High BLMs

[Dont Panic]

Hello Everyone,

I recently posted on turbobuicks.co m and have been informed that a lot of the gurus have left and moved to this site.  I have been having high BLM issues across all cells.  This is a problem I was fighting with back in 2005 after the car was completed (engine and tranny in a Thunderbird Turbocoupe) and then I put the car away for a few years and I have started up where I left off.  Just to give some details about my set-up:
- 42 lb injectors
- TE44 turbo
- 2800 stall converter
- Front mount intercooler
- Adjustable fuel pressure regulator
- Turbotweak chip

In the last few weeks I have performed a lot of troubleshootin g including:
- Found and fixed a driver side header to crossover pipe leak (car spools better now and drives more smoothly)
- Verified no more exhaust leaks using seafoam (with car at idle).  Do I need to brake stand it into boost for a proper check?
- Checked all vacuum lines with a tube to my ear.  No leaks found
- Changed the O2 sensor with my spare
- Verified FPR increases fuel pressure 1-1 with increasing boost
- Unplugged the injector connectors one at a time.  #3 did not make much of a difference so I changed the coil pack and rechecked.  Ok now.
- Injectors are holding pressure.
- Checked the plugs.  All plug threads are wet.  The colour of the tips were not a nice straw colour but a bit lighter but not white.
- Checked oil.  It smells like gas
- MAF at 5-6 at idle.  I verified the MAF back in 2005 and it went to 255 at WOT (I am hesitant to check again with the fuel in the oil).
- Replaced the corrugated hose between the maf and the turbo.
- Checked all vacuum lines with the car in drive and used propane.  I looked at the O2 mV readings as I checked all vacuum lines and intake gaskets, PVC and EGR.

Using the propane I could not find any response until I came close to the breather on the passenger side valve cover, and the O2 mV spiked from 300 (lean) to 700 (rich).  Are the breathers supposed to suck in air while at idle?  Is it ok to temporarily block this off until I get a new breather as the grommet ripped when removing the old one.

I removed the breather and blocked off the port just to test things out.  The O2 mV readings immediately went from 300 to around 450 and the cross counts became active.  I cleared the computer and took it for a drive but BLMs went back up (147-150).  After the BLMs increased the car was running rich at idle as the BLM cell was 147.  I could not get the mV readings back down below 600 even by turning the fuel pressure down 10 psi.

Another bit of info (not sure if it is relevant), after blocking the breather, before taking it for a drive when all blms where still 128, when I give it a bit of throttle the O2 numbers went from 450 to 250. Is this expected?  After driving it and the blms had increased to around 147, the O2 numbers held around 500 when I repeated this test (down from 600).

Should I remove the valve covers and check for signs of a wiped cam?  Could a wiped cam cause high blms?  If there are no vacuum and exhaust leaks, and if the fuel pressure rises as expected, and if the MAF is ok, then what could it be,  ignition module or bad injectors?  Any suggestions on what to check next?

I am not driving the car now except to troubleshoot it due to the gas in the oil.  I have to drive it about 200 km next week as I have to move it to a new location, so I am trying to fix this issue so I don`t have to tow it.

Thanks for the help,
Devon

[SuperSix]

Welcome! I think we do indeed have some of the best TR gurus here, excluding me. ;p

Welcome to the board!

Old thread for reference:
http://www.turbobuicks.com/forums/buick-v6-turbo-tech/41772-high-blms-all-cells.html

[SuperSix]

lulz..

"TurboBuicks.co m is the premier Buick Regal Forum on the internet."

[Steve Wood]

Okay, high blm numbers say the computer thinks the car is very lean and is adding fuel to make up for it.

If #3 was bad due to a coil pack, then #6 would have had to be bad as well.  Both fire at the same time from the same coil pack.

Your spark plugs say the car is not getting too much gas just like the blms indicate.  Car holds fuel pressure when turned off so you don't have excessive gas getting into the oil.  It is not uncommon for the oil to smell like gas after awhile.  It accumulates some under boost.  That is a good reason to change the oil more frequently than a n.a. car.  Change the oil and don't worry about that right now.

I never tried spraying propane on the breather but I am not surprised that it made it go rich because the pcv probably picked it up and recirculated it into the engine.

Don't have any definitive suggestions per se.

I would check the pcv and maybe replace it.  If it is open too much all the time, car will be lean.

