stickmanmitch

I've been searching and tried a few things but haven't been able to figure it out yet. I just rebuilt my 88 pickup 22re and got about 200 miles on it until it started missing and sputtering under load whenever I'd touch the gas. That turned out to be a bubbles in the cooling system, but about five miles later had a similar sputter/missfire thing once it warmed up again. I still had the voltage feedback plugged into the ecu telling me it wasn't the coolant temp sensor but something else. It smells rich at the exhaust. Ended up finding big vacuum leaks at the pcv hoses, replaced those and was better for about a mile. Then ended up with a vacuum leak at the brake booster and my brake booster completely went out. Driving it with the booster vac line disconnected it is much better, but still when warm it's misfiring again, getting worse the more I drive it. When I had the pcv leaks disconnecting the tps made the problem better for a while, but would then start missing again. Disconnecting the cold start injector doesn't help.

So, runs great until I drive it for about 3-4 miles, then starts missing and sputtering when I try to accelerate after it's real warm. It's like the amount I can depress the gas pedal without getting the sputter decreases the more it's driven until I have to put it in 4low to drive it home without touching the pedal and eventually it'll flood out, die, and won't start again. Not getting any codes. Since the rebuild, I've replaced the fuel filter, new plugs (have some carbon on the base but none on the arm), new wires, new (accel not oem) coil pack, all new vacuum lines, new tps from autozone that I couldn't set the timing with so put the old one back on (tests good to FSM specs), AFM tests good, timing checked, valve lash set twice, and more but can't think of them right now. I have more details in this thread https://www.yotatech.com/forums/f120...-start-247313/ about trying to get it started after the rebuild (bored over 1mm, new piston heads, bearings, rings, rods reconditioned, crank polished).

Going to check the o2 sensor, spring on afm door, bypass a leaking heater core and re-burp the system, resistance of the wires, and the fuel filter if none of that other stuff works. I'm pretty sure I don't have an exhaust leak. Would a bad reed valve on the air suction system cause problems if too much air was being drawn in? Air filter is relatively new. Really need to get my daily driver back on the road soon, I appreciate any help y'all.

stickmanmitch

Swapped the AFM with a known good one today, no change. Also checked valve lash and head bolt torque and they were fine and didn't help. But inside the valve cover did smell like gas.

It goes purrrrrrrrrrrrrrrrrrrrrrrr-pop-purrrrrrrrrrrrr-pop-purrrrr-pop-purrrrrrrrr, super random but just gets worse the longer the engine runs or when I give it more gas. Disconnecting the TPS doesn't help anymore. Put a bottle of fuel system cleaner in too. I have no idea what to check next, fuel system?

Subaru2.5rsti

Try Testing the injectors, When its running let it idle so it will misfire and take the the plug off of the injector to disable it and if there is no change in the idle or sounds similiar and doesnt die than that injector is bad.

stickmanmitch

I'll try that today. I'm pretty sure it's a fuel issue but going to use a timing light to double check it's not an ignition issue.

Subaru2.5rsti

Keep us updated hope all goes well

stickmanmitch

Couldn't get the injectors unplugged while the engine was running. I had someone look at it and told me my thermostat was bad. And that was causing it to flood to keep the engine cooler, then eventually the engine shuts itself off to prevent it from overheating? The bogging/hesitation is because the pressure in the radiator hoses are way too high and water isn't flowing. The hoses are super pressurized, coming to and from the radiator, is that normal? The others aren't but definitely have fluid in them. I'm going to take it off and check it out tomorrow. Does this sound right? I did a vacuum gauge test and the needle is holding rock solid around 18"-19".

Subaru2.5rsti

If you couldn't get the injector plugs off then you didn't take the clips off them . There's small silver clips that hold them in place and you need a tiny pick to pry them off. After reading your first post again it seems to me that you have a head gasket failure. If you have bubbles in your radiator, a syrup sweet smell from your exhaust, minimal white smoke from the exhaust or radiator fluid dwindling you have a head gasket failure. You should definatly check your compression before it gets worse. A bad thermostat would cause this kind of failure. When you have air in your coolant system your water pump will hiccup almost and cause a bad idle or other problems but wouldnt cause a bad hesitation (from what I've seen first hand)

stickmanmitch

I don't have a burning coolant smell at the exhaust, but replaced the thermostat and rad cap today and it didn't make a difference. The damage might have been done already. My compression numbers are 135, 110, 130, and 130. It started doing the hiccup thing again before the thermostat opened. I think I'll be doing a leak down next.

TylerH

I have the same problem. Mine normaly happens between 2000-2500 rpm's usually under 45mph.

stickmanmitch

That's where mine started at then got worse

asas9800

i had the exact same problem on mine. turned out it just needed a noew o2 sensor

stickmanmitch

Took it to a shop the other day, they changed out the spark plugs and the problem went away??? I guess I'll have to see if it returns in a few hundred miles. Thanks for the help.

stanz

iTrader: (1)

I've had bad spark plug wires do it to me in the past as well

stickmanmitch

I'm thinking that could be it too. Sure enough, 200 miles later I'm having the same problem that came back with a vengeance. I also got codes 3, 4 and 5. 3 is no ignition signal to the ECU, 4 being coolant temp sensor, and 5 being O2 sensor. I recently drained my coolant again to fix a kinked hose, so the code 4 was bubbles in the system, and it's been missing and blowing smoke again, so I think that's why the code 5 popped up. I've read about ignitors going bad when they get too hot, but haven't found a good test for that yet.

Again, it ran perfect for about 200 miles, now it starts fine, drives fine, then starts sputtering when I get on the gas, won't idle, and blows smoke when it sputters. If I keep my foot off the throttle I can almost make it home, but usually have to stop, let it cool off, and try to get farther. Sometimes it'll die completely and not start up again.

TylerH

You can take the ignitor to parts stores and they can test them.

Wierdly enough i think its the O2 sensor. Mine used to not start. It would just crank and crank, let sit an hour get in it and it would fire right up. It would also cut out between certain rpms.

I would take a look at your sensor and look for a burnt wire/wires. And also see what kind it is.

If you buy one buy it from Densoproducts.com.

TylerH

My bad, if its a 1 wire sensor it shouldnt do that.

stickmanmitch

It's the 4 wire sensor. I'll take it in to autozone to see if they can test it for me. I'm pretty sure there's a bosch in there now.

Cmayer

Subscribed. Same issues, same lack of answer, and same checked/replaced parts. So frustrating. Hope you figure it out!

stanz

iTrader: (1)

Maybe try a heat gun on some sensors (when cold) to test out their reaction to heat. Just be careful not to melt any wires or plastic connectors.

stickmanmitch

I didn't think of that. I just replaced the coolant temp sensor. I talked to my mechanic and he had another guy with a similar issue which was solved with a new cts. I was thinking before that a purely resistive sensor like that shouldn't really jump around by design, but for 15 bucks I figured it was worth a try.

I noticed last time I drained my coolant it looked real dirty, like rust colored, and was only in there for about 200 miles. Maybe excess rust particles in the coolant are interfering with that sensor. I put new coolant in after the rebuild, then about 200 miles later had this problem. Couldn't get it figured out, but did drain the coolant and I'm pretty sure I put new stuff in. It ran great again for another 200 miles, so I think I might try a cooling system cleaner next.