Injection Duration Monitoring Directly from the TCCS?

[CajunKenny]

Does anyone know of a way to monitor injection duration while driving?

There's probably something out there that plugs into the harness; but, I was wondering if there is another way?

Is this possible to do in open loop?

I am an electronics technician and have my own test equipment. O'scopes, meters, function generators, and such... I was thinking that if it is possible to do, I could tap into the harness and extend the appropriate wires inside the car and attach the scope there.

My ultimate goal is to find out how hard I'm pushing my 440's.

Thanks...

 

[jetjock]

Hmmm. That's an odd question coming from someone possessing that kind of equipment and claiming to be an electronics tech..

 

[grimreaper]

^ JJ dont you have the plug in tester that toyota used?? man id love to get a hold of one to play with.... IIRC you talked about it on MKIIItech a LONGGGG time ago.

 

[Poodles]

I've always wondered why you could get the plug that actually plugs into the diagnostic port and get a readout of everything...

 

[jetjock]

I actually have two of those expensive factory TCCS tester/simulators and yes, they display injection duration directly in milliseconds. I rarely use them though. Scope is easier.

If I'd known you wanted one I would have pointed you to Ebay a few weeks ago. One there went for $100 and the guy had to list it twice to get even that...

 

[grimreaper]

I actually have two of those expensive factory TCCS tester/simulators and yes, they display injection duration directly in milliseconds. I rarely use them though. Scope is easier.

If I'd known you wanted one I would have pointed you to Ebay a few weeks ago. One there went for $100 and the guy had to list it twice to get even that...

:aigo::aigo::aigo: hell of a deal! ( i think given the age and usefulness) Yes please keep me in mind if you run across one again!

I need to learn how to use a scope...

 

[Poodles]

Damn... Just thought it would make testing and tune-up a whole lot easier.

 

[Piratetip]

This guy?
http://cgi.ebay.com/TOYOTA-DIAGNOSTIC-TCCS-CHECKER-TESTER-FAULT-FINDER_W0QQitemZ250416372194QQcmdZViewItemQQptZUK_Diagnostic_Tools_Equipment?hash=item3a4dfa99e2&_trksid=p3286.m63.l1177

 

[jetjock]

Actually no, that's a new listing from the UK I hadn't seen. It's the same tool though. A good deal considering what they went for new.

As far as I know there were only two testers for OBD-1 Toyotas. One plugs into the diag port and offers the limited information that port supplies. Although rare the few I've come across I've passed on for that reason. The other is the one above of which I own two. They work on many models as long as you have the right sub-harness for connection to each particular ECU/body harness. The sub-harness for Supras are also rare but can still be bought from SPX, the people who make most Toyota SSTs. They're expensive though. I sacrificed another model sub-harnesses (early Lexus iirc) in order to make it work on the Supra. For those interested in that auction let me check to see if it has the right harness number for our cars.

While the boxes are nice the only thing they offer is speed and the ability to check things without brain strain. That's why they were dealer items. Personally I find the hassle required to gain access to the ECU for plugging in the sub-harness more work than it's worth. It's another reason I wish our cars were OBD-II.

Edit: That auction includes sub-harness #13, good for later model (gray plug) Supras in the US, Canadian, Aussie, and European markets...

 

[grimreaper]

^ would you say your scope is a better option once its used correctly and the data given is correctly interpreted?

I want something more in depth then the multimeter. A scope could be alot more versatile for future use on other cars. Higher initial cost but the price for perfection is often hefty...

obdII would to easy I miss my 03 truck, $150 scan gauge and i knew more then i needed to about what was going on...

 

[Doward]

Wouldn't just tapping the freaking injector wire and watching it with the o-scope do exactly what you're asking?

 

[jetjock]

Yes John...that's why I said it was an odd question

Grim: A scope is far and away the best tool. Note the word "tool" though. Like all tools you'll need learn how to use it and it's no substitute for knowledge. Because I'm fluent in electronics I use a general purpose DSO but you might want to look into an automotive lab scope. Still, depending on what you want, prepare to spend some money...

 

[SupraDrew]

You could use an old school HKS IPM with the universal harness. I really not sure how accurate it is. I am going to be using one when I get my f-con installed. If you were just going to monitor the injectors, you just need to get power, and then the yellow and white wires can monitor different signals. I would assume that if you just use one signal, you will only see one bar on the unit.

 

[CajunKenny]

Hmmm. That's an odd question coming from someone possessing that kind of equipment and claiming to be an electronics tech..

It was more of a question of 'How'd you do it?' than 'How do I do it?' I guess I should've worded it differently.

And just for the record...I am very much what I claim.

My fear is isolated and non-isolated grounds. One does not want to cross them... I've looked through some schematics in the TSRM and still looking...

So would taking the signal right off the injector be safe jetjock...connecting to chassis ground that is?

 

[CajunKenny]

Hey Grim: You can pick up an older Fluke Hand Held Scope (I forget the model) for pretty cheap on ebay. They lack some features; but, for basic testing purposes it'll do just fine.

 

[Nick M]

I've always wondered why you could get the plug that actually plugs into the diagnostic port and get a readout of everything...

There is limited serial data through the port. And you can plug in with it, instead of the paper clip and counting. It seems like the scanner(Vetronix) and adapters with software runs close to $5000. But that was 10 year ago that I inquired about it.

 

[jetjock]

Kenny: The injectors are sunk (ground sided) so probing #30, #20, and #10 at or after they leave the ECU will work for pairs. Reference battery positive or any other part of the positive side. Or just go across the clips. If you have a current probe for the scope use it. It'll tell you a lot more than voltage...

 

[CajunKenny]

Suuweet! Thanks!

I can get a current probe from work to use.

My 440's have got to be in the ~90% duty cycle range; but, wanted to see where they were before I drop my 550's in. Just curious...

Still tweaking with the maft pro too...

 

[jetjock]

That'll tell you. Could always use a freq or universal counter too if all you're looking for is duration. Any worthy of the name will calculate period. Have fun...

 

[3p141592654]

You really want look at variable 0A6h!! That is the location in RAM of the computed 16 bit injector duration for the 87-88 7MGE ECU.

The TCCS has hidden diagnostic capability that blows the doors off of OBD2. I'm about 4 to 6 months out from demonstrating it. It does require some minimal mods to the guts to get access, but its there on every ECU that left the factory. The data rate is 1Mb/s and the command rate is about 200 Hz (the loop rate of the main loop in the ECU code). There are some pulldown resistors missing (see photo R606, R607, R608) that are used to set various diagnostic modes. The actual data comm is through two pads that are on the backside. In this photo of an 88 7MGE ECU, the CPU itself has been removed.

This photo shows my USB development board for 1Mb/s comm to the CPU.