Aack! Car won't go past 5psi / Rich AFR
#1
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Aack! Car won't go past 5psi / Rich AFR
WTF ..... I haven't done anything to my setup lately .... was driving along enjoying the spring weather .... suddenly my car won't go above 5psi and the wideband is showing super-rich AFR at that level. Vacuum leak? Bad injector seal? (I listened with a long screwdriver and they all sound fine.) No symptoms when not in boost, although my father says he smelled fuel when I started the car.
Last edited by evank; 04-06-2010 at 08:49 PM.
#3
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(Okay, I did one other thing. Last week I brought the plu gap down from .030 to .025, in order to eliminate misfires, in order to pass OBD-II inspection. But I had no problem getting full boost after that, so I don't think it is related.)
#6
I'll admit I am from the GM world where this was common on some models and am still learning about Miatas. If your car has a fuel pressure regulator that references the manifold pressure (which most do) then there is a possibility that the diaphram can leak fuel into the vacuum system. Look for a cap with a vacuum line attached to it on the injector rail or on the return line. Pull it off with the car running and see if fuel is coming out. The engine speed will go up or if it is a MAF based system you may throw a code, stall ect.
#9
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Like if the hose to the throttle body came off, or whatnot. MAF would read a shitload of air coming in that's being leaked. Car gets xxx fuel for that amount of air. Pig rich, low boost. Try it evan.
#16
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That's the plan. But first I will send it back to DIY to look for any glitches, and/or maybe I'll upgrade to MS-II. Right now I'm extremely busy with work and family stuff (my mom has cancer, so I'm going to NYC several times a week to visit her at the hospital .... luckily the bus stop is 100 feet from my house!)
#17
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Fixed!
Finally had time to dig into the problem today. Noticed that vacuum was less than usual at idle, so I figured. "Damn it, must be ANOTHER bad injector seal!!!" .... PITA to work on those in an MSM so instead I poked around the engine bay for a while .... and eventually noticed the throttle body elbow wasn't very tight where it meets the intake manifold.
D'oh!
Tightened. Test drove. Boost is back.
Finally had time to dig into the problem today. Noticed that vacuum was less than usual at idle, so I figured. "Damn it, must be ANOTHER bad injector seal!!!" .... PITA to work on those in an MSM so instead I poked around the engine bay for a while .... and eventually noticed the throttle body elbow wasn't very tight where it meets the intake manifold.
D'oh!
Tightened. Test drove. Boost is back.