Making Progress, but still very rough under load. Idle good.

[NC Tom]

Okay folks. I was able to get the AC compressor remounted and the serpentine belt no longer touches the water pump housing.

 

Starts right up, idles REALLY rough until warm. Mellows out some, but not running correctly. Engine rocks side-to-side quite a bit. Give her some gas and the idle gets pretty bad, seems to backfire. Let off the throttle and it settles down. I also experienced one helluva squeak-squeal/scream for a moment, but that settled down too. I was hoping that fixing the AC mount and re-tightening the serpentine belt would get rid of the squeal. Oh well. . . 

 

I unplugged and re-plugged the injectors with this result. Starting from the front, the first three injectors made little difference when unplugged. The next three made a very noticeable, near stalling, difference. 

 

Check the audio file:

I start revving at about 12 sec. You here a "pop" at 18 sec. When the "pop" sounds, a decent amount of smoke is forced up into your face from below the engine.

 

That's where I am today.

 

[ratrapp]

is it possible the front three arent plugged up in the right order?or maybe the intake gasket has a vacuum leak around the front cylinders?

[NC Tom]

14 hours ago, ratrapp said:

is it possible the front three arent plugged up in the right order?or maybe the intake gasket has a vacuum leak around the front cylinders?

Just checked and they are good. Here's 30 secs of terrible squealing for your listening pleasure.

 

I am about ready to throw in the towel and get this thing towed. Six weeks and hundreds of dollars later, I still can't drive it. I've heard rumors of a guy in my hood that is/was a mechanic in the military. Maybe I'll seek him out.

[ratrapp]

did it run like this originally or did this start when you swapped the injectors?truthfully it may be time to let someone else look at it.there is no shame in it.I'm afraid theres only so much members can tell you to try or check without being there.

[NC Tom]

14 hours ago, ratrapp said:

did it run like this originally or did this start when you swapped the injectors?truthfully it may be time to let someone else look at it.there is no shame in it.I'm afraid theres only so much members can tell you to try or check without being there.

It ran okay until I screwed with it. Is it possible that the CPS that I replaced just isn't up to the task? Or the new fuel pump and sending unit? I hate to think that all new parts for these trucks are worse than the original equipment. 

I actually didn't change the injectors, just cleaned the stock ones. I have a new set that I could try.

[ratrapp]

if your holding fuel pressure and the pressure is in spec i think you could rule out the pump.how did you go about cleaning the inectors?i have a friend that actually has an injector flush machine that cleans and flows them.cps are pretty sensitive on the 4.0s.i don't know what brand you used but i do think the oems are discontinued for the renix unless you can find a nos one.

[NC Tom]

1 hour ago, ratrapp said:

if your holding fuel pressure and the pressure is in spec i think you could rule out the pump.how did you go about cleaning the inectors?i have a friend that actually has an injector flush machine that cleans and flows them.cps are pretty sensitive on the 4.0s.i don't know what brand you used but i do think the oems are discontinued for the renix unless you can find a nos one.

It's holding pressure, but it's lower than spec at around 30. The CPS is NAPA. Supposed to be a good one. I guess not as  my OEM one read better voltage. I may put it back on. I cleaned the injectors with a long soak in carb cleaner. Added voltage to open them and forced cleaner through. I have new ones too.

[ratrapp]

this may sound like alot of work but if the front three don't seem to making much difference when you unplug them i would take the fuel rail back off and swap the front three with the back three and see if the front three cylinders start showing a difference.if it does then the injectors are bad,if not then you have other problems.if it ran fine before you done this then i would try this.ive learned over the years that if its not broke then don't fix it lol.

[NC Tom]

5 minutes ago, ratrapp said:

this may sound like alot of work but if the front three don't seem to making much difference when you unplug them i would take the fuel rail back off and swap the front three with the back three and see if the front three cylinders start showing a difference.if it does then the injectors are bad,if not then you have other problems.if it ran fine before you done this then i would try this.ive learned over the years that if its not broke then don't fix it lol.

Yeah. One if the lnjectors was leaking.

Swapping is a good idea. I'll try it.

[NC Tom]

22 hours ago, ratrapp said:

this may sound like alot of work but if the front three don't seem to making much difference when you unplug them i would take the fuel rail back off and swap the front three with the back three and see if the front three cylinders start showing a difference.if it does then the injectors are bad,if not then you have other problems.if it ran fine before you done this then i would try this. ive learned over the years that if its not broke then don't fix it lol.

I replaced all the injectors with refurbed set I bought a while back. When I run the unplug test, all of them have an affect on the idle. Not drastic like the original set, but you can hear it. Overall, it seems to idle really well. I got the squealing almost gone as well. However, you just can't give it gas. It runs like complete crap when doing so. Fuel pressure is at 30 at idle, bumps up to 35 when throttle is applied. Even if the pressure is below spec, it's the best it's ever been, to my knowledge.

 

So, what components/adjustments cause sputtering and popping when, and only when, acceleration is applied? Audio file included. You can tell when I adjust the throttle and hold it for a sec. I took this audio before I messed with the belt.

 

Pulled Throttle at 3 sec. Held it until 11 sec. and then revved a little more.

 

 

 

[fiatslug87]

EGR??? Is the MAP sensor tube intact?

[Ωhm]

23 minutes ago, NC Tom said:

Fuel pressure is at 30 at idle, bumps up to 35 when throttle is applied.

 

Fuel pressure at idle should be ≈31psi. When Fuel Pressure Regulator (FPR) vacuum hose is disconnected and plugged, pressure will climb to ≈39psi at idle. Both readings are normal.

 

 

 

Check distributor for indexing (crossfire).

[NC Tom]

7 minutes ago, fiatslug87 said:

EGR??? Is the MAP sensor tube intact?

MAP is good. My EGR was disabled by the PO. I have not enabled it, so I really haven't had one for the 4 years I've owned it.

[NC Tom]

6 minutes ago, Ωhm said:

 

Fuel pressure at idle should be ≈31psi. When Fuel Pressure Regulator (FPR) vacuum hose is disconnected and plugged, pressure will climb to ≈39psi at idle. Both readings are normal.

 

 

 

Check distributor for indexing (crossfire).

 Oh, good. I'll check distro, however, I didn't mess with it before all this started.

[ratrapp]

well if you still have the original cps i would reinstall it and hard wire it.once again if it ran fine before look back at what you replaced or worked on.it possible the o2 sensor could be stuck so if you just unplug it you can eliminate that.also tps could be out of adjustment or just going bad.at least you have it idling now.

[NC Tom]

4 minutes ago, ratrapp said:

well if you still have the original cps i would reinstall it and hard wire it.once again if it ran fine before look back at what you replaced or worked on.it possible the o2 sensor could be stuck so if you just unplug it you can eliminate that.also tps could be out of adjustment or just going bad.at least you have it idling now.

I was thinking about putting the original cps back. Can the cps cause rough running? I thought it was only for starting. 

[ratrapp]

i would try it.and i wouldnt worry about slotting/modifying it.this is what happens when you have a problem and just start replacing things.you end up with more problems than you started with.i just fixed a customers car that had a broken ground wire on the coil harness.he replaced both cam solenoids and sensors because of a no spark condition.i told him the best thing to do is put his oem stuff back on sice there was no problem with it before.

[AZJeff]

Now that you have removed the faulting fuel injectors from the equation, the only other possible reasons for rough running would be something like a large vacuum leak or (more likely) something amiss in the ignition system.

 

The ignition system should be pretty easy to diagnose.   Here is what I would do:

 

1.  pull all the spark plugs and examine for proper gap and no cracking of the insulator anywhere on the plug.   Regap/replace as needed.

2. pull the distr. cap and inspect rotor and inside of cap for carbon tracking that will cause misfires.   Replace as needed.

3. reinstall plug wires onto cap and do a "nighttime spark arc" test.  This is done by placing the vehicle in a location where it is DARK (nighttime works well for this.)   With the engine running, observe closely all the spark plug wires for any arcing between the wires and any grounds (or adjacent wires).  The will be easy to see in a pitch black environment 

4.  A  more definitive test than the nighttime spark arc test is to get a spark plug tester in the link below to observe spark when running for each cylinder.

 

https://www.amazon.com/Ram-Pro-Engine-Ignition-Tester-Fool-Proof/dp/B01HU2L1NU/ref=asc_df_B01HU2L1NU?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80882941400092&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584482468120795&psc=1

 

[NC Tom]

3 hours ago, AZJeff said:

Now that you have removed the faulting fuel injectors from the equation, the only other possible reasons for rough running would be something like a large vacuum leak or (more likely) something amiss in the ignition system.

 

The ignition system should be pretty easy to diagnose.   Here is what I would do:

 

1.  pull all the spark plugs and examine for proper gap and no cracking of the insulator anywhere on the plug.   Regap/replace as needed.

