1992 Toyota 3vze, automatic, 4 wheel drive. First off, I have searched this forum and read every thread I could find concerning flooding. Also, I am not a mechanic, somewhat mechanically inclined but definitely a shade tree type. I have owned this 4Runner since 2012 and have been able to keep it running good all this time until now. I have replaced the knock sensor & pigtail to get rid of code 52, installed new Denso AC compressor and converted to 134A. I have also replaced the water pump, timing belt, idler pulley and tensioner. In addition I have replaced the rear coil springs to get rid of the suspension sag and replaced the shocks. I converted the vacuum driven 4WD to manual hubs and did the mod to the transfer case with the hose clamp. So while I am not a mechanic by trade or training, I can usually figure out how to get the job done from the help on this site as well as YouTube. This is a third vehicle that I use for hunting and is mainly low speed off road use. As far I can tell from my inspection no mice or rats have been present and no wires appear to have been damaged. That being said the wires are old and kind of crusty looking.

The problem started out as what I thought might be an electrical gremlin. It would randomly die just like you had cut the key off, not often but would happen and would usually restart and run fine. This started back in March. It got to where it did it more often over time and then it progressed to dying when I put it into gear. I discovered then that it would only die when I put in into gear if my foot was on the brake. I could start it in neutral with the emergency brake set and shift it into drive, neutral, reverse and it would never die until I depressed the brake pedal and then put it in gear, it would die every time. Thinking it might be electrical, I pulled the ECU inspected it and it appears untouched by water intrusion. I re-plugged the connectors and reinstalled the ECU and surprisingly the problem went away for a few days. Then a somewhat new gremlin appeared but this time, I could start it up cold and while I was letting it idle to warm up it would stumble and die but this time it was flooded and very hard to restart. I would have to floor the accelerator and it would eventually start and once it cleared the flooded cylinders out it would run fine. Sometimes when driving it after one of the epidodes it would die like it did originally when pulling up to a stop but would always restart.

Based on all the threads that I read, I got the FSM out and started checking things out as best that I could, but again, I am not a mechanic. I have checked, cleaned up and tightened up all the grounds that I could find...including the ECU. Per the FSM I have checked the cold start injector, cold start timing sensor, engine coolant temp sensor. I also checked the VAFM per the FSM. I have cleaned the throttle body, double checked that the TPS was still set correctly and inspected and propaned the engine for vacuum leaks and found none. I also checked the pickup coils in the distributor per the FSM as well as ohming out the primary & secondary coil and ingiter. Here's is another weird part. I do not have a fuel pressure guage, so I did as Scope103 suggested in one of the threads and pulled the return fuel line off of the fuel pressure regulator. I turned the key on and jumpered B+ to FP in the diagnostic port. I got the fuel flow I expected based on Scope's description but 3 cylinders filled with fuel in the process! When I tried to start the engine after that I would not turn over and was basically hydrolocked. I pulled the plugs and cleared all the fuel and then proceeded to pull the plenum and then the fuel rails off. I sent the injectors off to a place here in Texas to have them cleaned and tested. I felt sure it was leaking injectors causing the issue as it was cylinders 1, 2 & 4 that were full of gas and not isolated to one side (circuit) or the other, however they tested them and found no faults or leaks in the injectors.

I have checked and did not find any of the injector plug wiring going to ground with the ignition key off. With the ignition key in the on position one side of all the fuel injector connectors do have continuity to ground. Does that sound right?

I also checked the injector wires from the connectors to the igniter and all had good continuity. I reinstalled all the injectors, fuel rails and plenum. The engine started & was flooded, running very rich and smoking and died after a few seconds. I could not get it to restart so before checking for spark, I pulled the fuel return line off of the FPR and jumpered B+ to FP just to make sure there was fuel flow & it filled cylinders again and it is hydralocked. I have not pulled the spark plugs to figure out which cylinders filled up and to clear them. I also now have a little fuel in the oil pan so I will be changing the oil if I can get this issue resolved.

Here are the other things I did when I was trying to get rid of the very first gremlin that was causing it to die. I replaced the fuel pump with a Denso, replaced the fuel filter, replaced the COR, distributor cap, rotor, plug wires and spark plugs. I also checked the timing and it was at 10 degrees BTC.

