REDTOP running rich with JWT ECU

[180Sil]

I have a s13 redtop, stock block and head, 740nismo inj and z32 MAF and JWT ECU for the 740cc and z32 maf. I finally got a chance to dyno the car today and it's running crazy rich. At 14.6 psi it was 10.x on the a/f, I thought it would be around 11.8-12.0 under load and 14.6 while idling and cruising.

The first run started with the car around 14.6 then dropped to 10.x under boost and this was only 12.6lbs. it got worst as more runs were made on the dyno the last run was worst the a/f was in the 12.x before boost once the boost hits the a/f drop to 10.x

I checked the MAF and O2 and they are both working, I don't think its the JWT ecu so the only thing is the 740cc inj, one of them would be stuck open. The FPR gauge was 43 without vacuum.

Any ideas? btw, the turbo is a 2871 .64 gtrs style

[rps13drift]

What was your power at? And also i bet you probably have a boost leak especialy if the conditions got worst as you did more pulls!

[WoolyS14DET]

with the vac line disconnected it should be 43.5 psi on the fpr gauge .The fuel pressure will increase by 1 psi for every
additional psi of boost pressure (above the base pressure of 43.5 psi).


With that in mind what turbo are you running ??

[johngriff]

Getting worse as the car got hotter? Rich running condition?

Start with the base timing set correctly against JWT recomendation.

Then, check/replace the coolant temp sensor/wiring.

Pretty basic, well repeated info.

[silnismo]

JWT tends to make their ecu richer for some reason, my a/f was around the same.

But as rich as mine was its not like its caused any problems when running through the gears except having a horrible MPG.

If it really bothers you, i just grabbed an SAFC and had someone slightly leaned out a bit.

[180Sil]

What was your power at? And also i bet you probably have a boost leak especialy if the conditions got worst as you did more pulls!

I was doing between 240-263 whp. I will check for possible boost leak monday.

with the vac line disconnected it should be 43.5 psi on the fpr gauge .The fuel pressure will increase by 1 psi for every
additional psi of boost pressure (above the base pressure of 43.5 psi).


With that in mind what turbo are you running ??

I will check/adjust the FPR, I'm running the GT2871 .64 GTRS style

thanks for all the info

[Ninjabread]

Lol.

That's why I'm going with an enthalpy.

jk, but I am buying one.

I remember a thread where the two were compared and the jwt ran super duper rich compared to scott's ecu ...

sorry, I know I'm not helping.

[JuDgeMentS13]

A friend of mine has the same problem.

[180Sil]

Lol.

That's why I'm going with an enthalpy.

jk, but I am buying one.

I remember a thread where the two were compared and the jwt ran super duper rich compared to scott's ecu ...

sorry, I know I'm not helping.

I'm considering that route too but been doing some research into e-mance as well.


A friend of mine has the same problem.



did your friend fix the problem? how?

[180Sil]

no one thinks it might be the ecu problem? I'm asking because my friend had the same jwt ecu on his redtop w/t25 and dyno at 242whp @ 12psi and the a/f was 11.x-12.0 under boost all the way to redline.

I was looking into enthraphy because the turn around was 2 days according to the website. I'm also considering AEM EMS/ Apex PFC but you need to get those tune for a specific boost or re-tune for any small changes while the ecu flash generally have a little fat for small changes but this 10.x a/f is way too rich for today's gas prices....

I also have a e-manage blue with PNP s13 harness. I'll try that after checking for boost leak and fpr reading.

[180Sil]

Getting worse as the car got hotter? Rich running condition?

Start with the base timing set correctly against JWT recomendation.

Then, check/replace the coolant temp sensor/wiring.

Pretty basic, well repeated info.

I will add the base timing and coolant temp sensor/wiring to the list of things to check on monday.

[johngriff]

I would use a Haltech before another rom tune. Especially no AFC. And the emu will not work with a tuned ecu. It needs to be hooked up with a stock ecu to work well.

