Ron_H

My '86.5 always passes smog every two years with exclamations by the tech that it is unusually clean for its age........until this year when I decided to register it after it has been sitting idle for 3 1/2 years. (My Saab engine self destructed!) Of course I started it up and terrorized the entire parking lot at my office building once a month in the interim. NOX was too high and all else was right on. Tech advised mixing one gallon denatured alcohol per eight gallons gasoline and running the s*** out of it to get the cats hot and burn off anything that accumulated while the car was idle. I did that and drove it for 100 miles late at night to clean it the cats. I also cleaned my MAF and found a broken O ring around the MAF housing which I replaced. I then returned for a re-test. I passed the 25 mph test, but failed the 15 mph NOX test. Tech said to change the cats and return. Instead, I was fortunate to borrow a known good MAF from Bill Ball. No noticeable change in idle or other characteristics from my MAF. Another tech advised changing the fuel filter and oil filter before retesting. Then another alcohol / gas tankful and a long drive on the freeway late at night. Then I'll return for another retest. If I fail I will get a one time two year amnesty exemption from the referee to give me time to tear into the reason why this car is running so lean at low speeds.

But that is not my problem, despite the fact that if I get cited without tags my car might be impounded. So I paid the fees and only need the smog certificate
My real problem is probably why the car is failing. At start up and initial drive off, it idles well but when I drive off, it stumbles and has zero throttle response, then a backfire in the intake manifold, then it suddenly catches and spins the rear tires as it accelerates like the proverbial bat. Whoa! After that it runs fine.......most of the time, until I try to stop for a light and idle. Then it starts loping like a cammy Chebbie, rrhump, rrhump, rrhump, and if in gear wants to lurch forward with each rrhump. If I let off the throttle it will die, usually but not always. Sometimes it will suddenly catch and return to a normal idle. Sometimes I can be running along and let off of the throttle and it simply dies! A few years ago these symptoms were cured with the replacement of the fuel shutoff switch that shuts off the fuel after lifting the throttle until the engine returns to about 1000 rpm at which time the fuel flow is restored by the switch. It was a difficult install but it worked. I fear it needs to be replaced again. However. Mark Anderson me to install an Idle Stabilizer thingie which I just ordered. It controls the balance of air supply at idle to prevent the rrhump, rrhump, rrhump loping behaviour. I reasoned that it might also help with the low speed NOX reading though I can't ever imagine why I would drive at 15 mph without falling asleep at the wheel....!

Anyone experience these symptoms? Anyone know how I can register my car in Nevada in case the "fixes" don't work? Thanks in advance to anyone who can put out this fire.

The Forgotten On

Sounds like a vacuum leak and or bad timing. Do an intake refresh and check your timing on the timing belt to see if it skipped a tooth.

Good luck on getting it to pass smog.

Ron_H

Thanks. I keep getting the same thoughts about an air leak and in fact replacing the O ring on the MAF housing seemed to improve the NOX reading at 25 mph. The interesting thing is that the car, once warmed up, will run seemingly normal and will scream up to Bail Denied speeds smoothly. Turn it off for a few minutes after that and it won't run smoothly from rest until the backfire occurs in the intake manifold. Then it returns to normal again. Checking the timing belt is another good place to look methinks.

soontobered84

You should make sure that your Temp II sensor is in spec. I had similar symptoms on the Stepson, replaced the Temp II and those symptoms were gone.

The Forgotten On

The cold start issue when it stutters, backfires and then goes, but runs fine when warm is a classic issue of intake leaks that are cylinder specific.

I replaced 2 gaskets on my 81 after I checked on the plugs to see which cylinders are running lean, turned out it was the back 2 intake runner gaskets, replaced them, problem solved.

You will have to remove the entire intake assembly and replace anything you can. Also replace your fuel lines if those are old. You wouldn't want a fire.

Definitely check your temp II sensor to see if it is within spec as those will have a larger affect on the later cars than my L-Jet.

