds (okay, given a _long_ time). However, now it's been confirmed that I've got problems. Check out the graph:



I've found some threads here that suggest stock rwhp ought to be around 90, and chipped cars might see ~110whp.

If you look at the air fuel ratio, my sense is that you'll agree this is way off. It looks too lean across the whole range.

This car has been in my family since 1990. I've got all the service records since new. I know everything that's been done to it from day one (fun fact: for example, I know the BMW dealer replace the head gasket in 1988 with 26,000 miles on the clock).

It's currently got only 69,XXX miles.

As far as I can tell, it's rocking the original injectors, external fuel pump, and internal fuel pump. It seems to be running the original fuel pressure regulator.

I believe I tested the throttle position switch back when I was having trouble with the manual trans conversion and it was fine. The AFM (flappy door intake gizmo) seems to... uh... flap and gives some varying readings as it's flapping.

I recently replaced all the ignition components (plugs, wires, cap, rotor, coil). It's got new 02 sensor, reference sensor and engine speed sensor pickups (gotta love that Motronic 1.0 that gets this info from the trans bellhousing).

After I got these results, I quickly performed a compression test on the motor. All cylinders got 181psi +/-4psi. I _think_ that's good, but I haven't compared that to others yet.

Given the above and the AFR ratios, I'm thinking fuel problem. I've got a new fuel test gauge on order from Amazon. I've got the Bentley manual. The plan is to slowly plod along (as I do) and narrow down the various potential problem areas.

What confuses me is the car runs smooth. Seems to cold idle okay (although if I'm honest, it is a little jumpy with the RPMs when cold) and its warm idle is fine.

Q1) Does anybody have anecdotal stories of power slowly disappearing from their cars without any real symptoms (other than the symptom of 62 rwhp)?

Q2)The other more insidious question: okay, so I had to reclock the flywheel to get the thing oriented to proper TDC (again, motronic v1.0 goodness). Is it possible I'm off 45* (i.e. one bolt hole rotated the wrong direction)? I wouldn't think so because that's a lot of ignition wrong-ness. If you read my thread when I was having this trouble with the trans conversion, I believe that my flywheel was exactly 180* off at that time and due to the batch firing mechanisms at play, I sort of lucked-out that the engine even ran albeit quite poorly. I would think that at 45* off, it wouldn't run at all - but all this is just unsubstantiated theory on my part.

In other words - please say it's not possible that I may have to pull off that transmission yet again and dink around with clocking that flywheel. I just couldn't bear it. (i've been wondering if I could convert to a front motronic 1.3 pickup sensor and somehow wire that up to the m1.0 computer to give it what is wants - not interested in converting the whole Motronic subsystem at this time).

[nando]

why is that graph so noisy? especially with such a high smoothing factor?

Is there a misfire or something, or could that be some other issue with the dyno?

AFR could be an issue with the TPS. I've seen it before - the WOT switch doesn't activate constantly, so it runs on the part throttle map (which is always lambda 1.0). if it crosses the threshold it'll go rich again as it switches to the WOT map.

[ahlem]

With that many years and that few miles, I'd guess you have partially clogged injectors. All the rubber parts have freshness date life expectancies and yours may be brittle and cracking, letting in lots of extra air. The biggest freshness date you need to worry about is the timing belt. All those little teeth dry out and go pinging off and you have a train wreck on your hands. Some say 5 years or 50,000 miles max on a timing belt.

[Leftlane]

why is that graph so noisy? especially with such a high smoothing factor?

Is there a misfire or something, or could that be some other issue with the dyno?

AFR could be an issue with the TPS. I've seen it before - the WOT switch doesn't activate constantly, so it runs on the part throttle map (which is always lambda 1.0). if it crosses the threshold it'll go rich again as it switches to the WOT map.

Good points. I recall the tuner having to dial up the smoothing factor to reduce the noise. Not well versed enough in such things to know what that means.

He did say it felt like it had some ignition stumble. In fact I had told him before that I feel some stumble at various rpms under WOT as it climbs from ~2500-4000 rpm. His suggestion upon hearing that I had just changed plugs was to check the gap and reduce. I did just that this last weekend too. Sorry I should have mentioned that. I had gapped the Bosch plugs at 0.28". The Bentley manual states 0.27" +/- .04 - so this time I chose to gap at 0.25". I will say that did seem to make the "stumble" better if not have it go away. I suppose that could be treating the symptom and not the problem, however.

I'll also have to consider your TPS comment. Seems it can fail in a way to have the DME not employ the WOT (richer) map.

[Leftlane]

With that many years and that few miles, I'd guess you have partially clogged injectors. All the rubber parts have freshness date life expectancies and yours may be brittle and cracking, letting in lots of extra air. The biggest freshness date you need to worry about is the timing belt. All those little teeth dry out and go pinging off and you have a train wreck on your hands. Some say 5 years or 50,000 miles max on a timing belt.

