Performance ECU PROBLEM

[mitsubluetalon]

hello, i just bought a socketed and caps replaced ECU that came with a stage 2 performance chip. the guy said it was from a galant VR-4 and that it will work on any 91-94 dsm as long as you swap pins 14 and 6 on the harness.

my problem is, i did that. the car runs like crap about a minute after cold start. almost as if it is missing, or wrong injector firing. the engine gets really shaky and just sounds bad.
i also get 2 check engine light codes. 1 is for the barometric pressure sensor, and the other is for the idle position switch.

it turns out that those codes correspond with the pins i swapped. i switched them back, car still runs like crap but no check engine light. did i get the pins wrong? does anybody know whats going on?

i have no other major mods exept for T-2 turbo, that has been ported to 3". my compression is 160 across the board and no boost leaks.

changed back to my regular ECU and engine runs perfect. i would really love to get this ECU going! 8000 rev limit, no fuel cut-off, stutter box!! come on!!

thank you in advance for any replies. they are all appreciated!

Jason.

 

[Talesin]

Dude... is your new 'stage 2 performance chip' compensating for larger injectors, perhaps? If it's lowering the time each injector fires so the larger squirters won't be running rich... and you have the stock ones... you're probably running super-lean.


Also, be aware that the 8Krpm limit is pretty high, unless you also have better springs and retainers to deal with the higher RPMs. If you haven't built the engine to TAKE 8K, then the higher rev limit seems more like a weakness than anything else.

 

[steve]

Got a number off that ECU?

If you got a baro sensor error it doesn't sound like you swapped the right pins. So first lets make sure you need to swap them and then if you do get the right ones swapped.

Steve

 

[mitsubluetalon]

hey guys, thank you for the quick replies. umm the add for the ECU didn't say anything about needing larger injectors, however could be possibility. there was one other problem when this ECU was in. if i were to slowly rev up the engine, at 2000 rpm, the injectors would shut off until it idled down to 1000 (tested with noid lights). if i were to give it a lot of throttle, the rpms would go above 2000 but as soon as i stopped accelerating or let off a little the injectors would shut off again until i either add more throttle, or let it idle down to 1000 again.

as for the ECU numbers, the case it came in says "MD169547" then under neath that it says "E2T36182".

And for the rev limit, 8000 is a 'little' high for stock, but it will be useful for when my rebuilt head goes in, i think i was telling steve about my woes from when my intake valves bent........ i bought a new head, and the wrecked one is getting tunned. thank you again and i hope you guys are able to solve this....

Jason.

 

[steve]

It's not a USDM GVR4 ECU. It is '90 style ECU.
Can you check the PCB number. I can't make it out. Is it JE331A954B or JE331A934B?

I see you have one of those cheap speedbounds EPROMs. I did a review of one a while back.

Steve

 

[mitsubluetalon]

Its "JE331A964B" and yes its a speedbounds chip i will check out your link now.

 

[mitsubluetalon]

hey i just checked out your review and i was wondering if you have a list of mods that are on a dsmchip? and where can i get one. do you have one?

my other question, do you know what is happening to this ECU to make my car run this crappy? in your review you said that you had a customer wanting to mod his ECU to run on 750cc injectors, do i have to get my ECU modded to work on my car? or should i spend the coin and get the right injectors? thanks steve

Jason.

 

[steve]

The speedbounds chip I dissected didn't have any changes made to the stock injector compensation or deadtime. The odds are good that one doesn't either.

The ECU seems to be from a 10/89- 7/90 AT JDM GVR4. The PCB revision is different from any USDM ECU and there may be problems due to changes in the board layout or due to not swapping the right pins. It's not an ECU known to work in our cars but that doesn't mean it won't just that you'll have to track down a JDM wiring diagram and verify all the pins and their functions. It's also possible that the routing of signals to the ECU ports are different requiring a custom chip for that ECU.

I still question your swapping the right pins. Tell me which ones you swapped by their location in the harness and wire colors.

Dsmchips.com otherwise known as a Keydiver chip.

Steve

 

[mitsubluetalon]

cool thank you. i will let you know tomorrow. i have a date with the miss's and she making that 'look' at me so i will talk to you later.

thank you very much steve

Jason.

 

[GVR4592]

The jdm vr4 ecu has some differences compared to the u.s. ecu. I think most of it is emissions and fuel pump related. There is a diagram on dsmchips forum to convert a jdm ecu to u.s. specs. It's just swapping some jumpers and thats about it. One major difference between the two is the maf compensation. The vr4 maf sensor is different than the 1g and 2g sensors.

 

[Deepsixer]

I have an ECU problem that maybe one of you guys can help me with. I have a JDM engine from a Galant VR4 and at exactly 110mph the car jerks back and can't go any faster. IT's not a fuel cut issue after talking to Roadrace and a few other people. Ever heard of this problem? I found a link that removes the governor from a 95 Eclipse and I wondered if this will eliminate the problem. Any advice will be greatly appreciated.

http://www.dsm.org/how-tos/speedlimiter.htm


Jasen

 

[mavisky]

cool thank you. i will let you know tomorrow. i have a date with the miss's and she making that 'look' at me so i will talk to you later.

thank you very much steve

Jason.

If you ever want something done for your car electronics-wise Steve is your guy, just pm him with what you want on your chip and he can get you exactly what you want. Stever my ecu will be headed your way as soon as the car finishes its first autox.

 

[mavisky]

I have an ECU problem that maybe one of you guys can help me with. I have a JDM engine from a Galant VR4 and at exactly 110mph the car jerks back and can't go any faster. IT's not a fuel cut issue after talking to Roadrace and a few other people. Ever heard of this problem? I found a link that removes the governor from a 95 Eclipse and I wondered if this will eliminate the problem. Any advice will be greatly appreciated.

http://www.dsm.org/how-tos/speedlimiter.htm


Jasen

A local kid here is having the same problem. Problem is that the ecu is some weird two tiered affair.

 

[Deepsixer]

Yup!! Looks exactly like mine. 110mph comes up really fast in my car and it's gotta get fixed. I just PM's him.

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[steve]

The dual board JDM ECU is just going to be an endless source of frustration.
The best thing to do is whatever is necessary to go back to running the USDM ECU.

Some of the single board JDM ECU can be converted to USDM pinout.

Steve

 

[mavisky]

Jeremy's nt-turbo swap is running off of a modded 2.0 nt harness and the pin switch for a 90 and it works just fine other than the 110 limiter. He's shopping for a new ecu as we speak.

 

[Deepsixer]

Will a normal 1G Eprom ECU work withe a JDM engine? I have one BTW and roadrace had some problems getting it to run when it was installed.

 

[mavisky]

Without knowing what mechanicals/electronics exactly that you're running its hard to say.