New 5.0L built, low compression and horrible MPG

[1997XLTRollover]

Which one is that?

That looks like it's brand new-dead injector- bad connection to injector?

All my injectors are also brand new (I really went all out when rebuilding this engine and tried to leave nothing to chance), but nope this spark plug has 2k miles on it. The truck doesn't run rough. It's definitely not missing a cylinder.

But here's the ironic thing, that's the front left plug which is exactly where that vacuum leak is. I bet it's pulling so much air into that cylinder it's running crazy lean especially on that cylinder. The truck does feel a little off idle wise but your average person would not notice it. I would expect a slightly smoother idle though out of a brand new engine. But believe me it's definitely not down a cylinder. I bet after I replace those intake gaskets my idle is perfect and the truck runs better. I'm just still leery about the mileage but who knows, maybe it's so bad it's really screwing things up. I just don't know how I have no lean codes.

I though I'd responded to your spark plug condition pics earlier, but I don't see it now. Your spark plugs indicate you are running WAY lean. They should not be bright white after 2000 miles. A normal plug running with the correct air/fuel ratio should be a tan color. There is something seriously wrong.

You did in my other thread, but no one posted in it so since this one is WELL documented haha I figured I'd put them here too Your post in my other thread is what gave me the final kick in the ass to check for vacuum leaks.

 

[Dono]

Did the injector connector locking clip become brittle and its not making proper connection to the injector? Sorry, I missed the pic of the injector in question.

The reason I'm asking is from experience. When it happened to me I was popping a lean bank 1 code though. I understand you are not seeing any codes. Its surprising how smooth my motor actually ran.

 

[1997XLTRollover]

Did the injector connector locking clip become brittle and its not making proper connection to the injector? Sorry, I missed the pic of the injector in question.

The reason I'm asking is from experience. When it happened to me I was popping a lean bank 1 code though. I understand you are not seeing any codes. Its surprising how smooth my motor actually ran.

No pic of any injector; I'm not questioning injectors. The only pic was of my spark plug. I think that plug being so white is because of the intake gasket leak. But I will double check all injector connections when I have my intake off to be sure they are tight and the connections are clean. If any clips are broken I'll zip tie the things tight against the injector or something.

 

[Dono]

Sorry, I what thinking Spark Plug, and typed injector. That's what I get for doing this stuff at work.
I'm still trying to get my head around the whole front of block (lower intake to block) vacuum leak thing.

Guys, correct me if I'm wrong here.....That spot has nothing to do with the cylinders. Its only an oil seal and seal for crank case. Correct? It would be a vacuum leak for the pcv system of course (the pcv draws vacuum from the crank case, and if there is a leak there it will pull un-metered air), and cause the computer to start compensating for a lean(er) condition, but not just one cylinder.

Now, if the intake gasket was not sealing around the intake for that particular cylinder, we could go lean on that cylinder. If the gasket was not sealed at the bottom, I could see it pulling extra crank case air during high vacuum conditions causing that cylinder to be lean? Probably the same if the gasket failed at the top of the cylinder intake.

Am I making any sense?

I am still betting its a fuel issue on that cylinder. I'm going to go back and try to find a picture of that plug.

 

[Dono]

Which one is that?

That looks like it's brand new-dead injector- bad connection to injector?

Great minds think alike! Or is it 'fools seldom differ'?

We are going to find out.

 

[1997XLTRollover]

Sorry, I what thinking Spark Plug, and typed injector. That's what I get for doing this stuff at work.
I'm still trying to get my head around the whole front of block (lower intake to block) vacuum leak thing.

Guys, correct me if I'm wrong here.....That spot has nothing to do with the cylinders. Its only an oil seal and seal for crank case. Correct? It would be a vacuum leak for the pcv system of course (the pcv draws vacuum from the crank case, and if there is a leak there it will pull un-metered air), and cause the computer to start compensating for a lean(er) condition, but not just one cylinder.

