1989 K5 350 TBI Fuel Issues?

[bassackwards]

let me know what part store you use all the time please so i can buy stock in the company .

How many sensors are there 4? 5? Total cost? $100 or so? What is your time worth? OP states that the engine is old and crusty, so are the sensors.

Garbage in=Garbage out. Learn Grasshopper

 

[Techson94]

I appreciate all info. The last thing I want to do is start replacing everything because in very short order I will be throwing a 5.7 vortec in and be done. This may speed up that if I cant solve it this weekend. It ran crappy but consistently for 3 years. Then it just went to garbage next day. Something broke.
cel does not work because circuit paper in dash light is as old and crusty as engine and only half the lights work. I will do a compression test before replacing distributor, pick up, and ignition. If that doesn't get it back to way it was. Time for new engine.
Labor of love these things. Wish my wife felt the same way about the thing.
I'll be reading all these posts again tomorrow when I tackle it and let you know.

 

[6872xtc]

How many sensors are there 4? 5? Total cost? $100 or so? What is your time worth? OP states that the engine is old and crusty, so are the sensors.

Garbage in=Garbage out. Learn Grasshopper

While I understand your point, this method doesn't seem to help learn how to diagnose the problem, in my opinion.
What if the problem is actually a wire to one of the sensors or the ignition system?
The wiring can get broken, chaffed or corroded and make a sensor act bad.
Just my thoughts.

 

[black dawg]

How many sensors are there 4? 5? Total cost? $100 or so? What is your time worth? OP states that the engine is old and crusty, so are the sensors.

Garbage in=Garbage out. Learn Grasshopper

Actually about 2 hundred bucks worth for "quality" parts.....but why stop there, ecms fail, so do injectors. Then when it still runs crappy or crappier because something you put on doesn't work right, or wiring you disturbed, then what?

Check fuel pressure
check timing
Find and old scan tool and datastream it.

 

[bassackwards]

While I understand your point, this method doesn't seem to help learn how to diagnose the problem, in my opinion.
What if the problem is actually a wire to one of the sensors or the ignition system?
The wiring can get broken, chaffed or corroded and make a sensor act bad.
Just my thoughts.

The sensors are still junk even if a wire is bad. It is impossible to get it right with worn out sensors. In both examples I gave above the sensor was sending a reading and not dead but the reading was garbage. The O2 sensors were measuring lean even though they were drenched in gas and the TPS was sending a WOT signal telling the trans to stay in low to 6k and not registering the true throttle position. I have countless other examples.

 

[6872xtc]

The sensors are still junk even if a wire is bad. .

This isn't a 100% true statement. It depends on the part that it's connected to for that to be true.
But if that's your angle, that's fine. I diagnose, then replace parts. It's what I have learned.

 

[frankin5]

I assume when you say you are replacing with a Vortec, that it is a complete assembly with all required fuel,sensors and ECM.

 

[dyeager535]

Then when it still runs crappy or crappier because something you put on doesn't work right, or wiring you disturbed, then what?

You replace one motor because the crank pulley is loose enough to make a rattling noise with no other symptoms, and you replace another that has low oil pressure and consumes coolant, because it was the wrong oil pressure sensor and the upper radiator hose weeped out of a tiny hole.

I get the idea to replace sensors, but if you think replacing OEM sensors with aftermarket junk (I venture to guess even Delco perhaps at this point, since some is coming from china now) is a surefire solution, you are dead wrong. Need I mention aftermarket thermostats? If I take something apart that works, and when I put it back together it doesn't work, I know it's something I did that is wrong. If I have a specific issue, I *should* track it down and figure out the root cause.

Things fail over time, but on my TPI setup ('88-89 generally) I'm running the original MAF, TPS, IAC, knock sensor, ECM, and distributor. Yes, the OEM injectors failed and needed replaced, and the pickup coil failed, but when I do proper diagnosis, parts replacement is minimal.

However. That said. If you decide to replace parts, keep the old ones as spares. It is often much quicker and easier to just swap parts when you have an issue to see if things change, especially if you buy a whole bunch of new parts and nothing changes...you know your spares are now GTG...assuming the replacement parts also weren't a problem.

 

[sweetk30]

How many sensors are there 4? 5? Total cost? $100 or so? What is your time worth? OP states that the engine is old and crusty, so are the sensors.

Garbage in=Garbage out. Learn Grasshopper

you grasshopper . . . i use to be a auto tech for years . there is a correct way to diagnose stuff other than parts changing . . . . to each there own tho .

 

[bassackwards]

you grasshopper . . . i use to be a auto tech for years . there is a correct way to diagnose stuff other than parts changing . . . . to each there own tho .