Thanks! Yeah, I think these are issues for sure.

I meant to also mention that I changed the timing belt a couple weeks ago. It was last replaced in 1988 with that head gasket. I wasn't going to make a dyno pull with that old thing still on there.

I've got a set of Standard Motor Products FJ21 injectors en route. I figure the car is due for that (along with new o-rings of course). Although I'm loathe to throw parts at this car without testing to really try to understand what's going on, I figured there's no good argument against replacing 30 year old injectors on a car that spent a lot of its life sitting around in a garage.

[LJ851]

I meant to also mention that I changed the timing belt a couple weeks ago. It was last replaced in 1988 with that head gasket.

I think you may have answered your own question. The first thing i would do is double check your cam timing.

[LJ851]

Q2)The other more insidious question: okay, so I had to reclock the flywheel to get the thing oriented to proper TDC (again, motronic v1.0 goodness). Is it possible I'm off 45* (i.e. one bolt hole rotated the wrong direction)? I wouldn't think so because that's a lot of ignition wrong-ness. If you read my thread when I was having this trouble with the trans conversion, I believe that my flywheel was exactly 180* off at that time and due to the batch firing mechanisms at play, I sort of lucked-out that the engine even ran albeit quite poorly. I would think that at 45* off, it wouldn't run at all - but all this is just unsubstantiated theory on my part.

You should not be able to "clock" your flywheel. It has a locating dowel in one bolt hole in the crank and only goes on one way. You do have the locating dowel, correct?

[2mAn]

and I thought my 89whp was bad when I dyno'd my eta... it still made 130wtrq though

[TobyB]

Yeah, I was looking at the very low torque numbers, too.

Are you sure you don't have an M10 in there?

heh

t

[Leftlane]

I think you may have answered your own question. The first thing i would do is double check your cam timing.

Thanks. Good suggestion. After installing the belt I used a ratchet to rotate the crank 720* (two full turns) to ensure both the crank line and the cam arrow+line were matched up. They were. Then I rotated it again twice just to make sure. It still was lined up. I think we're good there.

You should not be able to "clock" your flywheel. It has a locating dowel in one bolt hole in the crank and only goes on one way. You do have the locating dowel, correct?

Totally correct. One should _not_ be able to clock a Motronic 1.0 flywheel. Unfortunately, I can. My dowel pin was in the wrong spot (see thread I linked to in the first post) and when I removed the flywheel the second time, it sort of... well... came out. So now I'm left with a totally clockable flywheel. I've lined up the reference pin with the CPS. Hopefully that's enough. It sure made the motor run much better vs the first time I put it on (although I am missing 30 ponies - anything's on the table).

[Leftlane]

Are you sure you don't have an M10 in there?

Bwahahahaha...

I did count 6 plug wires - maybe two of those are just spares. ;)

[nando]

I would look at that flywheel pin. If your timing reference is off, that will throw off ignition timing - it could be way advanced or way retarded. that would explain your lack of power.

if your cam belt were off more than 1 tooth you would have destroyed your engine, and it wouldn't make that drastic of a change anyway.

[Leftlane]

Did the zebras escape? Nope, it was horses.

A wise man once told me, "when you're standing on the street and you hear hoofbeats, think 'horses' not 'zebras'."

I've been thinking zebras (fuel) while you guys have been telling me horses (ignition).

You are right.

Turns out I don't know TDC from a hole in the ground - or at least a hole in the side of the crank pulley. I used a poor method to determine TDC the 2nd time I installed the flywheel.

Here's a picture of what I now believe is my car at TDC ( please confirm/deny - the silver line is between the "O" and the "T"):


When in this position, the flywheel reference pin is not visible when I remove the CPS from the bellhousing. When I rotate the crank just a bit to get the reference pin visible in the CPS' bore, here's where the "O|T" line is:


Gack. Using my protractor to approximate 45*, this looks to me to be about that. 45* would be one bolt rotation off on an 8-bolt flywheel.

So, it appears the engine _does_ run when the flywheel is in just about any position on Motronic v1.0 Hell, I've had my flywheel in most positions now (except the correct one). Looks like I'm going to drop the trans yet again. Sigh.

Of course there's always the possibility of rigging up the motronic 1.3 crank pulse wheel on the front of my motor, welding a reference pin to it (and of course balancing it), and moving my m1.0 CPS from the bellhousing to the front of the crank. Meh... that's sounds like a lot of work too. Such loft decisions will require sleep and beer.

Thanks, nando and all, for your input. This is why these forums are great - you get me thinking clearly.

[2mAn]

ONLY think Zebras if you're in Africa