2. pull the distr. cap and inspect rotor and inside of cap for carbon tracking that will cause misfires.   Replace as needed.

3. reinstall plug wires onto cap and do a "nighttime spark arc" test.  This is done by placing the vehicle in a location where it is DARK (nighttime works well for this.)   With the engine running, observe closely all the spark plug wires for any arcing between the wires and any grounds (or adjacent wires).  The will be easy to see in a pitch black environment 

4.  A  more definitive test than the nighttime spark arc test is to get a spark plug tester in the link below to observe spark when running for each cylinder.

 

https://www.amazon.com/Ram-Pro-Engine-Ignition-Tester-Fool-Proof/dp/B01HU2L1NU/ref=asc_df_B01HU2L1NU?tag=bngsmtphsnus-20&linkCode=df0&hvadid=80882941400092&hvnetw=s&hvqmt=e&hvbmt=be&hvdev=c&hvlocint=&hvlocphy=&hvtargid=pla-4584482468120795&psc=1

 

 

Thanks, Jeff. I have a plug tester so that's all good. The plugs are new, however, I decided to recheck the gap and it's ok. The first 4 plugs were pretty carbon fouled, but not wet, if that means anything. I was surprised because they are new with less than an hours runtime. Distro OK.

 

[AZJeff]

3 minutes ago, NC Tom said:

 

Thanks, Jeff. I have a plug tester so that's all good. The plugs are new, however, I decided to recheck the gap and it's ok. The first 4 plugs were pretty carbon fouled, but not wet, if that means anything. I was surprised because they are new with less than an hours runtime. Distro OK.

 

Carbon fouling is an indicator poor combustion.  With the misfires you are seeing, that might be a contributor.

 

However, it takes more than just good plugs to make a good ignition.  When you say "I have a plug tester so that's all good", does that mean that the light in the plug tester shows consistent spark on each plug?  Rough idle is caused by inconsistent combustion, and that can be caused by a bunch of stuff, but ignition is the first place I always look.

 

I also talked about vacuum leaks in my other message.  Do you have a vacuum gauge?

[NC Tom]

On 5/8/2023 at 6:31 PM, ratrapp said:

this is what happens when you have a problem and just start replacing things. you end up with more problems than you started with.

The logical side of my brain thinks this should never be the case. But, I know it is.

 

Question. There are two hoses that come from the fuel pump. If I accidentally switched those during reinstall, what would happen? I haven't check, just thought about it while typing.

[NC Tom]

1 minute ago, AZJeff said:

Carbon fouling is an indicator poor combustion.  With the misfires you are seeing, that might be a contributor.

 

However, it takes more than just good plugs to make a good ignition.  When you say "I have a plug tester so that's all good", does that mean that the light in the plug tester shows consistent spark on each plug?  Rough idle is caused by inconsistent combustion, and that can be caused by a bunch of stuff, but ignition is the first place I always look.

 

I also talked about vacuum leaks in my other message.  Do you have a vacuum gauge?

I meant that I have spark. I do not have a vacuum gauge. Honestly, I have thought all along that I botched the vacuum system somewhere, but my vac system has been a mess/modified by PO's since I got the truck. I've checked everything I know to check, but certainly could have mis-routed a hose. Without a quality diagram, I'll never know. By "quality", I mean not the common black and white one from the FSM. I have that, but I need more detail.

[AZJeff]

10 minutes ago, NC Tom said:

I meant that I have spark. I do not have a vacuum gauge. Honestly, I have thought all along that I botched the vacuum system somewhere, but my vac system has been a mess/modified by PO's since I got the truck. I've checked everything I know to check, but certainly could have mis-routed a hose. Without a quality diagram, I'll never know. By "quality", I mean not the common black and white one from the FSM. I have that, but I need more detail.

The FSM vacuum diagram should work out OK.  One thing you can do is to blow into one end of a given vacuum hose, and have a helper see if the other end sees an output.   Of course, one needs to know the names/locations of the various items connected via vacuum to verify that some previous owner didn't make mistakes reconnecting stuff.   That might be worth a check.

[ratrapp]

I'm not sure it would even start if you had them reversed.i may be wrong but i thought they were 2 different size lines.somebody correct me if I'm wrong.

[NC Tom]

22 hours ago, ratrapp said:

I'm not sure it would even start if you had them reversed.i may be wrong but i thought they were 2 different size lines.somebody correct me if I'm wrong.

You're probably right. Figured I ask. Not starting would make sense.