No power after engine repairs.

[That90'sRanger]

Hello everyone, sorry this is a longer post but hopefully the extra info will help.

1990 Ford Ranger XLT 4.0L M5OD-R1 4X4

So I recently replaced the rocker arms, pushrods, lower&upper intake manifold gaskets, valve cover gaskets, and some u-joints while fixing some stuff. I got everything back together then turned it on and it runs terribly. It has no power, idles terribly, and falls on its face when going WOT while in neutral. I followed a printed guide from Prodemand and also had the Ford shop manual with me. I wrote down what I took apart and where the stuff was and the order it was disassembled and used tape to try to organize things. I don't know what I could have screwed up but there is always that possibility. I actually was able to drive very slowly around the subdivision but it can't go faster than 15 MPH and makes the truck jolt forward in short, uneven intervals while driving. In neutral the engine shakes really badly. I should also mention that it was in a state of dissaembly for several weeks while I was slowly working on it.

I replaced the fuel pump with a nice delphi unit like 1.5 years ago (the old one was finally wearing out after 32 years), new fuel filter, new maf, new spark plugs, new wires, I always buy gas with techron in it, new air filter, and the parts mentioned in the paragraph above. I measured 15 inches of mercury from the brake booster hose. I measure at idle ~30 PSI of fuel pressure and going WOT for a couple seconds the PSI only slowly climbs to 35 or so. Shutting off the engine PSI seems to only drop within ~5 PSI. The vacuum line to the FPR doesn't have fuel in it after running for 10 seconds then shutting the engine off for inspection. The vacuum lines have been checked and there aren't any massive leaks anywhere even with spraying some stuff all over the engine bay I got no response from the engine. The vacuum lines match what the diagrams show on TRS. I have checked the IAC valve and it is good. The PCV valve is new. I cleaned the throttle body. I recleaned the maf just in case. I checked and all cylinders are getting spark and no one cylinder is running more rough than the others. I have been trying everything and I am running out of ideas. I really don't want to throw parts at it but with winter coming I really need this thing for the snow. I tried to test what I can before posting on here but I am at a point that I don't know what else to do. I wonder if the fuel pressure regulator is bad but I am not 100% positive.

I would really appreciate any feedback. Thank you so much. If you need any more information please let me know and I will see what I can do. I don't have a lot of specialty tools and I am also broke because of uni tuition costs.
If you are wondering why I am putting so much money and time into this thing it is because my dad bought it brand new 33 years ago and since I have some very fond childhood memories of it (Lynyrd Skynrd in the cassette drive) I would be devasted to lose it.

 

[rusty ol ranger]

Dont worry about losing it. Whatever it is it can be fixed.

You seem to hsve covered the basics mostly.

Run a compression check.

Is it smoking? White? Blue? Black? Any residue in the tailpipe?

No vacuum leaks? 15psi seems a bit weak to me...i think 20 is closer to where it should be...but dont quote me.

No mouse nests in the air box?

An FPR shouldnt cause the issues youre having.

Did you mess with the timing chain at all?

What was the reasoning to do the work to begin with?

Any codes being thrown?

 

[That90'sRanger]

Thank you for your response. I have checked the compression recently before the repairs and had ~150 PSI on all cylinders. It was burning some blue smoke but that seems to correlate with the driver side bank having umbrella valve stem seals for some reason (the passenger side bank has what I think are called positive valve stem seals but I cannot remember). I thought like 2 or 3 years ago I checked the vacuum and found it to be 21 so I agree that 15 seems low. Luckily no mice have their way into the truck. I didn't mess with the timing chain during my repairs and it should be fine as this engine only has 44k miles on it. It had some bad lifter tick and after replacing those parts in the valve train it seems to have gone. I had so much of it apart I thought I might as well replace the lower intake manifold gasket because I had found that the bolts had come loose. I had read in some TRS posts that those bolts being lose can result in a messed up gasket and cause oil to be sucked in from the lifter valley. I did check for codes and nothing pulled up except for the neutral safety switch but it has always had that since this is a Frankenstein truck.

 

[gaz]

@That90'sRanger
If your lower intake manifold bolts were loose, you may have compromised both the oil and coolant systems; under those circumstances, I would take a hard look at both.

 

[rusty ol ranger]

I would take that lower intake into a machine shop and have it checked for warpage. Espicially after finding loose bolts on it

If its warped and not sealing correctly that would create a massive vacuum leak. Which would cause it to run like shit and obviously have low vacuum readings.

 

[Angry Possum]

Here's an easy start, I'd pull each plug and inspect, plugs don't lie. Did you use different plugs with different gapping possibly?
Stupid question- Did you put all the wires back in the correct order? Recheck them.

 

[That90'sRanger]

Gaz & rusty ol ranger:

My coolant and oil systems are good. I recently replaced the radiator and didn't see anything suspicious. I change the oil regularly and haven't noticed anything there either. What confuses me is that I had checked just before I made the repair and I got ~15" of vacuum and now I testing it again I get the same number yet it ran great before the repair and now it can barely move forward. It had the early style 1 piece lower intake manifold gasket and I replaced it with the revised 2 piece version so wouldn't that make the warpage, if there is some, less noticeable? I read somewhere in the TRS that going to the 2 piece helped with tolerances but I can't remember where that post is. It has been burning oil for some time and a lot of it. I think it is actually those dang umbrella valve stem seals because I found some carbon buildup on the valves corresponding to those seals and not any on the valves with the positive type. The lower intake manifold actually looked fine (to me but I don't have a lot of experience) except there was some bubbling where the coolant ports were but the oil didn't have any noticeable quantity of coolant in it and vice versa.

