giantjoebot

I'm new to this, and could use some advice. Please forgive my ignorance. I'm trying really hard to learn how to work on my truck on my own, and I would really like to get this old truck fixed up.

Its a 1991 pickup a 22re 2.4L 4 cylinder

So I had my truck at my mechanics, and I asked them why my engine would shake every few seconds. They told me that was common for an older engine. Then I start getting this vibration problem that I have been trying to figure out. While I was working on it, I noticed that with every shake there was a PUT noise out the tail pipe. So I start looking into misfires, and it turns out that vibrating is sometimes caused by a misfire.

So I think I have a misfire. I just put in a new TPS, and my idle greatly improved, but when I rev the engine the misfire is still there. I didn't have an OHM meter to install the TPS, like the fsm says to use, so I just turned it while the engine was running. I hope that was okay to do.

So I ordered a fuel filter, and I was thinking of picking up spark plugs tomorrow. I hope its not the chain, but its got a 140k, and it possible that has never been changed. If anyone knows any good how to's, please let me know. I have never even timed an engine before, but I am willing to give it a try.

Its weird, it only misses about every 5 to 10 seconds.

I hope I didn't damage the engine, because I have been driving it like this for a while due to what my mechanic told me. Do you think I could have toasted my cat?

Any help or advice would be greatly appreciated.

Jasper 83

My 85 22RE was doing that. Its likely that your new TPS is not adjusted properly. That's what mine was. Since you don't have an ohm meter, I would try to borrow one. The way I figured out it was my TPS was trying to set the timing. It was way off and when I set it right the truck was dead. Read the instructions in the FSM and try to set the to set the timing. When you short the terminal, you should hear an rpm drop. I wasn't getting that with mine. I turned the TPS slightly counterclockwise and heard an immediate drop. Try that and let us know and we'll go from there.

giantjoebot

Thats what I did, turned it until the idle dropped, and then open the throttle to see if it was working. If I turned it to far counter clock wise then I would get a sudden drop in rpms, so then turn it clock wise until it stopped doing that. I will try and borrow an ohm meter tomorrow. Maybe I can get one from the parts store as a loner.

I also have been meaning to replace the brake master cylinder thats been leaking. I have the part, but was waiting until I had time to do it, and then went chasing after the misfire. I wonder if its creating a misfire, or if the fluid drained back into the booster, and caused it to leak??? Going to go try spraying the booster now.

Update

Tried spraying the brake booster, and then I thought, "why the hell am I doing this", and disconnected the vacuum hose and covered it with my thumb and a pair of gloves. Nothing. So thats not it.

Earlier today I was listening to see how many seconds between misses, and it was not constant. the amount of time between misses and the severity of the miss was constantly changing. So I'm starting to think that its the timing chain. Like its slipping or something. I realize that they probably don't slip since its a chain, but maybe slack or worn guides. I'm also getting some really harsh sounds every now and then, sorry hard to describe, but sounds really bad every now and then. I got to get a torque wrench, and pull the valve cover and try and check the chain. Should I do it hot or cold? Doesn't the tentioner kick in when the engine is hot?

Jasper 83

Did you check your timing yet? I'm bankin on a timing/tps issue neing that its not a constant consistent miss. Before my tps adjustment, my base timing was 25* BTDC where its supposed to be 5*

giantjoebot

You were right, the timing was off. I set the timing to 5 at idle, and so far no misfires, but now I have no acceleration, and when idleing the engine seeks a bit. Its actually just like when I got it, and the guy said the timing was off, so I had my mechanic time it for me. I don't know, maybe I timed it wrong, or adjusted the TPS wrong.

I think that maybe I did things in the wrong order. I did TPS, then idle rpms, and then timing. Maybe the adjustments I did to the idle threw off the TPS. Or maybe I just did the TPS wrong. I'll try adjusting the idle, and then the TPS tomorrow.

My truck doesn't have a tachometer, and the one I bought kind of sucks. Anybody have any recommendations for a decent tach that doesn't cost an arm and a leg?

Update:

I adjusted the TPS, and got my acceleration back, but also got rough idle and miss fire when opening the throttle. Lets say the TPS has 5 positions, 1 2 3 4 5. When I used the ohm method from the fsm it was at 4, misfire stopped, but no acceleration and seeking. When I adjusted it myself it was at 2, and I got acceleration, but also rough idle and miss fire when opening the throttle. So next I'm going to try 3, dead center, and see how it does.

You were totally right Jasper. There is a direct relation between the TPS and the timing. So every time I play with the TPS, I have to adjust the Timing. Its a huge pain in the ass

I think I figured out what I was gdoing wrong. Its all right here
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

giantjoebot

Spent all day tuning the TPS. The above link said its suppose to be at 0.81, but at 0.81 I had no accleration. I got my acceleration back at 0.78-0.77, but was getting misfires. The best I could do was 0.75. I tried adjusting it 10 or 12 times, going one degree up or down each time, and timing it everytime. The idle is a little high, around 850 rpm, instead of 750 rpm. The idle is still kind of rough. I'm going to drive it around for a while and see how it does.

Still getting misfires, but not nearly as bad as before.