With the Haltech you can tune it for all boost ranges, and change boost on the fly without a laptop. It is the best of the best.

But if you don't have an idle issue, I doubt its a boost leak. Rich condition is from what I mentioned.

[aNskY]

turn the boost up?

[180Sil]

I would use a Haltech before another rom tune. Especially no AFC. And the emu will not work with a tuned ecu. It needs to be hooked up with a stock ecu to work well.

With the Haltech you can tune it for all boost ranges, and change boost on the fly without a laptop. It is the best of the best.

But if you don't have an idle issue, I doubt its a boost leak. Rich condition is from what I mentioned.

after the jwt ecu it idles around 900 and goes up when the fan comes on. other than the occasional hic cup due to the riches of the tune it pretty stable at 900rpm.

i did consider the haltech but I don't have anyone here to tune it. i like the fact that i can turn up or down the boost with the flash and still keep the same a/f and gas mileage. I thought standalone (PFC, AEM EMS) needs to tune for all the different boost the car might run or else it runs horrible.

[180Sil]

turn the boost up?

it actually ran worst with higher boost.

[WoolyS14DET]

JWT programs their ECU's to run rich cuz they dont want them to blow up and be held responsible for that. I'm running an JWT ECU an i got an S14DET wit Nismo 555 injectors, Z32 maf and a gt2835r turbo and it runs a lil rich but runs great ! I dont have any issues at all !!

[180Sil]

JWT programs their ECU's to run rich cuz they dont want them to blow up and be held responsible for that. I'm running an JWT ECU an i got an S14DET wit Nismo 555 injectors, Z32 maf and a gt2835r turbo and it runs a lil rich but runs great ! I dont have any issues at all !!

how rich? what's the a/f?

If mine was around 11.x-12.x under boost and 14.6 while cruising than I don't mind but 10.x under boost is too much. I'm back firing and my rear bumper is all black from 2 days of driving.

[180Sil]

I checked monday, FPR was set at 43.5 without the vacuum and can't find any vacuum leak but i did notice black smoke upon start up which means rich.

Will a stand alone like the EMS, Haltech or PFC be able to fix this problem with the car in this current condition? The car is not suppose to blow black smoke upon startup so there could be some mechanical problem that I can't find or think of.

[180Sil]

updates.....

it must be the coolant temp sensor cause the car is running strong now with the weather bring 15degrees cooler than last sunday

seems like problem fixed....thx everyone

I'm gonna flush my coolant, change out the sensor, clean the harness and put in a bottle of water wetter as a precaution

[fcdrifter20]

coolder wheather would only make ur mixture richer. the jwt tunes r know for running a little rich. check ur injector.s pull each one out and make sure none of ur o rings are pinched. that is a very common problem for people to force those injectors on there without knowing. wich will cause a leak. if u let it keep running like that u could blow a whole in that piston. i have seen this twice before on engine i have worked on. all that gas stays in the for a prolonged time, scince liquids do not compress it has no where to go

just make sure none r pinched. then when u r putting them back in, lube the orings up realy good(white lithium grease will work). push down and twist at the same time. if they dont go right in, dont force them cuz u will just pinch the o ring and cause even more problems.

[Def]

I'd check for boost leaks. Most people I've done ROM tunes for(for way less $$$ than the JWT rate, which is kind of a rip off for a rom tune IMO) and have had problems traced it down to a boost leak.

It's very easy to have a small tear in a coupler or a vacuum line get blown off and the whole thing goes ape shit with rich AFR and a tough time recovering an idle from higher RPM.

[codyace]

Someone takling shit on my rom tunes ;) Remind me to beat you up John ;)


As def pointed out, 9/10 'my jwt runs super rich and I don't know anybetter' threads all relate to huge vacuum leaks, not recirculating BOV's, and general haphazzard part installs.

[180Sil]

i do have a ssqv that's venting to the atmosphere right now so i'll switch to re-cir and see if the a/f gets leaner. i'll get on the dyno in about 2 weeks so we'll see.