I would check bolt at the back of the plenum to see if it is tight and spray some propane across the back of the plenum (and all the sides if you have not) to see if that makes a difference.

When blms are high in all cells, that usually means the car is not getting enuf fuel if they are consistently high cell to cell.  I never trust fuel gauges unless they can be verified in a case like this.  I would then turn up the fuel pressure to see if the blms begin to come down across the board in response.  If you have a TT chip, remember the idle is basically open loop so you should get O2s in the 780-800 range but it will take the idle cell awhile to learn so look at the o2s first at idle.  Be sure the car is good and hot and has been idling so the readings are correct.

I would not be afraid to drive it, but, I would put fresh oil in.

[Dont Panic]

Thanks for the response Steve.  Just a couple more notes since you have touched on the topics:

- The oil was changed a couple of weeks ago and it smells of gas after a few hours of troubleshootin g.  This is probably way too quick for it to be smelling of gas.  It also seems too runny when I rub it between my fingers.

- I did try to crank up the fuel pressure with no effect.  I went up to around 47 line off.  Should I try more pressure?

- When  you say that you do not trust fuel gauges, have you been led astray by them?  Have you experienced faulty fuel pumps or regulators that appear to be working correctly by looking at the gauges?

- If there is a vacuum leak that I have not found, would it result in high blms across all cells?  Would the spark plugs be a bit on the white side?

- If there was an exhaust leak that I have not found, would the plugs tips be darker from too much fuel?

I will check the plenum bolts and double check with propane.

I got a breather and PVC valve off a fellow member (thank you Just a Six) and I will also pick up some new plugs and continue testing Monday or Tuesday (the car is parked a bit of a drive from where I live).

[Dont Panic]

Also my speedometer reads low by about 10 km/h.  I sent a message to Eric to find out if this would cause a problem with his chips.  Once I get the computer hooked up to the cigarette lighter port, I will verify how far off the speedometer readings are, and I will also post some DS files.

[Steve Wood]

To get that much gas into the oil, you are basically going to have to have an injector that is bad.  In this case, you are going to see a wet spark plug or plugs and the fuel pressure is going to drop within a couple of minutes of turning the key off.  There is no other means of getting gas into the oil other than thru the injectors. Often the car will take a bit more cranking time to restart after setting a few minutes because it will be flooded.

Be sure, you have the cam sensor installed correctly and not 180 out because it can run.   Sometimes it will run fairly well and sometimes not worth a damn if it is out 180 but this can make it seem richer.

yes, crank it up to over 50 and try again.  That is not a very large increase volume wise.  Not as much as it sounds like.

I have found gauges that were 15 psi off from where they should be.  Cheaper the gauge, the more frequently they fail or are off.  usually, they read higher than they should.  Very seldom is a regulator bad.  If it is a modern adjustable one, you can take the top off and make sure the diaphragm is not cracked or torn.

If the fuel pump is really weak, you cannot raise the pressure enuf to get the O2s and blms up to where they should be.  Go borrow a gauge from David when he gets back.   If the pump is really bad, you may not be able to get the idle numbers up, but usually you can get it to idle okay but will fall on its face when the boost starts coming on.  On a car with everything working right, I can usually get the fuel pressure within two psi by simply adjusting fuel pressure until the idle O2s are right (on an open loop at idle  chip, anyway)

usually, a vacuum leak will show up worse at idle and less as the cells increase.

I did not mention cracks in the exhaust system, or leaks-before the turbo.  Again, this is usually worse at low speeds than as rpms increase.  Exhaust leaks suck air in and make things leaner so plugs will be lighter, not darker.

Do you have taller than 26" tires on the car?  28" tires will make a 7-8% in the speed and require a 27 tooth speedometer gear to get it right.  this is a percentage error and not a flat rate error.  You can use a gps, or a phone with gps, to get an accurate speed check versus the speedometer.

[Just a Six?]

See Devon that's why I said to come here & talk with Steve!
I have a verified good fuel pressure guage on a 3 ft hose you can borrow.
His PCV sounded like it may not be 100% so he now has a GM one that works.
I know it gets frustrating to work on the same issue for years but you are in the right place to get this fixed! 

[phil_long]

I can definitely second the bad fuel pressure gauge!!!!  Thats about as far as my expertise can go in this thread!!

