Went to the track... highly disappointed, and found a major problem.

[jetjock]

Go for it. Btw, always check cross counting off idle. 2500 rpm is good. You want a minimum of 8 sweeps in 10 seconds with an average sensor voltage around 450 mv. That'll give you stoichiometeric. Tuning for WOT mixtures are, of course, a different story.

 

[Doward]

on an '88 I'm still measuring between Vf and E1 for O2 voltage, right?

 

[jetjock]

That'll give you a digitized O2 signal which is not what you want. Measure the raw O2 signal on the diag connector between OX and battery negative. If it looks good you then should measure at the ECU itself. You've already established the mixture is rich though so focus on the reason why it and use the O2 signal as a check when making changes.

edit: oops, forgot you're using a WB. Check it's simulated signal.

 

[Doward]

Hmm... I'm going to toss my stocker back on there (tomorrow, it's too damn hot out @ 1:10am in Florida's muggy nights) and check the voltage and Vf again... even with the j tube drilled out, I'm still running rich. What I find stupid, is that it seems for all intensive purposes, that the ECM is commanding it to run rich.

I double checked for codes - still nothing from the ECM. :3d_frown: I think some food and a clear head will be needed in the morning.

 

[stratoayu]

my car lately has gone SUPER rich.. like off the dyno scale rich.. but yet i ran a 14.5 @ 99 mph with my worst launch ever (2.45 60 ft) i dont think the running rich is ur main problem... my car has intake, exhaust, hardpipes, 11 psi...

 

[Doward]

well... my car has... Nothing. It's totally stock - I like to have my cars running like they rolled off the factory, before I start modding them

 

[jetjock]

Sigh....read the post. He's complaining of richness under cruise. The entire computerized EFI system, the whole shebang, is specifically designed to keep the mixture tightly controlled to stoichiometeric under those conditions.

Doward: Stock is good. They're easier to fix that way

 

[stratoayu]

well i didnt read pg 2 so im prolly missing out on something. but all i read is that when he hits full throttle hes running at a 9.8 AFR. and im running the same. but im sure as hell not running taht in the 1/4 mile.

 

[IJ.]

Quick check would be to bypass the J Tube for now with a piece of hose.

 

[jetjock]

Might want to hook the stock O2 back up again too. I dunno what those WB jobbies put out for NB signals. I've said time and again I don't think using a WB for AF compensation is a good idea.

 

[Doward]

Well, JJ, I don't have a problem with it - but obviously if it's not working, there IS a problem then

I've already drilled the J tube - no change. Adjusted the AFM screw all the way out - limited change.

I'm going to pop the stock O2 back in tomorrow, and see if it moves the Vf at all - if so, that tells me that I have an O2 not reading right, somewhere here. eh, I want something to eat now, then bed. Tomorrow I'll look into it more

 

[jetjock]

Well, I think you'll find the O2 sensor is not the problem. Something is shifting the loop rich. Not all that uncommon. Could be a bad AFM, coolant temp sensor, etc.

 

[supramike7m]

well i have no clue about you runnin rich or what not. but just curious, what was the weather like that day? when i took my fourth gen twin turbo supra out to the drag strip the first time, she only ran a 15.1 i was like wtf? kind of like you now, the next time i took it out it was down to 13.2. the first time was in the middle of the summer here in AZ, was like 118 degrees, the other time was alot cooler, that could explain your slow ass time. i dont know? just tryin to help.

Mike

 

[Doward]

well i have no clue about you runnin rich or what not. but just curious, what was the weather like that day? when i took my fourth gen twin turbo supra out to the drag strip the first time, she only ran a 15.1 i was like wtf? kind of like you now, the next time i took it out it was down to 13.2. the first time was in the middle of the summer here in AZ, was like 118 degrees, the other time was alot cooler, that could explain your slow ass time. i dont know? just tryin to help.

Mike

It's not the ET that's got me worried - it's the MPH (indicating I am WAY down on power) as well as the fact I am *not* anywhere near stoich when in closed loop....

JJ, can you give me a list of parameters for the ECM to switch to closed loop? I'm going to test a couple things, but you mentioned the CTS, and that got me thinking - I did replace the CTS, but I went through the Wells Illustrated catalog, and simply found the CTS that had the correct metric threads + the correct wiring harness plug... The book listed it as being used in some Toyotas - but I wonder if my ECM is *not* receiving word that the car is fully warmed up?

I'll need to measure my voltage @ ECM, I'm pretty sure... it's gonna be a fun day :3d_frown:

 

[Doward]

Approx 80 degree F coolant temp -

TTS ohms to 74.2 ohms
CTS ohms to 1.797 K ohms

JJ, any help on that list of parameters?

 

[bigaaron]

Did you do the fuel pump relay/resistor bypass? That could make it do what you are describing. Also, an aftermarket afpr is a good idea to have with a Walbro.

 

[Doward]

I have done nothing to this car - but then, I have no clue what the previous owners have done, either (I really REALLY hate that fact)

So far, in trying to lean it out I have:

Drilled out the J tube completely.
Backed the AFM screw out as far as possible.
Checked the CTS
Checked the TTS (had a strange idea maybe my CSI was staying open)
Checked Vf (sitting around 1.005-1.009)

I really need to check fuel pressure. :3d_frown: I'm going to hit Lowes and pick up the parts to make the home built boost leak detector (LOL, I love it) and verify there isn't some damn vacuum/boost leak that I'm missing.

 

[Doward]

*UPDATE*

Alright... pressurized the intake to about 10psi - found some leaks!

Gasket to the ISC - fixed
90 degree hose that runs off the forward side of the intake manifold, to the little tree of vacuum lines - fixed

Now the fun... the 2 stupid lines off the throttle body are also leaking, but I can not find a 1/8" vacuum line ANYWHERE. I'm having to use 9/64" or something like that... I'm trying to find my pinch clamps, to see if that helps, though.

Once I get all these little leaks fixed, I'll see how my AFRs look.

 

[Wills7MGTE]

Yeah a guy here ran a 16.5 then a 15.8 with a stock 90 auto so I don't know lol, mines modded I never ran it stock and I ran a 13.8 and 13.9 pretty consistently with 10psi and stock turbo, just exhaust, intake, BC, Venom 400, hardpipes, HKS SSQV BOV and stock auto tranny.

 

[Doward]

Yeah, it's just really, REALLY disappointing that my '88 Camaro, bone stock, ran a 17.071 @ 79.58 mph :3d_frown: