Naild

Im reaching for help with my problem with a 94 capric engine swapped into my landcruiser. Engine is stock about 100k except for intake and headers.
The iac numbers are around 16 when warm idling, I cant find a vacuum leak but I believe a lower number is sign . So while it was warming up I pulled the pvc and stuck my finger in the valve cover and plugged the line running from the throttle body. After a little bit I had suction on my finger from the valve cover. Not a lot but some. Is this a sign of a leaking intake manifold gasket or internal engine trouble or what? Vacuum from the throttle body makes sense. Not the other way around.

hrcslam

IIRC, that's the fresh air vent for the PCV system. The actual PCV valve is on the drivers side intake manifold.

Did you confirm the IAC valve is actually moving (just because the computer commands 14 doesn't mean the valve is at 14)? Are your TB blades closed all the way? Did you make sure the TB gasket is sealing?

Do you have scan9495? If so, you can command an idle change while running to see if the IAC is actually moving or not.

Naild

I have scanned the system with Datamaster and attemped to post a run file. Not sure how to do so it rejected the file in the upload process?? Yes the iac valve is new and moves with throttle position and rpm. The TB blades are tightly closed, I didn't replace the TB gasket but did use gasket sealer when reinstalling. I have been around the engine with propane and starting fluid but no success at finding a vac leak.

You schooled me on the pvc valve. I looked over the engine to discover that is indeed a vent, the pvc valve is locked in with a clamp at the intake drivers side. Never noticed what that was before.

Recently the gas mileage has been horrible and the smoothness of the engine is gone. I just did a compression test and all were with in 10 pounds average 180. All electrical bolt in have been replaced over the last 3 years, 02's (not bosh) to injectors to MAP to TP sensors, plugs wires are good.. The opti is about 4 years All replacement not GM stuff.

Kinda stuck with this, it starts quick and runs ok, sometimes between shifts (manual) or coming to a stop it idles high and settles down after a few seconds, not longer than 2-3.

sweetbmxrider

iTrader: (13)

Is the tps voltage correct and did you do the iac relearn?

Naild

5.9 is the voltage at idle, i didnt do a relearn but the engine has had time to adjust, the valve has been in for a few months. It idled high for a few minutes and settled down to 700 as its been.

steveo_

perhaps your throttle plates are too far open.

the ecm doesn't really give a flying crap about "correct" tps voltage, that's leftover tpi knowledge. it's self-resetting, does not necessarily align itself with the throttle plates the same on all throttle bodies, and remembers the lowest voltage attained as 0%, so if you start your car without hitting the pedal, it's pretty much good to go.

the only problems arise when you increase the base throttle angle, then you should reset the ECM's memory.

despite whatever you read about setting 'base idle' or whatever online or in the FSM, the lt1 likes its throttle plates closed completely (or rather closed just far enough so they don't bind up and stick in the bore.

if the counts are still low, could be a vacuum leak.

Naild

I will keep looking for a vac leak. I wonder if its how I desmoged the engine. The egr is gone along with all non vial engine functions, per the wiring harness. Maybe I have something goofy with the routing of lines, I will keep checking. Thank everyone for the help.

hrcslam

If you're idling at 700, but with 16 IAC counts, your vacuum leak is pretty small. My car will occasionally idle high for a bit, then drop down after a few seconds (especially after a cold start). It will also idle higher when I'm over 10 mph or so too. But, my IAC counts are in the 70's at a 950RPM idle.

Are you MAF tuned? If so, what is your MAF AFGS at idle? When you said intake and exhaust aren't stock, are you talking about the intake tube (before the TB) or the intake manifold?

A couple places to look for a vacuum leak beyond where you have already looked is the TB gasket (remove and install with a new gasket, although that is unlikely) and possibly an intake manifold leak through the manifold to head gasket. You could also have a small leak where the EGR system was (maybe a block off plate is leaking a bit?).

Another possible condition is the TB IAC bore is worn out or cracked or otherwise allowing more air flow through the IAC than it is supposed to. We can tell this by looking at the AFGS at idle. I forget what it's supposed to read for a stock car (IIRC, 7-9AFGS??). Also, did someone drill holes in the TB blades? That'll do it too.

