OK guys, small bit of history here. We (me and Steve) were hoping the car could run a few MPH faster at the 2013 1/2-mile event in GA. Last fall, I upgraded to the 61mm pulley to try to improve on what the 65mm pulley had already given me. In order to make the 61mm pulley play nice, we had to upgrade some components.

• Swapped to 550cc Bosch EV14 injectors
• Swapped to Iridium spark plugs, one heat range colder
• Installed Magnecor wires

The plugs/wires weren't mandatory, just recommended by several sources on the forum (had more than one person recommend that I use the "one heat range colder" plugs since my motor was significantly over the stock numbers).

The Magnecor wires were a fail. I couldn't keep them connected to save my life. You'd be driving down the interstate, feel a misfire, pull over and one would be unplugged.

So, I swapped back to OEM wires. They stayed connected, but I continued to have problems with the car misfiring, but ONLY under the following conditions:

• 20 minutes of highway speeds when the temp is >70° ambient
• 30 minutes of stop/go traffic when the temp is >70° ambient

By the time I had begun to get SEVERELY annoyed with the issue, we hit December. And as luck would have it, I could NEVER replicate the issue during the winter. The car ran flawlessly. Like, you could drive to California and never worry once.

The fix is alarmingly simple -- pull over, pop the hood, and wait ten minutes. The longer you wait, the further you'll go once you start back up.

But, on the fist day the temp exceeded 70° ambient (back in late March), the issue returned. Each time, it was the same thing -- you'd feel a "cough" in the pedal, then you'd feel the misfire, then you'd get the blinking CEL, and if you didn't stop QUICKLY then you'd eventually lose all cylinders. Each time, the codes were the same -- P0300, P0302, P0305. If the issue happened when I couldn't immediately pull over, then additional cylinders would fall offline.

So... pop the hood, wait a bit, shut hood, clear codes, and continue.

It's safe to say, I haven't taken any long journeys in my car.

Since then, I've replaced the following (to no avail):

• Replaced CPS just to be safe (even though I never got P0335)
• Replaced all 6 (six) coil packs

So at this point, I'm at my wit's end. I can confirm that the car had ZERO issues until we changed to the new injectors and plugs. Wires are back to stock, so we can rule those out. I have a new CPS, new coil packs (all six cylinders), so we know those are good.

The only thing Kim can think of, is the plugs (retrace steps to last item changed before malfunction). The failures started happening right after the weekend we changed plugs.

Could this POSSIBLY be the spark plugs "overheating"?!?!? This sounds like complete nonsense to me -- plugs either work, or they don't -- right?!? I can't fathom the ambient temperature making a difference to a plug that's exposed to fire within the combustion chamber.

I checked RCM joints and they look fine. All wires are connected firmly. New CPS is installed.

I appreciate any insight you guys can offer. I just want this thing fixed (and sold) so I can move on and start the new chapter. But I refuse to sell it until I know for certain the issue is remedied.

Thank you all,

 

did u do a retune of the ECU? maybe that have effected the car somehow. try a re-tune you know works.It might help.

 

Injectors is the only other change...maybe they are the problem. It wouldn't be plugs. Plugs fail period. Although coils can get hot and cause problems as well. Injectors can over heat too... Good luck

 

I'd put the old plugs in just to rule the new ones out. A little work with no cost. The temperature part of the equation has me stumped, no real idea. Do you have a way to read AFR's? I'm thinking your engines running way too rich with the new injectors. The color of the plugs should give you a clue. Especially if they're damp.

Les

 

It would be nice to completely rule out the RCM by swapping with someone for a couple weeks.

 

What are your intake temps like? I have an N/A and last summer at the drag strip with the stock intake my temps got up to 180 before the car started to act a little sluggish. In Guam it's about 80F everyday and almost 90% humidity.

 

Crap John... I was really thinking it was the CPS. I know you said the joints look good on the RCM, but do me a favor and look at the relay's and those flat leads for burn marks. Maybe pictures of everything if you can.

Is it possible the gap is way off on the new plugs?

It's a PITA but I would switch the plugs back after I checked the RCM thoroughly. My occassional hot misfire's with the v6 were my RCM.

 

I'm running a tune right now that was set up for a car with my exact mods list... on his, he didn't have any heat-related issues. Having said that, the tune could definitely be dialed in a bit more on a dyno...

I've never heard of injectors overheating... but this failure occurs just cruising around... injectors aren't doing 50% of their duty cycle when this occurs.

