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Hey guys, I hooked up a radiator so I was able to run the L59 for a few minutes in the chassis. This was my first time flashing an ECM and have all sensors hooked up that I will use use and I am pleased it runs but I would like ya'll to take a look. Idle jumps around and it misses a bit and I noticed LT B2 is not even close LT B1.

Fuel is new, fuel pressure was 52 static, 42 running. E85 sensor is hooked up, 02, MAF, CT, TB etc, oil pressure is 40 psi at idle, plugs were new, I installed new wires today since I pulled the ends off of two like a dummy even after coating with dialectic grease.

Using a factory harness and under hood fuse box with no mods for testing.

I am new to using HPT, if I need to change the scan parameters or run other system checks let me know.

Thanks!!!!!

BTW, I didn't change settings in HPT that I can remember, same ECM that came out of the 04 Yukon.

DTC's





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Luke19901

without the engine earth to chassis they do very weird things. ask anyone who has left the earth wires off the back of the heads when fitted to the car.

your 02 sensor test is incomplete which may be why your trims are miles apart.

are your coil banks installed on the right sides?

243

The grounds all connect to the battery, is that acceptable?

I checked to be sure the coil packs are installed in the same location as I received the engine.

I noticed the O2 incomplete, will that even clear before I get it on the road?

Thanks!!!

Luke19901

243

That's an easy fix and I don't even have to crawl under the frame

It's been a year since I bought the engine and I helped remove it, and I asked for the y-pipe and the seller objected saying he intended to sell it, so he gave me exhaust stubs and O2's laying in his backyard. It's possible I don't have the sensors for the exact vehicle if that matters.

I swapped the O2's and the LT issue is still on bank 2.

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Battery, engine block at the back is grounded to the frame, no change with the LT or erratic idle.

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I pulled each injector connector and re-seated them adding dialectic grease. I pulled the plugs on B2 and all are black but not oily. Checked for vacuum leaks and found none.

The engine sat for a year, is it worth swapping injectors from bank to bank to see if the rich condition swaps sides?

If the O2 reads lean, does the ECM add fuel to one injector or all four on one bank?

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.....

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Cleaned the injectors on the B2 side, used a homemade contraption to shoot carb cleaner through the injector, all seemed to atomize well.

The idle smoothed up a decent amount but the LTFT's are still maxed out on B2.

Ran another log and I swear I hear a light clanking in the bottom end...I am close to selling all this fk'n stuff including the Cherokee and finding another hobby.

Compsystems

do you have full exhaust hooked up? If you have the 02 sensors too close to the end of the exhaust it can pull in fresh air and give a false lean code.

it looks like you may have a missfire condition thats causing the pcm to try and compensate.

Try to isolate the issue
1) clear all learned fuel trims in HPT scanner tools
2) Unplug the 02 sensors

see how the engine runs and if you still have missfire codes.

you can add scanner channels for each cylinder missfire counts to help narrow down where its coming from.

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Comp' thank you.

I tried a search on that specific topic and didn't find a single thread on any forum. The exhaust stubs end about 3" passed the O2's and I do plan to order some pipe to run a Y out the front with a muffler, the exhaust gas is killing me in the garage.

I will work on items 1 and 2 but it will take me some time to add the scanner channels, I have not worked with that function is a year and need to refresh my memory.

Last night I am pretty sure I narrowed down the knocking to a camshaft, I will explain later.

This morning the fact the problem exists on B2 and didn't change with the O2 sensor swap kept me thinking about an air leak. I changed all the gaskets and seals but I had not changed the intake because I needed the knock sensors and harness so I just bolted it back on with 14 year old gaskets. I pulled the intake and after I bought new gaskets it's obvious to me now, the factory gaskets are shot, the flexible material is almost as flat as the plastic.

I also cleaned the B1 injectors and re-cleaned the B2 injectors, I came up with a system that is LOT simpler than using the spray can and straw, I will explain later.

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Knocking camshaft

I could not see it with the plywood across the frame supporting the tank, and the transmission crossmember has the bolts in place but loose as a goose, definitely feel better today.

Maybe relaxed for nothing, I still hear the knocking down low on the drivers side

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Watched a bunch of Youtube videos yesterday for homebrew injector cleaning and those straws don't stay attached to the can for chit and less so fiddling with some hokey-A$$ contraption to clean injectors. I went to the shed in the back forty last night but couldn't find this pressure pot in the dark, I think it cost about ten bucks. Found it this morning and two hose clamps and short piece of fuel hose and I was in business, worked great. If the Berryman's didn't cook the internals I will add a valve stem that will be a lot better than the hand pump.

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It idles smoother and LTFT looked good for a bit then maxed out, a few gooses on the throttle and it looked normal again, so maybe the intake gaskets helped. Now to study Comp's post and try again later.

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Dead in the water, smoked the fuel pump after the tank went dry and it just hummed along without me hearing it with the shop fan blowing.

Pulled the pump and it was so hot I could not hold it, cooled it off with water and it ran again so I put it back in the tank and scanned again, pump is a consistent 54 psi.

I also noticed alcohol percent is 35%, I buy regular 87 so that seems strange and there have been high and low DTC's for the E85 sensor.

Appears to be a lot of mis-fires on B2 and when it fires up there is a good puff of black smoke.

Dont' know where to go with this other than keep searching.

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Any more input on this?

Ran a dry compression test tonight, all plugs out and hooked up the battery charger set on engine start for consistency.

1 - 200
2 - 202
3 ​- 202
4 - 202
​​​​​​​5 - 202
6 - 201
7 - 202
8 - 200

truckdoug

iTrader: (25)

35% is the default alcohol content for when the pcm gets bad sensor info. you might try disabling the flex fuel option

that compression is great