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Zxt richy rich


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Been searching for days, my 82 zxt all stock except upped the boost a little and hks bov, I have a wide band so I'm not just guessing.

 

Anyway my car was running rich everywhere, like 11-12/1 vac and 10.0 (maybe richer, limit of wb) over 3lbs of boost, until the other day it was hot out and after shutting it off for 30 second in a drive thru it leaned out to perfect! For 1 day, now rich again

 

I can tune the afm and get it to drive nice except under boost, chts checks out fine so does the air temp, the only problem I can find is there is it is o/l from pin33/ chts yellow/green to ground, when there should be like 2k ohms or something. Can't find any solid info on this except in the fsm it briefly mentions this

 

I even jumpers the chts straight across and it's still pegging 10.0 in boost

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  • 4 weeks later...

I am having the opposite problem, I am running stock ECU, did some minor changes to get ready for more boost, Innovate SG1 - boost controller and wide band, intercooler, palnet fuel rail (stock injectors) and Summit FPR. I am running at 13.7 - 14.5 at partial throttle. I am a little nervous to try WOT until I get a little more fuel. I am already up to 45 PSI on the fuel.

First time with the wide band so not sure how jumpy the AFR reacts. I am guessing at steady 2,000 RPM in neutral it should be below 14.0.

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If Stock ECU, adjust your Fuel pressure to achieve desired AFR at WOT. Let cruise AFR fall where it may. Rule #1 on all Turbo cars with non programmable ECU's. You want WOT AFR ratio around 11.0 to 11.5 on Turbo cars to be safe. Keep Boost and Timing conservative and AFR a bit rich until you dial it in. How much boost are you planning on running and what CR does the engine have and what fuel are you running? 

 

Stock ECU has limited ability to adjust. Don't go crazy with boost on stock injectors. You really need a standalone ECU that can be programmed with a Laptop to optimize everything

 

2,000 rpm free revving in neutral would be around 14.0 to 14.7 with stock camshaft. No boost and  minimum load at that RPM equals Stoich ( 14.7-1 ) or close to it with a good tune. .

 

Edit: Simple Digital Systems has some very good Tech articles on Turbo's and EFI. A good read:

 

http://www.sdsefi.com/tech.html

Edited by Chickenman
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Thanks Chickenman, that is very helpful info, link is nice also.

I am working on a MS ECU so until then I am keeping boost very conservative, today I am limiting to 5psi until I feel good about SG1, plan on going to 9-10, I am still running 86 gas (plus) will be moving to 93 (premium) CR is slightly higher than stock, I did cc combustion chambers when off so they have brought me back to 8.3.

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