2000 Taurus p0171, p0174

[fordjunky]

Well I cleaned the MAF and went and drove it.

It ran ok, didn't die. I was watching TPS, IAC and MAF. When I would accelerate hard everything correlated on the graph to match the TPS movement.

About 1 mile from my house the CEL came on.

I get codes p1132 and p1152

[behlinla]

P1132 - Lack of HO2S Bank 1 Sensor 1 Switching, Sensor Indicates Rich
P1152 - Lack of HO2S Bank 2 Sensor 1 Switching, Sensor Indicates Rich

So, still check that fuel pressure and MAF.

[sheila]

Jmxtwiztid, black plastic cap on iac is the vent (filter) cap.

[fordjunky]

I found my mechanical fuel pressure gauge. If it is above 10 degrees when I get home I will go out and test it and the MAF.

Thanks for every ones help so far.

[Jmxtwiztid]

Originally Posted by sheila

Jmxtwiztid, black plastic cap on iac is the vent (filter) cap.

I posted on the wrong topic Lol, I had my topic open and this one. My IAC doesn't have one, its solid. Sorry for the confusion!

[fordjunky]

So I tested fuel pressure,
KOEO Sensor and mechanical gauge were both 32.

KOER sensor reads 38-40, mechanical gauge reads 32-34

The MAF voltage is between .79 to 1.12 v at idle. When I rev the engine voltage goes up on the MAF

[behlinla]

I'd like to see a higher KOEO fuel pressure. It should be more like 40-50 psi. Try the test again and cycle the key a few times to see if the fuel pressure goes up any higher. Also monitor the fuel pressure for 10 minutes after a KOEO key cycle to see if the fuel pressure holds.

Fuel pressure should adjust so that the value on the scan tool stays close to 39 psi at all times (pressure referenced to manifold vacuum). However, your other fuel pressure numbers suggest your engine vacuum might be low unless you're at a high elevation. This would seem to point to an unresolved vacuum leak. Double check the intake vacuum if you have a gauge.

MAF voltage should be about 1 volt or just below at idle, so calibration doesn't seem that far off. However, the voltage seems to be moving around a little more than I would like. Is the idle unstable?

[fordjunky]

I am about 5000'.

I looked at vacuum this weekend. It was about 13 and steady, not bouncing around. I pulled it at 2 places 1. at the vac line at the FPR and 2. from the air inlet (post maf) to distribution block.

Idle sounds steady but watching the RPM it is moving around a couple hundred RPM.

I will KOEO and cycle the key to see where the FP gets to. and how long it stays there.

[behlinla]

At your elevation vacuum should be 13-17" Hg, so vacuum is still a little on the low side.

If the tachometer is dancing around but the engine speed isn't actually changing it sort of points to the crankshaft sensor. Normal fluctuation (with the engine sounding constant) is ±50 RPM.

Did you check the throttle bore clearance yet? With that low vacuum IAC duty cycle should be more like 40%. Throttle might be open too much. Older folks that used to work on carburetors do this without understanding the idle is computer controlled and that they shouldn't mess with it.

Here's a video showing this problem (I think your throttle is opened too far rather than closed):

You Tube

You Tube

[fordjunky]

Thanks for your help. I really appreciate it.

I don't have access to my scan tool tonight so I will have to reset the Idle speed tomorrow.

I checked the KOEO fuel pressure. If I cycle the key a few times it reads 42 psi. It does start to drop off almost immediately.