Needless to say, I am baffled and feel like I am getting in over my head with some of this stuff. While I found several threads concerning flooding in my search of this forum and while a few had some similarities most of the time they never get updated with what the final fix was. I need help and will appreciate any of you that have and idea of where I should be looking to solve the problem. I am wondering if it is ECU related but sure don't want to buy one just to try it. Something is causing injectors to flood the engine I just have not found the problem. I need professional help. My wife would tell you I need it with a lot more than just my 4Runner! :-)

 

I forgot to mention, in my post above, that the problem with it dying when put into gear was not caused by a vacuum leak in the brake booster. I pulled the vacuum hose off of the booster and plugged it and it would still die when I put it in gear with my foot on the brake. That is why I was thinking it was an electrical problem.

 

doublel:

While reading your post describing the problems with your vehicle, it was like you were describing the same problem I have been working on for several months now. I have a 1991 3VZE 3.0 AT Pickup that is the cab/chassis for Winnebago RV. Over a year ago, the vehicle just died for no apparent reason on the highway. After many cranks, we got it started again, but the flooding would return. We assumed that the culprit was in the fuel system, so similar to you we started replacing components that appears to be logical possibilities. The exhaust smoked white with a gas smell, at various times and engine runs we found anywhere from 2 to 4 quarts of gas in the oil, it hydrolocked while idling on another test and where we found gas in the air intake box and plenum.

Please note that not once during anything that has occurred associated with this matter, the vehicle never flashed a CHECK ENGINE LIGHT (CEL) - not once. I even did a shadetree mechanic hack at the control box beside the engine relay box that allows you to count and read the CEL flashes to determine the error codes, but no codes were displayed.

We were getting spark at the plug ends and a strong crank. The problem did not appear to be related to whatever gear I was in, or anything or condition at all. When flooded, it ran like a top (no misses, stalls, etc). - for a while - until it eventually flooded again. It was reasonable to assume that the flooding was a result of the injectors staying open rather than pulsing properly. Other components were replaced and/or checked out fine. The cold start injector appeared to be functioning properly and turned off every time after a short gas spurt into the plenum. It remains one of the few mechanical fuel items not replaced as it was not considered the source. Fuel pressure was fine for the most part, except when we noticed it being unusually low. We assumed this was caused by the injectors holding open continuously not allow the system to pressurize to the appr 40 psi.

We did pin out tests on the ECM which did not reveal anything out of normal. The noid light test was not reliable as the pulse (if any) was so fast that the light would not dim enough before the next pulse hit it OR because a STG was allowing it to stay illuminated somewhat. We did find continuity from the engine ground to the ground side of a disconnected injector connector that we could reach (cyl 2). Because the injectors should technically only receive a controlled pulse ground from the ECM, this indicated the problem was a STG someone reaching the injector circuit and therefore allowing the injectors to stay open. Then the question was is the problem a STG wiring or a faulty ECM. The vast majority of the internet research I conducted points at one of these two items as the problem. This test was simple by just checking the same continuity with the ECM connected and then disconnected. If continuity remains when ECM disconnected then the ECM is not the problem (or most likely not) and there is a STG somewhere else - but where?

We removed the upper plenum, disconnected the battery, the ECM, and all injector connectors and ran continuity test through different locations in the ignition circuit. We found that we had continuity (short to ground - STG) on one side of the injector ground circuit (cylinder 2/4/6) but not the other - which seem strange since most wring diagrams show ECM pins 10 and 20 wires (pulsed controlled grounds) spiced together so that they open all injectors at the same time (although this may not be exactly true since I have seen wiring diagrams that show both the wiring spliced together AND/OR running as separate lines to their injector banks. Convinced that the STG was the problem, I rebuilt this side of the injector and spliced it in to the old harness. With all injectors disconnected from the wiring circuit, the continuity of the new section was good, until measuring the ground side of the connectors to the POS (Black/Red) wire and finding continuity. WTF! I was quite deflated after feeling assured that the STG was resolved yet STILL had a STG from somewhere else.

After regaining some level of composure, and another scan of my FSMs and internet research, my focus has now moved from fuel system components to electrical related and primarily a STG somewhere else in the wiring. With the battery, the ECM, all injectors (and later the igniter and ignition coil) disconnected, I put the multimeter probes on the disconnected terminals ends of the battery and started pulling fuses and relays one at a time. While showing continuity between these ends, I started at the Relay Block 2 and pulled fuses/relays one at a time. When the EFI Main Relay was removed,l the continuity went to zero. I tested the ohms and other electric test on the EFI Main Relay and it checked out within spec. We checked other locations within the ignition circuit (primarily along the POS (+) Black/Red wire to various ground locations - all showing continuity.

