so.. what if I can't screw a different O2 sensor all the way in?

[daeron]

ECU has to be from an SPFI... probably even an 87. I know there's been wiring changes from 88-89, and 90+... I dunno if that would have an effect on whether or not you can use a later ECU.

 

Awww, HELL i didn't even THINK about that!!!!!!!

 

that makes that MUCH more difficult.. maybe the GL-10 turbo that they list is in fact a NON turbo, because it IS an 87......

 

hey wait, cool, i can yank the trip comp display out of that thing!! bingo!! AND maybe it has a sunroof, was that all GL-10s?? if so then i get a real driver side visor, too!!! (i currently have a non sunroof one, and they are longer)

[Gloyale]

Awww, HELL i didn't even THINK about that!!!!!!!

 

that makes that MUCH more difficult.. maybe the GL-10 turbo that they list is in fact a NON turbo, because it IS an 87......

 

hey wait, cool, i can yank the trip comp display out of that thing!! bingo!! AND maybe it has a sunroof, was that all GL-10s?? if so then i get a real driver side visor, too!!! (i currently have a non sunroof one, and they are longer)

 

Not to rain on the parade, BUT.....To install a trip computer, you need a fuel sender from a digidash car. And if you get that, then you will need a digidash to display the fuel readings. Sunroof installation requires removal of essentially the whole interior to get the headliner out. Dont' you already have big holes in the roof? LOL

 

On another note, I think you COULD use a ECU from a later SPFI, but it will require switching of some pins. My 87 FSM is at the Machinist with my engine right now. but if it comes to it and you want to swap ECU's tell me what year you get it from and MT or AUTO and I can scan you the pinouts for both. I'll get my 87 FSM back in a day or 2 here.

 

Ohh, and the *lean* condition is in reference to the fact that you're highest volt reading from the o2 sensor was .35v. That is a somewhat lean condition if it is working right.

[daeron]

yes i know. All of that.

 

My point was, I am not in any reality actually seeing a lean condition, correct?

 

I have a trip computer already; but the display is kinda fogged and the bulbs are shot.

 

I also have a sunroof already; but the drivers side visor that came with the car would NOT stay up, so I replaced it with the visor from a normal car. The sunroof controls take the place of the standard rearview mirror mount AND the standard "clip" for the visor.. so the slicktops have longer sun visors, and it doesnt fit in my car really. I need the sun visor from a car with a sunroof to fit properly.

 

all thats trivial, i was just realizing these things as I was typing that post.. "thinking out loud" so to speak....

 

Whats NOT trivial is this: does anyone know of any way to remove the pins from the plastic plugs on the ecu? I know that frequently, the metal terminals inside these plug thingies are held in by a locking tab that springs up when the pin is inserted into the plastic plug body; in doing all my relay work, i found a way to depress those locking tabs and remove the wires from the relay plug, so that I could replace them with thicker wires in appropriate spots. I would LOVE to find a way to stick an eyeglass screwdriver into the plug body on the ECU plug, and remove the pins; then it would simply be a matter of comparing pinouts from the two different year ECUs, and swapping my 87 plug to the 90 configuration. you get my drift?

[RenaissanceMan]

You should test it without it plugged into the ECU... just unplug the sensor in the engine bay and plug your multimeter's positive lead into the O2 sensor side of the connector, and ground the negative lead.... that should render the actual voltages the O2 sensor is giving as it generates its own voltage.

 

You can do it with the O2 sensor plugged in as well. Find the check connectors under the dash. One of the pins should be the O2 sensor output. Then you can open the throttle a bit and watch the O2 sensor cross hatch.

 

Well, we all got our own reasonig, my reasoning behind testing the o2 sensor while it is plugged in is because the computer no longer has control over the mixture when it is disconnected, and will probably set the code, go into limp mode, and run rich causing a constant high voltage. .8 to .9 volts, which yes works, but doesnt tell you anything IMO.

 

The computer does not add any voltage to the circuit when connected because it is a high resistance opamp or comparator type circuit, which is then converted into digital garble, and does not use a reference voltage like an ECT or a TPS

 

 

Sorry I forgot to mention with spark plugs that on some of the thread chasers they give you the really old school thread size which is 18 x 1.5.. they stopped using that size about the same time that flathead engines became obsolete. Didnt know you had that size chaser

 

FYI, if you disconnect your engine coolant temp sensor, your oxygen sensor will never be used (for help with diagnosis)

[Gloyale]

Awww, HELL i didn't even THINK about that!!!!!!!

