Jonny246

Hi, I have 2 questions that I need some advice on. I have a 1994 SR5 4x4 ext cab 3.0. Today while driving truck it just stalled out. It was sputtering beforehand, after getting truck home I heard no humming sound coming from fuel pump engine just cranked over no fuel smell . I replaced fuel pump last yr Bosch I checked connections all was fine. I checked the fuse box under hood a 15amp fuse for EFI was blown out I changed the fuse it blew out 2 more times , After the 3rd fuse truck started I let it run 5 min shut it off and restarted it all was well. I will drive the truck around tomorrow see what happens Was this a fluke? or is a underlying problem coming to bite me in the a**..
2nd Question My check engine light went on cpl weeks ago a mechanic checked it out code comes up bad Knock Sensor I was told a lot of the times its the pigtail coming from the wiring harness due to weather/heat/ect I checked part stores in my area no one has it or can get it. I checked online and found several sites selling em problem is they selling 2-4 different pigtails for the same application. Is it a case
where any of em will fit ? or do you have to match it up before ordering one . It says if you send em the vin# yr..ect they can tell you which one applies. My problem is this is the 3rd engine in the truck I did not do any of the engine swaps what are the chances of it being the original pigtail . Any advice or help would be greatly appreciated on either questions. Thank You

boobiebuzzard

If you had fuses blow there is an issue these things do not fix themselves they just can be a pain to find sometimes. Electrical gremlins are very good at hiding.

fierohink

I'm not as familiar with the wheezy VZ, but on the 22RE the O2 sensors are on the same electrical circuit as the EFI fuse.

You may have a chaffed wire for an O2 sensor causing a short which could be your stutter and stall. As well as fuse blowing.

Terrys87

iTrader: (1)

I dont think it was a fluke that you blew a fuse. I suspect you have a bare wire and it is just a matter of time before the right bounce moves the wire to where it could short out and blow the fuse again. If it was me and since you have had issues with the fuel pump, I would check and see if the harness to the pump has any bare wire exposed. If that is not the case, you are going to have to find what circuits are on that fuse and start checking each one at a time. Electric is not my strong point but that is how I have solved several issues.

Charchee

Check the harness to the O2 sensor. They are known to burn / rub though and give you a short. You will probably be able to see any issue with that wire since it's not a real long harness under the cab. Next look to your fuel pump wiring as a suspect. Long wires with lots of potential for resistance causing problems. If I remember correctly, you can use a multimeter with probes inserted into the two connections of the diagnostic port by the fuse box that are used to jumper the fuel pump when you want to test it without the engine running, and measure the resistance there. I think you will need to put the probes on +B and FP which are located top and bottom of the connector on the right side if you are looking at it with the clip to the top. If the resistance isn't too high and the fuse isn't blowing, have someone move that harness around and see if you notice it on your meter or if the shaking of the wires causes the fuse to blow. If you don't have access to a meter, you can use a wire to jump the two terminals and see if you can make the fuse blow. You may even put in say, a 10A fuse, to make it a little easier to blow. If it blows the fuse while jumped, that should isolate the problem to the fuel pump wiring because that is the only part of the EFI system that you are supplying power to at that point. Somebody else had this issue a couple weeks ago and ended up finding a wire, all the way back at the pump, that was corroded to the point of failure. His issue started soon after he replaced the pump. I guess his moving the wires around while changing the pump finished off an already bad wire. There may be some more tricks like that to help you isolate the problem but that is the only one I have done personally.

I guess you could blow the fuse if the pigtail on the knock sensor shorted out but I doubt it. You'll find out when you get in there I guess. Has your truck been running bad since you got the knock sensor code? While it's running, I'd try and clear that code and see if it comes back. You want to make sure that you need to replace that sensor before you dive in there because she is in there deep! Get the sensor and pigtail from Toyota for your specific vin and and check it against the old one when you get it out. I bet it's the same as the original because, up til now, it was communicating fine with your ECM in the cab. If it's wrong, it's wrong but that's the one I would start with. You are going to be taking off everything down to the heads to get to the harness. Do yourself a favor and purchase high quality gaskets for everything you separate. You don't want to have to go back in there to replace a bad gasket that you saved $3 on. You'll see what I mean when you start taking it apart. I used felpro gaskets on all of my top end and they were very high quality and did not give me any issues.