I'm About Done With The %**&ing Efi

[mjr45]

jonathan, the injectors were new about 18 mos ago, I'm pretty positive the AFM flap is moving easily and is not bent and yes she fires on all 6. I may have to look at new injectors, but I'm just not there yet.

 

Holy crap this has gone on for 4 pages!

Mike

Edited March 22, 2015 by mjr45

[FastWoman]

Mike, I'm running out of ideas, except for one thing:  We are taking you at your word that this is a rich running issue.  However, you can get a lot of soot from incomplete combustion (also low vacuum) if your engine is running extremely lean.  I know, because my lean-running engine did exactly that.  There cars are far more likely to run lean than rich, given that the CTS circuit is intact.  Your car might be running lean if...

 

• The exhaust blows hard at idle and spits out sooty drops of water.
• Fingering the AFM flap more open at idle causes the engine to even out and run a bit faster.
• Pulling the vacuum line off the FPR and plugging the end of the loose hose with your finger causes the engine to even out and run a bit faster.
• Cracking the oil cap veeeeery slightly causes the RPMs to drop.

 

Does any of that happen?

[mjr45]

Fastwoman, the exhaust doesn't blow hard but does spit out sooty drops of water, taking off the oil cap makes RPM drop I haven't tried just cracking it to see, I'll try the other two tomorrow and let you know. When I have fingered the wiper to the rich side in the past it runs worse which would mean to me that it is running rich already.  The vacuum reads between 14 and 15, but at 9000' that is OK so I don't think Ithere is a vacuum leak and checked with a propane torch(no flame) to see if I could get any increase in RPM and nada. If its really running too lean, I can try the pot in the CTS line to get it richer, I may do it anyway as a test to see if it helps.

 

I just had another thought(at my age they sometimes take awhile to hatch). This car has always "appeared" to run rich, plugs have always been black and sooty and when decelerating at times you get a good whiff of fuel smell amd has died twice from overfueling(the CTS got disconnected).

Thanks

Mike

Edited March 23, 2015 by mjr45

[240260280z]

I think you just have to lean the AFM (just tighten the spring)! I missed that you were 1 mile high. The AFM calibration procedure using the water is for sea level.

My friend bought a 510 from Colorado and we picked it up in Boston. It ran like crap until we enriched the mixture. I think your problem would be the reverse.

For completeness if you could read the part number on the plastic edge of the injector that would help us help you!

Edited March 23, 2015 by Blue

[FastWoman]

I had forgotten the altitude thing too!  According to my '78 FSM (sorry, don't have the '75 downloaded), the altitude switch (present on California models) closes above 3675 feet, signaling the ECU to cut fuel delivery by 9%.  So maybe that's the problem.  Maybe you're just running a non-California model at an altitude that's too high.

 

According to my '78 manual, the altitude switch connects between pins 9 and 12 of the ECU.  I'm guessing it's the same for a '75, but you should verify.  You could connect between pins 9 and 12 to see if that leans you to the correct mix.  If that works, you could either install a toggle switch to lean the mix for high altitude, or you could get fancier and install a proper altitude switch.  (I'm guessing non-California ECUs still have the altitude correction circuitry, even if the switch isn't installed in the car.)

 

Oh, and to clarify with the fingering-the-AFM thing, you say you fingered to the rich side.  Not meaning to doubt you here, but some people do get it wrong:  By that, you mean you opened the vane a bit (counterclockwise rotation of the potentiometer mechanism), right?  And as soon as you moved the vane slightly more open, the RPMs dropped a bit?  If so, then you're not running lean, but that doesn't necessarily mean you're running rich.  Also test in the other direction.  Close the vane a bit, and see if the RPMs pick up a bit.  If they do, then you're running rich.  When you're running at the correct mixture, the RPMs will drop when the vane is fingered in either direction. 

