Mongo

I'll be taking pics tomorrow of my findings and posting them here. Cross your fingers and grab those Roseries, it's exorcism time!

Mongo

**UPDATE**

I have checked the ground strap on the passenger side of the engine and cleaned the connections with some electrical contact cleaner. The CE panel was pulled back only to find lots of wires, but no exposed leads or hot wires. I didn't get the chance to take pics.

I put the OE O2 in the car and went for a drive. The LH has learned and adapted the idle. The following has cleared up:

- Car runs leaner now and does not smoke on WOT.

- Idle is smooth on cold starts until adaption occurred. GLASS SMOOTH.


I now am faced with the following symptoms at warm operating temperature:

- Idle is low when in gear. Put it in Park or Neutral and the idle climbs between 700-900 RPM

- Applying the slightest bit of gas on the accelerator causes a stutter or engine hesitation prior to a response.

- Intermittent Hot Hard Start. *SEE VIDEO*

- Restarting the car, the RPMs climb over 1000 RPM, then drop to about 200-300 before clearing itself up.

- Driving around the idle is slow at around 400-600 RPM. Hit the gas quickly and engine stutters. Will sometimes stall afterward.


Just took some readings of the idle and WOT switches. WOT switch IS functioning like it should and better now that the engine is warm. The bad news, Idle switch functions and goes infinite when pressed as properly, but when you apply gas real quick with the pedal varied between 1 and 10 degrees depression, ohmmeter reads 355 ohms and 173.5 on the second try prior to going infinite. This happened on 2 out of 6 presses on the accelerator. What does this mean?


I did a continuity test between pin 24 of the LH (O2 loop) and the O2 connector using the pins of my ohmmeter. I have perfect continuity there telling me the O2 loop is definitely functioning.

Here is the video while parked outside my house after the drive. Car is at operating temperature already:

John Speake

When you first cranked and had a no start, the tach was going crazy - didn't look correct at all.... when it ran clearly the Idle control loop is not working correctly.

Stumble off idle has to be a misfire or weak mixture. When you hit the throttle the LH should respond to the sudden increase of MAF volts by an enrichment to prevent the stumble, which you should easily see on your NBO2 gauge.

I don't know what to suggest. Maybe swap MAF for your spare, try a spare EZK.... check connectors at bottom RHS of CE associated with LH and EZK for any dodgy connections.

Mongo

What does the crazy tach mean?

Lizard928

Has the reference sensor been replaced?

Mongo

Yes. I replaced it because the tach was bouncing before. I really feel like I am getting closer to solving this. I am also glad I took that video so you can see what I have to put up with.

AO

If you have to give it gas to get it started when hot, that means you're getting too much fuel for it to start.

I'm sorry to ask this (I'm sure it's been asked and recorded) but what are the Temp II values at the LH and EZK? You can follow the link in my signature to see which pins to test.

jcorenman

Andy,

You continue to have problems with various engine-related components. You have changed or tested most everything, yet odd symptoms persist. That leads to something that has been suggested but maybe not completely followed up on: grounds.

All of the engine-control systems have their ground connections to MP-IX, located on the engine block. And the engine block is, in turn, grounded to the chassis by a heavy ground strap which also carries starter and alternator current.

If either of those ground connections is corroded, it will have resistance which will cause a voltage drop whenever current is flowing. In the case of starter current (a few hundred amps) or even alternator current (90 amps or so) it doesn't take much resistance to create a significant voltage drop-- which in turn will corrupt all of the sensor readings, leading to all sorts of problems.

MP-IX is on the top of the engine, at the back of the pass-side cylinder head. It is buried by the air filter, heater valve and hose, and some fuel plumbing. I think it is essential that you dig down there, disassemble it completely, clean and check each terminal carefully, and reassemble. If you find dirty terminals, clean them. If you find corrosion or any funkiness where the wire joins the terminal, fix it. Clean the block, clean the bolt, make sure everything gets reconnected (count the wires before disassembling, to be sure).

Now crawl under the car and find the main ground strap between the block and chassis, down low on the passenger side. Remove it completely, clean it up and check it over carefully. If you find any corrosion in the stranded braid, replace it. Clean the chassis, clean the block, make sure everything is bright and shiny and clean, and torque the bolts properly.

If you do those two things then you can be sure that all of the engine systems have a good ground reference, and have a chance of working properly.

Mongo

I pulled CE panel down again to take some pics. After reinstalling car won't hold idle! I have checked all the connections on the bottom of the panel and everything is clipped on! Help...

There is also bluish-gray smoke now coming out of the exhaust.

Disconnect the battery and reconnecting causes the car to run great for exactly 45-50 seconds than it starts idling like **** and stalling. No smoke comes out the back within those seconds until the idle acts weird. Rev the engine and smoke comes out. It just won't idle.

Video below - fiancee is saying the tach is bouncing "going to 6". Here are pics of the CE panel as promised.









Any help would be greatly appreciated. If anyone is willing to come over to help me resolve this issue, I'll take you out to lunch, beer, gas money, whatever... This car is driving me nuts.

123

Did you check to make sure those red wires under the clear plastic cover at the top of your fuse panel were all making a good connection? What about the smaller wires on the positive battery terminal.

That license plate seems rather appropriate.

Mongo

All connections were verified in the panel and battery

borland

Besides 6 degree retarded ignition, does anybody know if a defective hall sensor has an affect on starting?

jcorenman

Andy,

If you're not going worry about the engine grounds then please at least do one simple test:

Take your voltmeter, set it to DC volts, put the red probe on the engine block (any bare aluminum) and the black probe on the chassis (the bolts that mount the cross-strut are good), poke the sharp tips hard to get through any surface corrosion.

Now ask your sweety to crank the starter (don't worry about it starting, better if it doesn't). What does the voltmeter show, block to chassis, while the engine is cranking? 0.1V?? 0.5V? 1.0V?

If the engine does start, what does the voltmeter show then? Negative or positive?

Thanks!!

Stromius

Bummer this is still going on. I have corrected the following this on my S4 to resolve idle issues:

Temp2 plug and boot - both wires stripped under old rubber boot.
MAF plug and boot - 4 of 5 wires stripped and section of boot gone and taped by PO
@ TPS connection under the MAF - male plug disintigrated today during intake R&R and likely loose before giving bad TPS signals

Hope this helps!

Landseer

Andy,

Did you dive deep into the back of the engine bay and inspect the CRUCIAL ground terminals? Not just the contact surface between the ring terminals and the block. Also the possibility of a corroded solder/crimp where the multiple grounds wires enter the ring terminal?

Based on my experiences, LONG before this point in the project, I'd have stripped them and applied new ring terminals (expensive pre-solder/shrink type).

What are these grounds for? Like Mr. Coreman indicates, the O2 sensor ground. The MAF ground. The LH ground. The EZK ground...