 

that makes that MUCH more difficult.. maybe the GL-10 turbo that they list is in fact a NON turbo, because it IS an 87......

 

hey wait, cool, i can yank the trip comp display out of that thing!! bingo!! AND maybe it has a sunroof, was that all GL-10s?? if so then i get a real driver side visor, too!!! (i currently have a non sunroof one, and they are longer)

 

I have all this stuff if you need it.

[daeron]

okay, i am very seriously considering going and buying the brand new O2 sensor, but replacing it last time was a REAL PITA. I knew that the threads would be difficult, so I didnt even think twice about dropping the whole Y pipe/cat assembly.. but quite frankly with what limited supplies I have at the house, it was a ROYAL pain in the tuckus.... should I be able to replace the O2 sensor by just unbolting the manifold from the heads, and removing the one support screw between the cat and the first flange?

 

I just tried to "clear memory mode" and it refused to; it says it still has an O2 sensor code. When I connected both plugs, ALL difference that the "new to me" sensor had made vanished; the engine wanted to stall at idle (i dont know if it would have, i didnt give it too much of a chance) and it was VERY rough to start. I am going to replace the used O2 sensor with one that is brand new; i have had enough of these shenanigans, and I want to KNOW that my O2 sensor is NOT causing any problems. I hate to "throw parts at it" especially as broke as I am, but at this point I HAVE to... its what the FSM says to do in my situation, and the only reason I have been hesitant to do so thus far is my lack of fundage.

[Gloyale]

should I be able to replace the O2 sensor by just unbolting the manifold from the heads, and removing the one support screw between the cat and the first flange?

 

I think you can get it with the Y pipe still bolted to the heads. Box end wrench, preferably 6 point. The Y pipe secured to the heads will make it easier to get good torque on it.

[daeron]

I think you can get it with the Y pipe still bolted to the heads. Box end wrench, preferably 6 point. The Y pipe secured to the heads will make it easier to get good torque on it.

This may be true using jackstands; but I have none of those wonderful things here at my house. I just broke the adjuster wheel on my table saw trying to see if i could make a 45* cut on some lumber, and if i COULD have i would have made some ramps to drive up on to... but I am going to be stuck using my jack to hold the car up over my head. NOT something I relish; the other night I had it resting on a cinderblock with a section of 2x8 on top of the cinder block.. NOT a good idea either, but I have to improvise in some way. I guess if nothing else I will make some wood blocks to stick under the wheels once I jack it up...

 

okay, i just had to think that one out! thirty seconds ago I was stumped and resigned to just do it resting on the jack, now I know what to do.

 

BBIAB

[daeron]

Well, I just put a brand new O2 sensor in. Bosch brand. I left the battery cable unplugged for about 30 minutes or more (as long as it took me to change O2 sensors, plus about ten minutes) and fired it up... no dice. Ever since I tried to clear the memory earlier today it has been running worse than it has yet.

 

I try giving it pedal as its stumbling at idle, and it labors excessively to get up to RPM.. so now I am having a few new thoughts. I started analyzing it as if it were a carburetor problem, and tried anaologizing situations to the FI system.. SO, i want to try to disable the computers ability to enrich or lean out the mixture to a degree and see what data i can derive from that experimentation.

 

if I were to try running with the TPS disconnected, the ECU would fail to properly enrich the misture as the throttle opened, correct? in other words, if the car is for some reason giving it too much fuel, then disconnecting the TPS should help it not be bogged down, because it would fail to deliver so much fuel?

 

Similar questions arise regarding the MAF; if I am experiencing too LITTLE fuel, then disconnecting the MAF should improve my run condition somewhat, right?

 

As I type the car is roughly idling in the driveway, and im letting it come up to temp and then I am gonna give it a good spirited drive, I want to heat this O2 sensor up good and plenty and see FIRST if a brand new O2 sensor will behave as it should. I also want to see what the car does when it gets input from a good, hot, new O2 sensor.