Mrmerlin

I would suggest to replace the connector for the temp 2 as well as the temp 2 sensor ,
also swap in a new ISV these wear out.
Inspect and replace the short harness to the TPS these harnesses connectors will shear and then the TPS will be taken out of the loop.
Inspect the intake plenums for proper seating of the rubber collars and clean out the plenums of oil.

Try resetting the idle by using the tool called a blinkr made by Porken there are threads on using it
If the MAF is old then this should be rebuilt.
I know it sounds like a lot of stuff but restoring the engine to top condition should fix this,
IDK if adding the alcohol is a good idea

Ron_H

Sounds like some good advice. The car will idle perfectly once warmed........until it is shut down
for about 15 minutes and then restarted, at which time it begins to lope again and adopt a lumpy
idle, or even die if the throttle is released too quickly. So I drive with my left foot for braking in order
to keep that idle up until it stabilizes. And it has power galore then.

The tech that suggested alcohol / gas mixture said he had seen cars that were close to passing smog pass after using alcohol. All I need now is to pass smog NOX levels at 15 mph and then I can stop limiting my driving to night time only to hide from Smokey. Once I get my tags, I can devote serious time to dealing with the other running problems and a noisy rear wheel bearing. The problem is all the
other ills are likely related to the failure to meet smog requirements in California What a joy we must endure every two years in this bankrupt state.

joejoe

Ron, I'm going through seemingly same symptoms as you. I have changed (86.5) plugs, rotor, caps, temp II, wires, MAF, injectors 'rebuilt' at witchhunter.. It seems to run better now but has a low idle at cold/ warm start. My old MAF would work at 980 ohm. Rebuilt MAF at 380ohm and idle screw only opened about 1/4 turn. (this seemed not enough but blinkr' shows good.

This car was a gross polluter That I bought for fairly cheap. It had all original equipment (save for driver side injectors replaced) and new porsche cat put in about 6 years before I got it. The car had a pretty hard life.

As I need to get smog soon ( busy with building fence) I am interested in what you or others may come up with. When I did the intake refresh I found the isv stuck and bad plumbing to it. All this has been replaced and isv freed up to open/close.

Also when I get my lift free the oil will be changed before test. I have been told by the guy I go to this can help with smog.

Settings for MAF set up are now 340 ohm, and 1/4 open on idle (co). Idle is at 780/810 and hunts for about 1 minute. When in gear it seems to be low. Can MAF be richened and idle opened to get betted initial idle?

dr bob

Ron--

Start looking fro a vacuum leak. In one of Dwayne's intake refresh write-ups, he shows a simple fixture using Home-Depot plumbing parts, and a way to connect low-pressure air to it from a compressor.

Considering it's been sitting around for the years now and just had enough running to add a new layer of varnish to the injectors, I'd look at R&R those, either with new or have yours cleaned.

Drain the tank and put fresh gas in it.

Use a Miti-Vac to verify that the fuel pressure regulator and the dampers aren't leaking.



----

My '89 regular driver was getting really marginal on NOx as years went by, to the point where I'd ask the tech to do the 15 MPH test with the gear selector in 2 to get the RPM's up a little off idle. You can sort of force the issue for testing by tying the TV cable lever full forward on the side of the gearbox with the TV cable disconnected. You may be able to just jumper the two wires at the pedal kickdown switch to get a somewhat similar effect. Still, just a band-aid to get the test passed.

The final cure came with new injectors during an intake refresh that was otherwise for cosmetic reasons only. All it takes is one or two injectors wimpy to give extra NOx from a slightly lean mixture. The oxy sensor reads the average CO from all cylinders mixed, so a couple low will only richen the mixture enough to bring the average back up. New injectors made mine pass with barely a bump on the analyzer needles.

A 'lister in San Diego found a place that would do the full B-G injector and intake cleaning on the car for him when he had similar symptoms. Less than $200 IIRC, and it brought everything back to original great tailpipe numbers. The DIY tool is almost $200 to buy new, with the three chems on top of that, plus an adapter for the fuel rail fitting. I have the tool and fitting if you want t try it, the chems are on ebay regularly. Takes an hour or so and kills all the flying insects for blocks around from the tailpipe smoke though. For a one-time it might be worthwhile to let a pro do it for you.

danglerb

One clogged injector could bump up the NO couldn't it?

