cricket

Hello All,

This is my first post to this website. I have been searching the forums here for a month or so after I purchased a '93 4x4 (3VZ-E, 85,000mi) truck, learning as much as I could about it, since I've never owned one before. I was amazed at the huge amount of data available at all levels. I wish I had done some of that research before I bought the truck, but I still feel that I have made a decent decision, and got a decent vehicle for my purposes.

I was very interested in learning about some problems I was having, and have now solved, regarding a rough idle and stumbling under acceleration, and poor fuel economy. I clearly understand that with a truck, I cannot expect great fuel economy, but even an older, less efficient engine design pulling a heavy truck should be able to do a bit better than 13-15mpg around town and 19 on the highway (in my opinion, at least). BTW, the truck is totally stock.

So: the symptoms:
-Rough idle/misfiring at idle
-heavy stumbling, esp under light acceleration
-lower than normal MPG

I started with new plugs. No effect. With the help of some threads here I then looked into the TPS. After several attempts, and figuring out one aspect of the re-set process that none of the threads mentioned, I set it correctly. No effect. (ask me about the TPS adjustment...there's a trick that I have only seen mentioned in the Toyota Service manual)

I then decided that I would have a mechanic do some things that I had read about, and could do myself., but didn't want to mess with: Fuel filter, new OEM plug wires, airfilter, O2 sensor. All worthy tasks, (and $790.00, but that included drive belts, too) but sadly, NO EFFECT.

Once again, I got onto the forums here and elsewhere on-line and started doing more research. My next target was the fuel injection. My symptoms matched fairly closely some descriptions I had found of dirty injectors. Plus I had seen plenty of posts here about "Sea Foam" and the like.

I downloaded a '93 Toy Service manual (found here, too) and decided I could pull the injectors myself for inspection and possible cleaning. Plus I was feeling broke after the $790.00 hit. Pulling the injectors seemed better than Sea Foam or whatever, based on the wide variety of feedback on those kinds of products. I'd rather take a look at the injectors themselves and see what was going on. So I followed the manual and proceeded. NOTE: The Chilton manual has one brief paragraph, and no diagrams to describe a process that in the Toyota Service Manual requires several pages of notes and detailed illustrations. It makes me suspect how accurate any other procedures in Chiltons are. Had I tried this going by Chiltons I would have been totally screwed.

So I pulled the injectors (took about 3 hours, taking my time to mark everything and get my head around it). The injectors were a mess: the tips were covered with black oily crap; the actual orifice where the fuel comes out was barely visible on most of them. I cleaned them with acetone and a toothbrush. They cleaned up beautifully. I'm sure that the professional injector cleaners like "cruzin" or whatever its called do a much better job, but the crud came off great. I then set up a home-made testing jig to test the spray pattern/flow of each injector. I'm not going to say how I did it, because it was somewhat risky in terms of sparks (from turning the injectors on and off) and proximity to gas fumes. But the test proved that I had cleaned the injectors enough to provide a clean, even flow in each one. I put them back in (another couple of hours) and the truck RUNS GREAT. I haven't driven enough to give you a read on the MPG, but already the tank seems to be lasting longer than normal. And of course, it's still slow and relatively gutless (compared to my 2.8l V6 passat wagon) but I think it's doing as well as it ever could.

If you have any questions about what I've done so far please don't hesitate to post and let's talk.

Crick

ebelen1

No questions but how about a "thank you." I'm sure someone will ask a similar question and if they research well, will run across this thread.

My only comment is you did the injectors but paid someone $790 to do basic stuff that you could have easily done faster than the injector cleaning. Why?

hamish_18

okay I have done all that, changed out the distributor(whole thing) and re timed it and changed out ignition, from another v6 my friend has. and checked the valves, made sure all the shims were still right. and I STILL have the hesitation on acceleration. Its very very frustrating, and i have searched and searched online, and haven't really found what my truck was doing. Until now. THANK YOU! maybe the mechanic didn't really check all the injectors? and maybe the tps is messing up too, I think he might have only checked cylinder #5 because it had the least psi. which was a marginal like 1 psi lower than all the rest. and is still way way within specs. so maybe I need to check them all. you said 3 hrs? I think I will do this. And I understand about not saying how you tested them. but if you pm me, and i do whatever you want me to do to release you from any liability I will. because I really want to know. and thanks again for the post. finally!

chris

ps hope this old thread still gets a look at hehe

rollem

I'll be your mech...lol... J/k no pun intended...