O2 sensors should be changed occcasionally even on new vehicles. Everyone I know has replaced a TPS sensor on their vehicle around 150-160k because it failed. It was degrading a long time before that.

 

[Techson94]

Allright. I fixed the check engine light. Bonus.

Code 44.

This is what internet says.
.) O2 sensor wire - Sensor pigtail may be mispositioned and contacting the exhaust manifold.

2.) Check for an intermittent ground wire between connector and sensor.

3.) Poor ECM to engine block ground.

4.) MAF Sensor - A MAF sensor that causes the ECM to sense a lower than normal airflow will cause the system to go lean. Disconnect the MAF sensor. If the lean condition is gone then replace the MAF sensor.

5.) Vacuum leaks can cause a lean condition and/or possibly a high idle. Check for cracked hoses a bad gasket or a faulty EGR or PCV Valve.

6.) fuel pressure - system will go lean, if pressure is too low. It may be necessary to monitor fuel pressure while driving the car at various road speeds and/or loads to confirm.

7.) Clogged injector or lean injector - perform an injector balance test..

Any other thoughts?

 

[Techson94]

I assume when you say you are replacing with a Vortec, that it is a complete assembly with all required fuel,sensors and ECM.

Upgraded fuel pump. Refurbed and bored tb. Custom tune.

 

[black dawg]

44 is the lean code for tbi stuff. I would check fuel pressure first.

 

[6872xtc]

44 is the lean code for tbi stuff. I would check fuel pressure first.

This could lead you to the hose which connects the pump to the tube inside the tank being a problem. But considering that you have upgrades planned, I would install an EP381 pump if you go into the tank.
I would definitely check ground connections well. The O2 sensor is working with less than 1 volt. A poor ground to the engine and consequensly the exhaust, can be a problem. It's a one wire O2, so it grounds through the ehxaust pipe

 

[bassackwards]

O2 sensor. Check a plug and see if it is in fact lean or if it is black and giving a false lean reading to the ECM

 

[rampage]

To check #5 for vacuum leaks, with the engine idling spray carb cleaner around any hose with a vacuum in it, also around intake manifold. If the idle changes then you found a leak.

 

[natemc]

Allright. I fixed the check engine light. Bonus.

Code 44.


Any other thoughts?

What was your compression?

Follow your wiring from the O2 sensor to the main harness. Anywhere it contacts metal you'll want to inspect for bare wire.

Disconnect the sensor and run the engine. See if the code goes inactive or you get a different code.

 

[natemc]

The sensors are still junk even if a wire is bad. It is impossible to get it right with worn out sensors. In both examples I gave above the sensor was sending a reading and not dead but the reading was garbage. The O2 sensors were measuring lean even though they were drenched in gas and the TPS was sending a WOT signal telling the trans to stay in low to 6k and not registering the true throttle position. I have countless other examples.

I have a whole lot of examples for troubleshooting sensor wiring first before putting sensors in. This pic is the most recent, not an engine realize, but proof to follow a troubleshooting tree. Pump 1 and pump 2 hydraulic pressure transducers. Pump 2 was erratic and intermittent. 3 wire sensor. Supply wire was good. Sensor wire or data read by ecm wire was good. Ground wire was bad. I actually swapped the two identical sensors/transducers and made the problem worse. Disconnected the plug and reconnected again. Problem fixed. Wiggled the connector and got it to fail. Pulled the terminal apart and the ground wire came apart. Sometimes you get lucky and moving the connector, like when you change a sensor, fixes the problem. Sometimes, the sensors are bad. Proper troubleshooting requires not forgetting the basic flowchart for every problem. No where on any flow chart does it say to go to Napa and purchase every sensor

 

[bassackwards]

I have a whole lot of examples for troubleshooting sensor wiring first before putting sensors in. This pic is the most recent, not an engine realize, but proof to follow a troubleshooting tree. Pump 1 and pump 2 hydraulic pressure transducers. Pump 2 was erratic and intermittent. 3 wire sensor. Supply wire was good. Sensor wire or data read by ecm wire was good. Ground wire was bad. I actually swapped the two identical sensors/transducers and made the problem worse. Disconnected the plug and reconnected again. Problem fixed. Wiggled the connector and got it to fail. Pulled the terminal apart and the ground wire came apart. Sometimes you get lucky and moving the connector, like when you change a sensor, fixes the problem. Sometimes, the sensors are bad. Proper troubleshooting requires not forgetting the basic flowchart for every problem. No where on any flow chart does it say to go to Napa and purchase every sensor

View attachment 285725

Old sensors can be transmitting incorrect data an not trigger a code. I'm planning on just changing all of mine before taking it on the road and I don't have any CEL because I want it to run the best it can and have seen too many that have lost their accuracy.

 

[Billyworld]

Check your ecm ground