Got a pickup awhile back and was smoking excessive mostly blue. Pulled the motor and had exhuast valve with hole in it and intake valve not seating on separate cylinders. All new gaskets and put back in truck. Deleted catalytics since they were both destroyed and cleaned muffler as best I could. Now it smokes but mostly white when reved up and maybe slight blue at idle. It's not using coolant or oil but went through five gallons of gas in short time.

Tests I have done

Checked fuel pressure and holds 38 psi all day. Tested maf o2 sensors, one is bad and tested vacum and compression all good.

It seems to be over fueling to the extreme. idles a little rough and will backfire on occasion. No check engine light but had all the o2 sensor issue codes.

I'm leaning toward bad PCM... Would that cause the smoke rough idle and super rich condition??

Any help appreciated or any other tests I can do. Thanks

 

It sounds much like some assembly errors.
First, all the valve stem seals should have been replaced while things were apart for the small cost of the seals.
Worn seals, valve stems and valve guides will allow oil to be drawn into the cylinders from the heads past the intake stems.
It is scarce event to hear valves are a problem in these engines. Possible a head has a crack?
Second, is the cam position sensor set in and adjusted properly?
White vapor is usually coolant that has changed 'phase' because coolant does not burn.
If that is the case, it will have a cooing effect on the OX sensors and even ruin them.
When that happens, the computer reverts to a fixed fuel tables in it's program. These tables are made rich by design.
Transmission fluid often shows up as whitish but don't think it is your issue because the two areas usually can't get together very easy.
Sounds like the motor has not been reasonably well taken care of.
Good luck.

 

The valve stem seals were all replaced aslo. I'm not no backyard mechanic. Been doing motor work for some time just more diesels. I'm confident the assembly was done correctly and it isn't using any coolant. I know the truck has had a hard life after seeing the amount of sludge build up inside. And it's manual trans so no chance of that being the issue.

As for the cam sensor I'm not sure is there a way to check that?

 

My reply is based on your report and description.
I have no way to know of your expertise otherwise.
Don't take exception to the reply if we do not know.
Depends on the backfire being either back into the intake of out the exhaust.
You have not indicated which.
Either one can be a fuel or ignition timing issue.
Being the ignition is timed out of the PCM and non adjustable, it likely is fuel injection timing. It is adjustable.
The location where the distributor usually is on these older motors is the fuel injection timing for EFI engine control.
A Haynes repair manual would be a good investment.
Good luck.

 

When you remove the cats don't you have to do something with the o2 sensors?

 

So bad cam sensor would cause fuel timing to be off... But wouldn't it set a code for that?? And as for the backfire I can't say for sure if it was intake or exhaust, it was a few days ago when I was working on this. I would rather get advice here then buying a manual if it's all the same to you.

 

I left the o2 sensors in place if that's what you are asking.

 

There are no codes for an out of adjustment cam sensor or backfires.
There is no way for the system to logically tell these conditions.
Only electrical failures and diagnostic test results are code supported.
That's all that is needed.
If the system operation is known, then the person doing the troubleshooting puts the observed actions together for a logical conclusion as to the likely fault.
Good luck.

 

There ya go. Which one is bad?
Which O2 sensor codes do you have?

 

The passenger rear o2 sensor tested bad, the codes were
P0161
P0155
P0153
P0141
P0136
P0135
P0133

After clearing them P0141 and P0161 came back right away still no check engine light though.

Also after further inspection the exhaust smoke isn't horrible anymore and is more black after prolonged idle but not alot and if reved up turns more grayish and smoke increases. Exhuast smells of raw fuel and it went through over 1/4 tank in about thirty or so mins of running. The idle is still a little rough, rpm doesn't change it just seems to vibrate more then it should.

Pulled spark plugs one by one while running and none seemed to change any tones or idle more then another...

 

P0133, P0135, P0136, and P0141 have to do with fuel control on bank 1.
(Does the Check Engine Light work?)


Do the plugs look like both banks are running rich or only bank #1?


(I imagine the muffler holds quite a bit of old coolant that needs to be burned off).

 

The cel has never came on and looking at the plugs both sides appear the same. Not that clean white but more of a black shine I guess. Seems fuel fouled I would say but what is causing it to inject so much fuel?

And I did pull the muffler and clean it but I'm sure there was some amount of oily water left in it too

 

When I deleted the cats on my mustang I had 3 options. 1) get a custom tune. 2) get 02 emulators. 3) Get spark plug anti foul inserts for the o2 sensors.
How To: Install An O2 Sensor Non Fouler to Eliminate a Check Engine Light with Pics - Chevrolet Colorado & GMC Canyon Forum

I have a tuner for my mustang so I just retuned it

 

I'll definitely give those non foulers a try, thanks for that info

I pulled the PCM to Check connections and to see on replacement but the PCM number is a F85F-12A650-AKA and says it's a reman unit.

according to parts place that is for a 98 truck and wouldn't work right in a 97, Is that true?

The truck build date is February 20, 1997.

 

Does the CEL come on for bulb check at KOEO?