Overboost cutout, pig rich, and some other gremlins, possibly related

[itsbudda]

Hey all, I've been working on making a recently acquired basket case 1989 Daytona Shelby awesome again.

The car is a 2.2 Turbo 2 with a TL;DR list of mods, including FWD-P Stage 5 computer, +40%s, meth injection, block bored .030 over, Menegon ported head with 1mm os valves, 94 TBI camshaft, ported intake, exhaust, 52mm tb, FM T3/T4 turbo, and 3inch exhaust.

When I first start the car, the wideband reads rich for the first few minutes but otherwise drives normal and then settles down around 13.8-14.8 (normal I believe) After this, whenever I hit the gas, the A/F ratio spikes to 15-18 and the car sputters, but then quickly picks back up. It's less drastic If I push the throttle in very slowly.

After about 10-20 minutes of driving, the fuel mixture switches over to pig rich, and the wideband is showing between 9-10.5. Strangely though, the hesitation/sputtering is gone. I think it's going into closed loop, because it reads exactly as it does when the car is first started.

Also the car hits overboost cutout at 5psi for some reason. I reset the computer and went on a short drive, but only got codes 12 and 55. Since resetting I haven't driven hard enough to hit overboost or long enough for it to go pig rich since. I had a code 45 earlier for overboost, and a 23 a that turned out to be a shorted wire to the air charge temp sensor. I remedied the short right before resetting the comp, but it had essentially no effect on how the car drives. The sensor was relocated from the manifold to the intake tube by the previous owner for some reason, with the wires strewn across the intake. I'm thinking they might be getting warm and causing more resistance. Could that make it revert to open loop?

Any ideas? I'm not sure if all or any of these issues are related. It seems more of a basket case. I'm gonna recheck timing tomorrow. I never figured out the vaccuum advance on the dist, but at idle looks to be right at 12 before TDC. Maybe the cam's a tooth off or something.

[NAJ]

Check all of your basics...
1)Cam/Ignition Timing
2)Fuel Pressure
3)Vacuum Line Routing/Condition

What does engine vacuum read @ idle when the car is running correctly???
When the car is running poorly???

You need to check at a manifold source and at the Map Sensor.
The vacuum/pressure gauge needs to be "tee'd" into the line(s)

CAM TIMING
http://www.turbododge.com/forums/f4/...n-84-95-a.html

FUEL PRESSURE
http://www.turbododge.com/forums/f4/...-93-turbo.html

IGNITION TIMING


89 T-2 VACUUM ROUTING

[itsbudda]

Thanks! The vac/boost gauge hangs out just below 20psi at idle under both conditions. I checked timing again, putting a point and shoot at eye level. It's perfectly aligned at TDC. The distributor timing seemed to be about 4° advanced. I unplugged the sensor and redid it. About to go on a little test drive to see if there's any improvement.

[DetroitTurbo]

Do you mean negative 20psi?

[itsbudda]

Yeah 20 in hg. oops. Still hitting overboost at 6-8 psi, around 11 a/f. Codes were 12, 51, 45, 62, 55. Pressure at the rail was around 40psi. It's adjustible, so I just turned the baseline up to 57. Pump, filter, and fuel lines have already been replaced.

[NAJ]

I am not into performance mods so I am not familiar with your Turbo or Controller.

I can give you factory overboost diagnostics but normally overboost will be caused by...
1)Small turbo(VNT or Mitsu) without enough exhaust backpressure to keep the turbine from overspooling.
2)Wastegate sticking closed
3)Vacuum line routing
4)No pressure signal to wastegate

Your symptoms of overboost and lean to rich and sputtering all sound like vacuum/pressure issues affecting the wastegate and Map sensor.
I am assuming this is a 3 bar map, if so I do not have a voltage chart for a 3 bar but you still need to verify the Map is seeing the correct vacuum/pressure.
If it is not a 3 bar, doesn't a stage 5 controller require a 3 bar map?

[itsbudda]

It is a 3 bar. The vacuum is one of those nifty vacuum blocks, and all the lines look good. Without dismantling the dashboard, I don't really have a vacuum gauge I could hook up to test each line. I'm fairly certain there's a wire that must be shorting when the engine gets warm or getting excessive resistance. That's the only thing that could make any sense to me, especially given the fact the car came to me with a slew of bad rewiring jobs. This caused my air charge temp sensor code from earlier. These two splices were wrapped together in the same piece of electrical tape.

Since turning the fuel pressure up, there is a slight improvement of condition during it's normal A/F period after starting up, a little less hesitation, but after 10-15 minutes it still switches to crazy f**k rich and barely even idles, although now even richer. I'm almost sure it's going into open loop for some reason. Still hits overboost at 8psi when running either cold or hot, pig rich or stoich, so I doubt the two problems are related at this point.

I've lost a fault code though. I'm down to 12, 45, 55. The hesitation, erratic idle, and early cutout are reminiscent of when my spirit's TPS gave out, but that threw a CEL immediately, which this has not. Possibly bad coolant temp sensor? Could it possibly be a bad cal? The car was in perfect working condition when the PO got it, and since only changed the cal and throttle body, and oil pump (which I had to redo timing anyway when the camshaft broke on the way home) I believe it was around this time he started having trouble with it.

