4-Banger 2.3l 2wd manual Low power up hills. (Chasing Ghosts?)

[CarsonRanger]

Where to start...

I've owned this truck for a year and a half, and since I've owned it, it's never had any real power.

In regular city driving it has no issues that I can perceive. The problem seems to be more pronounced under load. This can be a hill, or simply a strong head wind which is common for the drive from Reno to Carson.

I haven't tried topping out the speed on flat land, but I feel it can easily get to 80 or more. Under load and up hills, I have to put it into 4th gear to stay within even 5 to 10 mph of the speed limit.

On this particular stretch of hill leaving Carson (Let's just call it The Hill)... If I stay in 5th (65mph zone), it slows down as far as 50 or worse. This is with it floored by the way.


Current status and progress if you can call it that:

Immediately after purchasing the truck, it threw a code (I forget which), and I had a shop diagnose and fix. It was the PCV valve. Since then, no other issues besides the lack of power.

No check engine light.

New plugs as of about 6 months ago, but this didn't improve performance any.

I've purchased an OBDII scanner (BlueDriver bluetooth adapter), and have been trying to learn and understand the readings I'm getting.

LTFT generally sticks around 14% and more (I can provide a log of the trip from home to work). During The Hill ascent, both STFT and LTFT level out at about +10% each for a combined of +20%.

With these numbers and a crapload of youtube/googling I'm leaning toward a few possibilities.

With high positive fuel trim being suggestive of a vacuum leak, I've pulled the vacuum lines for everything right of the vacuum chamber (ball) on the passenger side. All the lines hold a vacuum and are in serviceable condition.

I've tried a trick of disconnecting the idle air control electrical connector and the truck idled very poorly (Which supposedly suggests there isn't a vacuum leak.)

I removed the upstream? O2 sensor on the engine side of the cat and drove to work and back with no change in performance.

I checked the fuel pressure at Autozone. Pressure jumps to 38 when priming the fuel pump and drops to about 35 when cranked. I haven't yet run it down the road with the gauge connected, so it's possible I'm having a flow issue.

I'm hearing what sounds like a low pitch whistle or whine from the passenger side floor board when I'm trying to accelerate quickly. I'm not sure if it's the sound of a vacuum leak or just the engine straining. It's possible that's where a vacuum leak could be, but I'm experiencing no problems out of the AC. Still I intend to do a end-to-end check on the remaining vacuum lines that are part of the AC system just to rule it out completely.

At this point I believe it is not a vacuum leak (Still TBD) and I don't think it's an exhaust backpressure issue, so I'm thinking the following:

Either the trim is high because I'm getting unmetered air, or it's high because I'm getting too little fuel.

Without additional guidance here's my gameplan:

1) Examine the vacuum lines through the rest of the AC side of things.

2) Clean the throttle body, intake manifold, and injectors.

For the sake of brevity I'll stop here.

Any advice is greatly appreciated.

 

[Mark_88]

Hi and welcome to TRS~!

I noticed your intro post today but was busy answering someone else and didn't get back to say hi....

Anyway...these engines are not necessarily the power house in the regular format but can be with a bit of work and a turbo charger. Short of that, they should be able to climb fairly low grades without downshifting from OD if they are in top shape. So my first recommendation is not a performance upgrade but to check the throttle cable for play. I didn't see this in your post but it is one of the most obvious problems with these engines in terms of not getting all that is available.

http://www.therangerstation.com/how-to/engines-fuel-systems/throttle-cable-mod/

That link explains the idea and if there is any play in that pedal then you could be surprised by the fix.

Short of that...I would suggest a compression test and a vacuum test to see what is happening with the physical components. if you find problems with those then it might explain things better and save you hours of tinkering with things that will probably not give you what you need.

The link above is from the How To Tech section and it also has the vacuum test indications and how it could be hurting your performance. If you can access a compression tester then it's not that hard to figure out.

The steps you listed may or may not help but if there was a vacuum leak it would likely manifest in different symptoms like high idle, poor acceleration, hard starting, and fuel consumption through the roof. Or others.

Cleaning things is always good but I would do the throttle cable check/mod first and go from there.

EDIT: Almost missed the low pitched whistle down by the passenger floorboards...that could be part or all of the problem...and could be from things like plugged Catalytic converter, DPFE hose that is loose but not off (it is on the exhaust side with two rubber hoses running off a metal tube), exhaust leak that can cause O2 sensor errors that would cause fuel trim issues...worth checking definitely...

 

[CarsonRanger]

Thank you for the warm welcome and for taking the time to respond.

It’s funny that you should mention the throttle cable because one of the points I decided not to mention was my readings of the throttle position sensor. It starts at 16.9% with my foot off the pedal and only goes to 93.7 regardless how far I try to push it through the floorboard. I’ll definitely be checking out your throttle cable link.

I don’t suppose you’d have an economical suggestion on a vacuum gauge and a gauge for performing a compression test would you?

 

[Mark_88]

I live in Canada so my version of economical would not be appropriate. We have a store called Princess Auto that imports a lot of stuff from China and in spite of it's origin I bought a vacuum gauge from them that has held up surprisingly well...its' brand name is Power Fist but it might be marketed as something else in the US.

https://www.princessauto.com/en/detail/vacuum-fuel-pressure-tester/A-p4230070e

I borrowed a compression tester or rented on the last time I tested my engine for that and I can't remember the name...but I'm sure there are others on here that can make better recommendations for those items in the US...

The throttle cable might be enough to put your engine back in the game but all you can do is try it and see where it gets you...

 

[tomw]

Princess == Harbor Freight for the most part from what I've seen at Youtube where AvE takes things apart and comments.
As usual, you have been given good advice. I'll add you can test for fritzed catalytic converters by removing the upstream O2 sensor, but you'd have to direct the exhaust away from things that could catch fire. A better solution would be to paste up some plumbing fittings and attach a vacuum/pressure gauge to measure the back pressure.
My impression is the numbers should be in the low single digits for a non-clogged converter.
Check also that the heat resistant 'rubber' tubes connected to the DPFE have not come loose as they'll diddle with the EGR flow, or report an EEC trouble code.
You may have a low fuel pressure condition. I don't have the spec, but think it is a bit higher than 38-ish. I thought, over 40psi, but don't take it to the bank.
You can also check fuel pump throughput by running it and catching the flow over a measured time period. It should be in the gallons per minute range, again, I do not have the number. I would also suggest checking the MAF for schmutz on the wires. Most times it will give hesitation upon acceleration, but it could be mis-reporting airflow. Along those lines, how clean is the air filter? Reno doesn't have a lot of dust flying generally.
Long and short, hill climb problems most times come to fuel flow.
tom

 

[CarsonRanger]

So my first recommendation is not a performance upgrade but to check the throttle cable for play...

...I would suggest a compression test and a vacuum test to see what is happening with the physical components...

The steps you listed may or may not help but if there was a vacuum leak it would likely manifest in different symptoms like high idle, poor acceleration, hard starting, and fuel consumption through the roof. Or others.

EDIT: Almost missed the low pitched whistle down by the passenger floorboards...that could be part or all of the problem...and could be from things like plugged Catalytic converter, DPFE hose that is loose but not off (it is on the exhaust side with two rubber hoses running off a metal tube), exhaust leak that can cause O2 sensor errors that would cause fuel trim issues...worth checking definitely...

Cable Mod:

I tried this last night and no change on my commute this morning. In fact, I've done so many things over the past month, I forgot that one of my first checks was just that, checking how open the throttle body goes when I mash the accelerator. I found that my floor mat had bunched up under the pedal, but using my phone camera, I took the air intake hose off and propped the camera up to look into the throttle body. Pressing the pedal before and after removing the floormat produced no difference and the throttle plate was able to turn perfectly horizontal. I haven't checked it since, but I figure it hasn't changed in a few weeks.

High Idle, poor acceleration, hard starting, high fuel consumption:

Nope, Nope, Nope, and maybe.

It idles fine after warmed up, leveling at about 700-750 rpms. Even during warmup, it is steady from something like 1500 to 2000 and steadily declines until it hits 700ish.

Accelerates normally, that meaning, I'm not shoved back into my seat, but I can get to 65 pretty easily.

It starts fine, only a second or two to crank.

I need to calculate my gas mileage. I believe the hose running to the tank from the cap is broken because when I fill up completely, it will spill onto the ground. I've just been putting 11 gallons in it when I'm near E. Strangely enough, I don't get a gas cap code since I'd imagine the tank wouldn't be holding pressure with it in that condition. Could this be my problem in its entirety?

Whistle/whine:

I played with the accelerator on my way home yesterday and I only hear the noise when I'm in OD and it's making me think it's just transmission noise from the OD gearing.

Plugged cat - This is a suspicion of mine too. As mentioned in another post below, I've actually taken out the upstream O2 sensor, but didn't see a change in performance during my commute. I wasn't thinking I could have caught fire from the exhaust fumes escaping, guess I dodged a bullet there. Still, I wonder because looking at my O2 sensor voltages on my obd2 logs, the upstream goes up and down steadily which is expected, but the voltage on the downstream sensor is very sporadic, jumping up to .7v down to .005v where it'll stay for a while. I've googled this a good bit, but I've seen other images of O2 voltages where the downstream stays steady and sometimes it's jagged like the upstream voltage. Maybe I'm just excited to be able to extract this information using my new toy and it's distracting me from something I should be focusing on. Do you know what the voltages should look like on the downstream O2 sensor?

DPFE hose - I'll be checking this probably tomorrow. Wife's birthday dinner tonight.