 

Other than that; and POSSIBLY the analog ohmmeter on the TPS, I am now left with nothing BUT the ECU. at least I made a decision to act positively... but now I appear to be out $20. :-\

[RenaissanceMan]

Okay, so I just looked at the link to the other thread, looked at all the other things you checked, and looked at the video.. Your stumbling acceleration problem is from low vacuum, O2 code gets thrown from misfiring causing an always lean miixture reading

 

One thing everyone forgot to notice... that car is an Ea82 TBI.. with god knows how many miles on it. After a long time those timing belt tensioner bearings and idler bearings can wear out, causing slack on the timing belt.

 

Long story short, one of the belts on that car has jumped a tooth. since its running, probably the passenger side. if its not a belt then it might be internal valvetrain damage.. (I have seen one of those engines throw a seat before)

Most importantly, if the timing is ok, then those symptoms are low (or fluctuating) vacuum.

 

-Mike

[daeron]

Okay, so I just looked at the link to the other thread, looked at all the other things you checked, and looked at the video.. Your stumbling acceleration problem is from low vacuum, O2 code gets thrown from misfiring causing an always lean miixture reading

 

One thing everyone forgot to notice... that car is an Ea82 TBI.. with god knows how many miles on it. After a long time those timing belt tensioner bearings and idler bearings can wear out, causing slack on the timing belt.

 

Long story short, one of the belts on that car has jumped a tooth. since its running, probably the passenger side. if its not a belt then it might be internal valvetrain damage.. (I have seen one of those engines throw a seat before)

Most importantly, if the timing is ok, then those symptoms are low (or fluctuating) vacuum.

 

-Mike

 

 

I just did the headgaskets; they were half blown (bubbling out of the radiator) for about six or eight months. I re used the old timing belts, and made sure that they were properly tensioned and installed. I have already had practice in installing the timing belts properly; I have no reason to suspect that they are off at all. The only thing left for me to be 100% positive that your points are irrelevant* is to do a compression or leakdown check on the engine as it stands, now. If the timing had somehow skipped a tooth, the problem would have NO sort of intermittent nature; it couldn't go "on/off" with my fidgeting on the gas pedal.

 

*PLEASE don't get the wrong impression; I GREATLY value your input. The last thing I want is for anyone to take offense to me saying something like "your points are irrelevant." I am just being brutally frank, thats all. I hope you understand this

 

The reason I did the headgaskets when I did was that between them (low PSI on one cylinder) and this issue that I still have (had before and have now) the car was undrivable. After the gasket job, it got MUCH better, but half of my problem was still there; that half being the issue that has since deteriorated, and that I am dealing with now. I DID mill the heads flat, IIRC the one bad one needed about .004 taken off, maybe .006. The timing was set with a light afterwards.

 

IF, somehow, I failed to mention something that would make your point still applicable, PLEASE let me know; I am tearing my hair out and spitting teeth over this and I do not have enough of EITHER left to be doing so.

[RenaissanceMan]

Headgasket failures arent that uncommon on that motor, did you get the block decked? almost every time I take a subie apart the spot on the deck between the 2 cylinders is .002 low (which is barely in tolerence yes, but if the head warps at all then it adds up)

 

Sorry bout the assertiveness of the last post, was still recovering a bit from an evening of spirits

 

anyway, fo sho get a compression check and a vacuum guage on it. (you can actually do a running compression check to check for sticking valves too, it runs pretty bad on 3 cylinders, but as long as it will run you can leave the compression tester in the tested hole and see if compression drops below normal under certain RPM ranges)

 

*edit* Just thought of something else so I thought I might suggest this also. I still definetly think the hesitation is a vacuum problem.. Have you tried eliminating the PCV valve?? Just unplug the hose to it and cap it off and see if it makes any difference? Also have you eliminated the EVAP canister? If that guy is stuck on purge then you can have a minor vacuum leak. (at least at idle when your not supposed to)

[daeron]

well, i am off to unhook the battery cable to ensure that the memory of the ECU is completely cleared from the Bad O2 sensor juju.. tomorrow I plan on calling my ASE certified brother, and having him bring his fuel pressure gauge, and i suppose a vacuum gauge home so that I can check these things.

 

I havent checked fuel pressure; but I HAVE swapped in a junkyard pump and pressure regulator with absolutely no difference.

