Hey men and women,

I have a 95 pickup 22RE. 215K miles. Installed an engnbldr head at 199K after the headgasket blew and it hydrolocked. Water in one cylinder and in the oil.

I did not have the block surfaced. Changed oil right away, replaced plugs and wires also.

It's been running great since then (16k miles), including a 3000 mile road trip of hard highway driving.

Just recently it's developed a consistent miss that's noticeable at idle and while revving (the gear shifter shakes and the tailpipe "puffs" or "chuggs").

I checked the compression when warm, and then again after adding a teaspoon of oil to each cylinder with a syringe. I realize now I should have added way more oil to test, but here are the numbers anyway:

1: 150 (160 w/oil)
2: 170 (185 w/oil)
3: 165 (180 w/oil)
4: 165 (168 w/oil)

Just replaced distributor cap and rotor. The center spring-loaded graphite pin in the cap was completely worn away. No change.

If I remove the plug wires one at a time while its running, the engine bogs down for every cylinder, though the effect is much less pronounced on #1.

All 4 spark plugs looked pretty much identical. What should I try?

 

Check timing.

 

Check valve lash then vacuum leaks.

 

Ok,

Checked timing and valves, both good. Went over all the hoses with a propane torch, I couldn't find any obvious leaks.

Could it be fuel system related? Or is 150 PSI just too low for #1?

 

I don't think the compression in that cylinder is low enough to give you the kind of symptom you are talking about. Elaborate on "tailpipe puffs or chuggs". Is that a sound, smoke or what? I think that will tell us a lot. First things first. Have you checked / changed your air and fuel filters?

 

The symptoms are a "puff puff puff" sound that you can also feel if you put your hand in front of the exhaust. There is no smoke. The engine shakes in the mounts. When it first began, it wasn't perfectly consistent. Meaning, it would go "puff puff ___ puff ___ puff puff ___ ___ puff" Now, its a very consistent "puff puff puff" with consistent timing. Idling at 750, the frequency is about 2 puffs per second.

Air filter is new. I have never changed the fuel filter (owned the truck for 40k miles), but it has no problem revving (I think it continues to miss while revving but it gets harder to tell at higher rpms). I can still do 70-75 on the freeway, could the fuel filter really keep it from idling but deliver enough fuel for 4000rpm highway driving?

 

Iirc fsm allows 10% variance and correct me if I'm wrong but in this instance 10% is about 16 psi. Assuming my math is right, the difference is out of spec per fsm.
One time I had low pressure on one cylinder so I pulled the head, pan and piston then honed and re ringed it.

 

I had a 22re that was about 125 across the board. No problem pushing 35s 80mph. It's more about the variance between the cylinders.

 

It would be a real bummer to have to tear it down, especially because it uses almost no oil and was running perfectly a week ago.

When I did the HG job 16k miles ago, i measured ~150psi in #1 then as well (where the water leaked). Figured it was marginal but went with it, and its really been running great until just recently.

I understand it's slightly out of spec, I'm just surprised it would cause it to run so bad all of a sudden.

 

I really don't think that's it. Try and take the head replacement out of your mind and troubleshoot it with just the information you are gathering now. The best piece of troubleshooting advice I ever got was from one of my field service technicians when I worked for Caterpillar. He said "Preconceived ideas are the mother or all fudge-ups." But he didn't say fudge. Do check for symptoms of head trouble but don't go straight to the head because that's what it was last time.

The way you describe the miss, I'm not thinking it's anything in the fuel delivery system but just maybe an injector issue on #1. That's only my thoughts on the fuel side of it. Not making that my final guess. Fuel filter would let you idle but bog down at higher rpm.

I'm really not sure where to go next on this one. Is there any smoke or smell to the exhaust? Are you losing coolant? Are you gaining oil? Think about anything you had to remove when you did the head replacement. I'd love for you to find a little old vacuum leak somewhere that would solve it. The lines are known to crack after they have been pulled off after long periods of time. Did you use a good quality plenum gasket when you last had it off. I can't remember what it was I bought one time but the replacement of the part required the removal of the plenum and the part came with the worst looking cork gasket I had ever seen. I wouldn't use it because I knew that a leak there would be very difficult to track down and repair. Just spit balling here.