97 Tahoe - Fuel In oil - Stall Condition

[TwoNeef]

So I have a 97 4 door tahoe with a 5.7 vortec.

I traded honda rims for the vehicle that was sitting for over 5 years with 350,000km on it.

What I have done

- New Injector System mfi
- new spark plugs
- new spark plug wires
- new distibutor assembly
- New crank sensor (old one did have any wear makrs)
- new fuel filter
- cleaned the intake
- new intake plenum gasket
- new pvc valve
- new oil change with filter
- compression was within spec (did not do a compresion leak down test.)


GM did a partial Diagnosis

- Inspected engine as it smells like raw fuel when running, and right after found the engine air filter to be clogged with dirt.
- All cylinders are misfiring (NO p01345 code)
- They did a fuel pressure test starts at 60, then plummets to 0
- When the vehicle is off and the intake is off, you can see fumes coming out of the pvc vent
- checked engine oil, and smelled like gas and doesn't look like oil at all
- They did a fuel trim reset as the numbers where +99

- Recommended that replace all o2 sensors in bank 1 and 2
- Recommended that you replace the air filter.
- Recommended that your replace the fuel pump assembly



I just want opinions if anyone has run into a issue like this? And has any opinions on what is going on as well as recomendations.

 

[wjburken]

So I have a 97 4 door tahoe with a 5.7 vortec.

I traded honda rims for the vehicle that was sitting for over 5 years with 350,000km on it.

What I have done

- New Injector System mfi
- new spark plugs
- new spark plug wires
- new distibutor assembly
- New crank sensor (old one did have any wear makrs)
- new fuel filter
- cleaned the intake
- new intake plenum gasket
- new pvc valve
- new oil change with filter
- compression was within spec (did not do a compresion leak down test.)


GM did a partial Diagnosis

- Inspected engine as it smells like raw fuel when running, and right after found the engine air filter to be clogged with dirt.
- All cylinders are misfiring (NO p01345 code)
- They did a fuel pressure test starts at 60, then plummets to 0
- When the vehicle is off and the intake is off, you can see fumes coming out of the pvc vent
- checked engine oil, and smelled like gas and doesn't look like oil at all
- They did a fuel trim reset as the numbers where +99

- Recommended that replace all o2 sensors in bank 1 and 2
- Recommended that you replace the air filter.
- Recommended that your replace the fuel pump assembly



I just want opinions if anyone has run into a issue like this? And has any opinions on what is going on as well as recomendations.

Welcome to the forum from Iowa.

Quick question. Who replaced the injector system and why?

Here is where my thoughts are. Fuel in your oil obviously is from unburned fuel. Either from constant mis-fires causing the fuel to not get burned or a leaky injector system. The fact that your pressure goes from 60 to 0, which could be due to a worn out fuel pump, could also be due to your new injection system not holding pressure and is letting fuel pass through.

When they diagnosed the presence of mis-fires on all cylinders, did they try and figure out the cause? Who installed the new distributor, plugs and wires? Has that work been double checked? What is was the gap set to on your plugs? What about the ignition coil itself? Has that been checked and/or replaced?

 

[TwoNeef]

Welcome to the forum from Iowa.

Quick question. Who replaced the injector system and why?

Here is where my thoughts are. Fuel in your oil obviously is from unburned fuel. Either from constant mis-fires causing the fuel to not get burned or a leaky injector system. The fact that your pressure goes from 60 to 0, which could be due to a worn out fuel pump, could also be due to your new injection system not holding pressure and is letting fuel pass through.

When they diagnosed the presence of mis-fires on all cylinders, did they try and figure out the cause? Who installed the new distributor, plugs and wires? Has that work been double checked? What is was the gap set to on your plugs? What about the ignition coil itself? Has that been checked and/or replaced?

Cheers from Canada.

Vehicle Starts up in the cold with no need to prime the pump, starts up instantly.

(15km on the vehicle since I did all the work, has been parked since I took it to gm)

I replaced the injection system and intake plenum.

Due to the previous injection system looked liked it got 3rd degrees burns, and intake washing.

Only after i replaced the distributor, spark plugs and wires and the crank sensor.

Spark Plug gaps are 0.062 I believe.

The ignition coil itself has not been replaced.

They did not figure out the cause of the misfire as they wanted to do more diagnosis but i refused due to not wanting to burn more money then I should.

consistent Miss fires on all cylinders is what the report said.

Their are no p01345 codes.

 

[wjburken]

Cheers from Canada.

Vehicle Starts up in the cold with no need to prime the pump, starts up instantly.

(15km on the vehicle since I did all the work, has been parked since I took it to gm)

I replaced the injection system and intake plenum.

Due to the previous injection system looked liked it got 3rd degrees burns, and intake washing.

Only after i replaced the distributor, spark plugs and wires and the crank sensor.

Spark Plug gaps are 0.062 I believe.

The ignition coil itself has not been replaced.

They did not figure out the cause of the misfire as they wanted to do more diagnosis but i refused due to not wanting to burn more money then I should.

consistent Miss fires on all cylinders is what the report said.

