idle hunting, 20v shenanigans

AlexFourTwenty
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idle hunting, 20v shenanigans

Postby AlexFourTwenty » Sat Dec 09, 2017 2:56 pm

So my friend put the cables on incorrectly just for a second and now won’t start. It’s getting no spark. Everything else is good. Car cranks but there’s no spark. I check at the spark cables, No spark. check at the coil cable no spark. I checked the igniter and it’s getting power and ground. How do I test the coil and if anyone can help with fuse locations related to ignition system. My fuse box covers are missing. It’s an ae86 with a 20v swap.
Last edited by AlexFourTwenty on Tue Dec 12, 2017 4:47 pm, edited 1 time in total.

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jondee86
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Re: Jumper cable mishap burrrnnnnn

Postby jondee86 » Sat Dec 09, 2017 9:42 pm

Copied this from somewhere else...
First you need to test the coil. Test the primary side of the coil by taking the
plug off the coil and checking the resistance between the two pins with your
multimeter. You should get between 0.36 and 0.55 Ohms.To test the secondary
side, take off the high tension lead from the coil and test between the positive
pin (one nearest the key/spline/slot in the plug) and the high tension terminal.
You should get between 9.0 and 15.4 kOhms.

It was for a 16V smallport and I think the coil is near enough the same. And you
might as well pull all the fuses in the underhood fusebox and check to see if any
are blown, there aren't that many :)

Cheers... jondee86
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Re: Jumper cable mishap burrrnnnnn

Postby notnilc20 » Sun Dec 10, 2017 7:40 am

AlexFourTwenty wrote:So my friend put the cables on incorrectly just for a second and now won’t start. It’s getting no spark. Everything else is good. Car cranks but there’s no spark. I check at the spark cables, No spark. check at the coil cable no spark. I checked the igniter and it’s getting power and ground. How do I test the coil and if anyone can help with fuse locations related to ignition system. My fuse box covers are missing. It’s an ae86 with a 20v swap.


So you got an ae85 and an ae86 both w/ silvertop swaps? :o . After you test the coil, I wouldn't let your friend near your battery after that as well.

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Re: Jumper cable mishap burrrnnnnn

Postby AlexFourTwenty » Sun Dec 10, 2017 12:32 pm

No this is my friends ride, we both have st swaps my car is just lighter :D we actually found it does have spark just not very strong. The spark is really weak. Anyone can shed some light?

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Re: Jumper cable mishap burrrnnnnn

Postby AlexFourTwenty » Sun Dec 10, 2017 12:34 pm

jondee86 wrote:Copied this from somewhere else...
First you need to test the coil. Test the primary side of the coil by taking the
plug off the coil and checking the resistance between the two pins with your
multimeter. You should get between 0.36 and 0.55 Ohms.To test the secondary
side, take off the high tension lead from the coil and test between the positive
pin (one nearest the key/spline/slot in the plug) and the high tension terminal.
You should get between 9.0 and 15.4 kOhms.

It was for a 16V smallport and I think the coil is near enough the same. And you
might as well pull all the fuses in the underhood fusebox and check to see if any
are blown, there aren't that many :)

Cheers... jondee86


Jondee I’m getting .7 ohms and 13k ohms. This sounds about right correct? Why would it be getting weak spark. Do you think I shorted to ground somewhere and now it’s weak sparking?

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Re: Jumper cable mishap burrrnnnnn

Postby CloudStrife » Sun Dec 10, 2017 2:41 pm

Dude, don't just randomly try ****. You were on the right path when you were going down the line investigating spark.

There is a measurement in the FSM. You should have one anyway. Coil/igniters are pricey, you want to make absolutely sure it's still good.

That's very strange you are getting spark, but it's weak. If that is the case, your fuses will not be open and they will look "good", so it will be hard to tell. Are you getting spark directly from the disty leads? Or are you talking about from the coil wire coming from the igniter?
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Re: Jumper cable mishap burrrnnnnn

Postby AlexFourTwenty » Sun Dec 10, 2017 3:00 pm

CloudStrife wrote:Dude, don't just randomly try ****. You were on the right path when you were going down the line investigating spark.

