4x4jeepmanthing

Hi all,

I wanted to make this issue more specific for other reader's. Recently I have swapped engines and now I have a p0122 code, and p0171 once the engine is up to temp. I'm in a 99 xj auto with a new banks header, new plugs, cap, Rotor.
I took all 99 parts and put them onto the donor engine.

I've tried adding front jumper cable to starter bolt-battery negative, tested fuel pressure before and after running(49 psi). All injectors ohm test 12.5-12.9ohm. the motor sounds like a bad drag car once warm.
I've been using a Bluedriver scanner and this is my current display when warmed up:



now I need to know what/where to check and HOW to check, 02, vacuum or anything I need to check. I'm completely new to this stuff and I've gone this project alone. I just want my only wheels back and running, so I'm all ears for how to proceed.

thank you all for any assistance !!!!

jburg318

Wow! That is super lean.

So, I have to check, but my MAP typically reads around 36 kPa or so at idle. The higher pressure reading on your MAP suggests more air coming into the system (i.e. less vacuum), but unmetered air typically causes rich (negative) conditions in the LTFT.

What is the LTFT in closed loop and what does your upstream O2S voltage look like?

Did you hit the throttle when everything spikes?

Don't run it too long with trims like that btw.

4x4jeepmanthing

This is upon start??, no idea what I'm looking at.

is Ltft not what the picture shows 32%?? Yes I did hit the throttle when it spiked, this aided to it running poorer, quicker than of it let it idle to poor running.
I run it only to where it is running bad then shut it down.
how do I find 02 voltage as you aaked?
WHAT is going on with this thing, what should I do next?

jburg318

The LTFT is pictured here but obviously it is hitting a plataue once it's moving into closed loop.

Open loop is default engine operation that is stored in the computer. If those values appear normal than it suggests a sensor has gone bad.

Knowing little more than what you posted here and the picture, I am going to go out on a limb and say check your intake/exhaust manifold gasket and make sure you used the proper sequence to torque the bolts.

jburg318

Turn off you coolant temp. Keep on the MAP, add the O2S voltage bank 1 sensor 1, and long term and short term fuel trims from the main list.

Blue driver is slow if you monitor more than 5 at a time.

4x4jeepmanthing

should I monitor data until it runs BAD?

jburg318

We already know that you have a super lean condition. Your fuel trims and P0122 code are telling you that. Your MAP is also suggesting that there is air entering the system and reducing the vacuum on sensor.

I was just seeing what your trims were in open loop before all the sensors are communicating back to the ECU. Based on how lean you are running I feel like its a physical issue, not sensor driven.

awg

a vacuum gauge is an inexpensive tool that will show a major vacuum leak, and many other engine issues

if you have a intake gasket issue, ether spray should cause the engine rpm to surge

4x4jeepmanthing

can the leak only be upstream of the 02 sensor?

awg

I am not aware of how an O2 issue could be generated in the exhaust system, unless you had an obvious (audible) exhaust leak

if there is an air leak in the intake system, old skool basic diagnosis applies

you may even want to check Youtube on using smoke to test for a leak on the intake side...especially if you smoke, cigs, cigars, or you might be needing a herbal remedy by now

4x4jeepmanthing

ok haha, would you recommend loosening intake/exhaust bolts and re tighten?

awg

well it probably couldnt hurt, but not unless I had a reason, such as above stated tests indicating a leak.. which will be quicker

did the truck run perfectly at anytime after the swap, and then the fault developed ?

there is an issue with intake manifold not seated on dowels, engine usually revs way too high

4x4jeepmanthing

no the jeep always ran poor after it gets to operating temp. When installing the intake/manifold it fit very well, a little cramped for a wrench to tighten everything, but I thought I got everything very snug.

4x4jeepmanthing

I've tried spraying crc (50 state formula) carb cleaner over all vacuum lines, against the block where the manifold mates, with no luck of stalling the engine/ rpm increase or indication of a leak. Maybe it's the wrong stuff, would propane be a good option?

4x4jeepmanthing

Should the FSM give ideal readings for sensors, if so can some one help point me toward which section I should look at please.

I tried checking the o2 sensor grounded to battery, but I'm clearly doing something wrong because much I couldn't register an ohm reading from.
should I check the harness of the 02 sensor at it's plug in?