shiloh51933

iTrader: (5)

Could the O2 sensor/O2 sensor wiring cause the fuel pump fuse to blow? Somebody is sending me a sending unit but after further testing I'm starting to think that something else I replaced recently is causing the issue. I've pretty much tore my Max apart twice already and can't figure this one out. Plus I have a question, how many volts should be present at fuel pump fuse location with key on and fuse pulled out? If it's not the sender than I have no clue what I'm doing at all anymore I guess. This is the first time I have considered bringing my Max to the local shop that I go to for tire's. Tire's are all I will let anyone touch on all my rides. The one person I go to for automotive advice is being a shady character of lately and I refuse to call him for advice( I'd rather pay 90 bucks to a shop than ask him for help). Of course this is the 1 person that would know the answer to all my mechanical difficulties or for reassurance before I replace a part. He's never wrong, I'm good but not perfect or experienced enough being in my thirties, this dude is like sixty and has done it all, he has experience is every fuuckin' thing and I mean fuuckin' everything!!! When I get the sender from a fellow member I hope/pray it works but in the mean time I'm still searching/testing just to see what I can come up with. I only grow suspicious cause of what happened last time when just replacing the pump and everything working great until last month. Plus I have to re register her but can't do that until she's inspected and obviously that will have to wait. Any suggestions will be helpful and yes I have searched this out on the org but haven't got lucky yet. Maybe this issue is totally unrelated to my FP going last time.

James92SE

iTrader: (31)

I don't know if it can blow the fuel pump fuse. I know it can blow the ENG CONT fuse if the 02 wires fray/touch the underside of the car/etc because I had problems with that a few years ago

IIRC aren't you running an eBay fuel pump that differed in design to the stock one?

shiloh51933

iTrader: (5)

I was yes but I already went that route and installed the Walbro I had copped. It's mos def not the fuel pump itself, I disconnected FP itself and turn key on to pop fuse. I was trying to find out how many volts should be present at FP Fuse Block connection. I'm starting to believe it's a related system involved in this situation but the only code I was able to pull was the fuel pump system open circuit code. I know from what the ECU was telling me that it has to be an open circuit in this system but I just can't fuuckin' find this shyt!!!

Chris Gregg

iTrader: (59)

+1 with James, O2 pops the Eng Cont fuse. You've definately got a short or ground condition when setting the ignition to acc. IIRC, there is both a safety switch in the rear as well as a fuel pump relay. Either of these could have gone bad and my simply need to be replaced. Check your factory service manual to trace these components down.

BenStoked

iTrader: (7)

here's what I am thinking; you said the insulation on the terminals to the sending unit assembly were bad, the power wire may be grounding out, and *pop* goes the fu-use. (maybe)
and a shop tracking down electrical gremlins is gonna cost you more, simply because most mechanics (esp. tire places, and with all due respect to real mechanics) don't really know how to.


Chris brings up a good point, check the relays.
red is the path from fuse to pump, blue is the safety relay (duh), and yellow, I am trying to figure out.

jbbons25

iTrader: (2)

That yellow is apparently a shield that protects wire surrounding it which carries a small voltage. Like the wrapping you see on the knock sensor harness. It should go to ground.

Augustus Maximus

iTrader: (6)

If the diode in the safety relay is conducting in both directions (it's like a one way valve) you will blow the fuse. Pull it and turn the key and your fuse should be ok.

89badmaxse

iTrader: (1)

+1 on the ENG CONT fuse, i had that happen in my 90 se5 the day after i bought it, i would have to keep spares with me becasue it would randomly blow, then i installed a new 02 sensor and it never happend again....

shiloh51933

iTrader: (5)

Safety relay, where is that? I have only tested the fuel pump relay in my trunk. I really didn't think the O2 could short this circuit out but I had changed it after doing the FP, so I thought maybe I crossed something. The yellow part in that diagram is the fuel pump electrical connector under the rear seat right. So the safety relay in the blue is before the fuel pump but after fuel pump fuse in fuse block right. So the safety relay is where, behind the kick panel under dash to the left of your feet if your sitting in drivers seat or is it one of the relays to right of fuse block. My Haynes manual doesn't contain this info but I don't think I checked the safety relay.

shiloh51933

iTrader: (5)

The safety relay in the trunk next fuel pump relay? That's for the fuel pump right? I'll go get another relay, cause I keep spare's for the fuel pump relay but not that one in particular, thanks for suggestion cause I usually focus on FP relay cause that's what normally causes issues.

