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SPFI EA82 Swap idle misfire


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I've got an 86 GL wagon with the 3at that I've successfully converted to SPFI from the hitachi carb, thanks to the help from this forum.

 

Here's what I've got going on:

 

At hot idle, it will idle at about 800, but it mifires pretty regularly. You can hear pops out the exhaust and the engine will shake slightly. Drives well enough.

 

Motor has been completely resealed with head gaskets, OEM intake man gaskets, cam towers sealed properly with OEM o-rings, etc.

 

Timing set at 20 with green plugs plugged.

NO VACUUM LEAKS (tested with my homebrew smoke machine)

 

New:

Plugs

Wires

Cap

Rotor

Coolant temp sensor for computer

Timing Belts tensioned properly

 

If I unplug the MAF, it idles perfectly. I'm assuming that's because it forces it rich to compensate for the lack of info from the MAF.

 

If I hook up a timing light, I don't get a perfect pattern of flashes. It will drop out from time to time, and that's when the engine stalls. I don't know if this is a symptom or a cause of the underlying problem.

 

I smogged the car in OR (which is where it needs to be registered) and I'm assuming it failed because of the miss at idle. I got 600s for HC (limit 220), but I'm at .7 (limit 1.0) on CO.

 

I'm leaning towards a weak coil (since a lean mixture is harder to ignite), but possibly a bad CAS.

 

I need to get this thing smogged by the end of January, since that's when the current WA tags expire.

 

Any thoughts?

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Coil resistance checks out in spec, but I know the ohms don't always tell the whole story. I have an extra ground cable going direct from battery neg to the LH strut tower so it all should be good because I cleaned all the grounds when I installed coil and ignition amplifier.

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Coil resistance checks out in spec, but I know the ohms don't always tell the whole story. I have an extra ground cable going direct from battery neg to the LH strut tower so it all should be good because I cleaned all the grounds when I installed coil and ignition amplifier.

sounds very similar to my experience after my spfi conversion..the car didn't like the timing setting at 20…I first of all checked for vacuum leaks and then used a vacuum gauge as my guide to set the timing…green connectors unplugged..adjusted the idle screw on the electronic idle control switch..been good for many thous. of miles...

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Well I got ahold of a loyale (mother in law's) that she said I could pull some parts off temporarily to check on the GL. Tried coil, no luck. Tried ignition amp, no luck. Changed whole disty--bingo! Timing light flashes steady with no missed flashes and idle is noticeably better. I still get the occasional pop out the exhaust, but it seems to get worse if I get too far away from 19, which is where I have it set.

 

Petersubaru, do you remember whether you had to advance the timing further or back it off from 20 in order to make it run right? I will set the timing with a vacuum gauge if it doesn't pass again, but the idle is sooo much better.

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If your distributor is the optical pickup style, you can open it up and clean the wheel and sensor with electronic cleaner. Just remove the screw on the dust plate(Don't disassemble beyond that point to ensure nothing is messed up).   I did this last summer to mine when I had the engine out. I don't have any misfires.

 

112_0014.jpg

 

 

Of course I cleaned mine up for my trip this past summer.

 

112_0016.jpg

 

112_0080.jpg

Edited by MR_Loyale
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Opened up the dusty and found that the little disc with the slots for the optical sensor was loose on shaft. Distributor is in pieces on my workbench now. Have been unlucky finding an optical sensor from parts places that includes the disc, so I'm stuck with a reman or junkyard disty. Reman distributors are $$$ even with my commercial acct.

 

Anybody know where I can come up with one in the Portland, OR area?

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Remember you distributor and block are dissimilar metals as well as bolts. Look for any oxidation on mating surfaces. Sand appropriately and never be afraid to use "Neverseize" on steel bolts that go into aluminum or magniesium. Also, use a little di-electric grease between mating surfaces of block and distributor base.

Oxides on these surfaces prevent electrons from flowing (i.e. It prevents proper grounding of current).

Good luck and stay thirsty :)

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Well I got ahold of a loyale (mother in law's) that she said I could pull some parts off temporarily to check on the GL. Tried coil, no luck. Tried ignition amp, no luck. Changed whole disty--bingo! Timing light flashes steady with no missed flashes and idle is noticeably better. I still get the occasional pop out the exhaust, but it seems to get worse if I get too far away from 19, which is where I have it set.

 

Petersubaru, do you remember whether you had to advance the timing further or back it off from 20 in order to make it run right? I will set the timing with a vacuum gauge if it doesn't pass again, but the idle is sooo much better.

Using my "back to zero" timing light ..it reads the timing at 24…the engine has many miles on it which will somewhat affect vacuum …I use mid grade gas...

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Ok built a good disty out of a couple of old ones, and the idle's much better but not perfect. I even put a gallon and a half of alcohol in it with it on E, and it still won't pass emissions.

 

I've ordered a new cat and Y-pipe, since the old one's an aftermarket anyway and the honeycomb is loose. Also I think where I mounted the O2 sensor is too far out of the stream--it never reports anything over .2 volts, even at 2500 rpm, so I think it's dumping fuel in all the time at cruise. But that doesn't explain my idle misfire.