There is a measurement in the FSM. You should have one anyway. Coil/igniters are pricey, you want to make absolutely sure it's still good.

That's very strange you are getting spark, but it's weak. If that is the case, your fuses will not be open and they will look "good", so it will be hard to tell. Are you getting spark directly from the disty leads? Or are you talking about from the coil wire coming from the igniter?


Well I’m getting weak spark from the coil lead and then I tried it from the spark plug cable leads and I have spark as well. I’m guessing it not enough because I keep cranking to start and nothing. Idk if I did the coil test correctly but those measurements seem to pass spec. What is fsm?

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Re: Jumper cable mishap burrrnnnnn

Postby CloudStrife » Sun Dec 10, 2017 3:29 pm

Oh ****, I think it's Field Service Manual?? Haha, it's just the OEM service book for our cars. You can download it online, but I don't remember where.

However you have a 20v, right? Your igniter is different if I remember correctly. It's not like it's vastly different (Like JohnDee said) but your measurements might be different.

Basically, all your looking for is an open. Or something close to an open, but you are right, the measurements you took are still basically in spec.

Hmm. If you are getting spark, it must be something else. When you check for spark, I don't think it matters how much is coming through, I mean hell, in the service manual it just says "you see spark?" "GO TO NEXT LEVEL, YOU WIN". So I don't think it matters what volts or current.

Did you check ALL of your fuses? Like I said, sometimes they look good, but they aren't.

If they look good, I would check your starter. It's a bitch, but pull it out and activate it on a bench (you basically put one jumper on the positive and one on the terminal) and make sure it shoots out and spins. I used to have a video of it actuating but I lost it :(
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Re: Jumper cable mishap burrrnnnnn

Postby CloudStrife » Sun Dec 10, 2017 3:30 pm

Oh wait, it cranks, but it doesn't catch, right? So maybe EFI fuse?? You have spark, your starter is engaging, so you must not be getting fuel or air.

Just for my interest.. Can you make a video of sparking the disty wires? Just find a chassis ground, have someone hold it close and get in the car and start cranking. Just want to see how weak it looks..
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Re: Jumper cable mishap burrrnnnnn

Postby AlexFourTwenty » Mon Dec 11, 2017 5:39 pm

CloudStrife wrote:Oh wait, it cranks, but it doesn't catch, right? So maybe EFI fuse?? You have spark, your starter is engaging, so you must not be getting fuel or air.

Just for my interest.. Can you make a video of sparking the disty wires? Just find a chassis ground, have someone hold it close and get in the car and start cranking. Just want to see how weak it looks..


So you were partially right, Spark was fine. Like you said spark is spark. I found out the problem was Engine was flooded with carb cleaner and spark plugs were soaked due to me cleaning the itb’s beforehand. I removed the plugs cleaned them and spun the engine a bit to get all the excess out put the plugs back and with a little struggle it started and now I’m a happy 4age owner. It’s running real hard now with the clean itbs. Breathing tons better. Only thing my idle is fluctuating now? Is this the ecu getting used to the new parameters? Thanks for all your input guys. Really appreciated!

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Re: Jumper cable mishap burrrnnnnn

Postby jondee86 » Mon Dec 11, 2017 7:43 pm

Heheheheh.... I was just going to suggest trying a new set of plugs :) Same thing
as happened to someone else on here recently... cranked for so long the engine wouldn't
fire. Tried everything else just like you, and then put in a new set of plugs and it fired
up first turn of the key. Glad you got it sorted... drive safe !!