Now, if the intake gasket was not sealing around the intake for that particular cylinder, we could go lean on that cylinder. If the gasket was not sealed at the bottom, I could see it pulling extra crank case air during high vacuum conditions causing that cylinder to be lean? Probably the same if the gasket failed at the top of the cylinder intake.

Am I making any sense?

I am still betting its a fuel issue on that cylinder. I'm going to go back and try to find a picture of that plug.

You're making sense. I kind of assumed that since I have a coolant leak there and an air leak thorough the intake, (I put the smoke in using the brake booster hose) that that part of the intake to head gasket is just flat out not sealing right near that port. A coolant leak can only happen if the intake to head gasket was not sealing properly correct?

That being said what you said is also possible. I did only pull 1 plug recently but I did pull all 8 before and all did look white from what I remember. So it's possible it's causing an overall lean condition. I would just think with all 8 plugs that white this sucker should be screaming I'm lean! I'm lean! on both banks.


I'm debating checking my ECU code to be sure someone didn't replace it with another V8 computer that's using the wrong fuel tables. Or hell maybe I have the wrong injectors. They're yellow tops which is what I pulled off my truck but maybe they're not flowing right?

 

[Dono]

Leak 1: Intake manifold gasket.
It actually hissed when I ran the smoke machine through it, so it must be pretty bad. I also have a small coolant leak here (why I expected an air leak too), so the intake or head must not be flat or the gasket is junk. I'm going to get Felpro gaskets and maybe put some rtv on them too and hope that does the trick.

I'm re-reading some of this for what I may have missed. A coolant leak at the front around where top of intake meets block? Maybe your upper intake isn't seating quite tight on the one corner at the front. I'm surprised the motor isn't sucking some coolant. Please have another look at the coolant and see if its coming from somewhere else.

As I keep re-doing my motor (come to think of this, I'm in no position to give advice) I always rub an extremely thin coat of rtv around the coolant ports on the lower intake manifold.
Also, before laying the lower intake gaskets on the heads, I spray them with super tack gasket stuff ( http://www.permatex.com/products-2/...matex-high-tack-spray-a-gasket-sealant-detail ) and let it air dry slightly so its super sticky and lay on the heads.

 

[Turdle]

Have you tried re tightening to torque specs?

 

[vroomzoomboom]

like don said, a buddy of mine made his smoke machine for about $30 from this video



and it works great. i to saw smoke form the egr. don gave me a pic of his because its off the truck. there are 4 vents on the bottom. i found a small leak at one of my vacuum line tee's and discovered my pcv valve popped out for the umteenth time.
i am going with jon on this. your plug shouldnt look like that, even after 100 miles. if you havent done it already grab a welders glove and while the truck is running start pulling one plug wire at a time at the coil pack. if the idle changes, you have found your problem or cylinder. or who know, you might even have a died coil pack. another thing you might also want to see is what is your volts when running. i chased a problem i had for a month. the voltage was dropping off at wot. after checking the alt thought it was belt slip. changed the belt, alt pulley, tensioner, and adding a bigger idler pulley, it still dropped. after rechecking the alt, the volts would drop if you snapped the throttle, but at idle or cruising speed it was fine. i even noticed after i changed the alt it ran better and picked up a lot of grunt.
long shot as well, but even tho you checked under the hood when you did your smoke test, did you look inside under the dash? you have to remember all your heater controls also are vacuum operated. its a long shot, but sometimes even the simple stupid things are over looked. just ask me about the vacuum problem i had earlier this summer......thats 3 weeks of my life i will never get back

 

[Turdle]

Maybe my eyes are deceiving me, but that plug looks so lean it appears to be right out of the box. There should be some ash or soot, discoloration of the ceramic, I still think that cylinder is dry.