A bit of a confession, I have very little experience diagnosing these things and I've been learning on the fly this past month. While I've read a lot of stuff that's out there, I'm always open to suggestions on informative articles. Heck, before the new year I had no clue an engine had a vacuum system. lol

 

[CarsonRanger]

I'll add you can test for fritzed catalytic converters by removing the upstream O2 sensor, but you'd have to direct the exhaust away from things that could catch fire. A better solution would be to paste up some plumbing fittings and attach a vacuum/pressure gauge to measure the back pressure.
My impression is the numbers should be in the low single digits for a non-clogged converter.
Check also that the heat resistant 'rubber' tubes connected to the DPFE have not come loose as they'll diddle with the EGR flow, or report an EEC trouble code.
You may have a low fuel pressure condition. I don't have the spec, but think it is a bit higher than 38-ish. I thought, over 40psi, but don't take it to the bank.
You can also check fuel pump throughput by running it and catching the flow over a measured time period. It should be in the gallons per minute range, again, I do not have the number. I would also suggest checking the MAF for schmutz on the wires. Most times it will give hesitation upon acceleration, but it could be mis-reporting airflow. Along those lines, how clean is the air filter? Reno doesn't have a lot of dust flying generally.
Long and short, hill climb problems most times come to fuel flow.
tom

O2 sensor: I pulled it a while back but didn't see a difference in performance. Glad I didn't catch fire though. As time allows I'll see about getting a pressure gauge of some sort rigged to get some numbers to share.

DPFE Hoses: This is on my list now, thank you for the suggestion.

Fuel pressure: The spec for the 97 2.3 ranger is 35-40, so that's in spec. I'll have to dig up my source on that number to verify it's reliable.

Fuel pump: Can you make a suggestion on how to go about running this test? Lawn mower gas can and keep priming the pump? Direct wire to the pump from battery?

MAF: I did check the sensor, it looks slightly darkened (grayish, not black), but I didn't feel it was in bad shape. It has no obvious contaminants like oil on it. It's dry. This is hard to describe in text, can you point me to a pic of a good comparison between a good and bad one?

Air filter: Lookin good, not new, but I've blown it out with my air hose pretty well and it's not covered in gunk or anything that would significantly hinder the airflow. It was changed when the plugs were about 6 months ago.

Like I titled the post, I feel like I might be chasing ghosts.

I'm building a list of things to check, but I'm starting to think I should do the vacuum test and compression test before going too much further. The compression test has been on my list for a while though, time to bite the bullet and get 'er done.

 

[CarsonRanger]

One more thing to add about the cat. When I first purchased the ranger, it had an incredible rattle which I've only recently 'repaired' using a couple of large hose clamps. It's silent now, but I'm sure that rattling for more than a year couldn't have been healthy. No telling how long it had that before I bought it.

Is this a thing? Welds coming loose on a cat and it rattling itself to death? Still, I thought I ruled out the cat when I took out the upstream O2 sensor. Just a layperson's pondering.

 

[adsm08]

The rattle from the cat was probably just broken spot welds on the heat shields. That won't hurt it.

One thing I didn't see mentioned in this thread, what gears do you have?

 

[ricardoguitars]

I have the exact same issue, but I also have random power issues when taking off on hills, sometimes I floor the pedal and nothing happens, other times it does burnouts and takes off like a rocket. I have a P1409 code, which is related to a vacuum issue, I replaced the vacuum regulator without improvement, the last thing on my list is to replace the cat, it looks like it has been there forever, so I wouldn't be surprised if it is shot.

 

[CarsonRanger]

I have the exact same issue, but I also have random power issues when taking off on hills, sometimes I floor the pedal and nothing happens, other times it does burnouts and takes off like a rocket. I have a P1409 code, which is related to a vacuum issue, I replaced the vacuum regulator without improvement, the last thing on my list is to replace the cat, it looks like it has been there forever, so I wouldn't be surprised if it is shot.

Ha! welcome to the club man. Only problem is I don't have any codes. I think I'd feel better if it did.

What is the vacuum regulator? The EGR vacuum solenoid?

 

[CarsonRanger]

The rattle from the cat was probably just broken spot welds on the heat shields. That won't hurt it.

One thing I didn't see mentioned in this thread, what gears do you have?

According to the manual, I have a 3.73 rear axle.

Edit: I'll check the tag on the diff and update if it says differently.

 

[ricardoguitars]

Ha! welcome to the club man. Only problem is I don't have any codes. I think I'd feel better if it did.

What is the vacuum regulator? The EGR vacuum solenoid?

Yes, that's the one.

 

[CarsonRanger]

Yes, that's the one.

Roger that, yeah I swapped mine too, most likely unnecessarily. I was using the vacuum pump at Autozone and could hear an audible rattle from it (with the truck off mind you). Bought a new one cause that's clearly defective right? Nope. New one works the same way. I'm assuming it's me due to my inexperience and that it would have held a vacuum if the truck was running. Anyone want to confirm this for me?

Thanks again guys.

 

[adsm08]

It probably would have held a vacuum with the truck running. EGR flow at idle will quite a diesel engine. Even a little EGR flow at idle will stall a gas engine, so it the valve was sticking open because it was getting vacuum right away the engine probably would have either not started at all, or stalled very quickly.

The 1409 code is for an electrical malfunction which probably didn't effect how it ran.


3.73 gears aren't terrible, but you would probably be happier with 4.10s.