Cheers... jondee86
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Re: Jumper cable mishap burrrnnnnn

Postby AlexFourTwenty » Mon Dec 11, 2017 8:52 pm

jondee86 wrote:Heheheheh.... I was just going to suggest trying a new set of plugs :) Same thing
as happened to someone else on here recently... cranked for so long the engine wouldn't
fire. Tried everything else just like you, and then put in a new set of plugs and it fired
up first turn of the key. Glad you got it sorted... drive safe !!

Cheers... jondee86


Thanks jondee, any recommended steps to tackle first for the idle fluctuating up and down? TPS?

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Re: Jumper cable mishap burrrnnnnn

Postby jondee86 » Tue Dec 12, 2017 12:05 am

AlexFourTwenty wrote:any recommended steps to tackle first for the idle fluctuating up and down? TPS?

Don't remember ever hearing of a fluctuating idle problem with a 20V.... as in the
idle making a regular repeated high/low cycle. If the TPS is not set correctly you could
get a rough (irregular) idle. Good idea to check it every now and then. You need a set
of feeler gauges and a bit of patience :)

Also check for vacuum leaks. Make sure there are no hoses that you haven'y hooked up.
The ISCV should hold the idle steady if your ECU is doing its job. Are you running the
factory AFM and airbox ?

Cheers... jondee86
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Re: Jumper cable mishap burrrnnnnn

Postby CloudStrife » Tue Dec 12, 2017 4:29 am

I agree with Johndee, vacuum leak would be more suspect than a faulty TPS for 20v, never really heard them go wrong, but 16v on the other hand... haha.

I think the motor is just sorting itself. Just drive around like you usually do, and maybe even treat it like a rotary and run it hard for a few days.

If it's idle "hunting", then that's a clue. Like he asked, having an AFM/stock setup or aftermarket would be essential for figuring it out. Have a picture of the bay? The easiest test for a TPS is to just unplug it while idling and see if the idle changes.. even slightly. Leak-down test on vacuum would be next.
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Re: Jumper cable mishap burrrnnnnn

Postby AlexFourTwenty » Tue Dec 12, 2017 4:26 pm

Yes I have stock plenum and stock afm. I had set the tps as best I could with an identification card which is .30 as a feeler. Set it so as soon as I touch the throttle it reads infinite. The idle cycles high and low and sometimes it stays up high for a bit then starts the high low again. I sprayed around the plenum to look for leak but it’s kinda hard with the idle all erratic. What I did notice is if I take off the booster hose and cover it with my finger the idle settles but still stays a bit higher than normal. Also forgot to mention I’m not running O2 Sensor and it has stock plenum but I think there’s a lot of vacuum deletes. I know the scavenging hoses are just pooped under the itbs but it was idling fine before I cleaned the itbs.

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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Wed Dec 13, 2017 6:23 am

This morning I was fiddling with tps and afm while I was warming up and if I disconnect the afm connector it idles better but it doesn’t accelerate for ****, with it connected it pulls good. TPS seemed to affect idle a bit but not as much as the afm. Also noticed if I push back the throttle it calms down as well. Is There a way to adjust the throttle? Maybe the throttle opener is staying a bit open?

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Re: idle hunting, 20v shenanigans

Postby jondee86 » Wed Dec 13, 2017 12:19 pm

AlexFourTwenty wrote:Maybe the throttle opener is staying a bit open?

The throttle opener is a vacuum servo, so when the engine is running and making
vacuum, the throttle opener should be retracted. It should not be touching the
throttle linkage. When the engine is turned off, the opener extends and holds the
throttles slightly open. If the adjustment becomes loose, it can hold the throttles
slightly open when the engine is running, raising the idle and messing with the TPS
setting.

You don't need it... the engine runs just fine without it ;)

If the idle drops when you block the brake booster hose, that suggests that you have
a leaking brake booster. Might be worth checking.

