Hey everyone, New here. Did tons of searching prior to posting on here. I know my problem is very common but I couldn't find anything that fit my exact criteria.

Anyway my truck has been surging at idle and even worse when I apply the brakes. I went to lower the idle but mt idle screw was already all the way down.

I decided to check the engine timing but I noticed that my timing mark is not consistant. It will stay at the same spot for a while and jump over just a little bit. I haven't found any vacuum leaks , and I've changed the temp sensor and thermostat so far. I can't figure out why this thing is running so bad all the sudden. I have no problem buying a new EGR or TPS if thats the problem but I would hate to buy them and it not change anything. Anyone have any suggestions what might be going on?

 

The idle adjustment screw being set all the way down/in is a pretty big give-away that there's a vacuum leak somewhere. They can be very tough to nail down sometimes though. But I can almost gaurantee you've got one somewhere. Try replacing the o-ring for the idle adjusment screw first. It's cheap and is also a pretty common spot to find vacuum leaking.

The timing bouncing around a bit is just the way that goes with these engines. You just have to set it at where you think the mark is MOST of the time during the oscillations. It's also going to be complicated by the steadiness of the idle rpm during adjustment. The rougher the idle, the more bouncing around. It can be a little tricky to get it set exactly where you want, but it's not critical to have it set EXACTLY at whatever the book says either. Close enough is close enough.

BTW, it's kinda nice to know which engine we're talking about if you want any specific advice on how to diagnose troubles with it. 22RE? 3VZE?

 

Hey thanks for the reply. I have a 94 22RE. I'm going to replace the o-ring on that and see how that works out.


As for the dashpot, I don't know much about what that is or how that works so I'm going research that a little more and see what I can do about that.


Also I'm wondering if I'm timing it right.... I read somewhere that you take the two vacuum lines off by the distributer and plug them with golf tees while your timing... Is that right?

 

if you have 22re there is no vacuum lines on the distributor. and if you have a 94 I highly doubt you have a carbed truck anyway. so that leaves the 22r out. the proper way to set the timing would be to use a jumper on the diagnostic box under the hood. it looks like it's time for you to download the Factory service manual so you don't mess up your truck.

 

Haha, Thanks xxxtreme. Yea I had a feeling I was disconnecting the wrong lines. I keep reading about the jumper thing and I can't figure it out at all! I guess I'll figure it out eventually.

 

FSM has everything you need in it. and under your hood if it's still there should also tell you show you how to do the timing.

 

Yea, I I'm gonna get that. I noticed you have a E34 too. Niceee, My other car is a E46 M3. I love BMW's.

 

yup a 92 with 245,000 miles on the original motor and tranny, been troubleshooting what I think might be a trans problem though. Picked up from the original owner for $750 with a busted radiator from being overheated because of a fan clutch problem. was turned off and blew out the plastic sides on the rad. $500 in new cooling components rad, fan clutch, water pump, temp switch and it was on the road. have since replaced the upper and lower control arms and front sub frame from being ditched by the G/F. and have put on bilstien hd's, ceramic brake pads and drilled/slotted rotors. Less than $2500 into the car right now. And the body is pretty much perfect.

 

Niceee..


So I figured out how to jump the data link. I did that and set my timing. It was running smooth and as soon as I pulled the jump wire out it started surging like crazy. even worse than before. I also switched that 0-ring out like mentioned before. I'm not too sure what to look at next.

 

so now you have a crazy up and down idle when cold? does it have a full amount of coolant in it?

 

Yea, well originally i was having trouble with my temp getting very hot and then shooting back down to regular temp (esp when the heat was on). I replaced the thermostat and temp sensor. I'm pretty sure I got all the air out of the system and it is full. I spent a lot of time getting the air out of it.

 

I am wondering if it has something to do with my TPS? When ever I disconnect it , it smooths out. It idles very high but it does smooth out.

 

man I have seen that before on someones yota that lived next to me, for the life of me I cannot remember what it was. lol. BTW it wasn't the TPS I know that. That's the first thing I did on his was remove that wire to it his did the same thing.

I want to say it was the Idle Control Valve but not sure.