General Bad ISC Destroying ECU?

[sniver]

Well no traces on mine are burnt, the capacitors I would buy new now, and where do i get the burnt up ic105 driver from? And as stated It would be nice to know either how to find out what it (burnt driver) does or perhaps someone already knows, but my guess would be steve is the only realistic chance of someone knowing. I would hate to go through all the effort fixing it for the problem to break it again. And I'm assuming it isn't for the ISC since the it is 3 up from the one you guys said is the ISC driver for Bryce.

 

[oldman]

If I were you guys, I would just send it to Steve and let the pro handle it, he has fixed many of my ECUs in the past including the one I'm currently running in my car, he also does all the socketing for my DSMLink customers, not a single return so far.

 

[bryce]

But thats not the problem, there is something causing the ecu to do what its doing so im just trying to pin point the problem so i don't explode another ecu. Im going to try tomorrow to start up the car with a working isc and see what it does.

 

[oldman]

But thats not the problem, there is something causing the ecu to do what its doing so im just trying to pin point the problem so i don't explode another ecu. Im going to try tomorrow to start up the car with a working isc and see what it does.

How is the working ISC going to help if the ECU is already fried? You need a working ISC as well as a working ECU.

 

[white90gsx]

Sorry to interupt as i keep reading this post every 5 min to see what has been said because i think im haveing the same problem and i needed to know if the bad isc destroys the ecu will there ALLWAYS be visual damage to the ecu?

 

[steve]

I needed to know if the bad ISC destroys the ECU will there always be visual damage to the ECU?

If your asking can you always see a blown ISC driver, then no.
You can only see the ones that were a dead short tried to discharge the battery through the ECU and the resulting current released the magic smoke in large amounts.

I was seeing about 25% of the ECUs that didn't have visible fried parts had one of more blown driver (there are two per chip). Some of these were from blowing the driver when C106 leaks and some from ISC's that had a coil with low resistance.

Many of the questions being asked here can be answered by searching.
Sometimes filtering the search with a wiseman's name (like mine or luv2rallye's) will improve the quality of the results. Searching the tech archives will also help.
For example: http://www.dsmtuners.com/forums/showthread.php?t=116585

Steve

 

[white90gsx]

ok good because i was having an eratic idle problem and a code show ISC system even after i replaced the ISC and i was driving it for a week with that problem so im thinking its either bad wires or a bad ECU what do you think?

 

[oldman]

ok good because i was having an eratic idle problem and a code show iac system even after i replaced the iac and i was driving it for a week with that problem so im thinking its either bad wires or a bad ecu what do yoy think?

First thing first, read the rules about using proper punctuation and capitalization in your posts.

 

[bryce]

I have a new isc and ecu. I will try it out tonight and let all you guys know what happens.

 

[white90gsx]

Sorry i posted that from my pda and i dont have spell check and stuff.

 

[92awddsm]

Sorry i posted that from my pda and i dont have spell check and stuff.

If the grammar, punctuation, and capitalization rules were pointed out in your last post, why did you not pay attention and do the same thing again. Your post should read more like this:

I'm sorry. I posted that from my pda, which doesn't have spell check and (stuff?) thinking ability.

Even without spell check and stuff, you should have enough brains to know that I is always capitalized and what a run on sentence is. Im not going to bi*** about the lack of an apostrophe in don't because I sometimes do the same.

 

[oldman]

Sorry i posted that from my pda and i dont have spell check and stuff.

No problem, you don't have to be perfect, all we ask is that you put in the effort. It may seem trivial to you now because you're new but if you stick around long enough, you will see the importance of it.

 

[bryce]

put the new ecu in and had my isc unplugged tonight and it still ran on 2 cylinders. I then put the ecu on a buddies dsm and his car ran on 4 cylinders and ran good except for one thing. What happened when i put the ecu out of my car in was the cel started to flash kind of weird, so i checked the codes and there was the crank angle sensor at first, then cam angle i think and coolant temp, then i reset them and it ended up being just coolant temp sensor. Then i put my eprom back on the car and the car ran without a Cel. Any ideas guys? This stuff is crazy!