Naild

Tonight I spent some time checking all vacuum lines, egr, oil cap, valve cover vent and supporting lines, intake cap and everything seams to be in order. The intake manifold bolts were 1/4 to 1/2 turn loose. Intake manifold gasket leak. I took pictures of the run file The IAC numbers go down as the engine warms up. What do you think? intake leak

Naild

from tonight while warming up

Naild

Engine warm

hrcslam

Looking at the AFGS vs IAC and Idle RPM. I'd say you don't have a vacuum leak anywhere.

I'd start by addressing the very high LTerm Counts on your RH bank. That's usually indicative of a dead injector. But, you don't have any injector codes. So it could be a working injector (electrical circuit side) that isn't flowing fuel (clogged??). Or your tune could have injector fault DTC's turned off.

An easy way to find out which one it is, is to unplug each injector (one at a time) with the engine idling until you hear no change in idle. If they all change the idle, look into replacing that O2 sensor (RH). OR you have an exhaust leak at or before the O2 sensor.

Naild

This engine has run the same since the swap and retune. Rich at idle that can make your eyes burn with a sputter.Runs ok going down the road but I know it can be better. It has been running in my landcruiser for 4 years and I have replaced every electrical part from 02's to injectors to map throttle position IAC plugs wires ect. Purchased the data logging software ect. Nothing has changed the way it runs. I did find a partly installed injector that was making it miss, the reason I started this thread so thanks all for that. So now I am on a mission to finally get this thing to run perfect. How can I post a full run file from data master? My phone video files are too large to post with the small limit.

I ran a noid light on all injectors,it shows pulse at each injector. When unplugging them while running they all make a difference. No exhaust leaks at the header or O2 sensors. I ran it tonight down the road with each injector unplugged and they all make a similar difference? Its rich on the drivers side and lean on passenger at idle, up in the 2500 rpm range it evens out. The run files look good at speed and on a recent trip my very large brick (landcruiser) with 37" tires on a 2 lane hyway got 15 mpg. Which is amazing considering my 2007 dodge 1/2 ton gets that. I have though about installing the old injectors on the lean side to even out the split trims as they did show a similar but richer condition, but that will not deal with the idling issue. Any thoughts?

sweetbmxrider

iTrader: (13)

Who tuned it?

hrcslam

In order to post datalog files you have to convert them to .zip files then attach them to your post.

Do you still have the EGR system? Bank 2 is the passenger side. That side is asking for a CRAP load of fuel (20% more).

If disconnecting all of the injectors makes the same difference, you can rule that out. It should even out much lower than 2500 rpms. Have you tried to re-load a stock tune and start from scratch on that? Maybe the ECM you got was previously tuned and is messed up? There's a possibility that the intake manifold IAC passages are clogged up on the drivers side or there's something allowing the passenger side to get more air.

Honestly I think you need to start over. Go back to a stock tune. Here's a link to a website by Steveo (a member here) of stock bin's. That website will also generate a Tune for you with basic bolt on's and such (which you have) for free.

I think more information is required. Do you have a wideband hooked up? How are you confirming the O2 BLM trims are the same in Open Loop?

Naild

I often wondered if the intake IAC passages are blocked on the drivers side too. Before I give up on the tune I will switch back to the other set of injectors that I have and try to zip a run file, it was tuned to old injectors and has run leaner since. Anybody tried to seafoam through IAC and throttle body in attempt to clean the IAC ports? Thats been in the back of my mind for a while.

No wide band, I believe the O2 BLM's are the same in open loop but I havent specifically looked, they are always moving??

Good info!!!!! Thanks for the help

Naild

I switched out the cleaned injectors with my old ones, it runs richer overall like what I remember before they were replaced. I will try running seafoam through the intake to clean the IAC passages. Then post another run file.

Naild

Run file after cleaning the AIC ports. I pulled the intake elbow than took a funnel with a flex spout and a short piece of rubber hose stuffed it in the IAC track. Had my kid keep it running while I poured seafoam down the funnel. It didnt do anything but definitely got down the track.

Looking at the files the speed signal is wavy. Is this normal? My gps agrees with the speedo.

If there was a exhaust leak on the drivers side would it be rich or lean?

I have a code 41 EST open error what is that?

hrcslam

An exhaust leak will make it lean, thus the O2 will ask for fuel, so increased BLMs. That's why I asked about the EGR. Thats on the passenger side. That could also bring air in to the intake causing the low IAC counts.

Naild

Hrcslam,

Skipped the egr question, its removed, blocked off and sealed well, I cant imagine its pulling air. I will send a run file to the tuner and talk with him.

Did the zip file load OK? engine only data is the file I am using.

Thanks for the help