Ok so I have posted on Naxja, and they haven't been super helpful, most of them are actually pretty rude.

90' Cherokee Limited 4.0 aw4 242 30/35. 4.5" RC x series, 33x12.50 MTR/k


Things I have replaced.

All vacuum lines. map, ccv,FPR, booster, everything.

CPS, TPS, CTS, MAP, IAC, O2, ICM. I did both of cruisers CPS mods. .6v cranking.

TPS is adjusted spot on. 4.87v input .83 at ecu side. 3.86(IIRC) at tranny side.

I also replaced all wheel bearings and brakes. rolls smooth.

fuel pump, and filter.

alternator.

180* t stat and open cooling mod with new rad. never gets above 210.

main engine ground with 4ga wire. I had a chunk that was just the perfect length. did a battery to body ground.

I pulled the harness apart and cleaned all grounds and re crimped and re soldered all factory crimps. .2-.3 ohm on sensors grounds.

Getting 12v to the O2. Need to look into the wiring on it more.

IAC and TB were cleaned.

I pulled the exhaust manifold and welded the cracks, and I had to ditch the EGR.
I folded and crimped the EGR line and welded it. then I filled the hole in the intake mani with quick steel.

The idle and poor mileage has remained through all of this.

Only other things I haven't replaced is the Cam position sensor,(hall affect). and the manifold temp sensor.

Put in 6 gallons and got 42 miles non corrected. I just add 20% so 50ish miles.

The idle is smooth when cold, and IT doesnt seem to idle up for a warm up cycle. It idles to about 800.

once warm the idle im park is around 500 and 300 in drive. with a slight surging.


I have tried everything to get the idle up. I adjusted the throttle stop, but after a while it just brings it back down.

I replaced the ccv/orifice line and have changed the orifice size, works for a bit then comes back down.

There has to be something I'm over looking. Or maybe the o2 is bad already.

help me please. this is my DD I cant afford to spend 10$ a day on gas..

Jeep for those interested.



Better?

 

I just went and double checked all the grounds at the dipstick and sanded them all clean.

And then i checked the O2 wiring, no volts to heater with key on, 14v to heater with engine running. 5.1v from ecu.

 

I fought a vacuum leak for many, many months. I even make myself a smoke pump to look for vacuum leaks. Nothing.

Finally found it by spraying around with some throttle body cleaner, and found I had a leaking o-ring at one of my injectors.

 

I suspect that I may have a vacuum leak from the injectors but wouldnt that raise the idle?

I can turn the injectors pretty easy so i'm sure they are loose.

$5 each for new o rings, meh whats another $30 in this 6k pile lol

 

What gear are you running?

 

What's the condition of the tube from the throttle body to MAP??

A set of Volvo 746 injectors is never a bad idea.

 

Yeah. And is the speedometer accurate?

 

Stock 3.55's

Cruiser! glad you chimed in. I replaced the line from TB to MAP with vac hose. just using the last 1" of original line on each end. I plan on finding some neon injectors pretty soon. theres a yard with what must be 30 of them here.

Speedo is off by about 20%. I compensate for that.


Just went and bough new injector O rings, will let you guys know if anything changes.

 

It is done. the idle is smoother, but lower......




I wasn't sure if these "pintle caps" were supposed to be installed. but the quick research I did on my phone said they should be. so I put them in.
They snap into place tight. they wont be coming off.

I can see why they would be useful, there is about half a millimeter between the pintle hole, and the hole in the cap. should help atomize fuel.. if my thinky thinky parts are right.




After all this i warmed up the jeep and took it for a short drive. no real difference in power, but its running smoother. now the idle is around 300 in park.

 

So for my own sanity I adjusted the throttle out about 1.5 turns to bring the idle up to where it should be, then I adjusted the TPS back to .83.

Idle is good but it still goes up and down. by maybe 100 rpm..

with it adjusted the throttle response is better, before if you tapped the gas it would bog down for a split second..

is there such a thing as the throttle plate being closed too far?? when i adjusted it before closed it, then turned it till the butterfly just barely moved.

Not sure yet if this will fix my issues or just a bandaid.

Also one of my injectors is leaking, i know that for sure. when i checked the rail this morning after sitting all night there was no pressure. i dont think it is the antidrainback as the whole hanger assembly is new.

I looked into those volvo 746 injectors and I think thats the route i'll take. some pretty good deals on ebay.

Would these be them? http://www.ebay.com/itm/3-Year-Warranty-Volvo-2-9L-V90-960-S90-OEM-GENUINE-BOSCH-Fuel-Injector-Set-/281092945874?hash=item417271f7d2&vxp=mtr
I think part of my bad MPG's is just gas draining into the motor when i shut it off..

 

Programbo here on cF has the refurbished injectors you need.

Tip 14.

Cruiser’s Renix Throttle Body Butterfly Adjustment

Okay. Let's start from scratch. First off, that's not an idle adjustment screw. It's a throttle butterfly stop screw. It's purpose is to allow the butterfly to be as close to completely closed as it can be without binding or wearing into the throttle body. It was never intended to be adjusted in the field. But, Uncle Bob didn’t know that, did he?

Engine off. Back off the butterfly stop screw with a 3/32” allen wrench until the butterfly is completely closed. Now. turn the screw in until the FAINTEST movement of the butterfly opening is detected. This can be done more easily with the throttle body removed. If you remove the throttle body, be sure to replace the gasket underneath it after thoroughly cleaning the old one off.

Revised 07/07/2012

Fluctuating idle CAN be a bad O2 sensor. Only use NTK if you replace it.

 

I followed that when i adjusted it the first time when i had the intake off.

I was just wondering if those are the correct injectors not sayin ill buy those i just wanna see if thats the right part number

 

So today I dealt with a couple issues..

First, had coolant dripping off my transmission crossmember.. though that was a bit odd. after looking around i discovered the coolant seemed to be coming from the back of the manifold. so I spent quite a while tightening the bolts on the underside. most were pretty loose..

leak persisted( thought there was a coolant passage in manifold) but running issues seem better, the idle doesnt hunt as much but even with the butterfly adjusted out to raise the idle it is still low.

And then i discovered the leak id from a freeze plug on the back of the head. not the end of the world, just time to finally put in a new motor.. yay. this one has a slight wrist pin noise. so for now some good ol KW stop leak should sort the problem.