I am doing the same smog thing on my 85 Euro S, and other than wrecking the cat that is in it from running rich too long (Magnaflow speced for 928) which is getting replaced today with a factory dual cat, its looking like poorly matched injectors.

Tell me more about the one time 2 year amnesty smog thing. Did you need to go to a referee station for that? (not a smart move for me in a Euro S).

Ron_H

Thanks Bob. Lots of good advice in your post. I wouldn't have thought about doing the 15 mph test in 2nd gear but that makes lots of sense. If it works, I'll get my tags and can then come out of the dark while I work on other issues as you mention. I wonder if using denatured alcohol would have cleared the injectors by now. I've already run through two and a half gallons of the stuff. However, new or cleaned injectors sound like a good idea and can't hurt a thing. First I'm going to do the obvious stuff this weekend and then try the test once more as you suggest using 2nd gear for 15 mph. My NOX is close so that might just be enough to pass. Then I may take you up on your offer

danglerb

AFAIK the alcohol does only one thing, water is soluble in alcohol, but not in gas. Adding alcohol removes any water in the system by running it through the motor.

During my STAR test I asked about using a better gear and was told the computer would not allow it.

dr bob

They wouldn't let me do it in first gear, but second was fine. I have the TV cable two turns loose, so the car rolls right up to top gear with the dyno load and 15 MPH, sits at ~~1000 RPM. Holding it in second or third brought it up enough without a red flag. Hence the previous suggestion to tighten the cable or force the kickdown solenoid.

The alcohol burns a lot cooler, so less chance of NOx --if close to stoich combustion--. If you have one or two partially-blocked injectors, they will need even more mass flow with alcohol blend, so not much if any advantage in this situation. Denatured alcohol is ethanol at heart, with a few contaminants that make it unpalatable. So for us we are taking pump E-15 and pushing it up to E-15+ something.

Ron, let me know quickly if you need the cleaner set-up. I saw it a few days ago, get it while I remember where it's stored. Honestly, you should probably bite the bullet and let a pro do the B-G cleaning if there's someone handy that can do it. I used it on mine twice in a short while, yet still saw a every significant improvement with new injectors a short while later. If your injectors and hoses are original, there' a real incentive to replace the old rubber bits as part of a clean/replace exercise on the injectors.

joejoe

Took the car out yesterday for about half the day. Needed to make many stops of 10 to 20 minutes in different stores. (this is when car had very hard time getting going again, would leave me stranded for up to 1 hour)

While it is not an instant start, (takes about 3 seconds of cranking) it never left me stranded, and upon start idle was perfect, no hunting at all.

Through out my work on this car here is what I found: crumbled tps wire that was spliced back together, driver side injectors replaced, passenger side had dry O rings cracked pintles, and one was missing. isv stuck, isv hoses cracked, vacuum lines leaking, MAF bad, orings for MAF hard.

The only thing ( i believe) not replaced has been fuel regulators/dampners. These have no gas smell so I am assuming (I know what can happen when you assume) they are good. I also need to check the check valve(?) but not sure where located.

Hopefully tomorrow will go for smog and be good for a few years.

joejoe

Took the car out yesterday for about half the day. Needed to make many stops of 10 to 20 minutes in different stores. (this is when car had very hard time getting going again, would leave me stranded for up to 1 hour)

While it is not an instant start, (takes about 3 seconds of cranking) it never left me stranded, and upon start idle was perfect, no hunting at all.

Through out my work on this car here is what I found: crumbled tps wire that was spliced back together, driver side injectors replaced, passenger side had dry O rings cracked pintles, and one was missing. isv stuck, isv hoses cracked, vacuum lines leaking, MAF bad, orings for MAF hard.

The only thing ( i believe) not replaced has been fuel regulators/dampners. These have no gas smell so I am assuming (I know what can happen when you assume) they are good. I also need to check the check valve(?) but not sure where located.

Hopefully tomorrow will go for smog and be good for a few years.