Took the 'Stealth Fighter' out for a drive today. I'm still trying to stabilize the car after swapping

• Heads (Lt1 ported castings off, Canfields on)
• Wastegate springs (14psi springs off, 7psi on)
• Transmission (T56 out, TH350 in)

I drove it till she warmed up and then took some 'easy push downs' on the throttle. Still, the 'memory' function of the AEM TruBoost revealed I got just under 14 psi. It felt great. But, I noticed the Wideband. At idle, it shows 13.x, somewhat rich. At cruise, it also shows 13.x with the occasional 14.0. But under boost, she runs lean by ALSO running about 13.xx at the 13 psi mark. Add to that, it doesn't idle after all the swaps. I have to add throttle pressure to keep it at idle. It's set to idle at 1,000 in the pcm but the idle quality is weak, weak, weak. As I let off the throttle at idle, it will dwindle and then die in short order.

Of course, when I try to log it with Datamaster, the freakin ' laptop can't find a com port using my AKM USB cable. I have a second laptop (older than dirt) with a real serial port but I can't find the serial version of my AKM cable. Phock... I want to see what my TPS settings are, my IAC counts and my MAF reading. Something is off but I can't find it yet.

 

lol ain't that the damn truth.

13:1 AFR is a bit scary under lotso boost. Keep in mind your AFR reading is an average of all 8 cylinders, and each cylinder is going to flow a bit different; even a 5% variance could be quite dangerous. I'll be shooting for ~11.8 soon on my new built 383 when it's boosting in the teens.

 

Yes. I can't figure out at this moment, what is going on. On the prior setup, at 14 psi, the WB was showing 11.x. It idled great, etc.

My luck is just (still) against me. I've got to go over to the "PCM/Tuning" forum now to see what guys are doing with their laptop says "You ain't got no stinkin' com ports". When I go into device manager, and click on com ports, there's none displayed. If I fire up DataMaster, it says "Com Ports: None". I've used this same laptop in the past (about 2 years ago) with the AKM USB connection and it worked great. Now, it's useless. Always something, no? Hehehe..

Your upcoming build sounds like a great project. I look forward to your stories of going sideways at the blip of the throttle.

 

Hmmm... as I woke up this morning with my wife, my thoughts turned to the usual subjects. Sex and then my car.....lol... I got to thinking, "what would make the car that had previously ran fine, run rich at idle and lean at WOT? Hey... that would be the fuel pressure regulator I bet!". At atmosphere, the non-adjustable FPR I have would deliver approx 43.5 psi. Too rich for idle. Then, at boost/WOT, the 'tune' is designed around the anticipation that the FPR will be pressurized by the boost and close off the fuel return, bumping up the fuel pressure to a higher level than 43.5.
Of note, the plastic tube that goes to/from the manifold/FPR had 'pulled out' of the rubber boot where it goes into the intake nipple on the passenger side back when I put the motor in. I re-inserted it but it sounds like something is amiss here. I have a handheld FP gauge that I can hook up and tape to the windshield. I'll give it a look and see what goes on.

 

Good luck man I hope its finally something simple for ya.

 

Dave, I'm still doing troubleshooting on mine - but I've got a laptop with a serial port and an AKM cable for it that I know works. If there's still a lot of issues, maybe a bit of logging would help clear things up.

 

Well. The fuel pressure regulator is working at idle. 43 or so PSI at atmosphere and 38.x connected at idle. Opening the throttle by hand and watching the FP, It would jump up in response to each 'blip' of the throttle. Holding it at a steady higher(2,000 or so) RPM would show the pressure steady at sub 38 psi.

One thing I've done is to completely block all induction via the two ports on the side of the Throttle body as well as that port that is under the TB. I assume the PCM thinks it should be getting 'some' air from those venues so by my blocking all 3, perhaps it's just too much fuel for the air that is present. I unblocked the port under the TB (has a tremendous vacuum at idle) just to see what the Wide band would do. So, before unplugging this pipe, my AFR was 13.3. Once it was unplugged and getting completely unrestricted airflow, the AFR was 17.x and the idle quality went up as well. With that in mind, I put an extra PCV in the pipe (so it could draw air during vacuum but would seal shut during boost) and one of those mini-air filters on the end of the PCV so it would draw filtered air. Taking it for a drive, it felt a LOT better and wouldn't dwindle and then die at stop signs like it had before. I still have to hunt down the lean at WOT issue but it at least appears I'm making progress.

