The Mule rides again (sort of) - pics.

[Series8217]

Next time that happens spray some starter fluid in the intake and see if it starts. That will expose or rule out a fuel issue.

Fieros have horrible power wiring, especially after so many years of corrosion on bare copper connectors like the C203. You may not have enough voltage at the injectors to open them when starting hot.

Have you already repinned your C203 (assuming you still have one)?

I had the exact same problem as you and it turned out to be the fuel injector power wiring through the C203. The car always started fine first thing in the morning... but once it was warmed up it did not. It took me forever to figure it out because the car started fine on starter fluid and continued to run. The starter fluid was enough to get the motor running and then the alternator's output increased the voltage so the injectors could fire.

[The Dark Side of Will]

Interesting... good troubleshooting method, too.
It is a little bit difficult to have that level of access to the intake tract, though. The coupler does not come out from between the MAF housing and intake tube very easily.

I have replaced most of the engine-side C203 pins during the course of the Northstar install/build. I *think* those are the female ones, which are responsible for contact pressure.

Where are you taking your fuel pressure reading from? It also sounds classic vapor lock to me, especially with how common that is on these.

I have GM's stainless steel fuel rail. The pressure port is at the opposite end from the regulator.
I noted that the original nylon fuel rail was a "circulation" design with the pressure feed at one end and the regulator/return at the other end.
The SS fuel rails are a "shunt" design with the pressure feed, regulator and return line all at one end. This keeps the fuel in the tank a little cooler, but allows the fuel in the far end of the rail to get hotter.
I would still expect to see fuel pressure drop if the problem were vapor lock. Thoughts?

Run a full data PID scan thru TorqueScan by doing the following...

1) While connected to the PCM with the key on, open TorquePro
2) Click on the menu button on your android phone to bring up the popup menu within TorquePro
3) Click on SETTINGS
4) Select PLUGINS
5) Check the box next to "ALLOW PLUGINS FULL ACCESS" then close out of the settings menu.
6) Start TorqueScan
7) Click on the menu button on your android phone to bring up the popup menu within TorqueScan
8) Click on PID scanner
9) Click on the menu button on your android phone again to bring up the popup menu for the PID scanner
10) Click on START SCAN
11) Check the box next to the FULL SCAN option & leave "auto" as the entry in the "Enter header to use" field
12) Click on OK to start the full PID scan

Would you mind doing this?
13) From the PID scanner screen, tap the menu button and select "Email Results".

This creates an email to the Torque development team. I just saved it as a draft and copied/pasted into the post I previously made on the topic... I'd like to see what you're seeing. Email it to me or post it here.

Thanks!

[Shaun41178(2)]

I highly doubt its vapor lock. I am leaning more towards weak spark or cps.

Get the car hot by driving around. Park it then pull a plug and verify you have a strong spark. Does your software pole cps data?

[The Dark Side of Will]

The OBD2 datastream reports ~100 RPM when cranking... it's not the crank sensors.

Probably will start by probing injector connectors... Will have to toss DVM and noid socket in the trunk

[Sinister Fiero]

Invoke a hot non-restart situation. Immediately remove the air intake from the throttle body and spray in some starting fluid - then reconnect the intake tube. See if she will fire right up. If so, your cranking fuel settings in the programming are too lean for hot restart.

If it will not start with the starting fluid, check for spark immediately. If you have spark, then we have to assume it is flooding out and the cranking fuel settings are too rich when hot.

[The Dark Side of Will]

Yeah... I hadn't thought about it from the tuning perspective.

The cylinder size and injector parameters are obviously right or it wouldn't run as well as it does the rest of the time. Could the hot start tables really be so far out that it wouldn't start at all?

Also, I would expect it to sputter and at least TRY to start if the hot start fueling was off... It sputters for a split second and then doesn't fire AT ALL. Have you seen that before?

[Shaun41178(2)]

If it won't start then you could also pull a plug and see if it's dry

When my car would do a sputter and then stop either the spark is completely gone, or there is no fuel. Even if the timing is off, it will still sputter, unless its way way off

[Sinister Fiero]

Yeah... I hadn't thought about it from the tuning perspective.

The cylinder size and injector parameters are obviously right or it wouldn't run as well as it does the rest of the time. Could the hot start tables really be so far out that it wouldn't start at all?

Also, I would expect it to sputter and at least TRY to start if the hot start fueling was off... It sputters for a split second and then doesn't fire AT ALL. Have you seen that before?