 

[vroomzoomboom]

Maybe my eyes are deceiving me, but that plug looks so lean it appears to be right out of the box. There should be some ash or soot, discoloration of the ceramic, I still think that cylinder is dry.

or not firing. my motor ran on 7 cylinders and i didnt even know it....to bad it was also on break in

 

[Turdle]

or not firing. my motor ran on 7 cylinders and i didnt even know it....to bad it was also on break in

I would think after 2k miles it would be wet with fuel, or, at least discolored from fuel if it was not firing.

 

[1997XLTRollover]

Have you tried re tightening to torque specs?

Everything on this engine was torqued to exact Ford spec. But yes I did re torque the intake manifold when I found the leak. I kind of over torqued it a hair too which helped but I don't think it stopped it completely.

like don said, a buddy of mine made his smoke machine for about $30 from this video

https://www.youtube.com/watch?v=qe6hEMTxZy4

and it works great. i to saw smoke form the egr. don gave me a pic of his because its off the truck. there are 4 vents on the bottom. i found a small leak at one of my vacuum line tee's and discovered my pcv valve popped out for the umteenth time.
i am going with jon on this. your plug shouldnt look like that, even after 100 miles. if you havent done it already grab a welders glove and while the truck is running start pulling one plug wire at a time at the coil pack. if the idle changes, you have found your problem or cylinder. or who know, you might even have a died coil pack. another thing you might also want to see is what is your volts when running. i chased a problem i had for a month. the voltage was dropping off at wot. after checking the alt thought it was belt slip. changed the belt, alt pulley, tensioner, and adding a bigger idler pulley, it still dropped. after rechecking the alt, the volts would drop if you snapped the throttle, but at idle or cruising speed it was fine. i even noticed after i changed the alt it ran better and picked up a lot of grunt.
long shot as well, but even tho you checked under the hood when you did your smoke test, did you look inside under the dash? you have to remember all your heater controls also are vacuum operated. its a long shot, but sometimes even the simple stupid things are over looked. just ask me about the vacuum problem i had earlier this summer......thats 3 weeks of my life i will never get back

I didn't look under the dash yet because I found this intake leak and all my heater controls work fine. I actually just had that problem with my dad's F-150 so I'm well versed in heater control vacuum leaks haha. I'll have to check voltage and I think I'm going to pull another plug or 2 and see how they look. I did pull my passenger inner fender and look at the vac ball and lines, all look fine.

Maybe my eyes are deceiving me, but that plug looks so lean it appears to be right out of the box. There should be some ash or soot, discoloration of the ceramic, I still think that cylinder is dry.

Oh it looks virtually new. But I promise I'm not lying it actually has 2k miles on it. Look at the ground strap.

or not firing. my motor ran on 7 cylinders and i didnt even know it....to bad it was also on break in

Yeah my engine is/was on break in too :/ but I checked compression and it was dead nuts even on every cylinder so I don't think one of them was not firing.

 

[1997XLTRollover]

Ok guys, I pulled a spark plug from the passenger side bank and for arguments sake it looks the same. 1 small small brown spot but still looks very lean. I also made sure it was a plug that's being fired by the other coil pack as well.

Also checked voltage with the engine running at idle and revved up and it reads 14.3v for both.

Then checked fuel pressure. Engine off key on its 30psi, engine idling 30 psi, rev engine and it spikes to maybe 40 psi. Let off gas and it drops to maybe 27psi and steadys back at 30. Truck in gear brake on running wot it pins 39 psi and holds steady.

 

[Dono]

Do all the plugs look the same?
If so, were in to tuning.

I'd find it hard to believe that both front o2 sensors could possibly be reading the same level of incorrectness.

 

[1997XLTRollover]

Do all the plugs look the same?
If so, were in to tuning.

I'd find it hard to believe that both front o2 sensors could possibly be reading the same level of incorrectness.

I have not pulled all 8 recently but I did probably 500 miles ago (6 months ago) and I'm 99% sure they were all just as white. The truck sat for probably 6 months because it pissed me off and I didn't want to look at it haha. I just drove my 99 all summer instead. But now with my 99 gone I'm stuck with this pile. It's really not a bad truck it just has a few issues that I have to sort out.