Cheers... jondee86
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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Fri Dec 15, 2017 6:31 am


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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Sat Dec 16, 2017 6:27 pm

Little update. Today I took apart the itbs, I removed the vacuum bird nest underneath them and the Iscv as well. I cleaned up iscv but I noticed it was blocked off. Why would they do this? This valve only moves about 90 degrees correct? I put everything back and deleted the bird nest thing along with the throttle opener thing. Adjusted tps again and thing wont even idle now. No vacuum leaks I sprayed carb cleaner to check. I disconnect the afm and it’s okey just very very rich. What’s going on here. Faulty afm? Is There a way to test this contraption? Also Is there anything I need to do to the vacuum lines when deleting the throttle opener and the metal vacuum lines underneath the throttle?

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Re: idle hunting, 20v shenanigans

Postby jondee86 » Sun Dec 17, 2017 6:21 pm

Hmmm... the more you fix theis car the less it goes :) Couple of things that need
to get sorted / made clear...

1. The AFM is the primary load sensor for the engine. It tells the ECU how much air
is going into the engine so that the ECU can calculate how much fuel to supply. It also
contains a switch actuated by the flapper to turn the fuel pump ON, so if the car is
upside down in a ditch and the engine stops, the fuel pump is no longer pumping fuel
onto a hot exhaust.

So at least in theory, if the AFM is unplugged, there is no circuit for the FC switch
and it is not possible for the engine to run. If it does run with the plug off, then I'd
say the wiring has been "creatively improved" to bypass the FC switch. Should this
be the case, then if the engine can be started with the plug off the default would
be RICH AS because the ECU has no idea how much fuel it should be adding.

2. You mention that the ISCV appeared to be blocked off. This is a bad sign, as it
says that someone has fcuked with it because it was not working. And as the ISCV is
designed to be the only avenue for air to enter the engine when the throttles are
closed, it is very likely that the same person fcuked with the throttle stops and air
bypass trim screws. If so, you will have to test to see if the ISCV is actually working
now that you have cleaned it, and that the ECU can control the idle using the ISCV.

If the valve is working correctly, then you are gonna have to reset the bypass screws
for minimum air leakage and reset all the throttle stops so that the throttles all close
tight at idle. Means checking and re-setting the TPS as well. Simple check is to pull
the large hose off the outlet of the ISCV and close the end of the hose with your thumb.
If the engine stalls or drops very low and nearly stalls, then the throttles are not
leaking huge amounts of air. But if the engine just idles like normal, then idle air is
leaking past the throttles and not being controlled by the ISCV.

If you disconnect the large hose and don't block the end, the idle speed should shoot
up to something like 3000-4000 rpm :) Might help to narrow things down a bit.

Cheers... jondee86
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Re: idle hunting, 20v shenanigans

Postby Jeonsah » Mon Dec 18, 2017 7:07 am

Keep following Jondee's recommendations. Only thing I have to add is the following:

1. Make sure your red/black vacuum switching valves are not reversed. Might be possible since you took things apart.

2. If the ecu does not throw a code when you unplug the ISCV, then you could potentially run with no iscv or dashpot. I am doing that on my car at the moment and the idle is hard set to 1000rpm. However, I am on an aftermarket ecu and I am planning on hooking up an aftermarket iscv.

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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Mon Dec 18, 2017 12:03 pm

OK SO, I disconnected the big hose from the iscv and the engine speeds up I plug the port on the throttle body where the hose goes and engine sputters and dies. This is normal operation correct? I’m getting a new maf tomorrow or the day after. I suspect that is my problem.

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Re: idle hunting, 20v shenanigans

Postby jondee86 » Mon Dec 18, 2017 12:15 pm

AlexFourTwenty wrote:This is normal operation correct?

Yes. See what happens when you try another AFM. Good luck :)

Cheers... jondee86
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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Mon Dec 18, 2017 12:19 pm

johndee86 can you please explain how the vaccum hoses are routed if i removed the throttle opener and the metal vaccum nest under the itbs. maybve a link?

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Re: idle hunting, 20v shenanigans

Postby jondee86 » Mon Dec 18, 2017 1:18 pm

I don't have a 20V intake for reference, so I just have to guess what lines run in
the small tubes and hoses under the ITB's. This pic helps a bit...

