Chasing low O2s' and KR

[Art-87TR]

Recently puchased this low mile car and it runs perfect except for some KR " about 3-5 and I can here it " At 15 PSI 1&2, No KR in 3rd.. O2's around 750.. All scanmaster #s are perfect except BLM 145 at idle. Has new O2 sensor FP and HW kit and I checked for Vacum leak. Thinking about changing stock Injectors only think left in fuel system.. How are the Delphi / Lucas 32 lb / hr Disc Injectors

Would appriciate any Help!!

Also New tank 93 fuel & FP at 46 Line off

 

[gaminoree]

I have a set of delphi 55 lbs used very little with a modded ECM. also two turbo tweak chips for this set up. one race and one street. $400.00 for all. Let me know. tgamino@yahoo.com 1-734-782-0853

 

[Lee_Burough]

Recently puchased this low mile car and it runs perfect except for some KR " about 3-5 and I can here it " At 15 PSI 1&2, No KR in 3rd.. O2's around 750.. All scanmaster #s are perfect except BLM 145 at idle. Has new O2 sensor FP and HW kit and I checked for Vacum leak. Thinking about changing stock Injectors only think left in fuel system.. How are the Delphi / Lucas 32 lb / hr Disc Injectors

Would appriciate any Help!!

Also New tank 93 fuel & FP at 46 Line off

The BLM number and the KR make me curious about your chip....If its stock, put some high octane fuel in there and see if the KR goes away. If its not a stock chip, put the stock chip back in there and test the BLM and O2 readings in the same conditions. Check your PCV valve too.

Also, I'd recommend a search on false knock and to go through those issues as a matter of normal tuning. You're on the line with that lean 750 O2 reading. I'd take the boost down a bit until you've ruled out some of the obvious causes. You might do well to go back and do some of the Spring cleaning....Specifically, the intercooler cleaning.

With fuel pressure at 46PSI + 15 PSI of boost, you should have a fuel pressure of 61PSI at WOT....Do you? You need to measure that with a gauge you can see while you're driving. How are you measuring your boost? At some point, you may want to check your knock sensor is torqued to 14 ft pounds.

 

[Art-87TR]

Lee, Had same problem with stock chip, changed PCV, Did spring cleaning except for injectors.. I do have a boost gage "15#" Don't know where knock gage is??

But, I can here it pinging It not false knock!

Checked Fp when it was set at 43psi and had 58psi WOT

 

[Lee_Burough]

Ttt

Lee, Had same problem with stock chip, changed PCV, Did spring cleaning except for injectors.. I do have a boost gage "15#" Don't know where knock gage is??

But, I can here it pinging It not false knock!

Checked Fp when it was set at 43psi and had 58psi WOT

I guess if you are really hearing some ping, the knock sensor can wait. Run the tank down to about 4 gallons of fuel and put a gallon or two of zylene in there (a couple ounces of tranny fluid or marvel mystery oil for lubrication)....Does it still knock?

Before you try the zylene, try some fuel system cleaner through the tank, in case a simple cleaning of the injectors will give you more fuel, that could get rid of the knock. I use Chevron Techron, its the next best thing to a cleaner introduced through the fuel rail.

Be on the lookout for false knock anyway....Do you have an engine tie down, are your motor mounts good?

Some old heads will chime in soon Until they do, go here for some more ideas, under troubleshooting or Basics.

 

[VadersV6]

First off, you should take a vacuum reading at idle. I had bad KR at low boost when I first bought my car. It barely idled and off idle running was terrible Tons of misfiring. It stalled constantly. I was getting 11-12 inches of vacuum at idle, and found a really bad vacuum leak at an injector. The O-ring was wasted on on a few of them. I found alot of other vacuum leaks too. After I fixed all this, idle vacuum is now up to 18-19 inches, which is more than what Ive heard of on most TR's. Your BLM's are a sign of bad vacuum leak.
As far as O2 readings, the readings are practically useless unless you have a sealed exhaust system with no leaks, (a system that seems totally sealed doesnt mean it is sealed. Its very hard to get a truly sealed exhaust system.)and a wideband. There is a chart somewhere that shows the A/F curve in relation to O2 readings. A 750 reading can be anywhere from 15:1 to 12:1. As voltage climbs, the A/F ratio shoots up like a rocket across a very short voltage range. Like 3 points in A/F across a 50 millivolt range. An 800 reading can be as low as 14:1. You can get a rough idea, but its far from being the right way to tune. My car seems to pull the hardest with 02's in the 850 range, and I can run as much as 18psi on 89 octane with only .7 degrees of KR. The plugs dont look like its running to fat, they look just right. At night with cars behind me and headlights aimed at me, if I jump on it, I see some smoke, but I see nothing in the daytime. Dont be scared of running a little fat. Take that vacuum reading right away and start searching for vacuum leaks with some 1/2" fuel line. Use it as a stethoscope. It works really well. Using propane or carb cleaner to find vacuum leaks is totally useless. It has NEVER worked for me on any cars.

 

[Art-87TR]

Checked vacuum, 17.5 inches at idle.. Lowered boost to 14 and had 2.7kr at
30 mph 1-2 shift, No KR throu 3rd O2s 740-750.. BLM 145 at idle..

 

[Art-87TR]

Put a couple gallons of Xylene with 2/3 tank 93 and knock is gone..
BLM went down to 139 Will this tank clean the injectors or will I have
to do it again?? What else to check high BLM?? Came sensor maybe

 

[Lee_Burough]

Put a couple gallons of Xylene with 2/3 tank 93 and knock is gone..
BLM went down to 139 Will this tank clean the injectors or will I have
to do it again?? What else to check high BLM?? Came sensor maybe

Stock chip now? A chip can cause the BLM to be off that much (not to overlook a possible vacuum leak). No KR with higher octane suggests that you have some poor fuel....There may be other occult issues too.

Run some Techron fuel system cleaner through it, can't hurt anything and may help.

Check BLMs with higher octane and stock chip.

The KR could just be poor octane.

Do you have an engine tie down? If no, poor motor mounts can allow contact under the hood that causes KR.

I'm not comfortable with 750 02 voltage at WOT....What do others think?

lee

P.S. Until some old heads chime in, you may find some good reading here and here for retorquing the knock sensor and strategies to find vacuum leaks, if the stock chip does not give you normal BLMs.

 

[Art-87TR]

I'm not comfortable with 750 02 voltage at WOT

Me either, Same Blm 139 with stock chip

Need moore input

 

[Lee_Burough]

Add some fuel via the TT chip. Try Razor's gasket to block vacuum to the vacuum block to see if that lowers the BLM. If you don't find some where to go with those things, I don't know.