Fried ECU fix?

[1YLOTLN]

Well my ecu is fried but the car still runs with it but very poorly and my datalogger wont work with it. I found out that it's been liek this since i bought it. So would you think that if i put an EPROM ECU in and DSMLink that it wouldn't fry anymore, ohh yeah because i talked to a guy that knew the guy who i bought the car fromn and he said*after i bought it* that he ripped on the car all the time and that he's fried out ecu from it before. Yet this could be an electrical problem since my manager at work's friend has an electrical problem with his 1g.

 

[FourG63 97GST]

so how many ecu has it gone through so far?
not trying to be Mr. obvious here but you might want to figure out the problem before putting dsmlink in it. that can be a pricey mistake

 

[lasertim]

so how many ecu has it gone through so far?
not trying to be Mr. obvious here but you might want to figure out the problem before putting dsmlink in it. that can be a pricey mistake

I agree. A common thing that I have seen on 1G DSMs is that the battery slides forward and the positive terminal arcs on the hood which can hurt the ECU. A friend of mine did that to 2 ECUs before we figured it out.

Fix the problem before you go any further.

 

[gsxbri]

Do not plug in new equipment until you verify there is no short!!!! I used to remanufacture ecu's and tcm's for chrysler and give support to garages when they could not fix the sensor/ecu/tcm issues. Check to make sure there are no popped fuses, and if they are popped make sure they dont blow right away when you replace them. Make sure all of your grounds are clean. I ran a couple 4 gauge groud reinforcements to be safe. Its rough but you can do check all of your power/ground connections on the ecu connector to verify there is no short also. you set your meter to continuity (will beep when the leads are put together, this will look for a short/low resistance) and then meter between all of the power and grounds in the harness. I assume your check engine light is on? if so you can check the codes without a logger.

cycle the key on off on off on without turning the motor

count the blinks, short pause is a digit count, long pause is a new number.
example
flash----flash-flash-flash
code 13

then just check a dtc list to see what you got.

While I was working there i found lots of the probs were due to bad grounds from dirt getting in the connection either at the connector or chasis connection, also the occasional short in the harness somewhere from something sliding against it, like the battery issue posted above. But as they said, just pluggin in a new brain could be a costly mistake.

 

[steve]

I assume your check engine light is on? if so you can check the codes without a logger.

cycle the key on off on off on without turning the motor

count the blinks, short pause is a digit count, long pause is a new number.
example
flash----flash-flash-flash
code 13

then just check a dtc list to see what you got.

Key dance doesn't work on 1Gs.

I can usually tell you what's bad based on what is burned on the ECU. The most common still are the ISC drivers but as people start disabling BCS and other engine bay solenoids they start blow those drivers from wather geting into the loose connectors.

I agree you don't want to put another ECU into the car until you identify and correct the problem.

Steve

 

[1YLOTLN]

hanks all of you guys i did a battery relocation to the hatch, i have the motor out right now on half being all of the piston rings are blown so i'll probily power wash it and check the grounds. a pic of the ecu....

 

[steve]

Hard to say but it looks like you burned up IC105, the second one in from the center.
That's caused by shorted winding in the ISC or water in the connector.

Steve

 

[1YLOTLN]

Here's a better photo

You must be logged in to view this image or video.

 

[steve]

Well, IC105 is clearly blown but it looks like IC104 and/or IC106 is also.

IC104 drives the MAF active reset (turbo only)
IC105 drives the ISC coils B1 and B2
IC106 drives the Boost and Fuel Pressure solenoids (turbo only)
IC107 drives the ISC coils A1 and A2
IC108 drives the Purge and EGR solenoids
IC109 drives the A/C and Fuel pump relays

These drivers only blow when they get connected directly to 12v through a shorted device, shorted wiring, etc.

The VFAQ site has the ECU pinouts and more in testing the ISC coils.

Steve

 

[1YLOTLN]

These drivers only blow when they get connected directly to 12v through a shorted device, shorted wiring, etc.

Does that mean i should make some of my own grounds, like tap into a wire or does thart mena i need to replace the whole harness cause of a short?

 

[steve]

Does that mean?

It means that you should first test the various device/solenoid to make sure that it's isn't a dead short between it's pins. Then check to make sure than the control wire (from the ECU) isn't shorted to 12v somewhere.

Grounds don't really come into play here. That's what the drivers are doing, connecting the incoming signal to ground and causing current to flow. If the incoming signal is connected to 12v without a winding or resistance to limit the current the driver goes up in smoke in the blink of an eye.


Usually it's the device on the end of the wire that's bad but sometimes it because people have disconnected the various solenoids and left the wiring harness hanging. One of the wires in the connector is battery voltage and the others run to the ECU. Add a little water and you have a short to 12v.

Steve

 

[1YLOTLN]

is there a website explaining howto do the tests? i couldn't find them on vfaq

 

[steve]

Yout have to figure out how to test the solenoids and wiring on your onw but the ISC has a couple of pages.

http://dmtalon.v8eaters.com/ISC.html
http://www.stealth316.com/2-isc-iac.htm

Steve