BenStoked

iTrader: (7)

it's in the trunk, by the driver's side tail light.

shiloh51933

iTrader: (5)

I was thinking of the relays for the stereo but there are two of them so I thought maybe one was what he was talking about. I usually never even touch those relays cause it's like always the FP relay on most vehicles. I'm gonna go ****** one or two out of the JY round the way to see b4 I copp a new joint, good lookin' my dude. You mann on the quick response.

Augustus Maximus

iTrader: (6)

Safety relay is located next to the fuel pump relay.

shiloh51933

iTrader: (5)

Finally my Max is up and Running again, I almost gave up for the first time in my adult life with something involved with my mechanical skills. I owe my boy Ben a big thanks for hooking me up with a sender for a digi dash, I couldn't find a used one anywhere and wasn't going new unless I was 100% sure it was the sending unit. It was the connector with the white wire w/red strip that was missing the plastic insulation on top of the sender cap. that is also the wire that goes to the safety relay and the reason why testing that relay checked out. The reman fuel pump is good but for some reason the 255lph pump I have doesn't work and now I have to try and return. I hate having to return something by mail, especially the wrong part being sent. Anyway good looking to all who kept me going at this until I got it right, I got the motivation I needed when I needed it on this site, thanks, Shiloh.

CMax03

iTrader: (3)

apply 12 volt to the 255lph fp and see what it does out the car....Maybe the motor is froze up or you placed it in a bench vise and squeezed it to much distorting the casing??????????????

shiloh51933

iTrader: (5)

Nah, I didn't use a bench vice or a vice of any kind, I already tried that and heard nothing. I'm going to send it back for another one, in the mean time time I put the 190LPH pump back in for now. I was just pissed off that I installed and then had to remove again to put the other FP back in. I probably shoulda tested it first to begin with but I was in a hurry as usual. I guess it's a good thing I found out now instead of months down the road when I would have problems exchanging. Besides that shyt, I couldn't be more excited to have my Max back so I can finish hooking up the new suspension parts I got.

Max_5gen

iTrader: (2)

I'm late to the party as you've already found your trouble but for the future you could connect 12V head lamp instead of fuse in case it keeps blowing up and proceed to disconnect everything along the current path from that fuse. The moment lamp turns off/decreases its luminosity you'll know you found the problem. A short serves as a ground on one end of the fuse while another is connected to battery that's why it keeps popping up. Lamp will simply lit up indicating the problem. This way you save on fuses a lot and you stay more calm when nothing pops up on your every move .

CMax03

iTrader: (3)

What are you running that needs 255 lph? Turbo? Or redline set to 10,000 rpm?

shiloh51933

iTrader: (5)

Yes, that is what I was doing, I just posted it as popping fuses so everyone could understand situation. From the beginning I had a feeling it was the sender but there were some other grounding issues that I had taken care of and was just getting frustrated cause I was having trouble finding a used sending unit for a digital dash to test my theory. Now that I have the used sender in with a new pump I will copp a new sending unit by the summer time.

shiloh51933

iTrader: (5)

I copped the 255LPH for the Boost set up I'm planning on doing this coming summer. I only installed to see what was up with the pump and though my other pump was malfunctioning. I know I can just test out of car but like to see how it would perform, check it's output to see If I even want to use it anyway. I'm returning and going with another brand when I get my dough back.

shiloh51933

iTrader: (5)

This was the short on my sender where the knife is pointing.

the108penguin

the electrical on these things seems like a nightmare

shiloh51933

iTrader: (5)

For what they were at that time/era, yes they were kinda heavy with the electrical systems but 20 years later... they are simple in comparison to the new Max or general automotive world. I'll take an electrical pump over a mechanical pump any day of the week...my old chevy's and ford's that had mechanical pumps sucked in the cold winters in New York.

James92SE

iTrader: (31)

Not hardly. These things RARELY (and I mean RARELY) have electrical problems/gremlins. Nissans, Toyotas, and Hondas are hardly notorious for electrical gremlins

If this seems like a nightmare to you I'd strongly suggest you stay away from any VW, Audio, or 90's - early 00's GM (bizarrely large array of constant dash warning lights/faults, anybody?)

shiloh51933

iTrader: (5)

I forgot to add...my 97' Volvo 850 GLT is real involved auto electrically speaking for her year. Now I'm not stating that they' re known for electrical issues... just that she comes from the factory fully loaded with everything. My 850 is an upgraded model from the base model but even the base model Volvo's are loaded up with options. There great automobiles and compared to a Nissan's durability they pass the test for longevity/dependability. My Max is a little easier to work on in comparison but both vehicles were ahead of there time.

James92SE

iTrader: (31)

Glad you've had great success with the Volvo, but generally, Volvos (and Saab - both Swedish) are known for their fair share of baffling electrical problems. Of course, there's also a ton of Volvos that will go 400,000 miles without an issue