blowing fuses

[jumpman83]

anyone remeber this thread about my fuel stopping in the middle of driving?

http://www.cb7tuner.com/vbb/showthread.php?t=49942

The same fuse that's on the line where that short that was the problem in that thread is now blowing constantly (this is #4 underdash, runs to reverse indicator lights and main relay terminal #1). I ran a straight wire with a fuse holder from the battery to terminal 1 on the main relay, and it's still blowing fuses, only a 20 amp will hold, which is double the rating. So, that eliminates anything with the reverse lights,which means something on the main relay somewhere is demanding too much energy, but I've got to be sure before I go dumping money, I havn't got much left. The 2 things that draw power from the main relay are the ECU and fuel pump. Everything else is a ground or puts power into the relay. I swapped out the ECU and it didn't fix anything, so I'm doubting it's drawing too much. That leaves the fuel pump, but it's still priming when it should, not making odd sounds... it seems odd that it would be the problem... but could it be? Or considering the situation, should it be?

Also, the guy at pepboys said that 4th gen Prelude and CB7 fuel pumps are different, can anyone verify that? Because if they're the same I can get one at a junkyard for $20, if they're different, then... well there are never Preludes in junkards so I get to spend millions for a new one...

[jumpman83]

someone... please... any information anyone has?

[SN2BH22CB7]

Doube check EVERY wire...something is grounding out...check ALL your grounds!

the wires from the MAIN RELAY wire connector..trace em....see if theres a break in one of your grounds!

its gonna be a nice long trace....but you gotta find out whats causing that additional power draw...

my guess is...check for any shorts...

good luck and keep us posted on your progress

[SN2BH22CB7]

OH shit.....

YOO...check that FUEL INJECTOR RESISTOR....check those wires on those connectors....one of those wires might have jumped and causing it to short out....causing your fuel to cut out...

check those wires!!!!! yo...that FUEL INJECTOR RESISTOR is under the hood..( Driver side...between the Cruise contron unit and the driver side strut...almost on top of the driver side engine mount...can't miss it!!!

just double check those wires to that resistor...to make sure there aren't any holes or wires popping out...

start from there!

[jumpman83]

are you talking about this?



I always thought that was an ignition control module. You know, I've always been curious why Preludes and CB7's have those on opposite sides of the strut tower...

[SN2BH22CB7]

Yeah...thats what Im talking about....check those wires on the connectors...make sure there aren't any holes or exposed copper showing...might jump and cause a short!!!!

I thought you was talking about a CB7...rather than a Lude...

or..

use a multimeter to check the OHM of the Fuel Injection Resistor...

it should be between 5 - 7 ohms..for each test

stick the POSITIVE probe in the ( A ) slot..and put the NEG. Probe in the other slots ( B/C/D/E )..thats 4 checks....if you don't have 5 - 7 ohms on each test...replace the resistor

MAKE SURE..you have the multimeter on OHMS...

so it would go like

A-B
A-C
A-D
A-E

you always keep the POS. probe in ( A )



UNDER 5ohms...BAD resistor ( getting too much power )
OVER 7ohms ...BAD resistor ( too little power )

between 5ohms - 7ohms ONLY!!





good luck mayne!


NOTE:::: DISCONNECT NEG. BAT. cable!!!!!!!!!!

[SN2BH22CB7]

check the IACV...it should be between 8ohms and 15 ohms.....check for Continuity...if that fucker is throwing out juice.( continuity )...REPLACE it


EDIT::: ( IACV ) disconnect the elec. connector and measure the OHM of the IACV..not the connector

--- turn the key to "ON" measure the voltage ...these wires of the connector

Yellow/black ( + )
blue/black ( - )

there should be VOLTAGE.. ( around 11 or so Volts )

if not...this goes back to the MAIN RELAY..check the connector of that MAIN FUEL RELAY...if might be damaged....

if WORST came to WORST...might be some BAD wiring..WITHIN that ...


check your INJECTORS..IF you get it running..

unplug each one...( idle )..

one at a time....NOT all of em..just one at a time while testing!

NOTE the change in idle..then plug it back up

unplug the next...same idle drop..plug back up....and so on..

IF..one is unpluged and it makes no idle change..that INJECTOR is bad!!

unplug the connector of that bad injector...and measure the OHMs of that injector

it should be between ...

