Problems with E38A VR4 RS

[trq-str]

I am wondering if there are problems associated with running an ADM E39A (450cc injectors) ecu on a JDM E38A Vr4 RS (yellow top injectors).

With the RS ecu the car would run like crap e.g. Bog down on boost and feel quite undrivable, but no ecu error light would pop up on the dash.

With the ADM ecu the car runs fine when it comes on to boost, but still doesnt feel quite 100%, however, the error light comes and goes on idle and sometimes it flashes threw out the rev range.
When the light pops up on idle a light rev gets rid of it for a while. I was thinking this light may be associated with things such as the rs not having ABS and the associated sensors or something like that.

Help would be very much appreciated.

I will do a diagnostics check with the ADM ecu, and take it from there.

Koray

 

[Entaran]

yellow tops are 510cc, standard bluetops are 450cc. You're basically forcing the car to lean out.

 

[VR-4Squid]

not all E38A's had 510's

 

[Entaran]

All yellow tops are 510's though.

If he puts an Aspec ecu on somethign with 510's it'll run way off in terms of A/F's and generally be a pig. It'd need an SAFC to correct the fuel.

 

[VR-4Squid]

All yellow tops are 510's though.

If he puts an Aspec ecu on somethign with 510's it'll run way off in terms of A/F's and generally be a pig. It'd need an SAFC to correct the fuel.

yes, sorry, I've just engaged my brain and read the first post again properly, oops :blink:

 

[Entaran]

haha, yeah I have that issue often

 

[milkandoj]

If you unsure if that ecu is meant to have 450's of 510's. Check the numbers on the ecu and do a search on here, google or galantvr4.org.au and you'll most likely find what injectors are standard.

But if its stock yellow tops (510) your running lean with 450's.

You want to get it sorted before you blow you motor mate.

 

[Entaran]

I think he's actually running overrich by having 510's with an ASPEC ecu which thinks it has 450's so it's pulsing way more fuel in than it's supposed to and running like 9:1 or some shit.

 

[trq-str]

I thought that it would be running rich.

 

[milkandoj]

soz, i though he meant he was running 450's with the rs ecu (written for 510's).

yeah if you have the aus spec ecu you want 450's or if you use 510's with the aus spec ecu, need to tune it to suite.

 

[trq-str]

Ill buy an ecu to suite 510's and see how i go.

Could the "check engine light" be flashing on and off due to a/f mixtures?

 

[CLuTZ]

Could the "check engine light" be flashing on and off due to a/f mixtures?

No...


The o2 sensor is just used for fuel trim on idle and cruise

 

[Entaran]

The CEL light will come on if the O2 sensor is BROKEN, not if it's cycling.

Although if it doesn't cycle across the 0.5v switch point at least once every 30 seconds it'll also throw a CEL.

 

[Dean]

How would you fix such a problem apart from getting a new o2?

 

[Entaran]

New o2.

It's the same code it throws when the o2's broken because the broken o2 won't cycle for 30 seconds... I think from memory it's code 23 or 27. I can't quite remember (would have to check)

Also, you could easily fix this car by simply socketing the Aspec ecu and putting a chip in to suit 510's.

Goto www.meek.com.au and email them see if they'll do a chip for you. I don't know if the yanks or kiwi's are still doing chips. And I think all the other guys in aus who do them have given up the game.

 

[Dean]

MMM interesting. Sorry to go O/T btw.
Mine has a mind of its own. It close loops when it feels like it, its so I run a little bit rich, especially at WOT.
Do you think it may be an auto elec job?

 

[Entaran]

http://www.ecmtuning.com/wiki/fueltrimupdatepoints

 

[trq-str]

Also, you could easily fix this car by simply socketing the Aspec ecu and putting a chip in to suit 510's.http://www.

What do you mean by soceting the ecu?
Does the JDM loom need to be modified to suite the ADM ecu? I just pluged it in and started up, hope this is ok.

Or do you mean adding a socket on the ecu to plug it to a laptop for tuning or something?

Koray

 

[CLuTZ]

What do you mean by soceting the ecu?
Does the JDM loom need to be modified to suite the ADM ecu? I just pluged it in and started up, hope this is ok.

Or do you mean adding a socket on the ecu to plug it to a laptop for tuning or something?

Koray

Socketing is when the factory eprom in your ECU gets de-soldered, and replaced with a plug that aftermarket eproms (chips) can get plugged in and out of.

TV repair places usually charge around $40-$50 to do it. That means you can get a chip from somewhere like www.meek.com.au to suit your mods (along with giving you a bunch of other features) and then it should be running heaps better.

If you cant be bothered working ECU's then i'd also suggest swapping back to 450cc injectors, and sorting out any more problems from there

I'm over in Coburg if you wanna catch up one night and I can run my laptop with EVOscan software on your car (assuming you have a single board ECU) and suss out this CEL and perhaps other problems at the same time. Drop me a PM if you're keen,


dre

 

[trq-str]

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