SpoiledAdoptedLab

I have a 1993 Toyota 4Runner with the V6 3VZ-E engine that I bought from some friends about six years ago. I've never had any problems with this truck, until now. This truck originally came from Florida, I know that there was a recall on it to replace the head gasket (it's been replaced twice), and I'm the third owner. The truck was in excellent condition, as it was from down south, and it had, and still has very low miles for being a '93 - it currently has around 170,000 miles on it.

About a month ago, I noticed that there was a slight hesitation after taking off from a top sign or traffic signal. My husband replaced the fuel filter but it didn't solve the problem.

Then a couple of weeks ago, I was driving about 55-60 mph when I noticed that my speed was dropping off. When I tried to accelerate, the gas pedal was at first unresponsive, then with it floored it would finally begin to accelerate again very quickly (as if the gas pedal were stuck). I backed off once I reached 55-60 mph and it was fine for a bit, then it would start the cycle all over again.

It has been throwing a code 25 indicating a rich/weak fuel mixture problem. My husband thought it was a vacuum problem and started searching for broken/cracked hoses - he found two, one he replaced and the other was the big hose that attaches to the throttle body that he band-aided temporarily with electrical tape until he gets the part. He also noticed a small crack in the distributor cap and that some of the little nubs had been worn down, so he replaced the distributor cap and rotor. Then he checked the spark plugs and learned that one of the wires was torn under the boot, so he replaced all the spark plugs and wires, as it has been about 4 years since the last time he had replaced them. None of this has fixed the problem - we're both getting very FRUSTRATED!!! I should also note, that I was standing behind the truck yesterday when my husband pulled out of the driveway and I noticed a very strong gas smell.

My husband has the original repair manual for this truck and knows that the problem that still exists could be caused by a number of things. We're hoping that someone out there has had the same problem and can point us in the right direction before he continues the process of elimination to find the right fix.

Any advice anyone can give us would be GREATLY appreciated!!! Thank you!

scope103

Code 25 is lean, not rich. But smelly exhaust is usually rich, not lean.

So start from the beginning. Pull the EFI fuse for 30 seconds to clear the codes. (You can just disconnect the battery cable, but that will take out all the station presets on the radio.) Take it for a drive and read the code.

If you get code 26 (too rich) that will make more sense. Vacuum leaks in the induction system are not the problem (but RockAuto has the cracked intake hose for only $34). (Vacuum leaks in the exhaust can cause a rich condition.) A common cause of too-rich is a leaky injector or mis-firing cylinder.

Don't forget to give husband an "atta-boy" for his excellent work so far. Replacing the fuel filter on a 3VZE is not-trivial.

SpoiledAdoptedLab

Thank you so much Scope103, it's great to finally be able to communicate with someone that might be able to offer a solution!

My husband corrected me, it DOES read a code 25, NOT a code 26, so I definitely have a lean fuel mixture problem. I should also have mentioned that my check engine light had been on for over a year, however, when it first came on he did a code check that told him to replace the fuel filter. He bought the filter but never put it on (don't ask me why) until I recently started having the acceleration problem. What is really strange is that just before the recent problems surfaced my check engine light went off. Seems like it was shortly after the light went off that I started having this problem. Why would it have ran fine when the CEL was on, and now that the CEL is off it runs like crap. We almost wish the CEL would come back on because that's when it ran fine...totally confusing me and the husband.

I will definitely give him a pat on the back, as he's by no means a mechanic and never has been. However, with the right manual he can usually fix just about anything...so thankful, as he's saved us a tremendous amount of money in vehicle repairs!!!

Thanks again, looking forward to your next reply...

scope103

New Fuel filter + code 25 could be dirt in the injectors. Loosened when the filter was changed. Since you're not likely to have hit all 6 equally, you could look at the spark plugs to see if one looks especially different.

SpoiledAdoptedLab

Well, he just looked at all the plugs and said they look fine, so he's still searching. He did just find that there is a crack in the EGR vacuum modulator...he's giving this a Band-Aid of super glue...could this be causing an air leak and creating the problem?

Punchy

Also weak O2 sensor, blown HG can fail the O2 sensor or weaken it (just happen to me and I didn't have coolant, only water.

IF its failing completely and going full throttle will send the EFI into open loop dumping a lot of gas in until cruising which then would close the loop and then start the affects again.

Just a thought.

SpoiledAdoptedLab

UPDATE: Well, long story short, yesterday my truck completely died after only going a half mile down the road. More tests, checking other things lead us to believe that the coil was bad...replaced it today, problem still exists.

Now my husband is thinking it could be the igniter/ignition module, as after running for 15 minutes this part gets extremely hot, so hot that you can't touch it...does this mean anything to anyone? HELP, PLEASE!

Corey Barlow

Have you checked the fuel pump? Sounds like it was getting weak and finally went out

SpoiledAdoptedLab

Well, we finally drew the conclusion that the acceleration problem was the fuel pump, however, before we started to fix that issue another problem has surfaced...we have no spark from the coil! Turns over great just won't start...replaced plugs and wires and coil...there might be some other things my husband has done, but that's all I can think of.

Can someone please tell me why this damn thing won't start?????

RSR

Air in fuel lines from replacing the pump/pump not working?

Are spark plugs wet with fuel when you pull them?

SpoiledAdoptedLab

We have NOT replaced the fuel pump yet...could this be the reason the damn thing won't start???

