I’ve recently noticed that my car acts funny sometimes. I first saw this with a ¼ tank of gas on a right turn freeway on ramp. The car will cut out, acts like its blown motor and the LM-1 shows 17-18:1 fuel ratios. I was not in boost when this happened and my knock was very low, not abnormal.

So I thought it was fuel starvation while cornering. I filled the tank up and tried again. This time it didn’t happen. So I thought that was the case. The weird part was that I have never ran into fuel starvation from corning ever, even with much less fuel in the tank going much faster, and under boost I might add, through the same on ramp. So I was a little confused.


But when the same thing happened again around a much slower right hand corner I was puzzled again.

Another time it happened I was in my driveway just after a cold start. I was able to watch my vacuum readings and my LM-1 at this time. My vacuum was about 100mmHg low and the fuel ratios were in the 18 range when they should be around 11.9:1. I revved it up a few times, noticed the exhaust note come around and bam, idle vacuum back up to normal. Weird thing is though it still happens every so often around right hand corners.


So my question is could a seal be sticking some times? Why only rights?


Could a fuel injector be sticking also causing high AFRs and low vacuum?


Could I have a slight ignition problem causing the same readings?


Could the oil metering system have a problem, or could the oil have broken down?


Or an electrical short that only shorts on right hand corners, sometimes?

Side notes:
I checked all my wiring in the engine bay and I don’t think the ignition is shorting out on any thing, although I could have overlooked some thing.

I know my fuel filter needs to be changes (about 30,000miles on it) although I have full fuel pressure from looking at my gauge off my FPR under the hood. Never was able to see what the fuel pressure was when this was happening.

I have a walbro that was replaced about 10,000 miles ago.

My plugs have 6000 miles on them and should be changed. Although I have no ignition break up under boost or higher RPM.

My plug wires don’t shock me but are older, they should be changed also.
I have not checked compression, cold and warm starts are fine. I will check this when I change my plugs.

Oil needs to be changed. Currently at 3000 miles.


I have about 9000 miles on a street ported rebuild.


Any thoughts or ideas are appreciated.
Thanks
Joe

 

Yeah, I'd think it was fuel slosh too. But other than that it's really hard to say.

 

i had that problem on my mr2. turns out it was a bad MAF sensor... but if you're using engine management, i would assume you don't use one anyway, so um i dunno :p

 

Ok, so its not oil level related.
Not gas level related.
Not ECU wiring related.
Don't think its ignition related anymore.

I'm going to look into the fuel pump, FPD (needs to be replaced anyways), stock FPR, aftermarket FPR (both are connected), fuel filter, fuel pump resistor (make sure its shorted for high mode) and maybe my injectors. Pull my hood off and put a video camera on the FPR and make this thing happen again, see if fuel pressure drops.

I need another running car, damn.

It is however only on some right turns. Very intermittent, sucks.

What about the fuel relay? Someone mentioned this to me and I was like, um, sure maybe.
Also (thanks CPT) I'll look into my MAP sensor and verify its working properly when this happens (I don't have a MAF, but the MAP is the same thing pretty much). I wonder if I've finally rubbed through my fender liner enough to start shorting wires on some right hand corners.

Which side do the MAP sensor wires go down? *edit* Just searched and the wires go down the passanger side so maybe this isn't the case, but I'll look into it anyways.

Thanks
Joe

 

Sorry to hear bout your problem Joe. I wish i could give some advice but it seems like a pretty borad issue. Hope you get it goin good soon.

BTW, when you pulled away from the Big BBQ down in Federal Way it was quite amazing. Im pretty sure you can wind out your first gear faster than I can dry rev my car to redline...

 

haha, Thanks

light weight alum flywheel and lots of wheel spinnage.

My buddy has a stock flywheel on his FD and loves/amazed at how fast I can rev match and down shift. I fully recommend the light flywheel if you don't mind loosing some of the rotational mass which helps build boost. My cars heavily ported and lots of lag (big turbo), but driven right she moves. Plus I can build 5 psi or so fairly low in the RPM range so she's not slow. Which works well for me.

Thanks, I'll figure it out. I'm just looking for suggestions as to what/where and if anyone has seen similar. Plus I know I'm not the most organized in my thoughts so bare with my posts.

 

IIRC, sometimes the baffles in the fuel tank break loose and can cause fuel starvation. That may be why you didn't have it before.