 

Judging from the way the car was running tonight, and the behavior of the O2 monitor LED, and the voltage that the O2 sensor was outputting once it warmed up (~0.25-0.35 volts) I am not getting adequate fuel. (OR am somehow experiencing a vacuum leak beyond detection of my ears.. I will verify this by flowing propane through the engine bay WITH CARE to see if i hear any change) Based on those results, friday I will go to the junkyard and get possibly:

 

A: fuel injector (even though the last time I checked mine the resistance was proper and to the best of my ability to tell, it was spraying fine)

B: ECU

C: ignition coil apparatus

 

and failing that, its spend cash i do not have on new cap, rotor, plugs, and wires... to replace the relatively new cap, rotor, and wires, and the ~40K mile plugs that were pictured above.

 

If all that fails then I may have to take my buddy up on the offer to borrow his bloody camaro... I dont WANT to, because that would involve taking the tag off of my already un insured car and illegally putting on that until such time as I can figure something better out... but I guess it would help him sell it if nothing else.

 

The system is well grounded, the O2 sensor is well grounded.... I am not so well grounded at this point but... I am lost. I am at wit's end. Maybe it needs an exorcism... "I've got it Odie!! Maybe theres Evil Spirits in the Distributor Cap!!" "The volcano, he no want de swahili, he want de 8-7!! he no get is soon he gonna make EVERYBODY die!!!"

[daeron]

Okay, I removed my injector today and inspected it; blew it out to the best of my abilities with the equipment nature gave me, and re installed it.

 

No change.

 

Unplugged the MAF.. No change.

 

Unplugged the TPS.. No change.

 

Unplugged the IAC (I am reaching here...) No change.

 

All of these were done independently.. IE, unplug, no change, plug back in, on to next component. I am sorely tempted to loosen up the dizzy and see if adjusting the initial timing changes anything.. but I dont think it will.

 

I cannot understand why trying to clear the memory sent me to a poorer running condition than I have experienced yet.

 

Thus far, the car has done one of three things..

 

1. Runs OK- this is essentially normal running, *maybe* a little down on power

 

2. Runs poorly- this involves alot of misfiring, very low power, sounds a bit like fuel starvation, but more like incorrect timing than anything else I can use to analogize.

 

or

3. Runs like CRAP. This resembles nothing more than total fuel starvation, ie, taking a turn at 40 with 1/2 a gallon left in the tank, at WOT. Sometimes this also involves backfiring and/or occasional fairly loud predetonation.

 

Before I did anything, with used O2 sensor #1, it alternated between "runs OK" and "runs poorly." I could fiddle with the pedal back and forth, and get it to come around eventually. WOT made no intrinsic difference. Used O2 sensor #1 produced little to no voltage under any circumstances.

 

When I put used O2 sensor #2 in, I had to chase the threads.. afterwards, the car ran OK MUCH more often than it had been.. BUT when it relapsed, it ran like CRAP. Didnt make much sense. O2 sensor #2 put out minimal voltage when I forced it rich by taking a spark plug off, but voltage was anything but consistent.

 

Then, when I tried to clear memory mode, it began a new episode.. Now it runs "poorly" no matter what I do. I put a brand new bosch O2 sensor in it last night. still runs poorly. Stumble, misfire, occasional detonation (moresoe if I put my foot into it) Left the battery cable off overnight; get in today, still runs poorly. I *think* and this is a big MAYBE here but I think the fuel mileage improved when it ran OK/CRAP... and I believe it is back to as bad or worse than it ever was now. I DO now get proper O2 sensor voltage from the sensor when it is warmed up; I can watch My O2 monitor LED and see what is going on.. and the LED is NOT on all the time. So my problem is (apparently?) NOT that I am running RICH.

 

I am so fed up with it all. The pisser is, at this point I have developed the pessimistic view that its GOT to be something in my ignition consumables.. but I no longer have the $$ to go buy plugs cap wires and rotor. I am going to borrow a hook sharpener tool from a buddy tonight and file down the contact points inside my distributor cap.

 

AND, I am going to my oldest brothers house this weekend to work with him painting, etc, to earn the $100 he gave me that funded this weeks food (i actually ate something other than ramen and PBnJ this week, :applause:) and the O2 sensor. so, no USMB, no workie on car. (brother lives ~70 miles away, just too far to be worth "commuting") I plan on getting his compression checker from him to confirm that I didnt mess up doing the headgaskets somehow.... but I cannot imagine that is the case. I had no opportunity to contact Other Brother about using HIS fuel pressure gauge, and vacuum gauge, and I doubt that I will have such an opportunity until monday at the earliest.

