christoc

iTrader: (2)

Running at the Arkansas SCCA Solo National Tour event this past weekend me and my codriver had some car troubles. Actually, he had car troubles, I had none. Let me explain.

We were driving my 03 Enthusiast with 43k miles on the car. We each took our first run on Saturday, no problems. On his second run the car died mid run, engine shut off, dash lights were on. He rolled a while trying to get the car started. Came to a stop, and after 4-5 tries the car started back up. He got back into grid, explained the problem, left the car running. It was as if the car was fuel starved, out of gas. It had 1/2 a tank, FAR more than I generally run in the car, I usually run less than 1/4 tank and have never had any starvation problems. We checked the car over, looked to see if we could see any problems, I rev'd the car, no issues, appeared to be running fine, still showed ~half a tank of gas.

I went out and had my second run, no problems, car ran fine, we each took our third runs, same result, car was fine.

Fast Forward to Sunday. His second run he says that the car seemed to bog twice on course, but came back to life with gas and kept going. I took my second run, no problems, car seems normal. His third run the car dies again, he tried keeping it in gear to keep the car running, but was unable to keep the motor fired up. He came to arest, after a few cranks he was able to get the car started and ran the last half of the course at full speed, no problems.

So we really have NO idea what the problem is? The TCS was turned off on all of these runs, so I'm thinking that should be ruled out. The only other ideas we have are this.

Bad Fuel Pump, that only seems to flake out on him
Fuel filter being clogged
Possibly something to do with him left foot braking and giving gas at the same time, maybe he got the brakes into Ice mode and they shut off gas to the motor?

Anyone have any thoughts on this? I ran 6 runs all weekend without any issues, so I really don't have a clue what to think here, and would hope to figure it out before I head to Atlanta in 3 weeks for another National Tour event?

EatMyZ

I am not a mechanic or anything, and don't really know crap about engines.... but isn't it unusual it only happened to him?

christoc

iTrader: (2)

I too find that to be the hard part to diagnose here. From looking at the G-Tech data I drive the car harder than he does, acceleration/braking, so why I don't seem to have the same problem I am not clear on.

christoc

iTrader: (2)

So I guess the LFB was the problem!

https://my350z.com/forum/showthread....12#post1333612 for more info!

I'm glad that was it, and not something major.

christoc

iTrader: (2)

So I think I have a NEW problem, anyone have any thoughts?

Driving today, down a street that's ~40mph limit, prolly in 4th, car dies. The motor tries to keep running as it's in gear, but if you give it gas it won't take it, take it out of gear and you lose power steering and the car shuts off.

Car starts back up, but won't idle. Rev it up and it'll go, but let the gas off and the car dies.

After a few minutes the car will idle again, albeit very rough.

Drive home, car seems to be down on power, idle is rough, but it'll run down the road.

Idle seems to get better.

Stop at a gas station, fill up, car is rough on idle again, idle gets worse.

Check the car out on an OBDII scanner, no codes, no check engine light.

Start car up, idle is the worst it's been, hardly stays running, give it gas and it'll drive.

I go to a dealer, try to see if they will scan it, they will for $66 but before they do a service guy asks if I have an aftermarket filter. I tell him I have a K&N, his response is the MAF is wasted, $481 or something for the part, I tell them I'll figure out what I want to do. I ask if they can scan it and see it's the MAF, he says it won't show up on a scan even if they tried. His response to how they would diagnose it's the MAF is "experience"

I leave the dealer, idle is a little rough, but better. Drive home, on the way the idle clears up, power seems back to normal. Get home, car appears to idle alright, it's now parking in the drive way.

What to do now? Anyone ever seen this before? Have any thoughts?

BTW, I'm WAY out of warranty, 43k miles < 2 years.

sisco534

iTrader: (4)

Sounds like your ECU

sisco534

iTrader: (4)

Sounds like your ECU is going bad , It has developed a mind of its own..it needs to be remapped or re-flashed you dont have any engine mods?

christoc

iTrader: (2)

No engine mods, just a K&N filter. Removed read muffler, running through a turn down.

jmark

iTrader: (1)

Chris I recall reading something here about the K & N oil causing problems with the MAP. Try a search.

christoc

iTrader: (2)

Thanks Mark, I'll search, though the K&N has been in the car for over 20k miles, I kept thinking it was time to clean it

removing the MAF in the next few hours, we'll see what I find.

PDX_Racer

iTrader: (2)

I seriously doubt an "Engine Defeat" mode. I regularly LFB my SpecV, and the only things that I notice is the engine "cut" (to 25% throttle) when the brakes are on. Lift off the brake pedal, and the throttle returns to the current position.

baileyrx

iTrader: (16)

Nope.....

I'll bet it the cats. Or actually 1 cat is blocked. The car can't breath out properly, hard to get a CEL on the older models when it's a bad cat.

christoc

iTrader: (2)

How would a cat get blocked? Are you talking about the NEW problem, or the engine defeat problem in the original post due to LFB?

baileyrx

iTrader: (16)

the honeycomb "stuffing" breaks down & blocks flow. sometimes gets in the way, sometimes allows ok flow, sorry i didn't see the 1st thread.

christoc

iTrader: (2)

I cleaned the MAF and so far the car seems to be doing alright. Will drive it again tomorrow to work and back and see how it reacts.

jmark

iTrader: (1)

Chris,

Did you just go back to an OEM filter?

christoc

iTrader: (2)

I actually haven't changed the filter yet

jmark

iTrader: (1)

OK. Good luck in ATL.