Progress Thread Komo's 1990 GT - Parts Gathering Purgatory & Home Remodel

gkomo · Apr 15, 2026

Noobz347 said:
If you had a hair on your ass, you'd rig up a vacuum operated vane system like the cowl on the old IROC.

That would be pretty sweet actually.

gkomo · Apr 17, 2026

Was out adding just about a 1/4 qt of oil (not bad for the miles driven since last top off considering my issues), and noticed the cap on my Throttle Body was looking a little fubar. I believe this cap was new and provided with the Paxton kit. Surprised it looks like this:

So, I replaced it with a cap we have at work. However, i'll probably need to replace it again soon as i don't think the caps we use here are rated for high temps. They are just data cable caps to protect the connectors:

Edit: ya its going to be close. P/N is VC-343-16 and has a 'maximum continuous temperature" of 200 degrees and a "maximum intermittent temperature" of 350 degrees.

AeroCoupe · Apr 17, 2026

Yeah those vacuum caps don't last very long. I have them on my EGR spacer and have to replace them yearly. I am waiting to drop the MSPNP in the car and I am just going to delete the spacer. You could get some vacuum line and glue a copper tube cap in one end and then put it on that vacuum nipple on the TB and that would most likely seal it up for several years.

gkomo · Apr 23, 2026

Finally scheduled an appointment get my wideband bung welded in. Bout damn time.

gkomo · Apr 23, 2026

Alright second bit of small progress today, I think I have my boost gauge holding reasonable pressure now. Finally got around to putting the new ferrule on the boost line and connecting it to the fitting. I tested the pressure and it held pressure MUCH better than before. It took like a minute to bleed off 1psi where as before it was bleeding off 1psi every 5 seconds or so.

I can’t rule out any slight leaks in the vacuum tester hoses OR the plastic tee I used to test so I’m fairly confident the new ferrule is doing its job.

However, still no functional boost gauge as I want to wait until I get the UPR vacuum tree installed and it hooked up to its own port (no tees). So right now I left the plastic tee fitting screwed in to ‘plug’ the fitting, and taped off the other two ends of the tee so dirt/dust can’t get in.

Baby boy is starting to take more predictable naps around an hour, so (unless my 4 year old is home) I should be able to do small things like this every so often.

gkomo · Apr 24, 2026

Got the UPR vacuum tree finished. May have went a little hambone with the thread sealer but it should be good. Only issue i foresee when putting it in, is the left most port, which i was going to designate as the 'source' port may hit the MAP/BAP (can't remember) sensor and bracket right next to the vacuum tree. So i may cap that one and use the left bottom most port for 'source':

The capped port will be used eventually when i install my bypass valve kit, which i already have.

I wish the UPR tree came with port plugs, or at least a couple. I guess i could have bought some instead of needing to cap unused ports.

But the vacuum lines will be (from left to right):

- Source
- Capped Off (?)
- FMU
- A/C
- S/C
- Boost Gauge
- Brake Booster

gkomo · Apr 24, 2026

Got the tree installed. I need to trim both the booster and source lines as they are too long for the ports coming off the side of the UPR tree to mount the tree to the firewall. Like the lines can't be bent enough to get the tree close to the firewall. So it’s basically free hanging from those two lines and just hits the hood when it’s closed.

I also need real vacuum caps for the two open ports. I’m just using some from the vacuum pump kit for now, one is neon green and the other neon pink, lol.

I also need to buy some hose clamps just to be 100% sure all the lines are secure and leak free.

With that said I started the car up and it held 20hg of vacuum just idling. So at least I know the guage is working again.

Edit: the more i think about it, the more i want to redo most of it. I.e. redo vacuum lines (FMU line is a little short), redo my boost gauge line (its a little twisted up), real vacuum caps, etc. Basically make it look nice. Looks like garbage at the moment.

gkomo · Apr 24, 2026

Alright ordered a bunch of evil energy vacuum hose is various sizes, hose clamps, vacuum nipples and a nice sharp exacto knife to knock this out.

gkomo · Apr 26, 2026

Vacuum caps came in but nothing else yet so here’s my temp situation:

nicholase · Apr 26, 2026

I have the source going to the bottom left. That way its not hitting for MAP sensor. Then you can run one of the smaller lines behind the MAP sensor bracket to the left side barb. Just a thought.

gkomo · Apr 26, 2026

Good idea!

gkomo · Apr 27, 2026

Alright, swapped the source line from the far left to the left bottom. Now i'm able to just get the capped far left port to sit under the MAP sensor bracket. After removing the brake booster line from the far right, i can get the tree to sit flush with the holes in the firewall. However (and i should have thought of/measured beforehand) the far right port (for the brake booster) just won't work, the actual port, with no hose even connected to it, hits the wiper motor. I could probably clearance that to make it fit as i checked the bracket and where it hits is not important, but moving around ports is probably the best way to make it cleaner.

For some reason i had envisioned the two large vacuum lines coming/leaving from the sides then having all the small lines coming off the bottom, but i just don't think it will work like that.

Moving the source line to the bottom makes it 'better' but i still can't bolt it to the firewall in its current configuration.

gkomo · Apr 27, 2026

Ok, got my wideband bung welded in and installed the sensor.