This is probably the next step... I just think it's really WEIRD that the problems happened immediately after switching to the new plugs.

Can someone explain the whole "heat range colder" thing to me? If there's no detriment in swapping back to the stock heat range plugs, I'll certainly do that. They're gapped at .36, not .40 like the factory. We gapped them a bit narrower due to the anticipated boost the 61mm pulley would provide.

I can confirm that my car is running RICH. The tail pipes haven't been chrome since the tune was added... and if I hit WOT, there's a "puff" of black smoke for one second as the car hits open loop, then it clears up. I don't have a wideband connected, but the tune I'm running was built for 550 injectors and he was in the high 10's for AFRs...

I know rich is safe (to an extent) but I agree that there is some scaling that needs to be done on the injectors. My confusion is surrounding the temp... If the car was running rich enough to foul the plugs, it would happen at ANY temp, right? Not just 70° and up... This is why I'm so stumped.

Is this failure indicative of a faulty RCM? That would be a quick fix, but I thought the RCM would cause a no-start issue. Car starts fine, it just misfires.

Intake temps are usually in the "ambient + 35°" range.

We get extremely hot here in TN, summer temps regularly reach 100° F

Last summer I was running the 65mm pulley, stock injectors, stock plugs -- and I could drive in ANY temp, ANY conditions, and not lose power.


Thanks everyone!! Really want to get this sorted.

 

Thanks for the input, Josh.

My gut instinct is telling me it's the plugs. Don't know WHY, and it doesn't make sense, but I just find it weird that the RCM (which had never given me a fit before) would suddenly act goofy once I changed plugs.

The new Iridium plugs are gapped at .36... OEM plugs are .40

**EDIT*

I'll double-check the RCM... I drove the car to work, so I'll check the RCM on my lunch break if I can get out of the office.

So the RCM would cause misfires? Learn something every day!

 

Dude, my RCM has given me specific misfire's, random misfire, both... No start. Start then die. Start, run, get hot, die. Start, run, get hot, misfire. I thoroughly cleaned my relay's with tech alcohol, and added solder to every single spot I could, and haven't had an issue since. (knock on wood)

I just have a hard time seeing plugs as the problem. It's completely possible I guess, just seems unlikely.

 

And you know by now that coincidence on these is just the xfire laughing saying look at this hand, while I smack the S*** out of you with my other lol.

 

Wow, that's enlightening. Definitely sounds like what I''m going through.

Boy... don't I. I have a love/hate relationship with these things.

 

You forgot to tighten the plugs! Spitting the Magnacors = plugs falling out. Heck I don't know. Logic says check all the changes and start with the easiest.

Les

 

It's just that typically it's the CPS over what I explained. I mean sure, it COULD be a lot of things. I would just give the RCM a run down, and look at the relays and contacts.

Same here lol.

 

If it's not the RCM solder problem, I would be sure the CPS does not have grit under it, since you where ham fisting around in there. MikeR hade the same problem, look through his old posts.

 

What are the chances of a faulty new bosch CPS? I sold him one I had as a spare that was still unopened.

If there's a chance that the CPS was faulty John, we could trade since I have another brand new one.

 

I highly doubt it's the CPS... Not once have I gotten the CPS error code (P0335).

I changed it as a measure of good faith, but there was absolutely zero change in the behavior of the vehicle after the new CPS was installed.

Regarding grit, I can confirm the CPS was squeaky-clean upon install.

Les may be onto something regarding the plugs... After all, the issue started immediately after they were installed. Steve installed them, but I haven't complained about the help because the price was right and he was gracious enough to assist with the install while I was at work (we were in crunch-time mode for the event).

If the plugs were loose, wouldn't the issue occur regardless of temp? That's what has me baffled.

Thanks again for everyone's input... greatly appreciated.

 

Josh,

I was referring to this thread below for the removal:

https://www.crossfireforum.org/forum...-no-start.html

And was curious if there's a specific joint that I should be looking for? Would it be the typical failure points that would cause the shut-down?

Thanks man,

 

Found this link today... I know my car is running a fair bit of timing with this latest tune. Still need to check tightness of plugs, haven't had time to rip everything apart for the 4th time this week

I Have Slightly Modified My Motor - Do I Need a Colder Spark Plug?

 

Honestly, I think some of the joints that looked fine on mine were bad, that's why I went over every single one with fresh solder. If the joints for the fuel pump relay are bad, that could be your issue right there. I wouldnt even bother checking the joints out, just run fresh over all of them.