electrical problem, 98 240sx, EGI fuse goes POP!
electrical problem, 98 240sx, EGI fuse goes POP!
the problem: driving normally, 1st and 2nd gear only. i rev to get going, and when i start letting off the clutch the car seems to buffer, dies, and my EGI fuse is gone / popped. i replace the fuse, get going again, and it repeats itself by blowing later on down the road. i've been diagnosing this as much as i can, and enjuku racing has as well. the wires coming from the EGI use have been replaced, the wiring harness going into the fuse box has been checked and re-wrapped, the fuel pump has been replaced, and i just replaced the alternator today because mine died which has nothing to do with it. this is getting extremely aggrivating and i just want to know what's going on. it feels as if the car loses power for a second, comes back on, then pops the fuse and the car dies until a new fuse in in tact. you may not think much of this but it's an extremely dangerous situation. it happened today 4 times, and once in the midddle of an extremely busy intersection in orlando. it wasn't cool to jump out of my car and replace a fuse in the middle of the day with cars going by me at all different speeds. i really do NOT want to have to go to nissan, but unfortunately that may be the case. i need to get this taken care of. i thought enjuku had it at first, then it came back. replaced my fuel pump the other day, it came back. and today it's REALLY bad. this sucks alot, and yes im complaining about it so flame on, but seriously im in a HUGE jam right now and im about ready to throw something through my window if this happens again, which it will. if you can help out please let me know. any logical guesses or anything are extremely helpful. thanks everyone.
Re: electrical problem, 98 240sx, EGI fuse goes POP! (chrislis)
I don't have a 240sx but know quite a lot of the Altima electronics. And since they both share a lot in common and you don't have any answers then I will give you my observations.
First off, I understand that the EGI fuse is actually a 7.5A fusible link that is used for the ECM and some other engine components. I don't know why that fuse is so small because my '94 Altima uses a 25A fuse, but that is beside the point.
Anyway, according to the electrical diagram that fuse is used for the following circuits,
1. The ECM relay.2. EVAP Canister Volume Control Valve.3. Distributor. 4. The ECM.5. Mass Airflow Sensor.
Now what you have to understand is that one of the above circuits is overloading and causing too much current flow. Think of it like the electrical outlets in your house when they get overloaded. It is not a complete short else the fuse would have blown immediately.
Let's run through the list,
#1. The ECM relay
I would say you can toss out the ECM relay as the problem. But if you insist, then simply take another relay from elsewhere in your car that is the exact part number and swap them out. If the fuse blows elsewhere then it was the ECM relay.
# 2. EVAP Canister Volume Control Valve
For the EVAP Canister Volume Control Valve system, simply disconnect all electrical connections to it then give the car a spin around the block and see what happens.
#3. Distributor
Actually the problem inside the integrated distributor would have to come from the Camshaft Position (CMP) Sensor. If that sensor was breaking down, it would have to be because of heat. There are limited ways to check for heat breakdown but I would suguest just simply doing a distributor swap instead.
#4. The ECM
Now if this guy is the problem then you have no real choice but to swap it out to confirm it. However, there is a small chance that it is good and that another circuit attached to the ECM is causing the overcurrent. I would leave this alone and sort through the other possible problems first.
#5. Mass Airflow Sensor
This is the one I highly suspect to be the problem area. Why? Because you mentioned that while rev'ing the engine bogs (loses power) and the fuse blows. The MAF is possibly sending the wrong signal to the ECM and that in turn is causing some crazy A/F mixture. That runaway MAF is possibly causing and overcurrent and the fuse to blow. There are some voltage tests you can do on the MAF and it might help pin this down as suspect. If not, a MAF swap is in order.
You got your hands full now. The only thing I ask is to please post me back what you found as the fix.
Good luck.
First off, I understand that the EGI fuse is actually a 7.5A fusible link that is used for the ECM and some other engine components. I don't know why that fuse is so small because my '94 Altima uses a 25A fuse, but that is beside the point.
Anyway, according to the electrical diagram that fuse is used for the following circuits,
1. The ECM relay.2. EVAP Canister Volume Control Valve.3. Distributor. 4. The ECM.5. Mass Airflow Sensor.
Now what you have to understand is that one of the above circuits is overloading and causing too much current flow. Think of it like the electrical outlets in your house when they get overloaded. It is not a complete short else the fuse would have blown immediately.
Let's run through the list,
#1. The ECM relay
I would say you can toss out the ECM relay as the problem. But if you insist, then simply take another relay from elsewhere in your car that is the exact part number and swap them out. If the fuse blows elsewhere then it was the ECM relay.
# 2. EVAP Canister Volume Control Valve
For the EVAP Canister Volume Control Valve system, simply disconnect all electrical connections to it then give the car a spin around the block and see what happens.
#3. Distributor
Actually the problem inside the integrated distributor would have to come from the Camshaft Position (CMP) Sensor. If that sensor was breaking down, it would have to be because of heat. There are limited ways to check for heat breakdown but I would suguest just simply doing a distributor swap instead.
#4. The ECM
Now if this guy is the problem then you have no real choice but to swap it out to confirm it. However, there is a small chance that it is good and that another circuit attached to the ECM is causing the overcurrent. I would leave this alone and sort through the other possible problems first.
#5. Mass Airflow Sensor
This is the one I highly suspect to be the problem area. Why? Because you mentioned that while rev'ing the engine bogs (loses power) and the fuse blows. The MAF is possibly sending the wrong signal to the ECM and that in turn is causing some crazy A/F mixture. That runaway MAF is possibly causing and overcurrent and the fuse to blow. There are some voltage tests you can do on the MAF and it might help pin this down as suspect. If not, a MAF swap is in order.
You got your hands full now. The only thing I ask is to please post me back what you found as the fix.
Good luck.
alright, here's the update of the century right here. i just replaced my battery terminals, and i never noticed this before since i clean mine about once every 2 weeks just for precaution, but after i took off the positive terminal, the inside of it had like a layer of acid coating it. i guess it just kept coming back after cleaning. so i replaced em, both neg. and pos. i just took the car out for a spin and it's running realll good. only went to the gas station and back, but no hesitiation, no lag, no blowing fuses, yet. knock on wood. lets see how it does tonight and tomorrow, hopefully this situation is now in the past.
Re: (chrislis)
The exact thing happened to a 95 240sx I once had.
Usually when cruising and slowing down - the motor will completely shut down and the EGI fuse under the hood would be blown.
After days of searching... I found the problem.You know the big stack of wiring where your injectors are? (the one that goes along your valve cover)
well, some wires take a turn to the distributor - some wires were rubbing against the sharp corner on the head (close to where your coolant bleeding bolt is)
ck that!
Usually when cruising and slowing down - the motor will completely shut down and the EGI fuse under the hood would be blown.
After days of searching... I found the problem.You know the big stack of wiring where your injectors are? (the one that goes along your valve cover)
well, some wires take a turn to the distributor - some wires were rubbing against the sharp corner on the head (close to where your coolant bleeding bolt is)
ck that!
Re: (struckinc)
what is the best way to test the mass air flow?? because mine is doing the same thing!!! and before i drop2 big ones i want to know that is the problem. thanks for any help
Re: (runyun)
i also have this problem with my 95 s14 with a s13 sr swap it only seams to blow while the car is slowing down has any one fixed there's yet