Emission test fail Nuts.

[Norcalbratcap]

  It's my property and the bi-annual smog stuff is a major pain. 

 

Don't mean to sidetrack, where in ca do you have to smog bi-anually? Is this only in metropolitan areas? Just curious as i live in humboldt and only have to smog once when you transfer a vehicle here.

[two85s]

Don't mean to sidetrack, where in ca do you have to smog bi-anually? Is this only in metropolitan areas? Just curious as i live in humboldt and only have to smog once when you transfer a vehicle here.

oops, what I meant to say was every two years or every other year.  

[Norcalbratcap]

Yeah i get thats what you meant, we only have to smog when we first get a rig, i was wondering where you live that you have to smog every other year?

[DaveT]

CT is every other year, until 25 year old car.

[DaveT]

Idle 800rpm. But erratic, bobbing to 700 ocasionally.

Sprayed vacuum hoses, intake boot with carb cleaner, no effect.

 

Vacuum gauge on manifold port around 18" Hg. Needle wiggls a little with the unsteady rpm, but not rythmic. The variat ions are random.

 

LED on ecu does not blink. Not in closed loop?

[DaveT]

The CTS reads 430 ohms at the ecu connector, actually lower than an old reference reading I have for 190F.

[87subbomber]

18" hg is a good standard vaccuum, however the bobbing, even with random vatiations tells me you've got oil leaking into the cylinder, thus producing a high emissions reading. The needlde should be steady, unless the car us cammed (if it is ill take some). Do a leakdown test, it will tell you if you have blow by

[DaveT]

More things... pulled each of the vacuum lines from the evaporate system 1 at a time, blocked them, no change. Pulled the vacuum line to the PCV valve, blocked, no change after settling out for the mix change.

 

Pulled the hose off the iac valve, sprayed carb cleaner into it. Obviously all sorts of effects while doing, but no change after reconnecting.

 

This engine is consuming far less oil than others I've run and passed, so that seems puzzling to me that it could be blowby.

[ihscout54]

I connot give you any more info on the LED monitor system since Im not sure if its the same on your car as what I have described. Ide say its not in closed loop at idle. its hard to see while driving but you should be able to force it into closed loop for your viewing. After a drive hold the accelerator at 2k while watching the LED. Check the FSM, or wait for a replier that knows if the silver ECM is the same as the black unit (at least in this aspect).

 

How much variation are you seeing max, both RPM, hg's?

Are the vac readings varying with rpm fluctuations, or just dropping and climbing? You could just be seeing a miss. Did you check other possible leak points like intake manifold gaskets, TB base, EGR valve, vac solenoids, canister purge valve ....? Weve mentioned the egr befor if it isnt closing all the way it may act as a leak. Some leaks are tough to catch, think brake booster HVAC system etc.

Did you try pinching off the purge line while watching the vac gauge? Im surpised plugging the pcv valve had no effect at all.

Ign system is good right?

Fuel pressure check and injector spray pattern check may be next on the list.

[ihscout54]

If you feel and agree the idle situation is an issue, Ide like to add this again, or just state it if I havent yet. HC is hydrocarbons, or unburned fuel. Rich, or too lean causing a miss and spitting fuel, or anything that could cause a miss. Of course the cat plays a roll in elimination of these emissions. Just trying to help keep you on track.

[DaveT]

Ok, I'll check those too.  Didn't think of the booster, or the EGR.  That one's a lot bigger pain to block!

 

The RPM jumps is more like uneven, the needle will touch 700 once in a while, mostly at 800.  Vacuum wiggling isn't much, just a division or so on the gauge.

 

The PCV had strong vacuum on the side going to the manifold, near zero p or v on the side to the valve covers.  I pulled the line at the T.  The idle temporarily reacted to the change while the line was open, but went back to what it's doing when I blocked the lines.

 

The purge line?  is it one of the 3 on the canister?  I pulled and blocked both sides of all of those one at a time.

[DaveT]

Yes, I figure the cat would reduce them.  But the idle isn't smooth, so I'm thinking something isn't quite right.  When I swapped the known good exhaust = cats in, the O2 sensor came with them, so that's now been removed as an unknown.

 

The engine twitches a bit with the uneven idle.  It's not rhythmic, it's randomly uneven.

I'll have to think overnight.... I could swap out the entire throttle body, or just the injector.

 

It seems to be running great otherwise.

 

I will also look at my other EA82 to see how it is idling tomorrow when I got to work.  I don't want to drive this one much until I get it running right, so I don't kill a good set of cats.

[ihscout54]

Needle nose pliers make great hose pinchers.

[DaveT]

Today:

Ordered a leakdown tester.

EGR valve functions with test vacuum, not leaking.   Moves.  inspected the seat, looks like any other I've seen.
Fired the idle air control valve with 12V.  Moves the same as another spare one.

More tomorrow...

[DaveT]

Unhooked the line and capped the brake booster port on the intake manifold.

Discovered I need a fuel pressure gauge that reads higher than the one I have.  Guess I haven't had a reason to test fuel pressure since my carbed 86....