And speaking of o2's I tried swapping them already. The old ones looked like hell when I took them out. It looks like someone ran some engine cleaner through the old engine and probably destroyed them (all white and burnt looking). I had a pair off my old Navigator or F-150 I forget which and I swapped them in for the hell of it. They didn't seem to help any.

Is it possible that even though they plugged in that the o2's are the wrong o2's for my truck? I figured Ford is Ford and if it plugs in it's fine. But maybe my old 02's were shot and then I swapped in the "new" ones and although they work they're not sending my computer the right info? It's probably a stretch but I figured I'd put that info out there.

 

[Dono]

I just find it strange that swapping o2's gave you exactly the same result. If they were the wrong o2 sensors, I'd think you would have at least had a different result.

You don't have a wide band o2 sensor system by chance? It would be great to have a completely independent system to check the a/f ratio (Although, the plugs are probably the best indicator anyway). Can you check your fuel trims? I wonder if the computer is trying to richen up your mixture as much as possible.

 

[1997XLTRollover]

I just find it strange that swapping o2's gave you exactly the same result. If they were the wrong o2 sensors, I'd think you would have at least had a different result.

You don't have a wide band o2 sensor system by chance? It would be great to have a completely independent system to check the a/f ratio (Although, the plugs are probably the best indicator anyway). Can you check your fuel trims? I wonder if the computer is trying to richen up your mixture as much as possible.

As do I. With the truck this lean I would think those sensors would toss a code. I have a couple widebands but they're in my other vehicles. Course this is my only running driving vehicle I have at the moment but I'd prefer to not rip apart my other cars.

I do have an Ultra Gauge on the explorer now, I'll have to see if I can read the o2's. If not I also have an SCT but it's married to my Mustang. Can I do any testing with it without unmarrying it from the Mustang? The Mustang is in a million pieces and I really can't get the tune off it at the moment.

I plan on buying a laptop soon too so I can run forscan. I have the little attachment so just need the laptop now. Then I should be able to see what's going on. I have to check out my damn ABS too so I have to get forscan working ASAP. Changed both front wheel bearings and all 3 abs sensors and the damn abs pump still kicks on when it shouldn't.

I'm going to try to get those intake gaskets changed this weekend and see if that changes anything.

 

[1997XLTRollover]

Ok guys I finally got Forscan working. Here's my first run at it. I'm not 100% sure how to use it but I got some data and hopefully something jumps out at somebody. The truck seems to run a little rough when cold and smooths out a LITTLE BIT when warm, but still isn't right. Cats not warming up beyond 500 degrees and the very lean looking plugs I think gives us conclusive evidence the truck is running lean, the question now is why.


I picked a few things off the list to log that I thought might be relevant, I don't really know what every one means but hopefully someone else does and can point me in the right direction or ask me to log something different. The one thing I noticed is the real time RPM was not working correctly. It didn't move regardless of what RPM the engine was at, (not sure if this is an indication of a problem or not). I have an ultra gauge and the TPS seems to work fine with no dead spots I can see on the gauge, unless the ultra gauge reads something different than the computer. It shows throttle percentage and it looks ok and moves when I move my foot.



Here's some data, you can get an idea of the engine being revved or idle during the test based on the maf voltage.

 

[1997XLTRollover]

Here's some other tests I ran. Might have found an indication as to where my abs issue may be coming from. The ECT out of range I'm assuming is because I ran all these tests before the truck was warm, but maybe not? My ultra gauge reads engine temp no problem but maybe that's reading off a different sensor? It also looks like the ECT sensor is working well based on the real time data in the above post so I think I can ignore that. The other things are interesting too and I'm not sure what to do with them either. My rear wiper works fine and so does my drivers window. I don't even know what the other ones mean.





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