Just got a 1986 Supra it needs help, Please, Running Poorly
 

Before I get started I just want to say THANK YOU to the many people who have posted help and input for others. I have spent the last 4 days becoming a fan of the search tool and you all have so much great info.
I just purchased my 1st Supra this week and I am thrilled to have something to go completely overboard on. I have reached my 47 years the hard way leaving behind a trail of broken bones, torn ligaments and nerve damage. I will miss motorcycles but plan on enjoying my Supra on the twisty roads of the North Georgia mountains. So anyway Thanks..great stuff.
I just bought a 1986 Supra HB 5 speed about 100 miles from the house. The seller says that the following work has been done after the car owner brings it to him apart. Seems like a honest guy running a small repair shop, he tells me he had to purchase a download manual to help him assemble the car since he wasn't familiar with the car. This is what he did; Head Gasket replaced, cylinder head received a valve job,head resurfaced, brake master cylinder, plugs and wires. The car has sat for a couple years then sat again for 6 months after the repair.
Starts up easy and does a cold start high idle of about 2300 and only drops to about 1300 rpm at warm idle. Wack the throttle and the idle will drop to about 1000 rpm and then very slowly climbs back up. Taking off from a start it doesn't seem to pull very hard, while accelerating if you roll back off the gas a little it seems to clean out a little and pull smoother. If you stay in it at about 4800 rpm it starts to pull a little harder and more smoothly. It doesn't smoke or knock at all.
I included some pictures from under the hood, please feel free to ridicule and abuse but in return offer a fix for me. The distributor seems a little jacked to one side of the adjustment range. I am thinking that I hear a vacuum leak and although it looked like it was sealing OK the duct tape intake repair may be some of the problem.
I appreciate any thoughts or suggestions. I can't figure out exactly where the parts that were left hanging go. There is a green one wire plug hanging there that I don't know if it should be hooked up. The code it's spitting out is 52, have not tested the Knock Sensor yet. The cruise doesn't work and the fuse is good.
Thanks for your help.
Dave


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Oh yeah,
Where do you recommend to but OE parts? I need things like the Intake boot and chrome trim and probable a knock sensor orlike part. If you have any suggestions like a OEM seller or a OEM type aftermarket company. I do have a few salvage yards pretty close by.

Thanks

First off welcome and i hope you find the forum as much use as i have. I cant see the pics as im on mobile atm but if you suspect the intake may be leaking post AFM that would cause high idle and iffy power so thats first on your list. Before you buy parts though check the pas idle up valve connection under the intake pipe, its 1/2" approx rubber hose leading from the intake to a round valve on top of the pas pump then from that to the steel vac pipe that runs across the front of the motor under the water pump. If that and the intake pipe checks out and you still hear a vac leak the tsrm has great diagrams of all vac hose routing, maybe someone on a pc could post a link?
Failing all that the idle control valve could be sticking, although that would usually cause more distinct issues. I'm tired and my phones being funny so am gona post quick an if i think of anythin else il get back.

Thanks for the post that is some stuff I didn't even think of, Thank you. I may have to get some more details I will check it out. Sounds like you are going to be sleeping soon but the Supercross is coming on TV at 7:30 est. I will be in the "Supra Web Search" mode for the next 3.5 hours while watching. So a Honda 500 Custom, those CX motors are tough, cool.

Just to save someone some time I have scored the diagrams mentioned. Awesome stuff that online manual, allot I pulled from the search option.

Looks like you may not need a knock sensor, that green one wire connector is your knock sensor wire. IIRC, it should plug in to a fairly large knock sensor a little closer to the front than half way down the block on the intake side of the engine.

if it don't work, duck it.

welcome to the bored.

Thanks BTWilson I was hoping someone would tell me where that went. Would there be any reason someone selling the car would disconnect it? It could be he couldn't see where it plugged up once he put most of that area together.

Can anyone tell me what he may have done in order for it to run without the knock sensor hooked up? Would this explain the low power as well?

And to Green7mgte, Thanks for the welcome.

Found a brass nipple with a red o-ring on the side of the block below the intake manifold. Because of the current routing of the wire it looks like I will have to remove the manifold in order to reach the sensor. Any hints or tips on this. It might be a good idea for me to recheck this repair anyway. What do you all think, what would you do?