Carb cleaner had no effect spraying around intake gaskets.

 

Idle still jumping around 700 +/- 40rpm.  Don't know how smooth to expect this to be.

 

Things to do tomorrow - Fuel pressure, MAF cleaner. 

[ihscout54]

700-737 rpms is pretty slight. 700-920 isnt. Is it possible you have already solved the problem?

 

Did you ever end up doing a compression test?

More thoughts on the EGR and IAC, its not just the diaphragm on the EGR than can cause issues, the pintle or seat could have wear or carbon what ever keeping it from closing all the way. Sounds like its good just confirming. Did you plug the hose for the IAC too see if any change occurs? For that matter take some needle nose pliers and pinch every hose to the manifold looking for a change.

Throttle shaft play or leakage there? -long shot...

IIRC Injector spray pattern can be inspected with the MAF unplugged and boot off. Look for any leakage in there first. I cannot remeber if I used a timing light (Gm style) or just looked at it with a flash light. Ive had GM TBI injectors drip, dribble and spray a with 70% pattern and cause weird but surprisingly minor issues.

[DaveT]

Update so far.   EGR seat looked good.  Moved normally.  I'll have to try that method of watching the injector.  Tonight, I powered the fuel pump with cord I made from a spare wiring harness.  Fired the injector via an engine harness and test leads.  Didn't go crazy continuous, as I didn't want to fill up the intake with gas....  Talk about flooding.   Seemed to spray and stop nice. 

 

With the boot off and MAF unhooked, it will just re start?  I'm assuming I should do this with it warmed up.

[DaveT]

Here is a video.  Warmed up.  Green test connectors connected.  The timing was off a couple degrees.  Adjusted before making the video.  Vacuum, RPM and fuel pressure gauges.  Also, a couple of views to try to capture smoothness / or lack of same.

 

 

[DaveT]

no hints?  Anything look good / bad here?

[naru]

I think you have a lean misfire based on the unlit O2 led, unsteady idle, and high HC.

IIRC.the O2 monitor will light w/the mixture toggles rich.Unlit is lean.Steady unlit is steady lean(once warmed up).

You can use a digital voltmeter to monitor the O2 sensor output to see what it THINKS is going on.

 I would probably feed the motor a little propane at idle to see if anything changes.

[ihscout54]

I cant get the video to work and I havent had a chance to try it on a non mobile device.

Naru, thank you for telling us what the led flashes are corresponding to. You also confirmed that the silver ECM works the way we assumed. Steady unlit could also mean the O2s is not warmed up or is weak dying what ever. It seems this system is very forgiving when it comes to setting an O2S code. Trying to use just any old ohm meter will give varying results, but may still be of value for his testing purposes.

[ihscout54]

The video gave me no ahah revelations. Just a few eh maybe's. I have not had the privilage of working in a speed shop full of new engines to be tuned. I have only used vac gauges on old beeters in the 150-200k range, and those readings didnt seem real outa the norm, same goes for the tach. There were a few blips that made me think "yea maybe a miss". The fuel pressure seems to be on the high side as well, but not extreme.

Have you tried unplugging the MAF (engine off) and then running the car? I suggest checking for codes first, as you will have one to clear after.

[DaveT]

Today, so far....
 

Capped the small vacuum port on the passenger side that powers the egr, and the hvac controls.  Capped the brake booster port.

No changes.  A couple of the short hoses were hard, so they will be replaced.

 

Tried injecting propane into the intake boot - via the crank case port in back, and the one for the IAC, and into the AIC.  Made no difference.  Pulling / capping the IAC line caused rpm changes.  Propane  / no propane seemed to have little to no effect.  Note, I turned the gas on & off a normal amount for a torch flame, not trying to flood the engine, etc.

 

Unhooked the FAM sensor, pulled the intake boot.  I can see gas traveling across the throttle plate to the edges at idle.  evenly all around.  Looks like it does on my other EA82, which I did the same on.

The O2 sensor started off about 0.26V.   Calmly dropped to about 0.2V until idle went down to normal after warming up.  Moved between 0.25V and 0.5V from there.  Kind of jumpy unsteady hard to get good readings on the digital meter due to slow updating.  Analog meters are way better at dealing with varying voltages.  After a while, it stopped the switching and stayed at 0.25V.

 

Off to do the leakdown tests.

[ihscout54]

With the MAF unplugged did everything seem smoother? I cant even remember if the car runs without it but I think it will and Ive done it before. If its much smoother unhooked it might be indicating unmetered air is getting in behind it. The O2 readings aren't good sounding, and actually may confirm what Naru has said (lean), but again without a scope or a nice meter it wont be a useful test.

[DaveT]

Ok, I can hook up an oscope.

MAF unplugged and boot off ran about the same.

 

Leakdown test:
Cyl.  -  Leakage
1  25%

2  12%

3  27%

4  12%

 

Note - I have no idea what to expect, but it seems odd that one side is so different from the other.