 

[white90gsx]

Well if you tried just about everything else try a simple compression test maybe something else happend.

 

[bryce]

i dont think poor compression would lead to a no spark condition.. around the new ecu i have on the caps. it looks like they started to leak and theres a little bit of acid on the board. I going to try to put a working Cas in the car tonight. Do you think that the cas could affect this?

 

[steve]

Do you think that the CAS could affect this?

What, That the car runs on two cylinders?
Yes a bad CAS could cause that, if your losing 1 and 4 or 2 and 3.

 

[bryce]

yes im losing cylinders 2 and 3.

 

[bryce]

so i tried the cas and it didnt make a difference. What else could be causing me to be running on only 1 and 4... im suspecting a bad ignition module now too because it only shows half the rpms that its at. and my afc reads the actual amount. So im going to check into that again and see how to test that.

 

[steve]

With my logger on i get code 44 all the time, and i think the first time i did the scan there was code 12 and 14. I know code 44 is ignition coil and i know its not that or the transistor cause i got 2 working ones out of a buddies car tried them out and did the same thing, and then he went back and put them back in his car and they worked completely fine.

You claimed to have already tried the PTU.

There's only the CAS, ECU, PTU, Coils, Plug Wires, Plugs, and wiring harness in the ignition circuit. If your changing more than one thing at a time your results are questionable and you need to retest.

If I were getting a CEL 44 I'd go check at the coil primary to see if it had power, measure the resistance of both the primary and secondary windings, and look to see if the PTU was pulling it's side low as the CAS was turned. Depending on what I found I'd log look at the PTU and see if it had 12v on the wires from the coil, that it gets a signal from the ECU to charge and fire the coils and that it did.

If the PTU is only firing one coil the car tach can read half the RPMs and the SAFC can read correctly if it's connected to the CAS for it's RPM input.

Make sure you have the locking clips on the harness connectors.

Steve

 

[bryce]

i dont have the locking clips on them actually.. and i tried another igntion control module but that was when i had that bad ecu in there that may have had the fried injector drivers, so maybe that could be my problem... if i have access to the other parts of a friends car would i be better off just to swap the parts over and see or is it a better idea to do tests and see what gets power and what doesnt?

 

[steve]

Putting parts in a car without knowing what's wrong is always risky. What if your car is killing a part?

 

[bryce]

true. so what do i need to test these items? Are there vfaqs on these tests? Im no longer thinking of a poor wiring harness any more considering its no longer popping ecu's. So where do i find the tests and what do i need to do so

 

[brute]

If you can get a hold of a factory service manual, it has the schematic for the entire ISC circuit. These tests are very easy with an oscilloscope, but they can be done with an ohm meter just the same. I can't recreate all the details here, so get your hands on that manual if possible!

Basically you just go through, test stuff with no power source (both drivers of the ISC, A1 A2 B1 and B2), test stuff with power, and etc. The relay box is tested for functionality, and the continuity is checked from the ISC connector to the relay box.

Sorry for my butchering of the instructions, but like I said, find a service manual; their instructions are very easy to follow as long as you do it step by step. If you haven't found one by Saturday, I can get some info out of mine when I go back home from school. Good luck!

 

[bryce]

Thanks, but i dont need the test procedure for the isc, i got that problem fixed and now the isc is unplugged and it runs fine, so i just had a shorted motor. Im looking for ignition components like coil, power tranistor, cas, etc.

 

[bryce]

so i found continuity in both my coil and power tranistor. So just for kicks i decided to try a good working coil and power transistor and it did the same thing. so then i unplugged my vpc harness and plugged my ecu right into wiring harness so now technically i was running without any air metering and it pretty much ran exactly the same. Could something with my vpc cause it to loose cylinders? Im about at the point where i just dont know what to do anymore.