 

I thought my handheld fuel pressure gauge had a long enough hose to reach to the windshield so I could see if I'm losing pressure at WOT. It's not. I'll have to see what I can do on that front. The little 'test' drive I took today (10.x Psi w/o really trying) was great fun.

 

Went out this morning, checked the fluids and then took her to the carwash(beautiful day here in Upstate NY). Got into boost a couple of times and smiled my *** off

Still to fix/figure out...

1. Coolant keeps getting out of the system someway. Can't figure it out just yet. I can top it off at night. In the morning, it'll be missing about a cup of coolant. Wiped a clean paper towel over the banjo bolts on the back of the heads to see if it's getting out there. Nope. Came up clean. Car runs on the first 1/4 mark of the Temp gauge from warm up till I shut her off during a 30 minute drive. Weird...

2. Pan gasket on the TH350 has leaked since I got it from Century Transmissions in 2003. Used to be a little. Now, it's a lot. I have a new 'cork' gasket(jeez, why hasn't somebody invented a neoprene gasket for these trannys in all this time?) The tranny has one of those deep pan cast aluminum pans and you'd think it would seal perfectly. Thing is, they say if you torque the bolts too much (110 inch lbs is the recommended spec), it can easily pinch the cork in two. Since it only leaks where the two shift cable bolts go, I guess "I'm" the dumbass that over tightened it long ago.

At any rate, the car is so much fun to drive on the rural highways where 55mph at 3,000 rpm is 'okay'. Trying to keep up with the 'real' freeway where everyone goes 75mph, I'd burn this thing up in short order. I have to wait till "Tickshift" fixes my T56 before I can go out on the freeways.

2.

 

After thinking about it for awhile, I think it must be the radiator cap. Coolant isn't getting to the ground. It's going into the overflow bottle. Sounds like the part of the cap that is supposed to let coolant back into the radiator as it cools down is not working correctly.

 

A fuel pressure regulator simply maintains a Δ(delta)pressure across the fuel injectors (in our case 3bar, or 43.5psi) under all operating conditions.

For example if we want to maintain a delta pressure of 43.5psi across the injectors, and there is 10psi of boost in the manifold, then we need 53.5psi of fuel.

The inverse holds true with vacuum. Since 1psi = 2in/Hg, then if the manifold is under 10" of vacuum we only need 38.5psi of fuel to maintain our delta pressure of 43.5psi.

The PCM assumes the fuel system maintains the steady 3bar pressure across the injectors, this is why it asks for a fuel injector flow rate constant. Newer vehicles use a returnless fuel system and fuel pressure just stays steady no matter what the manifold pressure/vac is. The PCM uses an 'injector curve' (as opposed to a constant) so it can calculate required injector pulse for a given manifold pressure/vac to give appropriate fuel.

 

Turbo Z28 rips!

 

First, do you have the driver loaded for that USB cable. It should be plug and play, but usually the serial apdater USB cables I've used always needed some type of driver.

If you have/need the driver, can you take the cable and install it on any other machine? like a desktop just to see it plug in/and be found by Windows. That will confirm that the cable is ok.

 

After searching on the 'net for a few hours, I found a guide on how to view the ports (they're considered 'hidden devices' on mine and some other machines. Bizarre.)
Here's what I have for notes after getting it going(using WINXP)...

Problem: No com ports visible/available.
Solution:
To see what's on the ports (if anything)
Click Start
Right click 'my computer'
Select Properties
Select "Advanced"
Click "Environmental Variables"
In system varibles(lower box) Click "New" button.
Cut n paste "DEVMGR_SHOW_NONPRESENT_DEVICES" into the top "Variable Name" text input box
Place a '1' in the Variable Value
Click OK twice
Click Start
Right click "My computer"
Select "Manage"
Select "Device Manager"
Select "View"
Select "Show Hidden Devices"
You can now see the Com ports.



To set the com port to the 1 thru 4 setting...
Go into Control Panel, System, hardware, device manager. Locate and expand the ports section. Right-click on the port you want to change and choose Properties. On the Port Settings tab choose Advanced. In the lower left is a dropdown where you can change the com port number assignment. CHoose OK back to the desktop, and the device should now be at that location.

 

shouldn't have to go through all that to see it in Device Manager. Are you able to see any ports installed in device manager? Do you have any yellow exclamation marks next to any of the items?