Stalling issues

[jtfab1]

Stalling issues, sometimes back fires through exhaust.

Readings are as follows:

170 - 185 degrees

O2 400-600 warm at idle

Air Fuel 07 - 08

IAC 07-12

rpm 750-800

New plugs, wires, coil pack, module, MAF O2 sensor and crank sensor. Cleaned and checked grounds at rear, and all sensor connections. Cleaned IAC. Checked cap and rotor on cam sensor, and setting. Changed ECM, no difference. Have not yet checked fuel pressure. Maybe fuel pump cutting out?
Does back firing occur in rich or lean condition? Plugs are nice tan colour. Starting happening out of the blue 4-5 days ago. Don't think it is the cam. Motor relatively new, as wiped a cam couple years back. No codes are registering.

What do I do now?

 

[ES1]

You just about cover everything.
I would try a known working MAF and try another chip.

 

[jtfab1]

Yeah, I was thinking of trying another one. The last time I replaced one it was running really rich, but could it make it run lean? I have had a couple of crazy back fires, so I was thinking that the pump might be cutting in and out, or the MAF is screwed up. I don't know. I suppose there is no code to register a drop in fuel pressure, or faulty MAF? If the MAF needs to be replaced, is there a better way to go than the stock replacement unit? I recently upgraded to a TA-49.

 

[ES1]

I run the translator and a LS1 maf from Full Throttle.
A better set-up than stock.
As far as the backfires, I would tend to look at too much gas - (maf, chip, ecm) or not enough spark (plugs, wires, ing.module, coil).
You have covered most everything.
What are your BLM's.
The thing I look at the most are blms while driving & O2 at WOT.

 

[pajo]

fire

just out of quriosity does it back fire when cold and also does it do it only under boost and how much ..?

 

[jtfab1]

Runs worse when hot. Not sure what you mean by blm's.

back fires both with and without boost.

I am going to try to find an MAF around I can swap, and see what happens. What are the advantages with the LS1 MAF, and is the translator required to use it?

 

[ES1]

BLM are a recording on a scantool that is used by the computer to adjust for fuel.
This is what I use to determine if the engine is running lean or rich while driving.
At WOT the chip will lock the blm to 128.
128 blm is considered optimum.
I think 90 blm is max rich and 150 is max lean
The computer will compensate between these numbers but it will still tell if you are having issues.
Example - you can consistently runs 100 BLM.
This indicates something is causing a rich condition.

A translator is required to run a LS1 or LT1 MAF.

No real perform gains to running a translator other than it is very hard to find a good working stock remanufactured MAF.

 

[jtfab1]

I thought that the "AF" read out on my scan master was referencing "air fuel ratio". Maybe I'm wrong. If this is true, than should this indicate a rich or lean condition?

 

[jtfab1]

Sorry, also do the rebuilt units from say kirban not perform like the originals?

 

[JC'sGN]

I thought that the "AF" read out on my scan master was referencing "air fuel ratio". Maybe I'm wrong. If this is true, than should this indicate a rich or lean condition?

a/f is the airflow in grams seen by the maf sensor.

 

[ES1]

Like said they may/maynot work.
As long as the MAF numbers show
MAF Mass Air Flow 4 - 7 idle 255 @ WOT, they should be OK

It would be good if you knew someone with a working unit to let you try, to see if that was your problem

 

[jtfab1]

So... if AF is the air flow the MAF is seeing, than can I not tell if the MAF is faulty by this read out?

Also, on the Scan Master is the "BL" the same as BLM as you discussed earlier?

Does anyone know if there is a site to obtain information of the Scan Master read outs, and what the values for the items should be?

 

[ES1]

Quick Reference Page For the '86/'87 Turbo Regals and '89 Turbo T/A

BL is BLM