Random Misfire Code Under Hard Acceleration

[nolacola]

Hey guys, hoping someone can help point me in the right direction here..

2008 speed3 - 95k miles.

Took it into a shop to have the spark plugs changed, after the swap a couple days later I went to get on the car (i.e. floored it in 2nd) and it misfired like 3 times. Tested again in 3rd and same thing, as soon as I got on it hard it misfired. Driving it normally it seems perfectly fine, even when I accelerate to higher rpms slowly it's fine. The only time it misfires is when you really push the throttle in.

So I took it back to the shop, they said they tested the plugs and they were fine, double checked and confirmed they were the right plugs and when they pulled the code it said random misfire and because of this they need to do deeper diagnostics which cost $150.

I guess what I am wondering is, does anyone have any idea what this might be? Is it possible they messed up some lines to the intercooler? Could they have gap'd the plugs wrong? Coils in wrong order? I'm really not thrilled about having to spend more money especially just to find out what is wrong..

 

[magicka]

Any mods? What plugs did they put in, and whats the gap? Do you have a monitoring device/gauges that can give you an idea of what's going on when you go WOT? Data logs would be helpful.

Also, any smoke at idle? Have you pulled the intercooler and, if so, is there any oil/soot in the turbo outlet/intercooler inlet?

 

[Outkast]

I have a 2008 Speed3 GT with 94K and experienced this last night. I was in 6th and dropped it down to 4th and the engine misfired. When I threw into 5th it misfired again. I backed off and eased into it and it was fine. My issue is the same as nolacola. Oddly, I had the 90K tune up and installed NGK Laser Iridium Spark Plug: MZR DISI (HR:6), which are basically the same as OE. The engine mods I have are: Turbosmart BPV, COBB SRI, ETS TMIC, Cobb Tuning Turbo Inlet Hose, SU Silicone Recirculation Tube, SURE M3 Track Pipe and SURE Torq R3 Rear Engine Mount. I do not have a Access Port to pull data logs. I believe the issue for WOT is related to the OE Fuel Pump at this time. I'm not sure of the Gap on the plugs as I had the dealership install. Would you agree my Mods exceed the ability of the OE fuel pump? Would the Deatsch Werks DW65c Compact In-Tank Fuel Pump fix this issue? Does anyone have any feedback on the Deatsch Werks DW65c?

 

[magicka]

There are two fuel pumps. You might be reaching the limit of your high pressure fuel pump (HPFP) with your flow mods, but there's no way to be sure without a monitoring device. If you can get your hands on a DashHawk or something similar, that will show a drop in fuel pressure under WOT. If that's the case, you need an upgraded HPFP or internals, NOT an upgraded ITFP like the DW65c. I would suggest checking the gap on the plugs first. While you've got the IC off to check plugs, look at the turbo outlet and IC inlet. If you have oil in there, it indicates that your turbo is going.

You're also running a lot of intake flow mods, and really should be tuned.

 

[Outkast]

Thanks for the insight magicka! Would a COBB AP or Hypertech show me data logs like a DashHawk will? What HPFP would you recommend? When you say it should be tuned are you suggesting that I flash the ECU with a AP as an example or take to a shop where someone can mechanically tune? Sounds like a stupid question, but my goal was to really just replace factory OE components with better after market components.

 

[magicka]

The AP is set up to record up to around 20 parameters at a time, and is a very useful tool for logging, but can only display one at a time. The DashHawk, if you can find one, is better for live monitoring. I don't have any experience with HyperTech, but I don't think it has logging capability.

I'd recommend either Autotech internals or a complete cp-e HPFP, depending on your budget.

When I say tuned I mean flashing the ECU with an updated map that takes your flow mods into account. You can use off the shelf maps from Cobb or HyperTech, depending on which unit you choose, but to get the best bang for your buck you should have a custom map made. Prices for a custom tune from any one of several reputable e-tuners will be in the $200-250 range.

 

[Outkast]

Since the AP vs. Hypertech is a bit more in cost, but the AP records as you said, might as well vest there as it has more bells. A Hypertech with DashHawk would be $800 bills (new). So the AP might be less overall and more feature rich when compared to a Hypertech (apples to apples). I'm just not the super tuner and was going down the path of better bolt on's over OE. On SU they have the Autotech internals which seems pretty reasonable. Regardless I need to tune as you recommended so the AP for me makes the most sense. Time to bite the bullet and unleash the true beast. If the WOT issue continues then I look to the Autotech internals. Thanks for insight and recommendations! Greatly appreciated!!!

