Suddenly super rich

[player1up]

Now that the ignition problem has been fixed I'm on to the next problem.

Car runs so rich at idle that it will blacken the plugs in 2-3 min of running.

History:
On the way home from work the car started fine, but within about 2-3 minutes of driving it starts idling really low and chugging and has no power. Like the timing is off or running super rich. Replaced some ignition stuff and that's all working well, but still chugging and running rough and is gonna foul the plugs in short order.

Car: 1990 Consulier, +40's, csrt 3-bar, BB flashable smec. Had been running on the same tune for about a month. Car gets driven once a week and was driven 40 miles that day prior to the issue.

Here's the "stuff to check" list for the weekend ( please add if I've missed something ) :
1. Fuel pressure and FPR function
2. Injectors and injector wiring ( already swapped back to the stock inj and scaled cal to match--same idle issues )
3. Grounds ( any that I should specifically look at besides the rail and intake? )
4. Voltage
5. O2 sensor
6. Coolant temp sensor ( already tested OK after ign stuff fixed )
7. TPS ( already tested OK after ign stuff fixed )
8. MAP sensor voltage signal and reference ( already tested OK at idle and key on engine off )

I'll most likely re-check the stuff that tested ok, just for sanity's sake

Stuff that's been checked / replaced in the last 2 days ( mostly ignition related due to some damage I found and the troubleshooting process from the "running rough" symptom ) :
1. Cam timing ( can't check dist timing as it wont run with the coolant sensor unplugged and the fans running )
2. Replaced distributor due to loose shutter wheel
3. Replaced HEP, damaged from loose shutter wheel
4. Cap, rotor, wires, tested with another known good coil
5. Verified all of the rockers are in place ( checked because I needed to re-seal the valve cover anyway )

Observations:
ECU has no codes ( except 12 and 55 ...normal )
I would have thought that if it was running rich enough to blacken the plugs it would throw a code 52.
Volt gauge says around 13.5v at idle
Vac/boost gauge shows steady 19.5"hg

At this point I'm thinking ECU or some sort of fuel issue..
Is it possible it's the injector driver / power board on the SMEC?

[Rrider]

FPR the original 1988 unit?

[player1up]

yep...I'll report back on the FPR status later tonight

[Reaper1]

Try the baro solenoid. I know it's not setting codes, but myself and some of my friends have seen that thing cause all kinds of dumb problems.

[player1up]

static fuel pressure 55psi....idling psi is 48-55 wildly bouncing needle on the pressure gauge...

[Force Fed Mopar]

Bad map? Maybe FPR or fuel pump issue?

[GLHNSLHT2]

Time to break out the Mityvac and test all the solenoids and vac lines on the car. I'd start with the Map/baro vacuum circuit.

[trewqa]

Check the O2 sensor. I had one that cracked in two. Did the same as yours.

[player1up]

ok the fpr wont go below 50 psi with 30" hg pulled on it.

Same symptoms with WB2NB conversion on in the cal or stock o2 sensor with WB2NB turned off.
I can swap the baro solenoid, but I'm not gonna chase anything until the regulator shows up on Tuesday...

[cordes]

You don't have to swap soleniods. You can bypass it and go straight to the MAP. I have several cars which don't even use the baro solenoid. You sure as heck don't need it in FL.

[tryingbe]

static fuel pressure 55psi....idling psi is 48-55 wildly bouncing needle on the pressure gauge...

ok the fpr wont go below 50 psi with 30" hg pulled on it.

Try another fuel pressure regulator?

[player1up]

The replacement regulator shows as delivered today, I'll install it tonight, reset the cal and report back.

Since I'm a "gotta know why" kinda guy... I cut open the old regulator.
It's a 2 chamber / 2 seal pod, front chamber is sealed from the second ( crimped seal around the diaphragm ) the vac/boost/spring chamber has the regulator spring and a flat seal that seals the body from atmosphere. The fuel chamber has the diaphragm / bypass plug and is apparently roll folded as one unit then the vacuum / spring cavity is crimped on the back side creating a single unit that has 2 chambers sealed from each other.

return ---Fuel diaphragm/spring and body seal---vac/boost port
|
Rail pressure

Now onto the failure:
They usually fail at the fuel diaphragm and that sends fuel into the vacuum line and low fuel pressure, this one failed at the body seal allowing enough of a leak to atmosphere to only provide regulated pressure at spring pressure and not below. Failed with high pressure. Definitely an uncommon failure.

