svest77

I bought a 1993 Toyota Ext Cab 3.0 V6, fresh from a complete upper/lower rebuild and am sorely disappointed by the lack of power. Rather than start a fued with the guy that rebuilt it, I'd rather fix the problems and move on. Logic has told me that a fued still wont get me my money back OR make my truck run better, so I'm wasting my time. Anyway, I'm hoping something is just out of adjustment and can be fixed. It has a terrible tick, but many people have said this isn't all that abnormal for this motor. It has almost no torque, runs very choppy, shudders, etc. Upon inspection I found a few issues...the breather lid was unclamped, and the tubes werent connected right. Fixing this did help, but not enough. There is also a small cap (just above left valve cover) that says AiRam on it, has a quarter sized filter inside. The cap was cracked and busted. I have yet to find another cap, so for the time I wrapped tape around it so it would at least seal. This helped as well...but still nothing significant. All the vacuum lines appear to be correct. I'm curious if timing or fuel/air was set with these other problems intact and could now be all wrong, or I could be totally off-base. Additional info I have: It is an Automatic. (Which I'm also told robs power.) It has 31" wheels. No lift, but does sport all new Rough Country shocks. (Also told bigger tires will change power.) Everything appears to be stock. I just thought a newly rebuilt motor should run a LOT better/smoother/quieter than this, and the transmission and wheel size shouldn't have that much bearing on the problems I'm having. Anyone know what I can repair/change/tweak/modify to get this thing running better?? Your help is greatly appreciated. This is my first 4x4, and my knowledge is quite limited. I'm already upside down on this, spent all I had on this truck. So I really need to make this work without dumping much more into it. Thanks again.

Steve

rattlewagon

Check your timing.

HeavyD

Does your check engine light come on at start up, or when you get above 1600 rpm? Have you checked for any codes, you need to know this? Code 52 knock sensor is a very common problem after rebuild, which is a power killer. Find out on codes, and there are many frustrating, varied results that you can read about on Yotatech.

OutlawMike

Also,

Run a compression check, see if any of the cylinders are low.

One area that rebuilders have a problem with is the valve shim adjustments on the 3.0. It has come up numerous times that a valve job is done, but the shims are not adjusted in thickness to get the proper valve clearance. If you are running too tight on valve clearance you can lose compression in a cyclinder and possibly burn an exhaust valve.

Mike

chuntr

I think 93's that came stock with 31" tires had 4.88 gears (Trim code G144). if your tires aren't stock though, its probably undergeared and it's gonna feel like there's a lack of power no matter what.

more than anything though, it sounds like it was just a bad rebuild job from all the stuff you've found already.

rlordjr

You can check the TPS as well. If it is shot you'll get that shudder and shake when the throttle is only slightly open. Like when pulling away from a stop sign or when the tranny kicks into O/D and the revs drop. Has to do with the out-of-spec resistance in the TPS sending the ECU and the tranny values they can't work with

badboycustom

my 91 4runner starts and runs fine but as soon as i take off driving the check engine light comes on and you feel the power drop maybe 10 to 15 percent. After you shut the key off the light is gone but comes right back on as soon as i go again and it loses power again, please help.

HeavyD

Badboy, that is the knock sensor Code 52 that I talked about. There are varied results that you can read about on Yotatech, which I am still working on trying to solve myself.

Code 52 is a short in the knock sensor circuit. I have replace the knock sensor, the wire whip lead, cleaned connections, check continuity in the main harness, and replace the ECU itself, but still have the code. This one is killing me!
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Lex.Luther

Agree with other poster that -- first and foremost -- check that compression. If it is okay, then you are practically home free as the low power should be something you can locate and correct. You have been given some solid advice. Get the timing right...a little on the advanced side should give you some power, but NOT so much that you get engine knock. Speaking of which, that knock sensor ain't thre for decoration. It needs to be working properly. It's located in a hostile are and the pigtail that connects suffers mightily as a result. It's such a pain to get to, my recommendation is to replace both it and the connector - I think you can get the two off of eBay for less than $75.

If you have ignition at each cylinder and the timing is where it needs to be and you aren't getting any other warnings from the ECU, you can consider your ignition good as gold. If some dumbass tries to tell you your issue is that you are not runnon Nippon plugs or some such thing, walk away. My experience with these motors is that the spark plugs are binary: they either fire or they don't. End of story...despite having more than one "certified" mechanic attempt to tell me otherwise over the years.

I noticed another poster mentioned the valve adjustment. This is important as hell. I don't know if you are familiar with the process...but, it is a bit of a pain, particularly if the mechanic doing it does not have a needed shim size on hand and has to order it. The dealerships toss ones that they replace in a common place in their garage and can ususally find the right size. However, this is not always the case and they have to order the proper shims. Suffice to say that there is a lot of opportunity for someone to pay short shrift to this area and THAT is a mistake. I overhauled a 3VZE and it ran like a top except one cylinder was slightly off. I gave up and took it to a Toyota mechanic whom I trust and he quickly dtermined that the valve lash was off a smidge on cylinder 6. He swapped out the shim and the truck was magically running like new after that.

So, definitely double check the valve adjustment. I was shocked at how much impact even being slightly out of tolerance can have.