Thanks

Thats the ks with the red seal. It was probably forgotten when the mani was refitted, i'd pull the thing and reconnect (drain the coolant as it runs thru the mani, also fit new mani gasket for the same reason).

Oh by the way, the cx is a eurosport (ec)! It just soldiers on, all ive done is oil, tyres, cables etc.
Oh and one time the temp gauge was running in the red for 2 weeks or so, i thought it was the gauge regulator which is a common thing, except when i opened the rad to change antifreeze it was dry! (never found the cause, no leaks) So yeah they are tough motors with a capital T!

Okay, well I guess I was looking for a good excuse to a redo, there are some things left hanging. Should I do anything with the injectors while I am there? The car sat several years but it ran. Any other stuff I should take care of let me know, for sure i will take care of the exhaust manifold gasket. I really liked Honda's Turbo CX's. My family owned a Honda dealership in the 1980's and early 90's.

Is there a section of the online manual that covers removing the intake manifold? Knowing what is necessary to remove in order to do the job. I have looked for it but do not see it. Do I separate the manifold assembly or remove it as one piece? Does the alternator need to come off ? You get the idea, I just am used to motorcycle factory shop manuals. Thanks

Hey, got your PM... sorry, been exhausted and busy...


Have you checked for diagnostic error codes?

An intake leak may be causing the high idle, but I'd also check to see if the TPS is properly aligned and that the throttle plate is closing ALL THE WAY when the throttle is released. The throttle bypass screw should also be tightened all the way... it's not used, but for some reason everyone's gotta screw with it (pardon the pun ;) ).

If the car is sluggish until around 4000RPM you should inspect the ACIS system, but it should be kicking in well before 4800RPM unless the TPS is WAY off. The ACIS system modulates the intake's air flow using a butterfly in the middle of the surge tank. If you look down between the forks of the Y pipe you'll see a metal can style diaphragm that's connected to a rod entering the surge tank... this should move when you rev the engine high.

What you need to remove to pull the intake's going to depend on just how much you're planning on pulling... the only trick bit is the coolant hoses which route through the throttle body and through the idle speed control valve and back under the lower intake plenum. Most of the bolt locations and torque specs are in the TSRM under the "Engine Mechanical" section.

No worries CRE, thanks for the additional input. It is great all the solid info that has been given. The code was a 52 and the KS is unplugged and incorrectly routed. In order to connect it and to check all these other things given I am going to disassemble down to the valve cover. I think that the ex. mani is leaking and a possible vaccum leak. I am not sure yet which screw you are talking about but I am sure the previous mech messed with it trying to compensate for the unplugged KS. Did you see the picture with the distributor bolt? Does that look to far off center for the norm? Hopefully I can get busy tommorrow. Still open to suggestions as to where to but OEM parts such as the 45 Intake boot and intake mani gaskets, etc.
Thanks All
When in Doubt...Gas it!

Removed the throttle body and was able to route the KS wire down between the manifold. Should be able to connect it tomorrow. This thing is nasty up inside the mani. Now I have tough decision of cleaning it all up now or get the car running correctly to be sure there aren't any major deals with the motor, then disassembling it to clean again later.
The steel line that runs across the front of the motor, it sure looks beat up, It looks a little dented and bent. Should that be a problem? Should I assume it's bad and replace it? What do you think?

This is the BVSV, it has nothing connected to it? Does it need this in the loop to run correctly?

Yeah, run the charcoal canister's purge to the BVSV and from there to the TB. It's a flow control which prevents the charcoal canister fro providing extra fuel when the engine is below a certain temp.

The BSVS has one of the nipples broken off. Is there a fix or just get another?

Nice info link at the bottom of your last post CRE.

Thanks folks

The BVSV's are very expensive new and I don't know of an aftermarket solution. The best bet is to hit up a salvage yard and grab a couple off any Toyota's of a similar vintage. Most will fit and operate at a similar temp.

Thanks, I really need to update some things and add a couple new wiring diagrams, but you know how it goes... other priorities and all that.