Image
http://www.my-acoustic.com/Car/vacuum/v ... _lines.htm

1. There is the EVAP solenoid valve that has one rubber tube from each ITB and
they all hook up to a metal tube that finds its way to the solenoid valve. The other
side of the solenoid will have a tube running to the charcoal cannister.
2. There is the throttle opener servo that must get vacuum from somewhere.
Maybe on top of the first ITB ?
3. There is a short hose connection for the FPR on top last ITB I think. This one
has to be connected or the engine runs rich at idle.
4. There is a vacuum connection (bit larger hose) for the brake booster from the
first and last ITB. This has a steel tube that runs underneath.

That's all I can think of right now. If you have more see if you can figure out
where they come from and where they go to :)

Cheers... jondee86
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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Mon Dec 18, 2017 1:36 pm

i started messing around with the afm wheel settings and i actually getting it to idle with the afm hooked up, since i have it disconnected now. i will mess around with it more when i get home. might be that someone fucked with the settings to compensate for something else.

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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Mon Dec 18, 2017 5:07 pm

jondee86 wrote:I don't have a 20V intake for reference, so I just have to guess what lines run in
the small tubes and hoses under the ITB's. This pic helps a bit...

Image
http://www.my-acoustic.com/Car/vacuum/v ... _lines.htm

1. There is the EVAP solenoid valve that has one rubber tube from each ITB and
they all hook up to a metal tube that finds its way to the solenoid valve. The other
side of the solenoid will have a tube running to the charcoal cannister.
2. There is the throttle opener servo that must get vacuum from somewhere.
Maybe on top of the first ITB ?
3. There is a short hose connection for the FPR on top last ITB I think. This one
has to be connected or the engine runs rich at idle.
4. There is a vacuum connection (bit larger hose) for the brake booster from the
first and last ITB. This has a steel tube that runs underneath.

That's all I can think of right now. If you have more see if you can figure out
where they come from and where they go to :)

Cheers... jondee86


So 1. I have them bypassed. Under itb they’re looped to each their

2. The vacuum servo has been removed I’m guessing I have to cap off where it was connected to? I’m not sure where it gets vacuum from.

3. Not sure which one this.

4. This one is blocked off at the front and using only the rear itb. I’ve read you only need one.

Also what is this vsv ok the 20v? I don’t think I ever messed with it while removing the iscv. If it’s for Evap then I probably don’t have it. The car doesn’t have ps or a/c no evap charcoal can none of that extra ****. Tomorrow I’ll put up some pictures of the engine bay

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Re: idle hunting, 20v shenanigans

Postby jondee86 » Mon Dec 18, 2017 7:15 pm

This blue hose is the hose for the Fuel Pressure Regulator...

Image

Yours will be black and you need it !!

Cheers... jondee86
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Re: idle hunting, 20v shenanigans

Postby jondee86 » Mon Dec 18, 2017 7:31 pm

AlexFourTwenty wrote:Also what is this vsv on the 20v?

The VSV shown under the ITB's is for the EVAP. On the OEM setup the ECU opens that
valve when the engine is above a certain speed, and engine vacuum sucks the fumes
out of the cannister and into the ITB's thru those four small hoses that you have looped.

When you look on top of the #1 and #4 ITB's, each one should have a skinny, bent, black
steel tube sticking out. The one above the #1 ITB should go to the FPR, and I'm pretty
sure that the one above the #4 ITB went to the throttle opener servo. This last one
needs to be capped off.

Cheers... jondee86
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Re: idle hunting, 20v shenanigans

Postby AlexFourTwenty » Thu Dec 21, 2017 5:50 am

Okay guys I got a new afm and new tps just in case. My buddy had spares off his running engine. I put them on and it won’t idle it’ll start up then die after a second. If I disconnect the afm It idle perfect. I’m not sure what’s going on.

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