No Spark, but everything tests good

[Victor Charlie]

I'm not making much progress with mine either. Similar symptoms, though mine was running pretty well for a week. Now I'm not driving it because it got worse. I haven't gotten any responses to my thread so far, though I'm still hoping someone will be available tomorrow to help. I wonder if you would check on my thread and see if you think you have the same issue or something different? Maybe we can help each other out. Thanks.


http://www.supramania.com/forums/showthread.php?t=109980

 

[Crazybobmundo]

Am I missing something here on my ISCV?

on the EPC it shows some two parts that look removable, mine doesnt have anything of that sort. Not sure if different years have different set ups but what do you guys get out of this?

This is the Intake manifold side.

This is the ISCV itself.

 

[89supra7mgte]

yes you are missing the two pieces one is a check valve and the other is a rubber grommet. go to toyota dealership and tell them you need the iscv check valve and grommet should be cheap. best advice

will have vacuum and boost leak without

 

[Crazybobmundo]

Damn. Its going to cost me $55 for both.

Oh Well I want to get it running properly. Well hopefully Im closing in on my real problem.

Ive switched harnesses too. One that I was working on reconditioning since last year and never got to finishing it.

 

[89supra7mgte]

55 for them, maybe do some price matching at other places. there was a thread on here somewhere that someone had picked them up for under 20 i believe? check the fs threads maybe there are some just laying around that are in good condition?

 

[Crazybobmundo]

So I decided to work on my car again. I bought the new grommets and check valve for the idle control, installed a better used harness and put e erything together but now I'm stuck with the no spark crap again.

I swear that this thing is making me run in circles.


Does anyone know how to test signals from and to the CPS and the ecu? I think that's where my problem is.
Reason is because when I crank the engine the RPM gauge doesn't move.
Please help.

 

[89supracrazy]

So I decided to work on my car again. I bought the new grommets and check valve for the idle control, installed a better used harness and put e erything together but now I'm stuck with the no spark crap again.

I swear that this thing is making me run in circles.


Does anyone know how to test signals from and to the CPS and the ecu? I think that's where my problem is.
Reason is because when I crank the engine the RPM gauge doesn't move.
Please help.

Don't forget to check the connector going to the cps on both sides. The connectors get baked from the exhaust manifold. Pull on the wires going to the connector and see if they are connected good. Don't pull to hard. I did away with my connector and solder the wires for good connection.

 

[Crazybobmundo]

Well, 89supracrazy I did check those wires. Thats whats throwing me in a loop.
I depinned the plugs and hooked them up together.

What I actually want to know is how do I test if the ECU is sendin signals to the CPS and virse versa.

In the TSRM it shows you how to test each component, CPS, Igniter, Coils and some part of the harness but doesnt say much about testing the signals from the ecu to cps.

What im trying to say is Im back to my original problem. No Spark, Everything tests good.

 

[Victor Charlie]

Mine has been running pretty well all winter. THere was no one thing causing my trouble with warm starts and irregular idle. I calibrated the TPS, retaped all the grounds and used fresh bolts, did the ignitor grounding upgrade, and it ran okay, no missing beats. THen I got a wideband, confirmed it was running rich, couldn't find a boost leak. Finally, I backed out the adjusting screw on the AFM to lean it out and now it works much better. STill not great gas mileage, but better, about 20mpg. Now my fuel pump is going, I don't know if that was relevant all along.

 

[jetjock]

What I actually want to know is how do I test if the ECU is sendin signals to the CPS....In the TSRM....doesnt say much about testing the signals from the ecu to cps.

That's because there are no signals sent from the ECU to the CPS. It's a one way street. Which begs a question: if you don't understand how the EFI system works how can "everything test good?"

You need a scope to check the CPS correctly. Assuming you can lay your paws on one you'll be looking for a minimum of 1 volt p/p at cranking speed. Or try a DMM set to AC millivolts. Fwiw you can take the thing out and spin it by hand while troubleshooting no spark issues. Saves wear and tear on the battery and starter.

Course, you'll have to reinstall and time it correctly when finished. As simple as that is there seems to be a whole lot of people unable to do it...

 

[mtx911]

dude that is one fuckd up car man i heard bout bad idle but damn the supra has a mind of its own or theirs a ghost reving it.. thats is seriously fuckd up!!

 

[Crazybobmundo]

Jet loc, I tested the ignition system according to the tsrm. The tests it gives in the book confirms that the ignition system is ok. Thats what I meant.

and you're right I clearly dont understand it because I cant fix it. Thats why I posted this in the first place to see if theres something else I cant do that the book doesnt explain.

But, obviously, I probably will never fix it then I dont have any of that equipment.

 

[Crazybobmundo]

I figured out my problem.

I didnt expect it but I guess some people probably did.

I was reading through the TWD and found the following paragraph:

"[9] Battery Signal System
Voltage is constantly applied to terminal BATT of the ECU. When the ignition SW is turned on, voltage for ECU operation is applied via the EFI Main Relay to terminals +B an +B1 of the ECU. Also, current flows via the IGN fuse to terminal IGSW of the ECU."

So I tested the pins and BATT had power and IGSW also had power with IGN SW on but of course +B and +B1 did'nt.

The car actually started when I manually powered the B pins. I was so ecstatic!

So now I have to find where the short is and fix it.

Now I can put this thread to rest.

Thanks everyones for the suggestions and help. The car is actually not haunted after all.

 

[EwGoetsch]

I figured out my problem.

I didnt expect it but I guess some people probably did.

I was reading through the TWD and found the following paragraph:

"[9] Battery Signal System
Voltage is constantly applied to terminal BATT of the ECU. When the ignition SW is turned on, voltage for ECU operation is applied via the EFI Main Relay to terminals +B an +B1 of the ECU. Also, current flows via the IGN fuse to terminal IGSW of the ECU."

So I tested the pins and BATT had power and IGSW also had power with IGN SW on but of course +B and +B1 did'nt.

The car actually started when I manually powered the B pins. I was so ecstatic!

So now I have to find where the short is and fix it.

Now I can put this thread to rest.

Thanks everyones for the suggestions and help. The car is actually not haunted after all.

Glad u figured it out. I had the same problem, and for weeks couldnt figure out why i had no spark. Untill i realized that 1 plug on the ecu was barely on.