95 Spyder VR4 Jester Chrome ECU Tuning (weird idle/part throttle behaviour)

Ok today i installed a "Jester Chrome ECU" i bought from 3SX, an AEM TRU Boost and an AEM WideBand. I then flashed the chrome V2 stock rom with the disabled peripheries recommended in the tuning thread here in the forum. The car starts fine and idles fine initially but after a bit it starts to idle a bit funky. Idle drops and vibration goes way up. Then when i try to drive the car under low to medium load let's say anything from 10-70% throttle the car runs like crap the Wideband is pegged lean if i hold the throttle there for a bit and let the rpm come up as i gain speed suddenly the car "jumps" into power/boost (almost like flipping a switch) and runs fine until i let off the gas and do it all over again. Additionally it seems that if i go WOT the condition clears up and the car runs ok, but ONLY while i am at WOT or close to it say anywhere above 80-85% throttle.

The car is basically just a BPU car. It has: No cats, 3" DP, K&N Intake CX Racing Dual Core FMIC, HKS SSQV 4 BOV (Open to atmosphere). Full Vac Reduction, Stock Fuel stock Turbos. The car runs PERFECTLY with this same exact setup on the Stock ECU. The only things that changed were the Chromed ECu and the Boost controller. ( i was running a Blackstealth LCDBC and switched to the AEM TRU BOOST)

Any ideas?

Check the fuel trims

i did a lot of searching last night, both here and on the other forum. I found a couple of threads that seem to describe cars exhibiting very similar symptoms to mine. Where the car seems to run on 3 or 4 cylinders after just a few hundred feet under load. Most of those threads mention that it is possible the Jumpers inside the Jester Chrome ECU could be set incorrectly. Now as far as i know all Spyders are "Cali spec" so i ordered a cali spec ECU from 3SX and the ECU is also clearly marked as a 94-95 VR$ "Cali Spec". The ECU case has warranty seals so i'm not sure i should just tear this thing open without further verification that this is in deed a likely culprit. In most of those threads i saw people suggesting that the front 02 sensor be disabled and to report back on how the car ran after. I tried it this morning and while it did seem to initially idle much better (WB showing almost perfect AFR jumping between 14.5-14.9) The same exact problem persisted once i drove the car around the block. After a couple of hundred ft it felt like i was down cylinders again and it would not run right unless i went WOT.

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Originally Posted by Forest Gump

Check the fuel trims

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I logged the car yesterday and unfortunately i don't have the logs with me now (work computer) but i do recall the trims being pegged at -12.5 & +12.5 i just cant remember which was front and which was rear off the top of my head.

yeah your o2's are backwards then.

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Originally Posted by Forest Gump

yeah your o2's are backwards then.

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How do i fix that is that a jumper setting in the ECU?

Yes, it is a jumper setting. Seems like almost everyone with Chrome has this issue in the beginning. Can barely runs when in closed loop.

Contact Adam on here (JerstersDeadd) and he will walk you through it. I had to break the seal on mine (with him on the phone) and I ended up swapping it out because I have a 1G wiring harness in my new car now, and there were zero issues. He's a super nice dude.

I thought I remembered reading somewhere that even though the spyders are cali-spec the O2s are wired backwards? can anyone confirm that, and if so that should probably be added all the places that these can be bought.

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Originally Posted by striker2

I thought I remembered reading somewhere that even though the spyders are cali-spec the O2s are wired backwards? can anyone confirm that, and if so that should probably be added all the places that these can be bought.

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Which would then mean that specifically for Spyders even though they are Cali-spec cars the Jester ECU Jumpers should be setup for Fed-spec in order to correct for that issue?

As far as I know every Spyder tuning with Chrome has had this issue. I fixed mine in the adapter harness since I have the Clone ECU, not Jesters Chrome one.

Well, i rushed home after work today to beat out this blizzard headed my way here in NJ in order to have a bit of time to work on the car. I am happy to report that these issues were in fact caused by the Jumper settings. All i did was switch the jumpers from Cali-spec to Fed-spec, started the car and it immediately idled better. I then took it for a test drive and everything was running smoothly just like it was with the stock ECU. So Jim, i think you are correct in saying that just about every Spyder owner has had this issue. I think it would be a good idea for Jester/3SX to put the info out there on their websites so that folks don't keep having this kind of frustrating experience.

Yes, it's amazing what a difference in having a properly working closed loop :) It takes about 20 minutes to warm up completely and then every 4 minutes the trims will adjust. Monitor them and they should settle in the +/- 5 range.

Now that i got it running again i need to tackle another issue... Wideband data logging. I wired my AEM UEGO 30-4110 per the instructions on chromedecu.org (AEM 0-5V wire to pin 77 in my 95 wire harness) but it does not seem to be working. When i try to log it in Evoscan it just shows a consistent 10.0723 value and doesn't change at all no matter how long i drive.

I have the same issue with my ECU the WBO2 reads a static value. I never managed to solve it, instead I connected the WBO2 to my LCDBC.

Well I got the WIdeBand data logging figured out with Adam's (Jestersdead) help. Now everything seems to be working as it should. Time to start logging and logging and logging...

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Originally Posted by D.I.P.

Well I got the WIdeBand data logging figured out with Adam's (Jestersdead) help. Now everything seems to be working as it should. Time to start logging and logging and logging...

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What was the issue with the wideband?

I don't think I had the wire/pin set in the plug deep enough. I ended up removing it re-pinning the wire and re-installing it into the ecu plug. I used the end of my multimeter lead to help push the pin real deep into the plug. Started her up and Evoscan was now reading my WB afr as it should.

Hey good info here.
DIP, can you do me a favor? Can I get a picture of your silver model plate beside your brake booster?
Also can you post your vin?
And the part number of the oem ecu?

Here you go...

Attachment 8656Attachment 8657Attachment 8658

So the car has been running well since i got the jumper issue resolved but has continued to idle a bit lean. The AEM WB shows AFR bouncing between 15.5 & 15.9 (sometimes it even jumps just over 16 but that is VERY rare). I'm guessing this is just a matter of tuning etc and have been doing a lot of logging to work on that. One issue i haven't been able to figure out is why i keep getting the following CEL's:

Code 24 - Vehicle Speed Sensor
Code 31 - Knock Sensor
Code 41 - Injector Circuit
Code 43 - EGR Sensor

I have all of my peripheries setup per the main thread here on the forums. I have cleared the codes multiple times and every time i do the CEL goes away while i drive but if i turn the car off and then back on the CEL returns with the same codes. I also seem to get a Barometric Sensor code once in awhile. Any ideas what could be causing this? The car runs seemingly fine otherwise...

I should probably sticky this thread.

http://www.3sgto.org/tuning-engine-e...ead-codes.html

To be fair that thread doesn't exactly say "hey if you are using Evoscan 2.9 and the wrong OBD ECU option you will trip or display XYZ codes and wont be able to permanently clear them" LOL

Thanks for the answer though, I was in fact using the wrong MUT Protocol for Displaying/Clearing codes. I switched to the correct one in your link and it seems to have worked. Drove in to work this morning and no codes came back as of yet.

Now on to more logging and trying to figure this lean idle out...

There's probably a couple peripheries you need to disable from the missing sensors between your car and a 98/99. Whatever code tripped will probably be back on again soon.