Team420

Did this ever get replaced? This is an important part, and as the crack/hole gets bigger (which it will) the problem will get worse. This creates a large vacuum leak, and if there isnt enough air coming thru the vafm, the truck will not start.
Electrical tape is not an acceptable "band-aid", and its likely at least a large part of your problem.

RSR

Yes, unmetered air into your engine will completely screw with your ECM too, even causing your rig not to run -- all air must enter through the air flow meter connected to your air filter housing so that the computer can provide the correct amount of fuel to avoid knocking/pinging/etc. I'm guessing it's this hose, which can be purchased relatively cheaply online:
http://www.ebay.com/itm/New-Air-Inta...-/350833332467

And yes if your fuel pump's gone completely, no or next to no fuel is reaching your engine, which means it won't run.

SpoiledAdoptedLab

Hey guys...WE'RE GETTING NO SPARK FROM THE SECOND NEW COIL...one minute the damn thing started/ran fine (other than the acceleration problem, that we have determined requires replacing the fuel pump - which will be replaced as soon as we can get it running!) and the next it quit going down the road. Towed it home, husband messed with some things (minor) and replaced parts listed above - then it may have started a couple of times, and have not been able to get it going since! Turns over just fine, just won't start!!!!

The husband suspects it's a wiring problem somewhere, so he continues to search! The f***ing thing has sat with it's hood up for at least 3 weeks now...I don't know at this point, who is more frustrated him or me, as he's computer phobic (drives me absolutely crazy!!), thus, I'm the one who searches all of these damn forums in search of information that I don't understand!!! Come on all you Yota Techies, PLEASE HELP ME save my marriage - lol! But really, please help...

Of all the forums I've visited, I must say "you all are the best"!!! No where else have I really received any assistance....KUDOS to all of you, and THANK YOU!!! With your knowledge I'm hoping my husband will be able to "git er done"...soon!

Team420

So.... You still havent replaced the large hose that goes to the throttle body ? If not, theres a good chance that thats why your not getting fuel. The "flapper" in the vafm (volume air flow meter) has to open enough to send power to the fuel pump. so if theres a big enough leak, the truck wont start!
I'm not sure about the spark issue... That could also be contributed to the vacuum leak, but I doubt it, I'd lean more toward either the igniter, or dizzy. Get your multimeter out, and start testing! BUT.... GET THAT HOSE REPLACED ASAP. I'm willing to bet that is a large contributor to your issues.

SpoiledAdoptedLab

THANK YOU TEAM420!!! My husband and I have been arguing about your suggestion...I told him I thought your point was very valid (but what do I know, I'm only a girl...), he doesn't seem to think that hose has anything to do with it. I assure you that first thing tomorrow morning he'll be heading to the parts store! I'll keep you posted, and thanks again!!!

If you can think of any other reasons why this thing won't start, please share...

SpoiledAdoptedLab

Well, it's been 2 1/2 months since I last reached out for help in getting my "sick" 1993 Toyota 4Runner back on the road. We started out with a fuel problem that we were in the process of repairing, however, it also WILL NOT START! If you look back over the postings you will see what we had previously done. My husband also just replaced the "valve body hose" as strongly suggested. We know that we have to order and replace the fuel pump to fix the acceleration problem, but what would be the reason that the damn thing won't start. I've never had any problems starting that truck, other than replacing the starter.

SOMEONE PLEASE HELP...I want my truck back!

jb451

Is it still not getting any spark? I'd start at the plugs and work back to the igniter, and then even further down the line.... Somewhere, something isn't getting power.

Also, if you haven't replaced the fuel pump by now, go ahead and do it. If you're not getting fuel the engine will just crank and crank as well.... Don't worry, these guys on YT can get you back up and running!

d.ammons11

Your Fuel pump could be the reason it's not starting...I've had this happen before on a 88 Ford Bronco where truck started running erratic and then finally just wouldn't start, replaced the fuel pump and viola! Try replacing it first and then see if she'll start.
Also, when you turn the key ON you should hear the fuel pump prime up I believe, someone correct me if I'm wrong. On my 89 toyota pickup theres a relay for the fuel pump under the hood in the fuse box that's gone out on me before, common problem...don't know if this applies to the 93 but if you jump it and provide power straight to the fuel pump you should definitely hear it turn on. That's a good way to tell before tearing everything apart. I believe the Haynes manual explains how to do this under fuel system troubleshooting.

scope103

No, the fuel pump does not turn on then. Not until the key is turned to start, at which time you won't hear the pump over the starter.

You can hear the pump if you jump FP to B+ with key-on, but it's not "priming up." There is a check valve in the pump so the rail is left pressurized. (A failure of that check valve will cause delayed starts.)

A dead fuel pump "can" cause a no-start condition, but replacing it is a big job. Doing it "as a guess" is silly. The easiest way to test the pump is to disconnect the return line from the Fuel Pressure Regulator and put it into a container to hold gasoline. Start the fuel pump with FP to B+, and see if fuel gushes out. If it does, the pump is fine.

There are approximately 1,000,000 possible causes of no-start, but remember that all you need is fuel-air-spark. I'd put my timing light on each plug wire to see if they are firing. (A timing light is only $20, and you need one anyway.) If you have spark, remove the plugs one at a time. If dry, you're not getting fuel.

Last, I had a crack in my throttle body inlet hose for several years, with no problem. The hole probably had the effective area of a pencil, and the ECU can easily trim for that.