KOER test problem... HELP ASAP

[rcfast]

Check the torque on your upper and lower intake manifold bolts, these intakes are notorious for developing leaks with age.

Checked already. Also a vacuum leak isn't going to cause it to run as rich as it is.

BTW, the fuel pressure regulator doesn't leak fuel when it's bad. The diaphram is for lowering the fuel pressure. At idle the vacuum pulls the diaphram, and thus it should be that 32psi range. The pressure should go up with the line off.

Only WOT should provide that high 40psi of pressure. Go back and check the FPR again, good luck.

Ya. Thats what I got when I checked it. The FPR is fine.

 

[rcfast]

I also forgot to add I tested the TPS and it is fine. The wierd part is that I can unplug the TPS and run the engine and it won't throw a code for the TPS. I also find it odd that i'm not getting any o2 sensor codes saying that the banks are running rich.

 

[rcfast]

MAF wiring checks out ok....

 

[rcfast]

Just checked the resistance of the ECT and it is functioning properly. I also voltage dropped the battery cables and they are fine. What next?

 

[Fredness]

It runs rich and throws MAF codes with the MAF plugged in.
It runs rich and throws MAF codes with the MAF disconnected.
This screams MAF, I realize there is no return on electrical parts, so a swap could be a dead end and expensive, but I would do a resistance test and voltage test on the MAF to be sure. Do you have one you could swap?

Sorry, "Fres-berg" is too far for me to drive to data-log it

Fred (RPS-Boss 3.0)

 

[rcfast]

It runs rich and throws MAF codes with the MAF plugged in.
It runs rich and throws MAF codes with the MAF disconnected.
This screams MAF, I realize there is no return on electrical parts, so a swap could be a dead end and expensive, but I would do a resistance test and voltage test on the MAF to be sure. Do you have one you could swap?

Sorry, "Fres-berg" is too far for me to drive to data-log it

Fred (RPS-Boss 3.0)

Put a new maf in and it runs fine.. It idles a little rough (barely noticable) now but not rich, I think the plugs are fouled. So I will do a plug change and change the oil and call it good.

 

[baby3848]

I have a 94 xlt 4.0 litre you know were going through the same thing as you changed maf and tps tested all other sensors, come up good ran good for a bit ........black smoke again less power again !husband ready to blow it up! last night I pulled the air filter out....power again and no smoke we are now going to change air filter to a cone maybe this could be part of your problem too

 

[rcfast]

I have a 94 xlt 4.0 litre you know were going through the same thing as you changed maf and tps tested all other sensors, come up good ran good for a bit ........black smoke again less power again !husband ready to blow it up! last night I pulled the air filter out....power again and no smoke we are now going to change air filter to a cone maybe this could be part of your problem too

You might be having a problem with the FPR. Is the check engine light on? If so have you checked the codes? The filter isn't going to make it run rich enough at idle to pour out black smoke.

 

[baby3848]

no check engine light coming on checked for codes and vacume leaks all checks okay not pouring smoke out at idle though just when it is reved up Fuel pressure okay aswell. when I had the filter on the other day it was surging and now that I removed the filter(which is brand new) it runs great pulled the fresh air intake out to check if it was plugged up but it's clear!!!!???