Have everything out of the way and was able to plug in the KS. Now I have to be able to check the vacuum line routing and connections. I guess I can understand the lack of clean up for a flat rate mech, but man it sure was nasty in there. What causes that much intake goo? It looked like mud/grease all though the intake plenum and box. It is now much cleaner.
There is a small 2 hole bracket with vacuum line hook ups, on the drivers side below the intake. Any ideas on what those 2 bolt holes line up too? This thing has been good to work on so far. Thanks

http://www.cygnusx1.net/Supra/Librar...spx?F=1708&P=2

;)

There is a broken wire on one of the connectors, VSV I think the filter is broke of it and now there isn't a bit of wire to repair the connector.

As far as the broken wire, I was thinking that I could take a straight pin and connected the wire and connector using the pin in the center and solder the area. Sounds pretty cheap, I haven't figured out how to push the remaining wire out of the connector and go at it that way. I am open to suggestions, please.

thanks

Running much better...just not good enough
 

So the car is back together and running much better. The cruise control even works. The vacuum lines where messed up so that helped but I still hear a vacuum leak. The motor started easily and had a rough idle for a while and then would settle down and idle at 1100 or so. It still doesn't have any snap to the throttle. It pulls better than before and seems to do it pretty smooth from about 2500 up. I have that one sensor, a vsv I think, has a broken wire and none of those type sensors have that filter on the end of them.
As far as the air leak, I am wondering if it is the mani, I sprayed a little brake clean near the front of the mani and the idle definitely changed.
Do these carss have manifold issues, the gasket was new so I reused it dry. I did not take off the bottom half, the real manifold. Oh well it runs OK, I could use a suggestion or 2. Oh and no engine light.

Thanks

Can the car run correctly without the VSV connected? I have a broken wire right at the connector. It will be a hassle to repair the connector. Any tips?

It still doesn't have any snap to the throttle. It pulls better than before and seems to do it pretty smooth from about 2500rpm.

:help:

IIRC one of those vsv's is to do with fuel pressure & should really be connected, it's possible the whole thing is u/s if the filter is broken off so I'd try find a replacement if possible. As for the broken wire I can't see exactly how it's broken but if it's inside the plug as I'm thinking I'd just shave the side off the plug & solder the wire back onto the exposed connector. Try that first off & see if that improves things.

If you can still hear a vac leak it could be that front metal pipe we mentioned earlier or even the broken vsv, ideally you want a stethoscope or similar to trace more accurately where the sound is coming from. Glad you have it running at least some better anyhow.

P.S. you said the idle changed when you sprayed round the manifold gasket, so that's another suspect for your vacuum leak I guess... are all the mani' to head bolts tight first off with that one?

Oh the joys of using a real computer, I can actually look at longer threads & replying doesn't cause cramp in my thumb!!!

There are three under the intake manifold on the N/A: EGR, ACIS and Fuel Pressure Control.

Both the ACIS and FP Control will affect the engine's operation at higher RPM operation although a defective ACIS system usually leads to crap performance up until right at 4KRPM... it's still worth investigating.


I hear ya. I've been so busy with work that all I really ever have time to check in with is my cell which I've recently replaces with a newer one with no physical keyboard... it's nice though, I can still access the full site and it's MUCH faster.

The wire is broken off flush with the back edge of the connector on the harness side.

I think getting this ACIS system working first may take care of most of the running issues.

The 3 sensors we are talking about, are they only on the NA's?

Would this explain why the car runs on 5 cyl. and the will skip into a 6 cylinder running mode?

Thank you again for your input.

I found a connector at the junk yard for $5. Nice. So the car idles much better but still will not pull under hard acceleration. Roll out of it a little and it feels as though the motor adds a cylinder and pulls smooth. It seems to get better as it gets hotter, not good, just better. I did the vacuum test from the manual and I have vacuum when I shouldn't or don't have it when I should.

Any ideas? Thanks

Can someone please tell me where in the shop manual you can find the factory settings on the screws on the TP? The stop screws and the one on the diaprahm do-dad? I appreciate it.
:dunno:

You mean the TPS, I presume? It's in the EFI section under Throttle Body and then Throttle Position Sensor.