 

Anyone still reading this thread, I heartily appreciate it.. it was NOT my intention to let all discussion of my problem move over here from the last thread but thats just kinda how it happened.

 

Gloyale mentioned an idea to me via PM.. with the major rust on my car, what are the odds that there is something afoul with the fuel tank vent canister and its associated plumbing?? I tried pinching my fuel return line as well, and that made no difference... Again, all I am left with is the methodology utilized in Garfield Goes to Paradise.. bang on the fender and chant, "check-a-buh-MOO. guh-Moo-kah!!" repeatedly. :banghead: :banghead:

[RenaissanceMan]

You wont find any ignition points on that car...

 

Get a vacuum guage on it, Looking at vacuum tells you so much you can even adjust your timing that way, lol

[daeron]

You wont find any ignition points on that car...

 

Get a vacuum guage on it, Looking at vacuum tells you so much you can even adjust your timing that way, lol

 

It took me a couple of minutes to figure out why in the world you thought, that *I* thought, that I had points in my distributor.

 

By "contact points inside the distributor cap" I meant the points on the underside of the distributor cap where the rotor touches the spark plug wire terminals, not the "points"

 

If I were THAT ignorant, I would have given up on this a LONG time ago.

 

"My points look funny, they are just this slotted disc thingy...wtf!?!?? Who put a strobe light in my distributor, is this a discotheque or something?!?"

[Cougar]

I think the best thing you can do next is get a vacuum gauge and see what it says, like RM suggested. From all the things you say, the problem again seems to be due to either a intake vacuum leak after the MAF or the fuel is running lean for some reason. It may be better to replace the injector than the ECU. If the vacuum readings seem normal then I would suggest replacing the injector. Before doing that though it would also be good to know that the fuel pressure is ok.

 

One thing about resetting the ECU is that it has to relearn the engine running conditions. It is not always the best thing to do in my opinion. I think this applies more to OBD2 than your system. There are proceedures that need to be followed while the ECU is relearning but again, I think this may only apply to OBD2 systems.

[daeron]

!@#$%%^&*

 

 

cylinder number four is not firing. The spark plug is sparking yellow, (it hit the hell out of ME) and it is not firing at all.

 

I do not know what this may mean (toasted ring, cracked piston, block problem??) because none of the logical potential problems could ever have been sporadically intermittent... I am going to try yanking a plug or two out of my Z engine and see if they might make a difference.....

 

but i think i may have blown the friggin engine somehow.

 

can you say "livid?!"

[daeron]

I DON'T BELIEVE IT.

 

 

I just pulled four nasty-rump roast rusted spark plugs out of my datsun, the electrodes looked like BUTT, the tip that attaches to the plugwires were all loose, etc etc...

 

 

 

ant the FERSHLUGGIN car is idling, and running better than it has in a pigs age.

 

I knew it was going to be something, and I've thought dozens of times about ripping plugs out of the Z, but they are just as high mileage as the ones that I was using, and they looked MUCH worse....

 

 

but looks mean jack ***************.

 

The next time I hear someone say "aww, plugs last forever if they arent physically damaged" i will laugh at them.

 

If only I hadnt been fired for saying "hey, since youre overstaffed today anyhow, could I take the day off to try to figure out why my car isnt running right?" three months ago, BEFORE i did the headgaskets, this would have taken all of a $40 tune up (cap plugs rotor and wires) to diagnose... but since I HAD to be cheap about it...

 

 

GOD i could KILL myself!!

 

I cant say 100% that everything is fine now.... BUT the car is idling as I write this.

 

i gotta go, anyone want to come down and shoot me for idiocy can feel free to do so.. but my hands were tied. I HAVE literally been surviving on Ramen, PBnJ, and the good grace of my landlord buying a real meal for me once a week for over three months now; the problems with the car have made getting a job a very difficult proposition.

 

I almost want to ban myself for a month for this.

[Zebisko]

Well, I figured it would be something stupid. But, hey, it works now! Good beans:banana:

[Cougar]

Well that is good news. I wonder though if something happened to make the plug go bad. The picture of the plugs you showed looked like they were running like they should be. Replacing the O2 sensor seemed to help also. BTW, what is the O2 sensor voltage reading at now that it is running better. Is it around 0.5 volts?