1995 Toyota Previa LE S/C Stalling and wiring issue

[vin]

Please Help. Just bought 1999 Previa LE S/C with 195k miles w/salvage title. Previous owner stated it has an intermittent issue with it stalling during driving. Drove 8 miles home and it did not stall. Decided to go get gas and it stalled as I was approaching a stop sign. Started right backup immediate and drove 15 ft before it stalled again. Made it back home 2 minutes later with no problem. There is no hesitation during acceleration or sputtering, the car simply stalls. When it stalls, all normal lights on instrument cluster remain on including check engine until I restart the car again. This evening I decided to start the car and simply let it idle a few minutes to see if it will stall if I am parked, and sure enough it stalls, but will start right back up again with no hesitation. On my second attempt, I started the car and let it idle for about 4 minutes and notice smoke coming out of fuse box under the front dash. Open up the panel and found a jumper wire between the EFI fuse & Engine Oil Lvl relay. The jumper wire insulation was melting onto the Engine Oil Lvl relay. I disconnect the jumper wire between the EFI fuse & Engine Oil Lvl relay and attempted to start the car, but got a "crank and no start." Obviously there is reason someone used the jumper wire, but I need help understanding how to troubleshoot this issue. The EFI fuse is good. So where do I start and how?

On a side note, I also found that the fuse box that's part of the positive battery terminal in front of the car is hotwired with a white jumper wire from the fuse box to the the positive battery wire. Furthermore, The main positive battery wire was too short to attach to the battery terminal so they spliced a jumper wire to the battery terminal. see attached.850

I would like to see a picture of how the front fuse box should hook up to the battery so i can resplice it correctly. All feedbacks are appreciated. Thanks.

[Previa dude]

the first thing i wounld do is go to your fuse box where the efi fuse is at and check for power. and trace the wire at thr battery to see where its going. let me know what you see. i checked my manual and the efi fuse pulls power streight from the battery. so the battery fuse box maybe your problem.

[Previa dude]

i am going to pick and pull tomorrow. i will try to find an s/c and take some pictures of the battery fuse box so you can see what it should look like. idk if a picture from my 91 n/a previa would work since its on the oppisite side of your s/c previa.

[vin]

I need to purchase a multimeter. For the meantime I alternatively jumped the wire from the headlight fuse to the oil level relay and the van also started fine. I need a wiring diagram to pinpoint the possible break in the link. Is the jumper cable allowing the bypass of the fuel pump relay? I Do not hear/feel a click from the fuel pump relay on the firewall. Thanks.

[timsrv]

It sounds to me like something on the EFI circuit is pulling too much current. Perhaps a wire somewhere is pinched or maybe the fuel pump windings have a short??? Regardless of what it is, it sounds like it's caused some damage on the supply side of the EFI fuse. Instead of finding and fixing the root problem, it sounds like somebody made a jumper wire to power up the EFI circuit off the oil level relay (not the best plan). Evidently the short (whatever it is) isn't strong enough to prevent it from functioning, just makes it pull enough power to create more problems. I believe the stalling occurs when the jumper gets too hot, then goes away when it cools down a bit (or arcs just right and holds for a bit longer).

For this type of problem I would use the jumper wire just long enough to track the high amp draw. Use a DC amp clamp to determine how many amps are there. If it's more than 5 then check for amp draw under the van where the power wire goes to the fuel pump. Check as close to the tank as you can get. If you're seeing excessive amps here then it's a bad fuel pump. If not then you'll need to track the harness backwards until you find the place that's eating all the amps. After that's repaired you'll need to find the damage to the EFI fuse supply circuit.

I despise "hack repairs" and "work-arounds" As soon as you determine the cause I would find a Previa in the salvage yard and get the parts you need to put it back to stock. Good luck. Tim

[vin]

Tested amp draw on jumper wire and got a reading of 0.4 amps. Have not got a chance to test near the fuel pump yet.

1) I happen to test the fuse box on the battery and found no voltage on the last slot Label AM2. Shouldn't there be voltage there with the car running?

2) Also, the ABS slot has a standard 20amp fuse instead of a big yellow fuse. I'm guessing this fuse is not the correct usage?

3) Also, the "power main relay" on the dash is hot to the touch. Is this normal?

4) lastly, is there a correlation between the oil pressure switch and the fuel pump not turning on, thus requiring the jumper?

[timsrv]

Assuming the jumper is 14 gauge (give or take) .4 Amps is not enough to melt the insulation off of it. Perhaps somewhere downstream a wire is pinched or touching the exhaust or something. Perhaps when the vehicle warms up is when the short occurs??? All just speculation I know, but this is the sort of thing you should be looking for. You should continue monitoring with your amp meter until the problem occurs to see if there's a spike.......I'm guessing it will jump up to 15+ Amps.

You need to take apart the battery fuse box & inspect for corrosion inside. Here's links to a couple of threads where this is covered:

http://www.toyotavantech.com/forum/showthread.php?157-Battery-Fuse-Box
http://www.toyotavantech.com/forum/showthread.php?395-Intermittent-Starting-Problems-amp-Check-Engine-Light!!!-91-Previa-LE-AWD

Yes, it's normal for relays to run hot. They have electromagnetic coils inside. Coils consume power and will run hot to the touch.

Based on what you said so far, if I had to guess, I'd say there's a problem with the AM2 circuit inside the battery cable fuse box & this is why there's no power to the EFI fuse position. If this is the case, the jumper wire is being used as a bypass to supply power to this circuit (band-aid). Although not a permanent fix, and one I wouldn't recommend, it should still work.........unless there's a problem downstream. That's why I'm thinking there's an intermittent short somewhere in the EFI circuit. Check for pinched or otherwise damaged wires in & under the vehicle. Tim

[Previa dude]

I agree with tim. It sounds like a battery fuse box problem, and that's where I would start. Tim is never steered me wrong. And after I check my manual , the ecu draws power from am2 slot on the battery fuse box..

[vin]

Correction. I re-tested the am2 fuse and got a 14v reading, so there is power. I didn't properly test the first time around, being a newbie with a multimeter. Checked the battery fuse box for corrosion and looks really clean, no rust. Does anyone have a circuit diagram available so I can trace the lines?

[jkaustria]

were you able to fix the stalling problem?