 

This car is making me tear my hair out. Any ideas?

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Dude, been there done that!

 

http://www.ultimatesubaru.org/forum/topic/97791-spfid-brat-poor-idle-and-pinging/

 

 

Whats ur intake setup like?

Fuel pressure readings on both sides of the regulator?

Tps readings?

Has any one touched the throttle stop screw? Its marked with a gob of paint, and yes it matters.

How are you setting your timing? Dont forget those connectors...

What was your engine condition befor the swap? Any idea of compression?

 

These were all things that casued me trouble after my swaps.

 

Btw your o2s completed the ten step program befor leaving the factory and no longer likes to drink alcohol. Might be time to try a heated o2s. Where is it? Moot point i suppose as your new cat will have the bung in the converter.

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Dude, been there done that!

http://www.ultimatesubaru.org/forum/topic/97791-spfid-brat-poor-idle-and-pinging/

Whats ur intake setup like?

Fuel pressure readings on both sides of the regulator?

Tps readings?

Has any one touched the throttle stop screw? Its marked with a gob of paint, and yes it matters.

How are you setting your timing? Dont forget those connectors...

What was your engine condition befor the swap? Any idea of compression?

These were all things that casued me trouble after my swaps.

Btw your o2s completed the ten step program befor leaving the factory and no longer likes to drink alcohol. Might be time to try a heated o2s. Where is it? Moot point i suppose as your new cat will have the bung in the converter.

Intake setup is stock.

Fuel pressure reading is 26psi from filter, that's only place I checked.

TPS checks good including idle switch.

Throttle stop screw still has its glob of paint in the right spot.

Timing 20 deg btdc set with warm engine and green plugs connected.

Engine condition is good. Have had heads off on this motor and compression was 135+ on all cyls.

 

I think I have O2 sensor out of the stream and it doesn't respond too well. I was under the impression that the computer ignored the o2s at idle because it knows it's a 1 - wire. But talk to me about a heated sensor!

 

I'm being tested only at idle. If you don't pass at the first time, you get to run it up to 2500 for 15-20 secs and then try again at idle.

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are "pops out the exhaust" a sign of crappy valve or weak valve spring ?

I had a weak valve spring that a machine shop missed when they reassembled it ( oh, yeah, it would have been within spec" he says

I say "pigs rrr's" ! There is no within spec on these EA82 - needs to be a figure and that is it. Plicks sent me on a long and expensive wild goose chase - chasing their stuff up :(

 

Is it a bad combustion that you can hear out the exhaust or is there something in the valve sealing causing this ?

 

A weak valve spring is really noticeable at all temps though, and I found a perfect fresh started engine idle would be screwed as soon as any throttle blip occured, took ages to settle only with engine off, or if drove it to upper revs, change gear - when in next upper gear idle went to crap again

 

Think I have ruled out a weak valve spring for you.

 

On your fuel pressure tested at 26 ...mpfi need about 36 ...did you test it with gauge T'eed in on a running engine? I think you can get inaccurate working pressure readings if you just take pressure at end of line from the pump in an engine off not running situation.

 

My only spfi experience is all non electrical, my spfi is a bit better....like..may I suggest now I think of it - it sort of sounds like an mpfi injector with a crook injector in manifold seat seal - they happen at a hot idle. No good if you are spfi though, and you are. It sounds like it stays with one pot...have you tried blocking off temporarily any vacuum hose ports, plate up the EGR valve on manifold etc ??

Edited by jono
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Ordered a cat. Coming soon.

 

Jono, I have tested the full intake manifold setup with a homemade smoke machine. It occurred to me in the shower that a smoke machine won't show a weak pcv. I'm reasonably sure that the EGR isn't stuck open, but I haven't checked.

 

>>Anybody know how to test to see if the misfire is confined to one cylinder rather than being multiple cyls? I would love a scope but don't have one.

 

It's an intermittent misfire; pulling spark plugs to various cylinders won't tell me anything. 

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Ok built a good disty out of a couple of old ones, and the idle's much better but not perfect. I even put a gallon and a half of alcohol in it with it on E, and it still won't pass emissions.

 

I've ordered a new cat and Y-pipe, since the old one's an aftermarket anyway and the honeycomb is loose. Also I think where I mounted the O2 sensor is too far out of the stream--it never reports anything over .2 volts, even at 2500 rpm, so I think it's dumping fuel in all the time at cruise. But that doesn't explain my idle misfire.

 

This car is making me tear my hair out. Any ideas?

 

Get the new cats in first, then see what you get.  If they're rattling, they are no longer doing their job.  How far out of spec are the readings on your test?

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CO is in spec, less than 1.0.

HC limit is 220 , and I'm in the 6-700 range, depending on which test were talking about.

NoX does not get tested.

 

They test me at idle only. If I fail on the first idle, I get to run it at 2500 for 20 or so secs and then test again. Numbers are usually a bit lower after run up, but not much.

 

The front cat isn't in pieces inside, but the honeycomb has separated from the housing.

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