Since boost volume is so high and my cal is on the safe side I never ran lean at full boost but I have to imagine this wasn't an instant failure. I'm going to assume it's the age of the unit at this point ( original unit from 1990 )

[Reaper1]

Wow...I would say that I don't think I've ever seen that mode of failure before. Interesting. I will keep that in mind for future troubleshooting.

[player1up]

Wow...I would say that I don't think I've ever seen that mode of failure before. Interesting. I will keep that in mind for future troubleshooting.

Yeah, the regulator had some corrosion around the seam at the bottom and when I took it apart it had a tiny hole in the seal. I'm assuming age and additional boost pressure in conjunction with the corrosion in the housing caused the failure

The new regulator fixed the fuel pressure problem but something is still off.

...still chugs a bit before it clears up around 2500 RPM and runs fine. I've had so much of the engine bay taken apart I've got to get my head together, go back over the car and make sure everything is where it's supposed to be then start troubleshooting again...

[player1up]

All bets are off at this point... Thinking the ECU has lost it's mind.

Got a few codes over the last couple of days. 14,16,17. Reset the ECU, started idled ( crappy ) for a few min then shut off. Pulled the codes again and got a 45, keep in mind the engine was only at idle with no throttle.

I'm going to swap the stock ECU, injectors and MAP this weekend and see what happens...if that doesn't fix it, I guess I'm gonna pull the harness and start looking for bad wires.

I'll make sure to post back if I make any progress

[Reaper1]

I was going to suggest that it sounds like you have a bad ground, or multiple bad grounds. This is something to be expected due to age. I know DeLoreans also have grounding issues and they also have a fiberglass tub. A lot of them run a ground wire that connects all of the grounds together. Obviously things like the stereo and other feedback sensitive items must be dealt with a bit differently, but for all the lights and such...that's what they do.

I also have seen the ground splices in the harness get all nasty.

[player1up]

Fuel regulator and distributor ended up not being the issue. Did find some connectors were corroded...but in the not taking anything for granted approach, I decided to do a leak down test. It's leaking compression on cyl1 into the exhaust.

So, I know why I was getting a code for overboost at idle...ecu is not toast. Blown ( burnt through ) HG between 1 and 2, compression into cyl 1 from cyl 2 into the vac system. Every cyl has cracks between the valves and #4 looks like it has yellowish crystals bubbling out from the valve seat...

[Reaper1]

Sounds like a cracked head, really. Not just a dropped seat.

[player1up]

Well this head is out, it's lived with a number of problems for years apparently. I know everyone says the heads crack fairly regularly, but these are very pronounced and I'm not to keen on doing this again so I'll be getting a new head.
It was missing 3 exh manifold nuts ( both on cyl 4 and one on cyl 3. Looks like the turbo was replaced sometime in it's life ( turbo is in good shape ) and it was too much trouble getting to the nuts, there are no marks on the exh manifold that would be evidence they were ever there.
The center 2 rear head bolts have thread damage due to rust....yes rust...hg was leaking coolant into the head bolt area.

Now as to why I never heard the exhaust leak... the manifold is about 18 inches from the tail pipe on the Consulier and at idle it's kinda poppy anyway.

I've got a line on a factory casting low mile head and will be ordering head studs, gaskets and things in the next couple of days.

I'm just glad that I wasn't beating on it when it failed or I could have been in for real trouble.

For anyone reading this in the future, the engine codes and bad fuel pressure stuff was most likely caused by compression getting into the vacuum system and freaking the computer out and blowing out a regulator that was on it's last leg anyway, and the bad shutter wheel could have caused enough problems with the timing to cause some detonation I suppose ( even though I never saw any on the logging runs and the tune was well into the safe range as far as the wideband was reporting.) So ya'll keep that in mind when troubleshooting odd behavior.

[GLHS60]

Post up some pictures if you get a chance.

Thanks
Randy