 

[nolacola]

Any mods? What plugs did they put in, and whats the gap? Do you have a monitoring device/gauges that can give you an idea of what's going on when you go WOT? Data logs would be helpful.

Also, any smoke at idle? Have you pulled the intercooler and, if so, is there any oil/soot in the turbo outlet/intercooler inlet?

Hey Magicka, thanks for the reply. No smoke at idle...everything was done by a mechanic so I'd have to get clarification from them..I know the plugs are NGK Laser Iridium Spark Plug though. The car is unmodded aside from a Cobb SRI. Would it be fairly simple to pull the intercooler and check the outlet/inlet myself? Assuming that was the cause, would I even expect to still see anything there at this point? It's been almost 2 weeks since the plug change and this started. Also, no way to log data unfortunately.

 

[magicka]

If you're looking to get both AP and internals, contact the guys at Edge Autosport. They often have package deals, which could save you some coin.

 

[nolacola]

I should mention too that they also did a coolant flush and oil change.

I found this guide for getting to the plugs http://**********************/showthread.php?t=348264 so I think I'm going to go buy a gap tool and try to check it all tomorrow myself

The more I'm reading about it, and based on the fact that it occurred right after the plug change I'm hoping they just put plugs with the wrong gap in. I'd call to double check but they are closed now.

 

[magicka]

Hey Magicka, thanks for the reply. No smoke at idle...everything was done by a mechanic so I'd have to get clarification from them..I know the plugs are NGK Laser Iridium Spark Plug though. The car is unmodded aside from a Cobb SRI. Would it be fairly simple to pull the intercooler and check the outlet/inlet myself? Assuming that was the cause, would I even expect to still see anything there at this point? It's been almost 2 weeks since the plug change and this started. Also, no way to log data unfortunately.

You have to pull the TMIC to get to the plugs, so it'll be trivial to check the turbo outlet/IC inlet for oil. Checking the gap is easy. Shoot for .028, just be careful not to damage the electrode.

Edit: If you didn't supply the plugs, check the part number while you've got them out. It should be ILTR6A-8G, stock number 3787.

 

[MSMS3]

^ This. I agree. If the new plugs are the one step colder NGK's (see my mods below) they come gapped waaaaay too large. At OP's mod level, stock heat range will be fine. In any event, gap with OP's mods should not exceed .032" and would be best gapped tighter - .028".

 

[Outkast]

Update: I have since installed the Autotech internals and it resolved my WOT issues. Runs like a beast, but I threw an engine code indicating the ECU was "retarding" the Fuel Output (Stock ECU Map). Engine check light would come and go. I just purchased the Cobb APv3 thinking this would place the proper map to balance out Internals fuel output. I installed the Stage1+Supported Intake+TIH+IC 93 OCT v231 Map. Cleared the original code. I am now getting a P2088 - Camshaft Position Actuator A Control Circuit Low (Bank 1) code.

Based on my research here:
1. The 2088 is oil control valve voltage low. If you're not seeing low oil pressure or having low oil level, the connector is possibly at fault.
2. Clear the codes (disconnect battery) and verify your engine's oil pressure, as a stop-gap measure. If oil pressure is ok, there's no risk in running the car like this, it's just going to be down some power.

Here is the deal though...when I had the car in to get the Internals installed I also had the oil changed. That night I was leaking oil. I took it back and "the dealer" did not install a plug correctly. Defective oil plug...

Is my issue with the P2088 related you think?
When Internals installed was it installed incorrectly; loose connections?
Would a simple replacement of OCV resolve the P2088?

Lastly, the engine mods I have are: Turbosmart BPV, COBB SRI, ETS TMIC, Cobb Tuning Turbo Inlet Hose, SU Silicone Recirculation Tube, SURE M3 Track Pipe, NGK Laser Iridium Spark Plug: MZR DISI (HR:6) and SURE Torq R3 Rear Engine Mount (Now Cobb APv3). Once I get this P2088 resolved could I reflash to Stage2+Supported Intake+TIH+IC 93 OCT?

I've read a lot of posts / replies from MSMS3 and I would like his opinion.

 

[Outkast]

Update: I checked the connector of the OCV and it was lose. I snapped it in, cleared the code with the AP and no more check engine light! Score for Mazda247 and Cobb! Now...am I Stage2+Supported Intake+TIH+IC 93 OCT ready after I drive several weeks on Stage 1?