Purs like a kitten...

[FastWoman]

Ah, but there's a certain magic about a Grammaphone, in comparison to an MP3 player. Same is true of the clunky vane-type L-Jetronic fuel injection. I don't know whether that magic is worth the cost of some loss in performance and added fuel costs, but there's still something rather cool about it.

I presume if you go to the MS system you'll post all about it on this list. I think I'll let you go first!

I did sort of close things up today. I did another cold start at last night's settings, and the start-up was fine. Idle was a bit low-ish (1200), but the mix was comfortably rich and stayed rich until the engine was warm. I've decided my air regulator does work. It's just that I don't get quite as much RPM boost from it now. Before, my engine was fuel-starved, so the enrichment made the RPM pick up a lot. Now the engine is no longer fuel starved, so the added fuel perhaps drops the efficiency a bit.

I set my idle to 900 RPM. It just sounded so much smoother/quieter than the 800. I advanced the timing to 14 deg BTDC. My vacuum, in the end, was about 17.5 - 18. I don't know why I couldn't get as high a vacuum as before, especially with the slight timing advance. At a faster run the idle was more like 21, whatever that means. I also found my compression gauge and checked compression. The dry/warm readings were 165, 165, 168, 173, 165, 168. Perhaps a bit of engine wear there, but at least it's pretty even.

I might still have some engine sludge issues. My engine was the sludge monster when I bought the car. I'm now starting to see about 60% clean metal. I changed the oil again today. I'm trying Chevron Delo now (for diesel engines -- very high detergent). We'll see how it goes. Anyway, with a bit of regular use and continued elimination of sludge and varnish, I might pick up a an inch or two of Hg.

[cozye]

On my cold start up, I'm getting a really slow idle. Before I would not get any fast idle, it just idled around 800-900. My air bypass is working so something is still not quite right on my cold start ups. I might be a bit to rich still. I need to dig into it further. I hadn't put a lot of effort into it yet since it started cold quite well before, but now with the richer mix I've got to hold the gas a bit.

Like you, I've found that a 900 rpm idle is much smoother than 800. Looks like your compression numbers are great. Mine were about 150-155, but I will check again after I've run a richer mix for a while.

It will be a bit before I try a megasquirt setup. It's not on the top of my list, suspension is next. I'll be sure to post up when I do though. Until then there is plenty of reading and info I need to do about the subject.

[cozye]

Thanks for posting your results as well. Your post above about the fast idle got me thinking about mine being too rich. I'd already suspected I might have gone too far, but you got me on a train of thought to take another look at it. I'd had 850 ohms dialed in to my potentiometer on the water temp circuit, but my AFM was still rich by 4 teeth. I went on and back out my AFM to the stock setting, and took another drive. The last time I drove it with the AFM at stock yesterday, the pot was set at 1150 ohms. Today at 850 ohms the car was much smoother and had good power. Also, the idle was smoother as well. I lost .5hg of vacuum, but thats not that important since the car is still at 18 and runs better. I'll try this for a bit, and see if it helps my cold start once it cools down.

[FastWoman]

No problem, Cozye! It was really nice being able to think out this problem with you -- somewhat of a "buddy" system, I suppose.

I think your decision to put the AFM back to OEM specs is probably a good one. It's a semi-mysterious device whose air flow and response patterns probably took a big investment of R&D. It's designed to peg out at a certain air flow rate, and the ECU, which is (literally) a black box for which we have very little information, is engineered to respond to readings from the AFM on the basis of those response properties. The better fix is probably the one that applies throughout the operating range of the engine -- i.e. via the coolant temp circuit.

I think time and use will help both of our engines. I know that my little BMW Z3 was a bit fussy until I drove it for several months. Then it ran great. Non-use really takes a toll on a car, particularly an older one.

[HusseinHolland]

On 11/14/2010 at 6:36 PM, FastWoman said:

I promised pics and details, so here they are. I apologize for the washed out photos. I didn't take them to be pretty, but rather to be clear. There's a whole lot of black in these photos!

I decided it would be better to put the inline potentiometer at the end of a pigtail, rather than inside the ECU. The first reason is that I can change out the ECU and still have the same mod. The second reason is that I don't have to go into the kick panel to change the mixture.

I tapped into the EFI harness inside the main connector shell. There's a screw on the end of it, and the shell slides apart I clipped the small black wire in the #13 position (labeled on the inside of the connector) and connected the two pigtail leads to the ends:

http://www.graphic-fusion.com/miscpics/efimod01.jpg

Here's the pigtail coming out of the EFI harness, which has been wrapped back up. The connector does not have the potentiometer attached:

 

 

Thanks to @siteunseen for linking this in the bad AFM thread - bumping it so I don't have to search for it, as I'm going to follow her layout, wiring the pot at the ECU harness

just have to recheck the two pins for the sensor - 13 & the ground - looks like 16, 17, 35 & 5 all tie together so I'm not sure it matters which I use

Edit - never mind, forgot that this is placed in series, not parallel 🤪

Edited October 15, 2023 by HusseinHolland

[HusseinHolland]

Did a number of things today.