 

An alternative theory is that your mixture is just right, but that you have some other problem that results in partial misfiring or incomplete combustion.  For instance, your ignition could be failing you somehow -- maybe a weak spark, maybe timing.  Or more likely it was the dirty potentiometer, which would plague more and more as you moved towards greater airflow (where the wiper doesn't travel as much).  If there were some skips in conductivity as the wiper moved over the potentiometer tracing, then voltage between 7 and 8 would have been zero, which would have been read as "maxed out" airflow through the AFM.  So you might have been excessively rich under load and at a more reasonable mixture at idle.  I suspect you've already fixed the problem and don't know it yet.  Your first good test drive should tell.

Edited March 23, 2015 by FastWoman

[siteunseen]

My '79 ZX dizzy uses a different coil, 1.5 OHMS, and hotter plugs than what my '77 had before the swap.  I was wondering if those 2 things and the lack of air up there would cause an incomplete burn leading to all the soot?  Maybe at warm up when the idle drops they are fouling then when you run it up they burn off?

 

 I had to throw another stick in your spokes, there's not many left.    

[mjr45]

Blue, the numbers I can find are on one side RIN 163 on the other is 7092, hope that helps.

 

Fastwoman, I did your ultra lean test, no change when I cracked the oil cap also when I removed vacuum from the FPR, vacuum off it idled up faster. Also today in talking with the guy who redid my exhaust(today) he said they had a similar problem with a FI car and it wsa due to too much fuel pressure and suggested an adjustable FPR. There is no altitude switch on my car since it was not a Cali car, but I'll try6 to do what you suggest, just not real sure how to connect 9 & 12, I assume you mean to put a SPST switch and run one side to 9 and the other to 12 by opening up the connector and wiring them thru that. I took her out today for a 100 trip amd didn't notice any reall change in performance (by butt dyno) as I've said it runs well just really bad MPG. On the ignition, there is almost like a miss that occurs randomly noticable at idle, it is totally irregular but it is there. Also, today after I got home, I tried fingering the wiper in AFM, pushing CCW almost made it die and going CW could move it a fraction maybe 1/16" the idle would go up and anymore would make it try to stall out

 

Site, I changed the coil to a Crane coil reccomended for the ZX  plugs are BPR6ES.  Here is a pic og #'s 3 and 4 the others look basically the same, this after a 100 mile run(not constant, 50 mi. down 50 mi. back) today. They actually look better than couple of days ago.

 

On a worse note, I suspect I need rings, saw some blue smoke out of the new exhaust, so I may be in for a lower rebuild. However I want to get the EFI fixed 1st., I can wait on the rings. I mean its not blowing a lot just a very faint blue haze.

Thanks

Mike

Edited March 23, 2015 by mjr45

[240260280z]

One plug looks much richer than the other. I wonder if something else is going on?

[240260280z]

Mike,

I find the 7902 seems to link to:

1991-1992 Mitsubishi Galant Fuel Injector - Fuel Injection ...

www.partsgeek.com/gbproducts/WC/7083-01011314.html

Fuel Injector, Fuel Injection Corp. Injector SKU: 7092-01011314 R

Another injector for the 91-92 N/A 2L Gallant is

Part No. 155-0213

Flow Rating: 12 - 24 lbs/hr

Fuel Pressure Rating: 43.5 PSI

Hardware Included: No

Line Repair Kit: No

New Or Remanufactured: Remanufactured

OE Replacement: Yes

Pressure Rating: 43.5 PSI

Seals Included: Yes

The data is not specific enough.

Stock Z EFI injector is ~18lbs/hr

[mjr45]

Blue, just to make sure that I get the best out of the Z, I believe I'll order some new injectors, I'll have to scour the club because I know I've read about which ones were the best. The other option is to send the old injectors off to be be re-done per se, but that'll leave where I'm at with this until they come back, hmmm. The "richer" looking plug was from #3, I'll recheck all 6 in the AM to see if maybe the front 3 are different from the back or any other differences. I kinda thought the #4 plug looked better.

Edited March 24, 2015 by mjr45

[Captain Obvious]

10 MPG ought to be easier to find than this...

 

Those plugs don't look all black and sooty as I would have expected. At 10 MPG, I would have expected loose fluffy.

[mjr45]

Captain, they were a few days ago. I'm not sure what I did, but they do look better, I'll see what all the others look like tomorrow.