Mudsandwich

Yep, first post and it's with a problem. 88 4-Runner, 22RE, manual. The truck has been sitting for about three years (had StaBil in the tank but the gas was bad) until I dusted it off and started driving it again. At first it was running pretty weak, but it gradually improved. After the third tank of gas it was running pretty well, but still a little weak in the mid to upper rpms. Today I filled up on the fourth tankful, took off down the road and let it wind up to about 4500r's before shifting, as soon as I shifted into third it started missing. By the time I made it the mile back to the house I was holding the gas all the way down running in first gear low range just to make it up the driveway. The engine is fairly new with less than 30K miles and the head, timing set, cam etc... have less then 5K miles on them (same for all the vacuum lines too). Cold or cool, the engine starts normally (fires first lick) and will run smooth for a few seconds before sputtering out.(you can floor it and it will run, but not rev over 3500r's.. and then you smell plenty of raw gas) I'm thinkking crap from the tank has lodged in an injector, but then I think it might be something with the ignition due to the raw gas smell. I'm going back out and start chasing through the fuel system (where's the filter??), any thoughts on if it might be ignition related? Any hope on unsticking an injector without taking it to a shop? Thanks!

Truckfiend

I would replace the fuel filter first. Did you flush the old fuel that sat in the tank for 3 years or did you run it through? The filter should be on the passenger side of the block just under the intake. If you do decide it's your injectors you can easily pull them out yourself and have them rebuilt. I just did mine last month. I took them to http://witchhunter.com/


Good luck

Mountain Cop

If you think it might be spark related, then it is easy enough to hook up a spare plug on the end of each wire, ground it and turn the truck over. If you see a nice, blue spark- then you have fire to that cylinder (unless the plug is fouled). Fuel filter is a good place to start, as well.

If you can get it to idle, drop some seafoam through the system. That stuff will help a lot with injectors and varnish.

CAFT- Compression, Air, Fuel, Timing.

myyota

Replace the fuel filter, i bet that will solve a lot of your problem.

Mudsandwich

Well, I finally got around to replacing the filter (working a bunch of OT..finally got a weekend off). It helped a lot, the truck now revs and runs, but not under any load. It seems to have a slight miss too.

I pulled the codes and was surprized to get five of them. 12, 41, 42, 51, 52.
One indicates the A/C was on... it wasn't. Another indicated a bad speed sensor... didn't think an '88 had one.

I read somewhere about a wiring connector that can go bad and cause CEL issues, but I can't remember where I found the info... can't figure out which connector it could be either. That's mostly what I'm wondering now.
I may have knocked something loose when replacing the filter... all the smog crap is still in place so it was a squeeze to do the job without taking everything off. I didn't get a CEL until the engine was running (roughly) for about 30 seconds.

ChefYota4x4

iTrader: (5)

Could check the fuel pressure. It's possible that a NASTY tank might have caused a restriction in the pump/screen. Also, that pump is EASY to pull, under the Passenger side rear seat. Just to be sure of the pump-sock not being clogged. Also might have freed something up in the tank that clogged a line, or, that is now clogged in the line.

Just to be clear, ...you did NOT; Clear out the lines, tank or otherwise when starting it up and running through 2 tanks? If not, crap in the tank VERY WELL COULD have found it's way into something. I had, with a brand new build, flushed tank, lines, pump, filter, ....a piece of gunk free up from somewhere and landed right in #2 Injector(just serviced), causing it to freeze shut.

Not sure if the Fuel Pressure Regulator can jam shut. But, it does, when operating at idle, limit the fuel pressure to the system to prevent flooding. Not sure of the damper, either, ...maybe someone can clarify? I would think either one being bad would cause more of a 'too much fuel' symptom,...but like I said, some guru will clarify all that. lol.

ChefYota4x4

iTrader: (5)

PS>

12 is Distributor.....this can also cause issues. Not sure if your system(mine is 87) notifies you of bad pick up, ...but it should, and that COULD cause a problem under load, but seemingly run 'ok' but not 'great' when not under load.
41 is TPS, VERY COMMON to cause this hesitation issue.
42 is Vehicle Speed Sensor ...not too sure, but I THINK it can cause problems under load
51 ????
52 is Knock Sensor Unit, and can VERY MUCH SO cause huge problems

myyota

It sounds like you might have a bad TPS, sometimes a bad TPS can cause many other codes to pop up.

Mudsandwich

It was the TPS. The thing was gummed up and sticking. I used a little WD on it and a little canned air and it's as good as new. While I was at it I also did the airbox mod and adjusted the airflow meter... didn't know it would run so good! Now when I get a front diff I'll get these Chevys out of my driveway!

Mudsandwich

I did pull the pump, which was a waste of time. the sock was dirty, but not bad for 320,000 miles! The tank was full and I put Sta-bil in it when I parked it, there was a little rust, but not bad.

The cel codes were all related to the TPS and MAF, except for one that was due to a broken wire at the temp sender on the side of the block.
I think 1988 might be an odd year, I know that the injectors are different than anything else, I wonder if the codes aren't different as well. Haven't looked to see...

ChefYota4x4

iTrader: (5)

Right on, Mud!

Only thing; I'm not trying to be a debbie downer, lol.... but the TPS is VERY sensitive to anything getting inside. Interesting that it was all gummed up, ....I just rebuilt mine with 265 on it and it was SPOTLESS inside. Hmmmm. Anyway, I only mention this because on some of the most respected Guru sites, ....in the manuals, ....in the Toyota Manual at their shops, ..... It specifically says not to even clean the throttle body with the TPS attached, as you don't want ANYTHING getting inside. I guess because you had pulled it, then rammed it with air to get anything out before 'powering it back up', ....it did the trick without doing any damage. Like I said, just a heads up. If you start having any problems again, related to TPS codes, etc., I'd suspect the WD40, .... but like I said, SWEET! Happy you're back on the road without issues!

Have fun,

Mark

Mudsandwich

I know... not supposed to use anything on the TPS... But I figgered that it wasn't working anyway and WD is pretty friendly to electronics. But stuff like carb or brake cleaner... nooo way! That junk will dissolve circuit boards on contact, I think that's the source of the taboo against cleaning the TPS with anything. I've seen some of the cheap contact cleaner lift the traces right off a board... generally I stay away from anything like that. WD... I've used it for years on pots, rheostats, relays, contacts, plugs, etc... If it does crap out because I cleaned it I'll replace it, but at least I bought some time. The stuff inside the unit looked like old, gummed up dielectric grease, looked like it had never been opened up before so I assumed it was factory. The upshot is, my 4-Runner has NEVER ran this well. A while back I replaced the head and cam with new parts made for an RV (forget the specs, but it's set up for bottom and mid range power). Formerly, it ran well, but now if I stomp it while rolling along in 1st it'll spin the tires. Getting everything adjusted/working right helped a bunch, the airbox mod was an added improvement.

ChefYota4x4

iTrader: (5)

Right on, ... Enjoy the Ride! lol.