Afr lean, plugs show lean

[drb5721]

Redtop is installed. Take it for a drive and wideband was showing super rich. Found 2 wires had been pulled out of the connector so i went and grabbed a bosch replacement sensor for my AEM. Now AFR says very lean at pretty much all times. Plugs are definitely showing lean as well.

Have checked for intake leaks via brake cleaning everywhere. Found a leak at the throttle body and fixed it.
Still running lean.

Running a Freddy Manifold.
Factory injectors.
Fuel pressure checks at 43.5 but doesnt really change when driving.

Fuel filter is a z32 filter with very little mileage on it. Never had an issue with running lean on the blacktop that toasted a bearing thanks to oil return line failure. Wideband wires got ripped out when pulling the blacktop. Car runs smooth, doesnt want to build any boost.

Fuel pump likely culprit?

[nisileighty]

Fuel pump, faulty o2, dirty maf, boost/vacuum leak you didn't find, fuel hoses switched around (line from filter goes to open end, open line goes to FPR)


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[drb5721]

No O2 sensor currently. Fuel pressure not changing with throttle is what im thinking the problem may be. Unless fuel pressure is regualted via voltage based off reading of other sensors. MAF is blow through btw so very little to check between maf and throttle body.

[nisileighty]

Are you on a stock ECU?
FPR is completely mechanical. 0 electrical control whatsoever. Is it hooked up to a vacuum source?

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[drb5721]

Stock ecu. Ive checked with and without vacuum source with no change and no change with or without throttle based off the inline gauge

[nisileighty]

Put your o2 back in. Or buy a 1995 300zx TT one if you don't have one.
Replace your FPR for a known working unit.


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[drb5721]

Never had an O2 since i bought the car. I have a senor but its never been installed. Guess ill have to find a fpr.

[nisileighty]

Which o2 do you have?


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[drb5721]

62 ecu uses skinny types and i have 1

[nisileighty]

Put it in! If that doesn’t fix it, try the FPR


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[drb5721]

Ill have to order an adapter as the only bung i have fits 18mm o2s. Aldo, tried another fpr. Car runs good. No boost above 2lbs and plugs are burning white. Maybe ill check maf voltages.

[nisileighty]

Check maf voltage and try cleaning the maf


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[drb5721]

URL=http://tinypic.com/r/2rh8pj8/9]View My Video[/URL]

Video start with me at idle. Engine at operating temp. I rev a couple times, pull off, u turn, and accelerate. Sorry for quality/noise. Solid engine and trans mounts.

[drb5721]

Power and ground check out on maf. Signal at idle is 1.7-1.9 volts. Tps voltage at closed will not go higher than .39-.4 volts.

[drb5721]

Picked up a z32 filter and realized i never put the z32 filter i bought on lol. Didnt fix the problem. Only stabilized fuel pressure some. Decided to pull the pump. Walbro 255 in tank to my suprise. Sock was grey, likely dirty but nothing in the pump that i could see. Found part of the hose right at the clamp tearing. Shortened the hose a little and moved the clamp. Helped VERY little. Checked voltage at fuel pump. On no pin can i see battery voltage. The highest voltage i can see is 11 volts. Might be a problem.