no check engine light?

[stratt134]

When I turn the "ignition" on, the check engine light comes on (as the test, so the bulb works)

But when I throw CEL codes, like P0170, P0446, idle code, speed sensor code, etc etc - the check engine light NEVER comes on!!

AND none of the emissions test will SAVE... like I -permanently- have the P0446 Evep code come up, once I clear it, it comes right back, no check engine light, 1000 miles later not ONE diagnostic test has been saved to the ECU (you know those 5-6 test that must be *completed* before you can pass emissions)

Anyone have any ideas?? Is my ECU retarded or something??

 

[architechnik]

Have you had any problems with electrical shortages?
It sounds like you might be losing power to the ECU or having some sort of grounding discharge that is clearing the stored memory. Otherwise, I would say it is the ECU itself.

Have you removed it and checked for any apparent damage?

Here is a nice thread about removing the ECU is you're not sure where to start.
http://www.dsmtuners.com/forums/newbie-forum/253650-resolved-need-diagram-remove-ecu.html

 

[stratt134]

Oh yeah i forgot to mention about the power thing... I wish that was the issue

It never loses the CEL codes that it has.... like P0446.... NEVER loses them... and never saves those "tests" things...

I will need to check my ECU... because I am ordering DSMLink or whatever v3 is called now... and I don't want it to run on a crappy ECU... BTW it's a 98 GSX...


So, no power loss or problems...

 

[TALONTRAX]

I have a similar issue with a P0325 (knock sensor circuit), the code will show up in memory which I`ll see during a log, however the light never comes on. After much thought & diagnostic time into why this is, I`ve concluded that this issue is a result of the custom timing curve in the chip I`m running. I swapped the firing order back to stock & installed the original ecu, & drove 350 miles, no code or cel. With the chipped 95 eprom box in there, that P0325 shows up in memory after just 15 minutes of driving. As far as your readiness monitors not setting, & your cel not illuminating, you may have more than 1 issue at work there. I`ve run into this situation where the monitors will not set to (ready) due to a kam (keep alive memory) power feed to the ecu. somehow becomes missing. This is like effectively doing a battery disconnect every time the innition is turned off, due to the lack of the key-off kam power to the ecu. As far as your codes, they need to be trouble-shot also, however, I would address the monitor or kam issue first . . .

 

[stratt134]

"readiness monitors" - yea, those =)

So, even if the KAM is disconnected on the ECU, in turn "resetting" the readiness monitors every time, it would still save the CEL codes?

When I drove 1200 miles from AZ to TX, it thru 4 CEL codes, the known Evap issue, 0446, 0170 (possibly o2?), the funky idle code, and the speed sensor code.... AND NO CHECK ENGINE LIGHT WTF

It has a stock tune and everything too...

Are you thinking internal or external ECU problems? (DSMLink coming soon... don't want issues)

 

[TALONTRAX]

Well, these symptoms could be that the ecu. is going bad also. That`s what I would try next then . . .

 

[architechnik]

That's sort of the same issue I was talking about. There are "stored" codes and "current" codes. If the ECU keeps getting a disconnect, like a bad ground or some other short while you're driving, then it will store the codes and not ever turn the light on.

A lot of the codes for non-critical issues it stores quickly, but only turns on the warning light if it is persistent. This is why for some that have made modifications they will get the CEL right away and then it will disappear for a little while, then come back on or it won't come on for a long while after the modification even though the ECU knows there is something different.

Do you have a spare ECU to swap in for a little while that will still run the vehicle? You said you are getting ECMLink, so I'm assuming you have a shipped EPROM; what kind of ECU modifications are done to it currently?

 

[KeelesKustome]

i think it would be worth the money to buy another ECU to test the problem.

Although.....

if it lost power.. wouldn't it make the car stutter or hesitate?

 

[stratt134]

... I do know for a fact that it saves the P0446 code as "new" and "saved" - as well as the rest of the codes - or whatever correct term I should be using - when I plug in the scanner...

 

[architechnik]

<Just got back from work.>
It wouldn't necessarily stutter significantly and it might not be noticeable, especially if it is only having something happen during deceleration or some other sudden movement. That the reader is displaying a new and stored code, without the CEL turning on, seems odd.

Do you have a logger? If you're able to track messages from the ECU during a quick drive then it might reveal something. Otherwise, you'll just need to start fixing each individual problem (each code) until something shows. (I would bet on a wiring issue or the ECU being faulty.)

 

[knochgoon24]

So you're getting DSMLink. Well you'll need another ECU anyways unless that 98 has an EPROM.

 

[1stGenTSi]

Either these codes don't necessarily trip the CEL, or someone has rigged your CEL. I've worked on a lot of used cars and have seen it done several times. Shady owners/dealers/mechanics that would take out the instrument panel, cut the wire from the ecu to the CEL bulb, then attach the wire to another light like the oil pressure or battery light. That way when you turn the key on the CEL lights up but when it's started it turns off, leaving the potential buyer thinking there is no codes.

 

[stratt134]

So you're getting DSMLink. Well you'll need another ECU anyways unless that 98 has an EPROM.

Don't I usually send them the ECU to have the EPROM added? How much is a new ECU? Do they sell them?

Either these codes don't necessarily trip the CEL, or someone has rigged your CEL. I've worked on a lot of used cars and have seen it done several times. Shady owners/dealers/mechanics that would take out the instrument panel, cut the wire from the ecu to the CEL bulb, then attach the wire to another light like the oil pressure or battery light. That way when you turn the key on the CEL lights up but when it's started it turns off, leaving the potential buyer thinking there is no codes.

with this car, I wouldn't doubt it

 

[dylnwit]

You can buy a new NON eprom ecu for under $300 at your local advance auto parts. From my understanding, you can send in (to the DSMlink folks) a non eprom ecu, and they'll desolder the chip and solder in a socket so you can put back in your stock chip or put in theirs. All an eprom ecu basicallly is is one that you can take the chip out and re-write it, and with 'link, the rewriteable chip comes with it. They will charge you a core charge if you don't return your old one at Advance, i think it's about $50. Took about a week to get one for a 1g from Advance Auto parts, i had tried Autozone, 3 weeks and they hadn't even placed the order...

 

[knochgoon24]

You can buy a new NON eprom ecu for under $300 at your local advance auto parts. From my understanding, you can send in (to the DSMlink folks) a non eprom ecu, and they'll desolder the chip and solder in a socket so you can put back in your stock chip or put in theirs. All an eprom ecu basicallly is is one that you can take the chip out and re-write it, and with 'link, the rewriteable chip comes with it. They will charge you a core charge if you don't return your old one at Advance, i think it's about $50. Took about a week to get one for a 1g from Advance Auto parts, i had tried Autozone, 3 weeks and they hadn't even placed the order...

You're understanding is wrong. The EPROM ECUs are rewritable. The non ones aren't. The difference is more than just the chip for 2g ECUs. To run DSMLink or ECMLink, you'll need a 2g ECU that started life as an EPROM.

To run either of those programs, you'll need to desoldier the EPROM chip, install a socket, then plug the DSM/ECMLink chip into it. The EPROM chips gets set aside for later reversion to the stock chip if you choose.

 

[dylnwit]

Ah, alrighty, thank you for clearing that up for me, and sorry for the misinformation.

 

[KeelesKustome]

Don't I usually send them the ECU to have the EPROM added? How much is a new ECU? Do they sell them?




with this car, I wouldn't doubt it

I have one out of my 98 up for grabs.. under $300 , i put my dsmlink in so i have just had it in my eclipse box of stuff.

thats crazzy they cost that much by the way.