CKit

Hello esteemed UTH'drs.

Here's the situation:
Car idles well. Pulls strong to WOT. However, if trying to accelerate under > medium load ONLY when steering wheel not centered... can feel stumbling. If keep pushing it, will get a transient flashing CEL (P1399)... if really keep pushing it, will get the misfire CELs (solid: P0300, 0301-0304).

It's really bizarre, you can be going WOT and it'll be fine... but turn the wheel a few degrees and you can feel the cut.

The choices: Mechanical (dirty injectors, clogged fuel filter) or Electrical (injectors, wiring, etc).

Here are the wrinkles: I installed the Racelogic traction control a few thousand miles ago, it taps in serial to the fuel injector wires on the ECU harness. But the cut is happening even with the unit off. And I didn't notice this problem until the last week or so.

Other confounders: Just went to snow tires this week. Also, the metal flap at the mouth of the fuel filler door has gone missing (you know, the first bronze piece of metal that the gas pump nozzle contacts before being pushed aside on the way into the neck)... I'm concerned that it's dislodged and wedged itself downstream by the fuel intake. I also have a Comptech SC so that means FPR and fuel pump are not stock. I've also had the head recently swapped in the past 5000 miles for a used AP1 (the long block is AP1 as well).

Things already addressed: Changed plugs, rotated two spare coilpacks in. Rewired the Racelogic connections, tried with the Racelogic off, swapped MAP sensor, Techron Fuel Cleaner. Full tank of gas. Checked Comptech ESM wiring.

In looking through the SEARCH it seems the likely possibilities:
1. Maybe fuel injectors themselves are going bad? But it's really odd that it is only with the wheel turned.
2. Maybe one of the coil packs really is bad, even though I rotated in two spares. Wouldn't explain the "only when turning" part and less likely due to all cylinder misfire.
3. Could be clogged fuel filter
4. Could be fuel pump going bad (but also doesn't explain why only with turning).
5. Going for the weird: Maybe the bronze "shield" at the mouth of the fuel filler neck traveled down to the gas tank and is blocking the fuel pump intake.
6. Maybe the ESM is bad, but I don't think this would be affected by a turned wheel.
7. Maybe the Racelogic wiring adds too much resistance? But it really is only with a turned wheel. In a straight line, no problem.

Any other thoughts that I missed?
Anyone able to rule out any these possibilities?

I'm still baffled why it would be only with turning. Either there is a mechanical aspect, where turning obstructs or blocks fuel intake or delivery (happens both on L and R hand turns, but even with ~15 degrees of steering... or there is an electrical problem, where some of my random electronic crap pulls too much of a load and the addition of steering input is too much to sustain the fuel injector power as well (but happens even when the unit is off).



I'm probably going to start replacing things, with the injectors first, then fuel pump, then gas tank. Posted this mainly to increase the library of S2ki wisdom for future generations.

RED MX5

Are you sure that the RLTC doesn't drain any current from anywhere when it's off? I'm really suspcious of the TC because of the relationship to turning.

Before you start replacing stuff, do some tests. Get a fuel pressure guage and see if it's related to fuel pressure. Test the injector flow rather than just replacing them to see if it will help.

I'd be tempted to remove the RLTC to see if it was causing this, becaused it's the most recent change and causes a misfire by design.

LOL, IOW, I haven't got a clue.

Here you just got your diff and head fixed, and now this. I'm truely sorry to hear that you're having yet another problem with the car.

Soul Coughing

maybe try disconnecting the EPS harness or the fuse. Maybe there is a large drain from the steering rack when turning? Pull the ABS fuse etc...

Does it happen when you are stopped and turning the wheel? do you feel the motor kinda die>? Also, do you have a Wideband gauge? what happens with the air/fuel ratios when this backfires? What Redmx said in regards to the fuel pressre gauge, only with a different way. You said its moderate pedal, so mabye part of the stoich burn, have a look at your O2 sensor? Try changing your plugs?

sorry for your misfortunes, good luck!

CKit

Hmm. I'm not sure. The RLTC is the most likely player, but a few things that are odd are: this didn't happen for the first few weeks of use and it shouldn't be active when the unit is off.

That being said, it's better today. The only things I did were: remove the powered subwoofer and turned off the heated seat to reduce other sources of current draw

I did just put in the injector cleaner the other day, though.

I did notice that the wiring for the ABS tap ran right next to the EPS cable. I moved them apart from each other in case there was electronic interference contributing.

I also made sure the connection of the EPS fuse was secure.

And it did happen from a stop + turn.

Mainly updating for the archives.

AssassinJN

Although it is less significant, also remember that our cars have electronic power steering assist, which could also put extra strain and drain on what may be an over worked system.