Replaced the ECT with a new Beck Arnley 158-0134  sensor. With that, (ambient temp 50ºF)  it started well (after the initial delay with priming), and during warmup. AFR's stayed nice & fat, which was not the case with the old ECT. Once it got closer to normal operating temp, the AFR"s went lean again (16's).

So, I put in the 1.1K ohm resistor in series with the ECT.

With that, warm AFR's are to rich (13.4-13.7) - so I don't even need 1.1K resistance added to the ECT circuit

Pushing very slightly on the AFM lever fattened it up a touch, and smoothed the idle quality

So, I lessened the wheel tension by 1 tooth

Also adjusted the WOT enrichment TPS settings - the factory position brings it on around 30º opening, so I moved it to closer to 50º

Stock

adjusted

Reset (lowered) the base idle closer to 800rpm, with those changes the AFR was sitting around 14.2 

So, I installed the 2.2K potentiometer, wired the 1.1K as well, but decided the 2.2K would give me more range. Since 1.1K puts AFR's at idle around 14.2, I need somewhat under 1K to get the AFR's in the 14.7-14.9 range at idle.

 Bolts to the left dash frame support

Used a 2pole HD090 series connector to join the pot to the ECU. Removed #13 wire from the ECU connector, now that goes into the pot, pot output goes to pin13. Set dial on POT so that 1K ohm is with #1 at 6 o'clock where I can see it

Full value (2.2K) puts dial @ just over 5. Unlikely I will ever need to use that end of the scale.

Connector tucked up above ECU

Warm engine, setting dial to 0 brings AFR's to 14.7-14.9. I'll see how it starts & warms up with that setting tomorrow after work. Still can't drive it to see how it performs on the highway cruising, due to the blown out clutch slave.

 

Edited October 16, 2023 by HusseinHolland

[HusseinHolland]

Got the replacement clutch slave installed, and wheel I had the car jacked up, I took care of the speedo drive inner & outer shaft seals. No pics.

I drove the car around, went to Harbor Freight & Home Depot to get some extra dot 3 brake fluid & regular antifreeze. Once the engine is hot then parked, it seems that it cranks slower. When I got home, I shut it down, then realized I didn't pull up far enough in the driveway, so went to restart it. Blew the 125Amp breaker on the starter cable again. I've replaced it with a 175Amp breaker. See how that goes, I'm going to drive it to work tomorrow. It's done much idling in the driveway while I worked the kinks out, so it's definitely. due to have the snot beaten out of it. One drivability issue is that I keep trying to upshift into (non-existent) fifth when I get up around 65-70 when accelerating.

[siteunseen]

Was there a difference in the way the motor ran that you noticed going to HF and Home Depot?

[HusseinHolland]

On 10/16/2023 at 8:24 PM, siteunseen said:

Was there a difference in the way the motor ran that you noticed going to HF and Home Depot?

The motor feels strong as it is. One reason I changed the TPS WOT setting was I could see the AFR's get really fat just revving the motor in the driveway.  After driving around & coming to work today, about 20min local & highway-  the enrichment values seem pretty good under load.  I reduced the ECT resistance value a touch as the cruise AFR was a touch rich. Now I have the wideband I do see that the system goes kinda rich right off idle before it levels out, but my old Volvo does much the same.

I think I should just put in the 250A breaker, as the first couple revolutions hot cranking with the 125A seemed slightly sluggish before it blew, and less so with the 175a, so perhaps the initial starter draw is high enough to strain the lower amp breaker, and actually induce the slow crank, I dunno. It just seems to crank better now than yesterday. (EDIT - excessive draw was due to faulty rebuilt starter, replaced)

I do still need to redo the compression test, as the one I did back in the Spring prior to any valve adjustments had one cylinder well over 10% deviation - 140ish vs. 165 range on the others. Valves were very tight on that one. Overall engine feels pretty darn smooth now it doesn't have a lean condition, for sure.

Edited November 6, 2023 by HusseinHolland

[davewormald]

17 hours ago, HusseinHolland said:

One drivability issue is that I keep trying to upshift into (non-existent) fifth when I get up around 65-70 when accelerating.

I remember having that problem when I had my 240Z back in 1984/1985. I also seem to remember that if you shifted out of 4th, then tried to go directly back into it, the result could be noisy. The problem got worse when I sold the 240Z at the end of 1985 and replaced it with a 1983 280ZX with a 5 speed. The problem was a bit more severe when you forgot you were already in 5th and tried to shift up one more time ...

[HusseinHolland]

48 minutes ago, davewormald said:

I remember having that problem when I had my 240Z back in 1984/1985. I also seem to remember that if you shifted out of 4th, then tried to go directly back into it, the result could be noisy. The problem got worse when I sold the 240Z at the end of 1985 and replaced it with a 1983 280ZX with a 5 speed. The problem was a bit more severe when you forgot you were already in 5th and tried to shift up one more time ...

Trans is definitely whiny - but it does have 250K on it. I only have to deal with it for a year or so, after that I'm doing a 350Z drivetrain conversion with the 6 speed. Should be all good after that.

 

Edited October 17, 2023 by HusseinHolland