Their are no p01345 codes.

What all did you replace when you did the distributor? The whole distributor or just the cap and the rotor? Have you double checked spark timing / retard?

Was all the work you did an attempt to solve these problems or did they start after you put the new parts in?

A little more info about when these problems started in relation to when the work was done might help.

Why did you tear into your intake and notice what the injector looked like? Did that make things better or worse?

Why did you change out the distributor? Did it solve the problem or cause another problem?

 

[TwoNeef]

What all did you replace when you did the distributor? The whole distributor or just the cap and the rotor? Have you double checked spark timing / retard?

Was all the work you did an attempt to solve these problems or did they start after you put the new parts in?

A little more info about when these problems started in relation to when the work was done might help.

Why did you tear into your intake and notice what the injector looked like? Did that make things better or worse?

Why did you change out the distributor? Did it solve the problem or cause another problem?

So when i got the vehicle, it would barley turn over.
-------------------------------------------------------------

New battery

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So I started with replacing the distibutor.

(p01345)

- I disconnected the spark plugs wires.
- took off the rotor cap
- marked the distibutor location
- removed the old distibutor
- Installed a new aluminium distibutor, with rotor, cam sensor, and cap.

Then vehicle still would not start.

-------------------------------------------------------------

Replaced crank sensor

- No more po1345 code at this point.

-------------------------------------------------------------


Then I replaced all the spark plugs


Then I replaced the spark plug wires


Vehicle started but would stall before it could even drive.

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Then I get it to the farm (Basically yellow stone ranch)

And I replaced the injection system (Reason being Looked into the throttle body and saw fuel washing from regulator and lines to injectors)

- I only replaced the upper intake plenum!
- Note: I cleaned the carbon build up inside the intake before putting it back together.

Started right up without hesitation.

-------------------------------------------------------------


- Did a fresh oil change including filter.

- Then drove it once, fuel trims be like gone way up.

- Then took it to gm, og report on top of this section.

And now its here.

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Should I do gm's recommendation?

Because the o2 sensors are not even reading.

But Also want someone professional opinions or a list of things to buy and replace.

Whats the best way to test lower intake plenum?

Best way to test injector system for a open loop?

 

[exp500]

Proper troubleshooting is a must on these trucks, or you will do a parts cannon and never fix or never know the cause. Start here-

Helpful Links

Helpful links- If this is a successful post maybe it could be stickied! Here's the first- https://www.gmt400.com/threads/88-95-service-manuals.43575/ https://67-72chevytrucks.com/vboard/showthread.php?t=700011

www.tahoeyukonforum.com

Fuel pressure Guage with long hose, spark tester, multimeter, scanner/code reader are must have tools.
Did you replace fuel pressure regulator?
What are fuel pressure readings KOEoff, and how long till it drops 10#?
Fuel trims at 99+ show that pump pressure could be low. Book 62-68 may run at 60.

Truck should run reasonably well even with bad O2 sensors- enough to troubleshoot root cause.
Where are you located? Some members may be nearby enough to help.

As far as what to buy, Use only delco/delphi/GM for CPS/ICM/Coil/Dist cap. Can also use DCR820X united cap/rotor.
Keep Posting here and We are here to help.

 

[TwoNeef]

BC Canada.

I have all those tools except for a fuel pressure gauage.

I dont have a tool that reads cam offset. But I know its good because of the very little spark advance. 5-12 degreeese.

The vehicle doesnt back fire.

It idles fine.

But the issue happens when the vehicle has been under load (driving conditions)

Shifts relativly fine atf fluid seems brand new. A bit slow jaged shifts.

Seems to bog out but can get to a decent speed.

TPS reads -1.5 to +1 on idle.

Vehicle sounds healthy when idle.

Just exhaust smells like you should not light a smoke.

But yea cold = fine
Short drive to then slow down and stop vehicle dies/boggs out = has to sit for 10m to start again
fuel pump = wine's more then my ex gf.
Obviously a lot of fuel in the oil after short trips.

 

[OR VietVet]

Welcome to the forum. Look through the recommended steps that have been shared.

 

[wjburken]

I would have someone with a good scan tool check your Cam Retard and make sure that when the motor is at 1000 RPM or higher that it is between -2 & 0 degrees.

 

[TwoNeef]

I would have someone with a good scan tool check your Cam Retard and make sure that when the motor is at 1000 RPM or higher that it is between -2 & 0 degrees.

Will do thank you.

When I get back to my home town.

- Replace the fuel pump assembly (its needs to be done anyways)

- Clean the fuel tank

- Put a new fuel filter in(again)

- Replace the ignition coil

- Double check spark

- Check the fuel pressure reading on idle, and while engine is off, and time the leak down.

- Do another oil change


Take it to a dealer

- I will get the Cam retard checked, confirmed, and adjusted if needed.
- And ask them to double check if their is a leak in the intake, and to find a repair said leak.


Does that sound like a fair reasonable plan of attack?