[NAJ]

I posted and sent you overboost diagnostics.
Unfortunately you cannot diagnose without the proper equipment.
You spent a lot of money on performance and upgrades now you will have to spend some on tools/equipment.
You need a handheld pressure pump to check the wastegate.

The controller gets its boost vacuum/pressure info from the Map Sensor so....
"Vacuum lines all look good" is not a diagnostic tool and does not give any info to help.
You will need to get a vacuum/pressure gauge and tee it into the Map line to see what is happening when driving.

According to FWD Performance's website your controller is set for 18 lbs of boost so you will not see overboost until you are over that.
Normal vacuum/pressure gauges will read 10 PSI(Advance or Autozone) or 15 PSI(KD Tools from tooltopia.com).
Obviously the Map voltage is showing higher than 18 or you would not see overboost.
You need to verify pressure to the Map to eliminate over 18 lbs as an issue.

HANDHELD VACUUM/PRESSURE PUMP
Save on MityVac MV8500 at ToolTopia.com

KD TOOLS VACUUM/PRESSURE GAUGE
Super price on KD Tools 2521 at ToolTopia.com

[itsbudda]

What sucks is I didn't spend any money on performance mods, and have no money to do so. As fun as it is to imagine some like me being so dumb as putting performance mods on a car that barely runs, this is someone else's project from 6 years ago that I've now bought thirdhand. I'm crazy broke. I just picked up this car on the kinda (but not really) cheap with a bank loan after my spirit was totaled, under the false pretenses that this car was pretty much drivable, but found out immediately I should have bought ANY other car. :(
When the camshaft snapped on the way home from maryland 2 hours after buying the car, I had to come up with $1,000 to that I totally didn't have just to get the car towed 340 miles home, and replace the fuel lines that conveniently ruptured during initial roadside diagnostics. There's really nothing more I can do at this point until I save up money. At my current salary of $500 a month, I suppose I'll be have an update in several weeks/months when I finally have the money to buy a tool that I'll use maybe twice. I can barely afford the car payment, but I've been in TDs a fairly long time. I'm used to paying on something that's barely, if even drivable. Kids, don't go to college for photography if you want a future.

I DO have a dinosaur of an air compressor in the basement that despite being 60+ years old, still puts out almost enough pressure to fill a tire. Suppose that would work if it's pressure has any regularity whatsoever, and I could actually probably swing for the gauge as soon as I free up room on my credit card. It's like free money, that you pay for with 25% interest later :)

[The Pope]

fixing the vac lines and going through the wiring isn't expensive. The vac needs to be clean to the map. No brake booster or cruise control or PCV hooked to the vac block with the map signal.

Clean and grease every connection. If you don't your going to have all kinds of ghost like codes floating in and out and nothing runs right. Fix the wiring, NAJ can find out what color goes where or help fix the plugs to be wired right. Clean and grease includes the pins at the computer.

Take the computer out and get the number off the computer, the chip. Contact Cindy at FWD and find out exactly what the chip was burned for and make sure your current mods match the chip. A must with a custom cal.

The computer may be bad, it may need to get replaced or the chip is wrong for it. May need to get a new chip from FWD, again common with mods.

3 bar maps often don't work right new. I've dealt with this. But there is a chance it is getting the wrong signal. Keep in mind resolution between maps. The range of voltage for vac is smaller. When you have a big vac leak to the map you have a compoundedly larger problem because the voltage range is worse with a leak and a 3 bar. So you can't have a bad vac source, even if the map needs it's own line off the intake.

What is the wide band? Innovative or ? Is it hooked up to the computer? You need to make sure the voltage setting on the wideband is set for the .5 volt range and that it is calibrated right for free air and that it is hooked to the computer for closed loop.

This is why I wrote the stage 1 thread. Because you need to make the jump to 3 bar and learn how to deal with all of this before adding big turbos and ported heads etc. All of this I mentioned and a scanner to watch fueling in closed loop and knock is a must. An OTC 2000 is maybe $25 on Ebay. When everything is getting a good connection the 3 bar setup with big injectors rules, rat nest wiring and poor vac lines won't let one run.

[itsbudda]

I've been talking with the previous owner and it seems the problem does stem from a bad cal. It had a cal in it by shelgame when the PO bought it that ran the car at high boost fine to 4500rpm. It hasn't liked any cal that's been put in it since. The shelgame chip came with the car. Perhaps putting the original cal back in might be a good idea while I save up for a new FWD-P cal. I'd do it today, but it's bitter cold, and I've never opened up an ECU. About to scour the forums for a walkthrough or something.

[itsbudda]

I swapped the chips out this afternoon and went for a drive. It's like not even the same car. It runs so silky buttery smooth. Doesn't go pig rich at all anymore. Maintains 12-13a/f consistently, and I was able to get it up to 16 psi with no cutout whatsoever. It's like a new car!

[DetroitTurbo]

Could've been the new chip was conflicting with the old cal board.

[itsbudda]

It's quite possible. I don't really know too much about the ECU's tuning. Whatever the case it seems to like this chip much better. It runs a little lean at idle at first, but after a bit of driving it's fine. This'll do until I can afford to get a FWD cal.