96 T100, 3.4L Cranks but will not fire (1 Viewer)

[MoCoNative]

Welp, after 7 years and 100,000 miles of ownership my truck failed to start this morning. It has been a very reliable vehicle, aside from my 60 series, I don't do much to it all and it always goes. Anyways, the truck is a 96 T100, 4wd model, 5spd, extended cab. Just over 223,000 miles, engine was getting sluggish and slow starting, changed the spark plugs a few weeks ago, they had 60,000 miles on them, and it was starting on the first crank and picked up some zip. I cleaned the MAF, and TB the best I could that day too. I also shimmed the TB shaft, as it has worn some and was sticking and causing a high idle. I daily drive it, runs great each day, been in the garage all winter for early morning starts. Last night leaving work it was 40+F out and it fired off in about a half second of cranking, I was impressed. I don't recall any hiccups or anything on the way home. Put her away for the night, and now no start.

The engine cranks with vigor, battery is good, lights were bright. I cranked and cranked it, but it never gave a single hint of firing. I checked all the fuses and glanced under the hood, nothing was suspect, fuses were good. I don't recall ever being able to hear the fuel pump on this truck, so I couldn't say whether I could hear it this morning. I didn't want to kill the battery, so after many long cranking sessions and looking around, I quit, I was late for work and had to go, took the 40 instead, a little cool at 20F this morning and a soft top though. I don't recall a fuel/flooded smell in the garage, I even shut the door to troubleshoot for a minute and cranked it some more, seems it would have been obvious in a closed garage.

So what does this mean, need some suggestions, I have the FSM for this truck, so I will pull it out tonight, but I hate digging through electrical troubleshooting. Truck is all original basically, regular maint. Timing belt and waterpump about 70K ago. Engine is very sanitary, no corrosion, wiring all seems very good, never seen corrosion issues anywhere. I'm suspecting fuel pump, it is the original. Can they just up and quit like that?????

Thanks, Graham

 

[joe dirt]

Sounds like what happened to my tacoma / 3.4 when original fuel pump went out at 298k.

 

[byrd_hntr]

Fuel, Air, Spark. Thats the place to start. Yank a plug as see if your gettting spark, if so check for fuel.

 

[MoCoNative]

I'm shopping fuel pumps, don't know if that is problem yet or not, but which one to get????

Toyota is like sell your first born child gold plated prices, and the cheapest economy one from rockauto is 15 bucks. I want one that will last obviously, what is a reliable brand of non-OEM fuel pump in this application?

 

[MoCoNative]

Still no joy.

All fuses looked good, EFI and Fuel pump Relay check out, fuel pressure VSV checks out. Pulled #5 sparkplug boot and stuck an old spark plug in it and laid it on the manifold. While cranking with the key I had lots of yellow spark on electrode. Not sure if that is a strong spark, but it was sparking, could just be the older plug, or marginal conductivity laying like it was, or lighting???

I also held the fuel line and cranked it over, and never really felt any flow, or pressure behind the pinched line???? However, when I walked in the garage yesterday afternoon, it was strong with gas smell. After many repeated crankings yesterday evening, it was and still is very gassy smelling???? I can't see any leaks, I think it is just unburnt fuel coming out the tailpipe, but not sure, why will it not fire if there is fuel getting out the pipe, and sparks. But the lack of any pressure on the line during cranking between my pinched fingers makes we wonder. There were still some voltage checks and such to run through in the FSM, and I will break a fuel line loose this afternoon and see if I can jumper the pump to confirm its operation.

Any other thoughts? I did strip a security system off this truck a couple years ago because it quit working properly. As I recall one of the wires off the ignition switch was cut in such a way I had to splice a small section of wire back in it to fix the tap. I cannot recall exactly how I did it, perhaps that is my problem, I can't remember which wire it was on, but if the plugs are sparking, I must have power to that circuit.

 

[Brake Weight]

Sounds like the fuel pump may be done. Try the $15 one and if that fixes it, get a good one coming. If it doesn't, then you got a $15 answer.

Plugged fuel filter would be my second guess.

 

[MoCoNative]

I was at a conference the last few days. Spent Saturday morning working on it before I had to leave. I confirmed I had power at the plug of the fuel pump and had it hotwired, it should have run and never did. Wanted to get the tank dropped Saturday afternoon but never made it that far. I did order a new Denso pump and gasket before I left, should be an OEM replacement and they are on the bench ready to go. So tomorrow I will get the tank dropped and see if that really is the problem, but everything else checks out, and I sure could not get it make noise wired direct to power at the relay plug under the dash. Nor could I ever feel fuel pressure in the line at the engine.

If I had planned this, it would not have 3/4 of tank of fuel in it and lots of spring time mud and road grime underneath. So there is some more cleanup to do before I get the tank down and opened up. At least it died in the garage. Got most the fuel siphoned off Sat afternoon. Each time I broke the fuel line open it was pouring out far more fuel then what was in the line. I didn't want 20 gallons of fuel to trickle out under the truck in dirty pans.

 

[Mudder]

Floor jacks with something over the top to even out the weight will help make the gas tank removal and install easier

 

[MoCoNative]

I have a screw drive transmission jack from Harbor Freight, sucks for transmission placement but should be ideal for this.

 

[Brake Weight]

An ATV jack may work if you put some boards on it. But it may be just as easy to pull the bed off. May be 6 bolts like the Tacoma and unplug the taillights.

 

[MoCoNative]

Cheap tranny jack worked great. One of the strapping bolts would not come out however, and because of the spring, impact driver was off targett and rounded the head clean off. Pulled the pin on the other end and was still able to drop the tank.

The old pump still would not make a sound even wired up on the bench, so I put in the new one. I still have a couple of things to wrap up tomorow,but I tried to start it and it fired right up just like normal.

Totally amazing it just up and died overnight in the garage. Glad it did, cold and snow flurries all day today, glad I wasn't having to do this job outside.

Thanks for the help everyone. Anyone else doing this job and have a question let me know.

 

[MoCoNative]

Wanted to note, the pump is about 3/4 under the cab of an ExtraCab T100, the bed cannot be pulled as a way to access the pump. You have to drop the tank.