98, 4.0 all wheel

[rgiancola]

Problem started 3 weeks ago. Needed to get it inspected, and had 1 code come up P0174, so I cleared out code and took it down to get inspection & emissions. Said I needed a tail pipe, they installed. Drove it home and the very next day, it wont start. Replaced fuel filter, Air filter, cleaned off MAF. It turns over just like its going to start, but does not.
Could the new tail pipe be effecting the O2 sensors? Thank you for any help

[shorod]

Welcome to the forum!

If the shop replaced your tail pipe with the idea that was going to solve your P0174 code, they really have no business diagnosing vehicles. The tail pipe is after all emissions sensors and would certainly not explain why you're vehicle has a lean condition code for only one of the two cylinder banks. It's quite likely though that the tail pipe was rusted out and replaced for that reason rather than as an attempt to fix the P0174.

For the P0174 you're most likely looking for a vacuum or exhaust leak that would be specific to cylinder bank 2. Depending on which of the 4L engines you have there may be some common issues to cause the code. I'd suggest you try searching this forum for both "P0174" and "Po174" (some folks don't realize it's actually a zero rather than an 'o'). You'll probably come across things such as intake manifold gaskets, exhaust manifold gaskets, PCV rubber elbows, and bad oxygen sensors.

You mentioned that you cleared the code. Do you have just a code reader or do you have a scan tool that would allow you to monitor some of the sensor values in real time? Although if you're unable to get the engine started currently monitoring sensors may not gain you much currently....

-Rod

[rgiancola]

Thank you for the welcome. Your correct on the tailpipe being rusted out. They had know knowledge of the code, I cleared it out so I could get a inspection. Im on my superglide about 3/4 of the year so its not tops on my list. Is there anything specific that would corelate with tailpipe replacement & the no start?

Yes, I do have a scanner that I could get readings on sensors, as you pointed out, it does not help much with the no start. Open for suggestions. Thank you for your time,

[shorod]

If it was just the tailpipe at the rear of the vehicle, about the only thing I can think of back there that could create the no start would be the fuel pump and associated wiring. I suppose if they torched off the old tail pipe or welded the new one on they might have managed to damage the fuel pump wiring. Or just the work back there wiggling the old off and new on might have caused an already fatigued wire to finally break.

Do you have some throttle body cleaner or starting fluid that you could use to see if the engine will start and run if that's sprayed in the intake? Or can you hear the fuel pump run for a second or so when the key is turned to the Run position?

-Rod

[fredjacksonsan]

Yup fuel pump wiring affected by shop...

[rgiancola]

I tried starting Fluid and i did not get it to fire, I might not be using enough fluid. Should I be using a generous amount? and I did not hear fuel pump working.

I will be back under there tomorrow afternoon and I will try starting fluid again.
Thank you for your time.

[fredjacksonsan]

Fuel, spark, air.

Starting fluid should have provided fuel. If air filter/intake isn't clogged, check for spark to the cylinder.

[rgiancola]

Thank you for your input and time.

[rgiancola]

Finally had a buddy come by and turn it over for me while I checked for a spark, negative. He thinks it's my coil Pack. Im going to get a coil pack, and the plugs & wires need to be changed out anyway its been several years since i replaced either.

Any other recommendations? Thank you for your knowledge and time.

[fredjacksonsan]

Well, hopefully that takes care of it! Let us know

[shorod]

If you have no spark on any of the cylinders I don't think you'll find the issue to be a coil pack, or that all coil packs failed at the same time.

Did you only check one cylinder for spark or multiple? If you don't have spark on any, or at least multiple, cylinders my first suspicion would be the Crankshaft Position Sensor.

-Rod

[rgiancola]

It was the crankshaft position sensor. Again thank you for your time and knowledge. I am sick of paying a ton of money to these shops for simple fixes. Thanks again

[shorod]

I'm glad to hear you got it figured out. And than you for following up with what you found.

In defense of the shops, some of what you pay them for is the knowledge, even if it's a simple fix. The tools to properly diagnose a modern vehicle don't come cheap, but can save time over the long run by helping to find the right part the first time. So after replacing spark plugs, a coil pack, and CKP sensor, you might have paid about the same for a good shop to properly diagnose the CKP sensor and replace it. And there'd also be the cost of a tow.

Considering the flip side though, you now have new spark plugs and a coil pack or more which were maintenance items anyway and therefore not wasted money. It depends on how much you value your time to install the different parts and be without this vehicle as transportation until you figured out the issue.

-Rod

[fredjacksonsan]

Ah, yes the CPS. Forgot about that.