1.5ohms - 2.5ohms

if its UNDER or OVER...REPLACE it

thats ONLY after you get it running

BUT like before...check that FUEL INJECTOR RESISTOR

dont forget

between 5ohms and 7 ohms...it should read..throughout the board of each test of the pins ( ABCDE )

keep me posted on your progress on getting it running

[jumpman83]

I thought you was talking about a CB7...rather than a Lude...

and

stick the POSITIVE probe in the ( A ) slot..and put the NEG. Probe in the other slots ( B/C/D/E )..thats 4 checks....if you don't have 5 - 7 ohms on each test...replace the resistor

So there's 1 positive and 4 negatives?

Damn that's a lot of crap to do.

and yeah, but there's not much of a difference between a Prelude S and a CB7. 10 more hp than the CB7 with the a1 for whatever reason. That's damn near it.

[SN2BH22CB7]

So there's 1 positive and 4 negatives?

Damn that's a lot of crap to do.

and yeah, but there's not much of a difference between a Prelude S and a CB7. 10 more hp than the CB7 with the a1 for whatever reason. That's damn near it.

nah..its just to test continuity!

[jumpman83]

yeah, on every wire that has anything to do with the fuel system, that's a lot to do... alright, I'm about 1/2 there, here's what we've got so far.

Injector resistor
a-b: 6.1 ohms
a-c: 6.1 ohms
a-d: 6.1 ohms
a-e: 6.1 ohms

Injectors
cylinder 1: 2.5 ohms, changes idle when unplugged
cylinder 2: 2.5 ohms, changes idle when unplugged
cylinder 3: 2.5 ohms, changes idle when unplugged
cylinder 4: 2.5 ohms, changes idle when unplugged

IACV
resistance: 12.3 ohms
voltage
-ign on, engine off: 1.53V
-Engine on: 3.5V
engine almost died when I unplugged it while running.

I'm supposed to be getting 11 or 12v to it? Is 3.5 too low or was I really just looking for voltage? These ratings were taken cold BTW, I know the ratings change to change the idle, but it should be higher voltage, lower idle, shouldn't it? I'll take it again hot now that I'm thinking it, but...

[jumpman83]

BTW, to go with the last post I should have mentioned that the car is idling perfectly.

I also took measurements on my fuel pump. 1 Ohm of resistance, and I'm getting 11.9V. I'm thinking there could be a leak somewhere since I'm not getting the full 12.6 volts, but more importantly the extremely low resistance could very well be the reason my fuse is blowing, no?

[jumpman83]

well, wether I'm done or not I don't know, but, I took my DMM to pepboys and asked if I could check the resistance of a new pump. It was 3ohms, so that means that the old fuel pump's 1 ohm of resistance was allowing right around double the amprage it should have been. I went ahead and bought it and I'm 1/2 way through right now... I need a new fuel strainer, it didn't come with one (jack/dumbasses) and mine's dirty. Find out whether this was the probelm or not once I get that strainer so I can get everything in.

[jumpman83]

No one carries a strainer... I wound up getting one for an Integra which goes off at an angle, but it was close enough it works. I put about 20+ miles on the new fuel pump without blowing a fuse. Thats 20x further than the furthest I made it before now. Looks like I'm finally good.

[jumpman83]

FAWK!!!!!!!!!!!!!!!! Alright, so I've driven 200 miles without a problem and now I'm blowing fuses again. What in the fricken hell is going on? The resistance of the fuel pump made sense, and it worked for 200 miles without the slightest bit of a problem. Then all of a sudden it starts gasping for gas when it gets low. I figured it was just the strainer facing the wrong direction and I'll have to keep the fuel high, filled the tank up and it was fine. Got to the freeway onramp just afterward, uphill turn, and it sputtered up it, got to the top and finally went when it leveled off. Hit a hill when I got home, cut out and blew the fuse, then didn't stop blowing fuses. I have no clue what to do now, besides rewiring the whole damn thing, because all the components are new, main relay, ECU, and fuel pump... Anyone got anything else?

[xfactortype1]

fuel level sending unit

im no fuel injection specialist, but if your having problems blowing fuses going uphill, have you checked the resistance of the fuel level sending unit?

1)-remove the fuel level sending unit from the tank.
2)-position the ohmeter probes on electircal terminal and check resistance.
3)-check resistance with the float completely lowered(simulates empty tank). The resistance should be 105 to 109 ohms.
4)- now check the resistance of the unit with the float at the highest point (simulates full tank). The resistance should be 2-5 ohms.
5)-if the reading are incorrect or there is very little change in resistance as the float traveks from full to empty, replace the sending unit.

This could explain why your blowing fuses, due to the lack of change in resistance or the float is sticking.


hope the info helps.

regards x