Yes, Jeff would because injectors. I wouldn't, most likely.

 

Like you said, might need it for a weak pump. And if yours is questionable...

But now that you have a wideband gauge , you could just install it and look for differences.

 

I don't believe my fuel pump was ever questionable.

Our dyno tuning session (sunday Aug 17) was a mess. We didn't know why, but now we know that the dyno brake wasn't releasing properly. That explains the inconsistent runs. We are thinking also that the dyno was causing soooo much more load on the car that it was causing it to go a little leaner than it should have, perhaps we had reached the limit of the fuel system or fuel rail.

Either way, this last time we did probably 8 or more runs at over 300 whp and the AFR was always solid where we put it and the car was consistent. I'm not worried about the fuel system in its current state at this point.

Really the only weirdness left is cold start idle oscillation and the AFR at cruise fluctuates quite quickly between 14.x and 17:1. Running a target cruise AFR of 15.5 and it seems the EMS is having a hard time being consistent there. Anyone think I should be particularly concerned about that? If so, I can turn the target AFRs off.

 

So, the other night we stopped in the miata to pick up a red box at the local ghetto hangout--i mean, 7-11. This guy came up to me and asked if I was at some event, he said the name, never heard of it. Then he said, as he motioned to my quarter panel:

"Oh, I thought you might have been drifting. I have a 240 so I like this kind of stuff."

I was mortified. I'd much rather people know I'm an *** than think I'm a drifter. So I added an explanation to my car which will hopefully set things straight:

 

*Tried to make love to Groot, Groot loves rough*

Time to get out your Illest stickers and +0 offset wheels bro!

At the autox event last weekend a bunch of guys wondered if I built it for drifting "because of the turbo". I had a very hard time keeping a straight face.

 

If anyone needs a "most disease" sticker for a car, its you sir.

 

propped

This made me so proud of you I almost shed a tear.

Wish I could prop that post 100x

Being called a "drifter" in my book is one of the highest forms of insult. Next is "stanced".

 

Ed, you should sign up for the drifting portion of the NASA weekend on the 20th

 

So why does your idle suck, again?

 

Lulz for all.

Cold idle sucks because we never tuned it and I'm still clueless about how to tune it myself. Kris is going to help me with it while we're at MRLS.

 

HELP.

On the drive down the car was running great for the first several hours. I am running a gutted thermostat because I kept having them fail on there dyno, so I took a piece of cardboard and slipped it in front of the radiator on the passenger side, which got the temps up to a normal level (180 ish).

Later as it warmed up I was running temps around 200 indicated, so I was planning on pulling over. Out of nowhere the car started losing power. I'd hit the gas and the AFR gauge just showed blank and nothing. I could apply just a teensy bit of throttle and it'd sorta maintain speed showing 16-17 on the AFR gauge. Made it to the next exit and it just died. Got it started up again but same issue. Pulled into a gas station and after letting it sit for a few minutes, fired it up and it seemed fine.

Pulled back onto the freeway and punched it and it went to 14:1 under boost and knocking badly. Backed out immediately. Just drove for a minute trying to figure out what to dso. Dropped it to the low boost setting and punched it again..... And it was totally fine.

The rest of the day on low boost every time I would punch it I would keep an eye on the gauge and it was fine. Sometimes I'd get a little sputter. The other weird thing is that it started dumping fuel again too. Running 13:1 in cruise whereas before it would just fluctuate between 14-17:1. Wasn't cutting fuel when I let off the gas, weird.

Tonight after dinner driving to the hotel it ran just like it did when I left home this morning. Put it back to high boost and did a couple pulls -- back to the old AFRs of 10.8-11.4:1.

So....

Wtf?

Could a heat soaked IAT cause this? What could cause this intermittent issue?

I am likely bailing the world record attempt baloney tomorrow so I can sort this out. I want to enjoy my car on the track.

Please help!

Love,
Ed

 

Again I wonder about fuel pump.

 

Do failing fuel pumps ever fix themselves?

 

Sure, depending on heat buildup.

 

I'd replace the pump, also where is your IAT mounted?

 

Assuming we trust the AFR gauge then
a) the car was losing power and showing very lean / totally lean when hot
b) after sitting the car ran fine

Heat soaked IAT should result in a rich condition, which would lose a bit of power and waste a bit of fuel but be totally safe.

So again, if we are trusting the AFR gauge then the car is losing fuel when hot. The only moving part in the fuel system other than the injectors themselves is the fuel pump. Well, I guess the FPR sort of has moving parts ... but I still vote for fuel pump.

How full was the tank? Full tank = fully submerged pump = cool pump. Under half tank, pump is probably no longer submerged and will therefore run hotter.

 

^ I had a similar issue in the galant! my Wally 190 was starting to go out but I'd only notice afr changes on warm days with low fuel levels in the tank. Replaced it with a 255 and it immediately stabilized again.

 

Stock vvt IAT is on the cold side pipe, halfway between the top and bottom of the radiator. I'm all about the fuel pump. Sounds like your sock is clogged, mounted backwards, or pump is going bad.

 

Ed, you have my number if you need DMM. I just took a look and it does not look like I've got a switch.

 

Fixed the brake light problem, popped stop fuse under the hood. I'm going to replace my pump tonight.