The screws I was talking about are on the firewall side of the TP, opposite of the TPS. One is on the linkage and the other on a diaphragm attached to the TP. Some type of stop screw I think.
I cannot get pics today but if that is what is needed, I will. The guy told me he adjusted the idle using them. I believe that is not the correct so I wanted to set the screws back to spec?
Thanks

Can a clogged CAT make the car stumble on hard acceleration? Not real hard, half throttle and up. I replaced plugs (NGK) and set the TP values(ohms). It runs better but has a rough idle and will not pull hard unless you gas it easy.

Appreciate your help. And hey if I am doing something wrong in my posts please let me know. First time forum user. Thanks

Help Please
 

I still have not gotten the car accelerate hard. It will go just feels like a 4 or 5 cyl most of the time.

Will a leak in the hose coming off the front of the valve cover, vent. hose #3, cause running issues?

I have read several places suggesting removing the egr and related lines. Is this a good idea? I have no emissions testing in my area.

The car seems to idle higher and better once it warms up.

Bad Form in my Forum.
 

Look,
I apologize for any incorrect "Forum" etiquette that may have caused any problems with my post. It seemed pretty lonely, so maybe I was just re-hashing things too much. Either way you guys helped and I appreciate it.

The car's biggest issue was the injectors being clogged due to sitting for over a year. (I may have failed to mention that). I read somewhere to run the injector additive, I used Lucas, and after 2 or 3 tanks the car runs much better. It stills runs a little rich below 3K and will not accept full throttle consistently, but it's getting better the more I drive.

If my check engine light is not flashing anymore and the EFI has been cleared, does that mean that I have no error codes? The light works fine, just wasn't sure what came first the flash or the jumper?

Thanks- I love this car.

So I re-read your thread, and saw you mentioning your distributor adjustment.

I think, since the car is running a little better, that now would be a good time to check your timing. I know that if one of your camshafts is just a tooth off, it will run similarly to what you're describing.

Remove the plastic upper timing cover, and verify that when the engine is at TDC on the compression stroke the 2 cam gear timing marks point straight up, inline with the raised line on the timing plate behind the cam gears. Also make sure your crank is pointed right at the 0 mark. If not, release the belt tension, slide the belt off the cam gears, and adjust as necessary.

Once that's all dialed in, replace your timing cover and idle the car up to operating temperature. You're gonna put a jumper wire in the diagnostic box (like you're checking for codes), hook up a timing light to the no.1 cylinder wire, and set your base ignition timing to 10? BTDC. Make your adjustments by loosening that dizzy bolt and turning it till it's set. Once dialed in, tighten the bolt, remove your jumper wire, disconnect the timing light, and go for a drive.


Let us know how it drives then


Oh, more detailed instructions on checking timing can be found in the TSRM

Great, thank you so much. I think that the exhaust is leaking at the header flange. Has a little spit sound goin on. I am impressed with the temp while running, regardless of town or highway it stays below the 1/2 way mark. Cool!

Just so you know I will be following your advice, just have to snag my timing light back from my brother.:crazy2:

Cam timing was out.
 

Just wanted you to know. I have been on IR and just now checked cam timing. Right cam off by 2 teeth. Improved performance. Can't thank you enough for your advice.

Update: The battery would start the car but as time went by it acted like it wouldn't hold a charge. I swapped the battery out and it improved the cars performance. I suppose I could have had a bad cell. The cruise is still not working, I sometimes can adjust the steering wheel and it will work. Any thoughts there? The idle still slowly climbs to 1200rpm after blipping the throttle. Today I will remove all the intake components and check the TPS and ISC. Can all the TPS settings be done off the car? It is running better all the time.

Really need help
 

I am checking the cam timing and I remember reading somewhere that you can look inside the oil filler cap and see the cam lobe pointing upward. I believe that the guys who did the BHG made white marks and a L or R on the cam gears. The issue I am having is that when I line up the painted lines and the crank is on 0, I can't see the upward pointing lobe. The look more closely and see stamped marks at 6 oclock. So my concern here is that somehow the guys have the cams 180 out. I don't even think it would run. I rotated the crank 360 and the lobe still cannot be seen. The car has been running OK just a idle issue.

So here it is.

1) Does anyone know about the looking at the intake cam and seeing the lobe when piston 1 is at TDC?

2) What is the deal with the marks on the cam gear? Painted vs Stamped?