[Dont Panic]

With the exhaust leak,would the air being sucked in make it to the combustion chamber, or would it only get sucked in enough to pass through the O2 sensor and out the tailpipe?  If this is the case, then wouldn't the O2 sensor read lean, and the computer would add too much fuel for the amount of oxygen being combusted, resulting in dark plugs?

A vacuum leak would add unmetered  oxygen to the combustion resulting in whiter plugs. I am just theorizing here.


When I turn the key to the "key-on" position (not starting) the fuel pressure jumps up to 43 then immediately falls down a few pounds. Is this normal? 


 

[Steve Wood]

yes, it is normal to drop.  the pump cuts off at 2 seconds and pressure eases a little.

I think the answer to your questions is yes, yes, and maybe...

Normally, a crack is apparent at idle when the pulses in the exhaust cause external air to be sucked back into the headers.  Some gets back into the combustion chambers during the overlap on the lobes and other gets pushed on to the O2 sensor.   As the rpm comes up, the velocity of the gases in the pipes and the back pressure caused by the turbo tend to minimize pulse separation and more exhaust gas is pushed out of the cracks than is external air sucked back.

Therefore, the ecm/blm adds more at idle than is added in higher cell numbers.

I have never seen enuf added to darken the plugs, but, you are more correct than me when it comes to the theory side

I have seen intakes that were not installed correctly whether by installer error, or by the heads being milled enuf to mess up the port alignment create a leakage problem as well

[Steve Wood]

a maf that is either bad, or miscalibrated as is common in rebuilts, can also fool the ecm into thinking that air flow is higher than expected and cause the blms to respond....I would expect the O2s to be higher in this case.

[Dont Panic]

I should check the voltage at the fuel pump. I have the battery in the trunk and the positive hooked up direct to the battery, however maybe the voltage at the battery is less than at the alternator. I do have a pretty serious cable running from the battery to the engine bay though.

I need to try and complete a good troubleshootin g checklist in the next couple of days. I won't be able to work on it again until Wednesday, and the more troubleshootin g preparation the better.

Thanks for all the suggestions!

[Steve Wood]

One of the problems is that many forget that the the body is the ground and try to ground the trunk battery to the frame instead of running a good ground up front...I prefer 00 welding cable and I think any thing smaller than 1/0 cable is too small.

In the end, the alternator is the suppy to the pump, but dragging the alternator down to keep the battery charged does not help.  No matter what, check the voltage at the pump as well as verify fuel pressure with another gauge.  Don't want to be like Phil and find out your gauge is not right.

Raising fuel pressure ten psi is only an 11% increase in volume so you can see why small changes may not show up.

If you are like me, you could use another pair of hands more than more suggestions!

[Dont Panic]

I changed the plugs, oil, and swapped out the PVC, with no change to the BLMs.

I did some voltage checks.  I am getting over 14 volts at the back of the alternator, and the same voltage at the battery in the trunk.  I am using the heavy weld wire for the power wire to run the length of the car.

I checked the voltage at the pump and it was about 13.7-13.8.  Not sure why.  I popped the relay socked off and checked the resistance between the battery and the relay, and the pump and the relay.  No resistance on either.  There must be a bit of resistance internal to the relay that is causing the voltage drop.  I swapped out the relay with another one on the car and same result.

I then checked the voltage while driving.  I could not do this with direct scan as my laptop requires 15V and shuts off when I put it in gear.  I used a volt meter and found that the voltage drops briefly when I go from park to reverse.  It drops from 14 to about 11 just for a split second (long enough to kill the computer) and then back up to 14.  When I am driving under boost it remains at or above 14V and if I take the foot off the pedal the voltage dips down for a split second bat to 11-12 then back up to 14.  I am not sure what is causing these blips.  I take it this is not normal.  Either way, I do not believe the high blms are a voltage issue.

Next I cranked the fuel pressure from 42 up to 59 lbs (line off) and took it for a drive.  The blms came down closer to 128.  Idle blm was 126, a few other were 132-134 and another was 125.  I have two gauges in the car, one at the rail and another in the car, and both read within a pound.  I suppose there is a chance they are both reading high but this seems unlikely.  I am going to borrow Dave`s gauge tomorrow and verify.

I suppose I could have a bad set of injectors that are not flowing correctly.  If so, it would be unlikely that they are all equally bad, so I could take all the plugs out again and compare after running at 59lbs fuel pressure.

Devon