Angry Possum:
I gapped every spark plug to spec just to be sure. I had really hoped that would be the problem but everything looked good. That is a good question but unfortunately I have checked probably 4 times now and the order is correct for the wires.

So I capped the vacuum port on the FPR and at idle it gets 40 PSI. I released the pressure, reattached the vacuum line, and then shut off the engine and used the key on position to cycle the fuel pump to max pressure to see how much PSI it loses. It lost like ~3 PSI within 5 minutes. I'm not that familiar with these FPRs but I think the numbers are probably not that bad. So I'm thinking that my fuel delivery system is probably fine. I dunno, this is tough to figure out. Man do I wish I had the picoscope from school right now.

If you guys would like pictures of gauges or components or anything let me know. I do have some photos of the parts I replaced and maybe that might give us a clue.

 

[rusty ol ranger]

Gaz & rusty ol ranger:

My coolant and oil systems are good. I recently replaced the radiator and didn't see anything suspicious. I change the oil regularly and haven't noticed anything there either. What confuses me is that I had checked just before I made the repair and I got ~15" of vacuum and now I testing it again I get the same number yet it ran great before the repair and now it can barely move forward. It had the early style 1 piece lower intake manifold gasket and I replaced it with the revised 2 piece version so wouldn't that make the warpage, if there is some, less noticeable? I read somewhere in the TRS that going to the 2 piece helped with tolerances but I can't remember where that post is. It has been burning oil for some time and a lot of it. I think it is actually those dang umbrella valve stem seals because I found some carbon buildup on the valves corresponding to those seals and not any on the valves with the positive type. The lower intake manifold actually looked fine (to me but I don't have a lot of experience) except there was some bubbling where the coolant ports were but the oil didn't have any noticeable quantity of coolant in it and vice versa.

Angry Possum:
I gapped every spark plug to spec just to be sure. I had really hoped that would be the problem but everything looked good. That is a good question but unfortunately I have checked probably 4 times now and the order is correct for the wires.

So I capped the vacuum port on the FPR and at idle it gets 40 PSI. I released the pressure, reattached the vacuum line, and then shut off the engine and used the key on position to cycle the fuel pump to max pressure to see how much PSI it loses. It lost like ~3 PSI within 5 minutes. I'm not that familiar with these FPRs but I think the numbers are probably not that bad. So I'm thinking that my fuel delivery system is probably fine. I dunno, this is tough to figure out. Man do I wish I had the picoscope from school right now.

If you guys would like pictures of gauges or components or anything let me know. I do have some photos of the parts I replaced and maybe that might give us a clue.

Warpage is warpage and i wouldnt think any gasket would make up for it.

However if its burning oil in massive amounts i would run a compression check to verify the engine is even healthy

 

[2011Supercab]

So I recently replaced the rocker arms, pushrods,

Why?

I have checked the compression recently before the repairs and had ~150 PSI on all cylinders.

Doesn't matter what it was before tearing it down, What is it now?

 

[Angry Possum]

Warpage is warpage and i wouldnt think any gasket would make up for it.

However if its burning oil in massive amounts i would run a compression check to verify the engine is even healthy

I second that opinion. Definitely do a compression test.

 

[Angry Possum]

I just remembered this. A good friend of mine rebuilt his engine on his 68 Charger. And had to put the original cam back in because it ran very poorly. The new cam was garbage. Once he put the original cam back in, BINGO, ran like a top. This can be a clue for you perhaps. Just saying.

PS Did you say you were burning oil also? If so another clue.
FWIW My girlfriends 2011 Toyota Camry used to eat up oil due to bad lifters.

 

[Manscout]

If it idles fine and falters with any throttle, check the MAF. I Just did an engine replacement with everything you mentioned. Mine ran like crap too. The first time I found my MAF still unplugged, two of the plug wires swapped, and an EGR sensor unplugged. Start with the little, simple things.
After some more work, I accidentally left a large rag in the custom plenum I had made. I hate telling on myself, but it's worth asking if you left a rag stuffed in anywhere.

 

[rusty ol ranger]

If it idles fine and falters with any throttle, check the MAF. I Just did an engine replacement with everything you mentioned. Mine ran like crap too. The first time I found my MAF still unplugged, two of the plug wires swapped, and an EGR sensor unplugged. Start with the little, simple things.
After some more work, I accidentally left a large rag in the custom plenum I had made. I hate telling on myself, but it's worth asking if you left a rag stuffed in anywhere.

Our old mechanic at work did this exact thing on a cummins ISX after installing a used engine.

10k and a whole year trying to figure it out between outside mechanics coming in and changing heads and all sorts of shit.

It happens

 

[gaz]

@That90'sRanger ,
Your fuel pressure should not be bleeding down after shut off. Left untouched, these who'll hold pressure for YEARS without changing.

The OHV 4.0l cylinder heads and intake manifolds must be installed/torqued together/simultaneous, in steps and in the prescribed torque sequence pattern (in accordance with service manual):
#1 heads to 44 (ft lbs)
#2 tighten intake 36 to 72in-lbs
#3 heads 59
#4 intake to 72 to 132in-lbs
#5 turn head bolts an additional 80-85°
#6a intake to 132 to 180in-lbs
#6b intake to 180 to 216in-lbs

Recheck spark plug wires on the coil pack:
- Passenger side, front to back is 1-2-3
- Driver's side, front to back is 5-6-4

Ensure O² sensor wires aren't swapped, left for right.

 

[Angry Possum]

How did you make out? Is it still powerless?