While I have not solved my problem just yet, I am leaning towards a STG in the Ignition circuit, with the likely possible culprit being the Ignition Switch itself. - Why this? Although I only witnessed this one time, it now seems to give more evidence to my current suspicions/hypothesis. When we pulled the vehicle inside when it hydrolocked while idling, the ignition switch was on so that I could steer the vehicle. When we stopped the vehicle, I turned the key off and noticed that various instrument panel lights in the dash remained on - even when the ignition was off and the key removed from the switch. I cannot remember how we made them go off - but most likely disconnected the battery. I did not consider any connection between this event and the flooding at that point. In fact, I assumed it that instrument light issue may have been related to a failing isolator solenoid (which keeps the truck battery isolated from the RV cabin battery, but alllows the alternator to provide a charge to the cabin battery while engine running).

While a STG in the iigntion circuit may not be the ultimate cause of the problem, and it seems unusual that a ground outside of the injector circuit could cause this flooding issue, it is where my attention is focused now. The injectors are new and within correct ohms spec. Injectors open when a ground (any ground - but supposed to be the ECM's controlled ground pulse) is present in the circuit. The POS stays on at all times which seems strange but appears to be the standard injection operation across most vehicles. The injectors should only stay open if there is an uncontrolled ground in the circuit. When it does not, the typical cause is a faulty ECM or a STG in the injector circuit (or so my researched indicated). However, now I am finding that there may be other factors that can cause them to remain open. You are correct that many people seem to have similar problems with flooding, yet no one seems to have posted their resolution (or very few).

I will promise to keep you advised of my tests and results and hope that you will do the same. I will try to update information on my post:

https://www.yotatech.com/forums/f116...t-saga-319176/

It may be a few weeks before I can get to the Ignition Switch as it is yet another component that appears to be in a location that makes it a pain in the a$$ to get to and replace AND yet another part that is recommended to purchase as an OEM even though the part was discontinued many years ago (although I think it might be available as a Toyota forklift component at an extremely inflated price).

Best wishes and I hope that you are able to find and resolve the problem.

Gary

 

Pinkflydxx,
You have gone deep into that rabbit hole. Unfortunately, I have not had time to get back to working on my 3.0. Between deer season and me tweaking a '95 4Runner 22RE that I bought, I haven't had time. I appreciate your post and will let you know if I have any success when I am able to get back to troubleshooting.

 

I know this is almost a year old, but did you ever resolve your flooding issue? I had replaced almost every single component within the fuel system. I completed multiple tests the CSI's function on engine startup. I also multimeter tested the Coolant Temperature Sensor, CSI Timing Switch, and a complete "pin-out" test of the entire ECM/ECU - all showing results in the correct operating ranges. However, in hindsight, all of these tests/checks were done in a "static" mode, as I did not have the ability to check if they operated properly individually or together after the engine was in service for any length of time.

About 2 months ago, I went ahead and changed the CSI, the CSI Timing Switch, the Coolant Temperature Sensor, and the actual ECM/ECU as I was literally at the end of the road in ideas and suspected components. After installing these, we cranked the engine, and in about 4 or 5 seconds, it started right up. Over the past two months, I have driven it several times over steadily longer distances, with the last one (a couple of weeks ago) about 350 miles one way. So far, there has not been a single occurrence, nor indication of any flooding, fuel in the oil, or any engine misfires, sputters, or stalling.

While I cannot say with 100% certainty which component(s) was the culprit, the circumstantial evidence is compelling to conclude that the problem was within the operation of CSI system..

One last comment - someone replied on my post about their experience with a similar flooding issue, and stated that (like my experience), all of the CSI components multimeter test within spec - however, they may have drifted towards the operational limits while aging, and when all of these actions operated together, it resulted in flooding of the engine. In hindsight, this could have been the cause of my problem as well, as there was no single item that individually was shown to be a "red flag".

I hope you have found and repaired the "gremlin" within your vehicle, and welcome you to visit my original post describing how my issue may have been resolved (at least for the time being) - fingers crossed. Best wishes and safe travels.