Finally, make definite dard sure that you don't have even the slightest vacuum leak. This is the easiest way to hobble an engine. Good luck.

badboycustom

i pulled my codes today and it is 52, i wonder if there is a way to fool the ecu and delete the knock sensor all together, as it seems to be a problem with alot of these trucks

Kiroshu

Alot of engine replacers or rebuilders tend to forget to "tune" the engine as its back up and running. Get a timing light and look to see what timing is. Should be aleast between 0* and 5* but if you can get it exact on 0 thats perfect. A little advance won't hurt but too much advance is not great for the 3.0. Possible timing advanced too much and idle turned down to much. This combo will keep it running but not very good... Check for vac leaks. Esp around intake hose. the tick you hear will prob go away for the most part as the new engines cams and valve lifters were out at one point so they need time to break in. Any codes? Air filter dirty?

Lex.Luther

As I mentioned in one post or another, we are about to drop in a rebuilt 3VZE from Oregon Engines. We went with one rebuilt with a bit of extra oomf, including performance cams. John, at Oregon Engines, told me it would take roughly a month for the ECU to stop over-compensating for the new cams, at which time we will realize that portion of the performance increase. That was a new one on me but has been confirmed by several gearheads more knowledgeable than myself.

jodee95

John from Oregon told me the same thing. I have 250 miles on my "Super Stock" 3vze.
I get a check engine light after the engine is warm Does anyone know if this will stop once the ECU sets up with the increase cam size?

Lex.Luther

No idea...but, I will certainly be interested to hear how it goes. How do you like the motor so far? Did you go with any other modifications: headers, thru-flow, cold-air, etc? We decided to add LC Engineering headers and exhaust system.

Team420

I have said it before, and i'll say it again, at the risk of getting flamed.....

I know the code 52 indicates a short in the knock sensor system...ie. the wires from ecu to sensor, or from ground to sensor..... however, I still believe that I fixed my code 52 by fixing a major vacuum leak..... I figure that if the truck is running lean(which it is if there is a vacuum leak) it will knock a bit, you dont hear the knock because the knock sensor backs the timing down.... but it will still be knocking enough for the sensor to pick it up, and when the system runs out of room to compensate for the knock, you get the code 52....

I havent been able to prove this theory, cuz I replaced the KS itself, and the pcv valve, and fixed a major valve cover gasket leak at the same time... just a thought anyway.... check for vacuum leaks.... they can be hard to find, so maybe have someone with you to hold the throttle slightly open while you spray starting fluid.

jodee95

Sorry for the slow reply. I went with the Oregon 3vze Super Stock motor.K&N Intake DOA 3mm Throttle Body Intake bore,LC Engineering Headers. I had the injectors done by RC engineering. I went way over my budget had a few suspect sensors and bit the bullet and had no choice but the dealer ship. Overall I am real happy with the motor except a couple of check engine lights and a slow valve cover leak we need to take on.I am looking at the LC Engineering Pro Flow exhaust system. I saw a few deals on the Thorley cat back single side exit which is no longer available from the manufacturer.

Lex.Luther

Thanks for the information. I am glad to hear you are happy with your purchase and you are getting the details sorted out.

I also went with the headers from LC Engineering as well as their new cold air intake and complete Pro Flow exhaust system. I am happy to be getting rid of the stock exhaust cross-over.

The motor is sitting in the garage. We are waiting on the headers and some other parts such as new motor and transmission mounts. Hopefully, we will have it going in the next 2-3 weeks. At some point, I will probably start a build thread on this site and let you know how things go.

BTW, with regard to buying OEM from the dealership. I have been buying parts for my two 4Runners (both 3VZE's) for many years now and have bought a lot of parts from various dealerships in the SouthEast. We both know Toyota OEM is high quality but also (stupidly) high cost. I have also been searching and buying parts off the web for years. With this latest project, I started getting familiar with what is on the web again. In the past, I discovered that roughly 90% of the websites sell exactly the same thing - in fact, their web sites look different but the 'parts trees' are identical. THIS TIME, I found something completely new and that is ToyotaPartsZone.com. Their 'parts tree' is based on the EPC (electronic parts catalog) and their prices just beat the hell out of what the local dealership has been charging me. They also have better availability. I have placed my first order with them - it hasn't shipped yet; however, they seem very reputable. I don't anticipate problems. Basically, this place can get any part that your dealership can. I combined this with a copy of the Toyota Electronic Parts Catalog program. It has the part numbers and exploded diagrams and matches up identically with this website. Combining these two tools has given me an ability I have never had in the past and is going to same me some serious bucks. If you don't have the EPC program, just do a search and you will find where to download it from and how to load it. There is a little process you have to go through, burning a couple of CDs, etc. But, I had no problem with it. BTW, both the EPC and TPZ.com allow you to simply type in your VIN (and save) resulting in the right stuff coming up for your truck.

betelnut

The dealerships that use trademotion.com for their parts catalogs, eg. toyotapartsoutlet.com, toyotaoemparts.com, do look identical, and do sell the same parts. You should be able to find anything in the EPC on those sites by typing in the P/N.

I used to use ToyotaPartsZone.com along with toyodiy.com to get the EPC diagrams (tpz.com) and match them to EPC part numbers (tdiy.com), but a few weeks ago the diagrams on tpz.com disappeared. I finally installed the EPC on my computer. Took a while to figure out how to install and use it, but it's really extremely valuable, and now I can just type part numbers into those trademotion.com parts sites to find the cheapest prices with lowest shipping. I placed about $500 in orders over the last month from those two listed in the last paragraph, and couldn't be happier with the whole process.

'BoatRunner

Bringing this back from the dead, I rebuild a 93 4runner and have done alright so far, except up hills! Runs fine on flats, but as soon as i hit a hill, i have trouble keeping speed going 30! in the rebuild i bored the cylinders to .040 over...maybe a af problem then? tried advancing my timing to no avail, so any advice would be great!