For just putzing around town, cruising home on the freeway, etc i am looking for being as close to 14.1-7 right?

WOT looking to be down closer to 12.5?

I need to adjust the display on the gauge as its currently set to the hundreth decimal which makes the numbers always look like they are jumping all over the place even though it staying in the right range. Would like to bring that down to just showing a tenth decimal. Just need to read the manual to see how to do that.

At idle it seemed good, was in the high 14's once the car was warmed up.

On deceleration it seemed to dip pretty low, i recall seeing the 11's a few times with decelerating in gear and no foot on the pedal. I only drove it like 2 miles back to work on side streets so haven't gotten to really look at it too much.

I guess my big question is, since i don't have any tuning software or anything, what exactly am i looking at with the AFR gauge? Just that everything seems in line with the ranges it should be in certain conditions? What am i looking for the gauge to show that would be bad (super lean/super rich, but when?)?

DadLife0724 · Apr 27, 2026

gkomo said:
Alright, swapped the source line from the far left to the left bottom. Now i'm able to just get the capped far left port to sit under the MAP sensor bracket. After removing the brake booster line from the far right, i can get the tree to sit flush with the holes in the firewall. However (and i should have thought of/measured beforehand) the far right port (for the brake booster) just won't work, the actual port, with no hose even connected to it, hits the wiper motor. I could probably clearance that to make it fit as i checked the bracket and where it hits is not important, but moving around ports is probably the best way to make it cleaner.

For some reason i had envisioned the two large vacuum lines coming/leaving from the sides then having all the small lines coming off the bottom, but i just don't think it will work like that.

Moving the source line to the bottom makes it 'better' but i still can't bolt it to the firewall in its current configuration.

Wiper delete...... Problem solved.

gkomo · Apr 27, 2026

So on the drive home which is a mix of city/highway driving… all looked, good?

Highway cruising was in the high 14’s (like 14.6-14.9), light throttle like to speed up stayed in the mid 13 to mid 14 range. Getting up to speed on city streets was all normal I think.

The only oddball thing I noticed was on deceleration it shows rich like in the high 11’s to mid 12’s… then when I go back to pressing the accelerator it leans out very briefly like 16+ but then settles back down into the 14’s. So I think I’m all good?

I didn’t do any WOT pulls but I got on it in 4th gear merging onto the freeway and it was in the high 12’s to mid 13’s for that ‘pull’.

gkomo · Apr 28, 2026

Ok so after researching AFRs a bit more, everything seems normal except for the 'rich' condition on deceleration. From what i gather, Foxbodies have a deceleration fuel cut off, which on decel then should show 'lean' on the guage (15+), right?

Why does my AFR show high 11's to mid 12's when decelerating in gear?

I also changed the decimal point to just show tenths, much better.

nicholase · Apr 28, 2026

That seems a little weird. It should be going pretty lean I would think when decelerating becasue there's no load and the engine is essentially being spun by the wheel rotation. I don't remember what mine was with the Ford computer. Whish I could help. My standalone goes up to 18 or 19:1 on decel but as soon as I push the clutch in it kicks to around 14.7.

Does yours change when you push the clutch in decelerating?

gkomo · Apr 28, 2026

nicholase said:
That seems a little weird. It should be going pretty lean I would think when decelerating becasue there's no load and the engine is essentially being spun by the wheel rotation. I don't remember what mine was with the Ford computer. Whish I could help. My standalone goes up to 18 or 19:1 on decel but as soon as I push the clutch in it kicks to around 14.7.

Does yours change when you push the clutch in decelerating?

I’ll have to test that. So now I’ve read that the A9L has a deceleration fuel cutoff but it’s not enabled?? Only the cobra ECUs enable it? I dunno I’m reading conflicting things on the internet.

I can confirm it goes ‘rich’ (or reading less O2) if in any gear I let off the gas and just let the car decelerate on its own while the rpm’s are for whatever speed I’m going in whatever gear I’m in.

Then when I get back on the accelerator it pops ‘lean’ (or reading a lot of O2) just briefly before settling back near stoichiometric(?).

All other driving conditions look to be what I would expect a good AFR to be after reading more about it.

gkomo · Apr 29, 2026

https://www.eectuning.org/forums/viewtopic.php?t=8078

Found this thread where a guy is changing his A9L Decel Fuel Cutoff values to match the X3Z (cobra) ECU values. I guess this leads me to believe maybe the A9L does in fact not have a decel fuel cutoff program enabled and therefore my 'rich' condition during decel is normal?

gkomo · Apr 29, 2026

nicholase said:
Does yours change when you push the clutch in decelerating?

Verified this on the way to work today. Car goes back to the 14.7 range with clutch in (or basically in neutral) and coasting. Only shows rich when decelerating in gear.

Probably not a huge deal and sounds like its just the ECU programming (or lack thereof) but it would be nice if someone could confirm they see the same results on decel.

Progress Thread Komo's 1990 GT - Parts Gathering Purgatory & Home Remodel

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

lube between the nut and the face. I know my lubes

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

I lubed and pushed, until it was all the way in

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

Active Member

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

I lubed and pushed, until it was all the way in

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

now i can hopefully expect to receive the shaft

Similar threads

Privacy & Transparency

Privacy & Transparency