P0170&P0171 power loss, surging idle......evap/o2/map/vacuum/fuel trim?

tommyp484

New Member
Cel will always be on at a drive cycle if reset. I have a code reader with live data and it says: P0170 (fuel trim malfunction) shortly after it will throw another code P0171 (Lean bank 1 sensor 1).
Car runs and drives well, no worries. just not 100% all there with power and it bugs the crap out of me. Anybody good with the live data? I have pictures/saved logs of all it for multiple drive cycles. I'd like to know what values, %'s, and voltages are normal compared to mine. I can't make much of it.

Problems: Loss of power (not a big loss but noticeable)
idle surges a bit then goes back normal, usually more when at op temp
rpm's drop really fast then surge up/down before normal idle
Occasionally after getting gas the gauge stops at 1/2 way mark (works fine below that)
Car after-fires (or backfires if you call it that) usually engine braking or right when I press the clutch shifting

I cleaned the aicv, changed the thermostat/bled all air, new plugs, used fuel system cleaner (why not try), and checked my vacuum lines as well as I could. I think there's a leak in the brake booster I can't find because the idle goes up if I pump the brakes.

My thoughts are:
Bad upstream o2 / bad map / vacuum leak / evap leak / bad sending unit / valve spring

Could an evap leak be messing with my gauge? It works fine but every once in a while when I fill up the gauge stops a little past 1/2 and won't read until it's below that or until I put more gas in. Also my stft&ltft seem high. Bank1 sensor1 reads .055 (low?) sometimes is at 0 and fuel system will be in 'open loop'

I have live data but need someone to make sense of it. All help is greatly appreciated as I'm going nowhere with it by myself
 

Volklord

Non V-Tec B18b1
Im thinking evap leak, my car had similar issues after fixing a surging idle by replacing a FITV. Car would run and surge irradically, turns out was the bottom line on the Charcoal Canister was disconnected.

Have you checked your Ignition timing ?
 

tommyp484

New Member
Volklord said:
Im thinking evap leak, my car had similar issues after fixing a surging idle by replacing a FITV. Car would run and surge irradically, turns out was the bottom line on the Charcoal Canister was disconnected.

Have you checked your Ignition timing ?
Click to expand...
Wouldn't it be more apparent of a problem if my timing was off?

I've noticed that when my car throws the cel it's fuel is in OL (open loop), b1s1 o2 will read a dead zero too... Isn't it bad if it's in an OL and not a closed loop? Also noticed the map sensor shuffles between exactly 7.3 then 7.6 every couple seconds... Odd. Short/ long term fuel trim also constantly adjust up and down until they both stop at 46.8 or I clear the dtc's.

What is the calculated load? It's usually right at 25.0 but when im looking at the cel trigger for recorded data the calculated load is at like 80.0 and the o2 readings all say 0 except my b1s2 downstream o2 which is higher than normal at 1.100(v?)

There anybody that can make sense of live data and atleast point me in the right direction?
 


phatintegra

Banned
Sorry I forgot the teg don't have a MAF. I was thinking of my Euro when I typed it.

If you say so it's not bad gas. I'm just throwing that out there. I have seen both of these codes on couple of vehicles due to bad gas from filling up at Shell.

Check the hose by the fuel pressure regulator to see for any leak and or damage any all vacuum hose like mention above.
Check for Exhaust leak.
Clean out Fuel Injectors.


Your running to lean or your getting to much air into the system.
 
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tommyp484

New Member
phatintegra said:
Sorry I forgot the teg don't have a MAF. I was thinking of my Euro when I typed it.

If you say so it's not bad gas. I'm just throwing that out there. I have seen both of these codes on couple of vehicles due to bad gas from filling up at Shell.

Check the hose by the fuel pressure regulator to see for any leak and or damage any all vacuum hose like mention above.
Check for Exhaust leak.
Clean out Fuel Injectors.


Your running to lean or your getting to much air into the system.
Click to expand...
Maybe it's not closing the solenoid for the recycled exhaust gasses?
Think I'd atleast get an egr code...

I'm in my garage right now taking a look over, suggestions would help haha
 


Volklord

Non V-Tec B18b1
Any luck? The wires going to my map sensor were a bit rough and open in some places causing an erratic idle. Have you checked the wires for the map and tps sensor ? Good luck!


Sent from my iPhone using Tapatalk
 

phatintegra

Banned
tommyp484 said:
Maybe it's not closing the solenoid for the recycled exhaust gasses?
Think I'd atleast get an egr code...

I'm in my garage right now taking a look over, suggestions would help haha
Click to expand...
That would of been a P1457 after charcoal canister and or maybe a P1456 before the charcoal canister.
 

Theasian

New Member
Get a vacuum gauge and check manifold vacuum at idle. a good reading is about 17-22 inches mercury at idle.

a steady low readying 8-14 indicates Small vacuum leak or valve timing off; could have low compression/worn rings (verify with a compression or leakdown test).

a steady low reading bellow 8 indicates a larger leak like the brake booster or lines. Pinch off the lines with a pair of pliers looking for a increase in vacuum

if the needle drops quickly with like a almost rhythmic sense your have Burnt valve, or a valve with clearance too tight

Snap the the throttle open and back to close quickly you should get a drop to around 2 and back up to 25. Thats a healthy sealing engine.
If you drops to 0 and back to 20 May confirm worn rings (especially if idle shows only about 15-20) Verify with a compression or leakdown test.
There is alot you can tell by reading vacuum

Fyi healthy vacuum map reading should be at idle .90V or less if its like .92 its fine anything really above .95 would worry me anything above 1v is deff a issue
 

Dc4Daniel561

New Member
im having the same problem did you ever find out the main cause??? I have codes for o2 sensor and my purge control solenoid
 
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