Few Questions

[cjsupra90]

IGf is an ignition confirmation signal to the ECU (the coil fired)...it's possibe to get spark, but not a return signal (different wire). Injection is shut down, but you will get spark.

Yes, but the ECU has to send several IGT signal pulses with no IGF return signals pulses before it shuts everything down... so again, it shoud at least fire over which doesn't seem to be the case...

I still do agree that we need to ensure that he is truly getting spark and see if there are any codes in the ECU.. but I dont fully believe that he is going to get any codes unless he was getting fuel from the old pump and the car shut down due to another problem... Now if he was getting fuel to the rail when he thought that he wasn't based on how he checked it, then in my oppinion, he shouldn't be working on the car......

 

[jdub]

Chris - you're missing it.
During engine start, ignition is controlled through the back-up IC in the ECU...it's relevant signals are G, Ne and STA...it outputs IGt. It could care less about IGf during engine start (STA active). The back-up IC is "dumb", it will happily continue sending IGt signals out as long as STA is active.

Read more about back-up mode here:
http://www.mkiiitech.com/forum/showthread.php?t=847

STA tells the ECU that the engine is being started (along with Ne) and the injectors are set at a base duration depending on coolant temp. No IGf signal terminates injector operation...it's one of the ECU fail-safe functions to protect the CAT from overheating.

Read more about fail-safe mode here:
http://www.mkiiitech.com/forum/showthread.php?t=843
(Note what #5 says)

Not sure where you are getting that IGf stops ignition, but again, I have to disagree

For educational purposes, here's what JJ has to say about a no crank/no spark condition:
http://www.mkiiitech.com/forum/showthread.php?t=842
(note that no spark will shut down injection due to no IGf, but not the other way around)

 

[cjsupra90]

Dude, your going way over on this. and Im not the one missing it, you are.. and now your contradicting yourself too in some aspects... You brought up the whole thing earlier about code 14 (no IGf signal) but now you just said about the system doesn't care about the IGf during cranking... Which this is true.

I understand the whole back up and fail safe mods and have known them and understood how they function for years.....

Just like you said, NE and G signals are relevant. Without them, you will not get anything (spark included).. If the the ECU (both MPU and or backup IC do not see an NE or G signal during cranking, then no IGt is sent to the ignitor, thus spark will not happen.
Look at page 5 of the PDF link, last paragraph...
http://www.autoshop101.com/forms/h23.pdf

So if he is getting spark like he said he is, then the NE and G signals are there.

The whole thing come down to it should fire over, might not run but should fire over which from what he is saying, it doest do anything.

You are correct about the loose of IGf and only shutting down fuel.. Like I said, "IIRC it should down ignition too" but I was mistaking it for something else. Regardless the system has to send several IGt signals with no return IGf signals before it shuts down fuel so this brings back the fact that it should at least fire over. Like I said, it might not run but it should fire (even if its a back fire or what ever).......

 

[cjsupra90]

Oh and the link if you are aware is papers from toyota engineers, not Jet... Jet is very knowledge and really knows his stuff and Im not putting him or his write-ups on MKIII Tech down in any way, but I think toyota engineers know thier systems and how they fuction more then Jet does... Afterall, they did design them..

 

[jdub]

Dude, your going way over on this. and Im not the one missing it, you are.. and now your contradicting yourself too in some aspects... You brought up the whole thing earlier about code 14 (no IGf signal) but now you just said about the system doesn't care about the IGf during cranking... Which this is true.

I realize what I said and the point of "going way over on this" is no IGf = no fuel injection, not no spark. In either case a code 14 shuts the motor down...you keep forgetting the car was running and shut down.

I understand the whole back up and fail safe mods and have known them and understood how they function for years....

Based on your "shuts everything down" comment:

it shuts everything down...

Preceded by this:

Code 14 = No IGF... Yes it shuts down fuel, but it shuts down spark also and again, he is getting spark....

I had to wonder if you did understand back-up and fail-safe modes. Because IGf has nothing to do with getting ignition spark.

Just like you said, NE and G signals are relevant. Without them, you will not get anything (spark included).. If the the ECU (both MPU and or backup IC do not see an NE or G signal during cranking, then no IGt is sent to the ignitor, thus spark will not happen.
Look at page 5 of the PDF link, last paragraph...
http://www.autoshop101.com/forms/h23.pdf

So if he is getting spark like he said he is, then the NE and G signals are there.

The whole thing come down to it should fire over, might not run but should fire over which from what he is saying, it doest do anything.

And all this is based on his "getting spark" statement...a very bad assumption IMO. Frankly, I'm surprised you made that assumption.

You are correct about the loose of IGf and only shutting down fuel.. Like I said, "IIRC it should down ignition too" but I was mistaking it for something else. Regardless the system has to send several IGt signals with no return IGf signals before it shuts down fuel so this brings back the fact that it should at least fire over. Like I said, it might not run but it should fire (even if its a back fire or what ever)......

Yeah...I know I'm correct. It just took several posts to get that across. And, it is just as likely it will not fire...especially if he is in fact getting no spark (that assumption again).

Oh and the link if you are aware is papers from toyota engineers, not Jet... Jet is very knowledge and really knows his stuff and Im not putting him or his write-ups on MKIII Tech down in any way, but I think toyota engineers know thier systems and how they fuction more then Jet does... Afterall, they did design them..

Yep and I have the TCCS book...same one JJ has (among others) that the Toyota engineers produced. I'm thinking it just might go into a bit more detail.

 

[jetjock]

Come on kiddies, play nice

I know a great deal more (and have far better documentation) than what I let on in either forum and could make corrections to what you both said but in the interest of brevity I won't. Better to say you guys ought to learn when offering help has a chance of success versus just pissin' in the wind. The OP has a very basic problem, basic enough that he should be able to figure it out himself. That he can't is why you don't see me in this or certain other threads. Rather than snipe at each other over what is mostly simple miscommunication you might want to take a lesson from that...

 

[jdub]

Yeah...I know JJ. I'm going to give up.

::fundy::

 

[cjsupra90]

Im assuming that he is getting spark based on the fact that his first post / Thread opener says he is... If he cant supply accurate info, then no one can help him, or at least not easily... The reason why he probably didn't answer me when I asked about spark in Post #5 is because in Post #6 I said about how I now understood what his first post was in the essence of which problems and checks were associated with which car.

both the MPU and the back-up chip have to have the NE and the G signals to produce a IGt signal to the ignitor... The ignitor does not read or understand how to read a NE or G signals, it only understands digtial square wave signal output by the MPU and Back-up chip, not A/C signwave like the signals produced by the NE and G sensors.. If you dont believe me, go out to your car and unplug the CPS / Dist. and see if you even get spark while cranking...

 

[Bigdough666]

Man, lots of info here guys, thanks. Didnt mean to start a war.

Ill check codes and see what I get.

I KNOW Im gettin spark because I pulled a wire and put a tester on.

For car #1 - I was thinking distributor and or cam timing, as you guys mentioned here so I'll check that out.

For #2 - I thought timing and maybe dead ECU or sensor somewhere. What throws me off about this one, is the car was running fine and all of a sudden, DEAD. I checked the relief valve on the rail and no fuel came out, even while cranking, which is why I figured fuel pump. Pump was replaced and I checked again, this time, I got a nice flow of fuel coming out of the rail, like stated earlier in the thread. But the car still wont start. Like I said, ill check codes and the injectors.

thanks for the info, stop fighting.