The cranking and startup fuel tables are separate from the main fuel tables in the programming. Most "tuners" don't even look at these tables, let alone make any changes to them unless they experience a problem while working on the tune. And why would they? Why would you make changes to a place in the tune where you aren't experiencing a problem while you are working on it? Can't really blame the tuner for not fixing that issue if it never occurred when he or she was working on it.

There is a running joke at the local dyno shop I use for the dyno tunes I do. We have to laugh (or we would cry) about groups of guys in the area who all get together and pay big bucks to have some out-of-town big name tuning guy fly in and do tunes on all their cars. The problem with these sessions is each guy only gets a limited amount of time for his car to get tuned on - and I guarantee you that isn't enough time to check and tune all aspects of engine operation (because the tuner guy usually has to fly back home that same night). So they are basically all just getting WOT tunes done which is the easiest part of the tune to do. The really hard stuff is tuning everywhere else besides WOT.

The stuff I dyno tune usually requires me to spend a few days on it because you just don't have that much time to check things like cold start before the engine heats up to a point you can't tune in that operational area anymore. It is not unusual for me to spend 2 or 3 hours one day dyno tuning on a car and then calling it that quits until the next day where I'll come back and check cold start operation again. Depending on the build, sometimes so much cold start work needs to be done that we end up tying up the dyno with 1 car for a week. But the dyno shop I do business with is great to work with and I don't think I'd find anyone else willing to do what it takes to tune a car right - on the dyno at least.

[Series8217]

Why do you need a dyno to tune cold start? Isn't it all low-load driveability stuff that you can tune just as easily on the street?

[Sinister Fiero]

Why do you need a dyno to tune cold start? Isn't it all low-load driveability stuff that you can tune just as easily on the street?

I don't need a dyno to tune it. But the dyno shop schedules these jobs and just pays me as a sub-contractor.

[The Dark Side of Will]

Had another problem. Once it was hot enough to have a hot/no-restart problem, it also started to go dead beyond a certain throttle application. By the time I got to my house, it was breaking up slightly just pulling itself and a light weight utility trailer at 70 mph.

This screams coils to me.
However, the voltage was a little low on the gauge. I didn't have the DVM in the trunk, but next time I will in order to check actual voltage at the battery.

I will be frustrated if my recently purchased NEW alternator is going downhill.

Couple of threads on coils:
http://www.pontiacbonnevilleclub.com/fo ... 29036.html
http://www.w-body.com/showthread.php/49 ... -wires-etc

What's the difference between the D576 for Bonneville SSEi's and D555 for everything else?

[Shaun41178(2)]

when hot and a load, like when pulling a trailor, sounds like ignition to me.

[The Dark Side of Will]

Every part of the ignition system is new except for the coils. There's a guy on Amazon selling a NOS set for $65, so I'll probably snag those.

I still need to remember to toss the DVM in the trunk to check some things, though.

[The Dark Side of Will]

Was able to do some troubleshooting today...

All measurements taken while engine was running.
Even though the gauge showed low, voltage at the battery was 14.01.

Voltage from #1 injector + terminal to battery - was 13.45
Voltage from the ICM side of my inline fuse holder supplying the ICM to battery - was 13.08

Don't see a voltage supply problem anywhere... Going to go ahead and replace the coils.

EDIT: Ordered via ebay and saved about $15 overall

[The Dark Side of Will]

Ahh... knew I'd seen electric power steering cheaper than Flaming River's: http://www.unisteer.com/search_by_produ ... steer.html

http://forums.hybridz.org/topic/109267- ... %20+spline

http://www.ezpowersteering.nl/23/Home.html

[Sinister Fiero]

Will, did you ever get TorquePro to show KR data and also log it?

[The Dark Side of Will]

Not yet... been swamped with a few other things. I'll probably set that up when I install the new coils.

[The Dark Side of Will]

Replaced coils with NOS units from ebay. Problem appears to be solved. However, the replacement resulted in a change of engine configuration. Now instead of cylinders 1, 2, 3, 4, 5, 6, 7 & 8, I have cylinders 2, 2, 2, 5, 5, 5, 1 & 4

[Sinister Fiero]

Replaced coils with NOS units from ebay. Problem appears to be solved. However, the replacement resulted in a change of engine configuration. Now instead of cylinders 1, 2, 3, 4, 5, 6, 7 & 8, I have cylinders 2, 2, 2, 5, 5, 5, 1 & 4

A little bit of carb cleaner or some strong brake cleaner will take those painted-on numbers right off the coils.

[The Dark Side of Will]

Cool. I'll give it a shot. Anything you'd recommend for a replacement? Silver sharpie?