Maserati Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
14 Posts
Discussion Starter #1
I would think it is a fuel pump motor going bad...any other suggestions?

For other cars I have changed just the motor itself, that is usually very standard motor, and I would not be surprised if there is a generic part available easily. Has anyone opened the pump and looked at the motor? I guess I will find out if I take my pump(s) out. I will share my findings then.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #3 (Edited)
Unless it's a short of some kind, I suspect you're correct

C
I worked on this issue a little today. I removed the pumps (not bad job at all), they ran well when removed with 12v, sounded a bit different though comparing, the other was a bit more quiet. Then re-installed the pumps and noticed that the 20A fuse will blow even if I have the pumps disconnected (well I could have tried that witout removing the pumps, but wanted to see how they look like)....so help my out here....must be a short somewhere, can a defective relay do that? Does anyone have wiring diagram for the pump system?

edit: tested the relays...when feeding power to 86 and 85, I hear click, and between 30 and 87 continuity changes, so I assume they are ok...I was hoping to find my problem there...
 
Joined
·
3,133 Posts
Is not going to be a relay and it sounds like it is not the pumps...There is probably something else on that fuse other than the fuel pumps blowing the fuse...The problem with getting just one diagram is you usually need them all...You can go to maseratitechinfo.com and pay for a subscription to access everything you need and print it out...Note the site is hard to navigate....Jason
 

·
Registered
Joined
·
14 Posts
Discussion Starter #5
Is not going to be a relay and it sounds like it is not the pumps...There is probably something else on that fuse other than the fuel pumps blowing the fuse...The problem with getting just one diagram is you usually need them all...You can go to maseratitechinfo.com and pay for a subscription to access everything you need and print it out...Note the site is hard to navigate....Jason
Thanks.....I think I will work on testing the most obvious first, wiring between fuse and relays and ground to relays and other simple stuff I can do.
 
Joined
·
3,133 Posts
Like I said..You need to check the loads on the circuit...Wiring doesn't have a lot of problems unless it rubs on something...The ground on the relay is not your problem...It is in the load circuit of the relay ...I have fixed tons of stuff like this over the years...From chaffed harnesses to rodent damage...trust me as it is not a hobby...Jason
 

·
Registered
Joined
·
14 Posts
Discussion Starter #7
Like I said..You need to check the loads on the circuit...Wiring doesn't have a lot of problems unless it rubs on something...The ground on the relay is not your problem...It is in the load circuit of the relay ...I have fixed tons of stuff like this over the years...From chaffed harnesses to rodent damage...trust me as it is not a hobby...Jason
another update.....the fuse blows when 1st speed relay is in place and I crank the engine. Tried with 2 relays, same result. If 1st speed relay is out, or only 2nd speed relay is in place, the fuse doesn't blow.
 

·
Registered
Joined
·
14 Posts
Discussion Starter #9
There is not a 1st or 2nd speed relay...There is a right hand and left hand pump relay...Use that to isolate your problem...Jason
The manual says that the relays are C ) Fuel Pump (first speed) and D) Fuel Pump (second speed). Because of that I googled that setup and found this explaining why it would make sense to have such relay setup
. However, if the manual is wrong then it does make sense that each pump has it's own relay as you suggested.
 
Joined
·
3,133 Posts
If that is what the manual says I could have been wrong...I was just kinda going off the top of my head...I looked at a picture...Look for an issue with one of the fuel pump resistors located on the RH side of the trunk...Jason
 

·
Registered
Joined
·
14 Posts
Discussion Starter #11
If that is what the manual says I could have been wrong...I was just kinda going off the top of my head...I looked at a picture...Look for an issue with one of the fuel pump resistors located on the RH side of the trunk...Jason
Yep, found the resistors. 1st speed relay 87 is grounded, and that wires splits into 2 that both go to resistors behind the battery. These Bosch resistors show values 1.5 and 2.6. Two red wires to the resistors are both grounded.....if they were connected straight to the fuel pump (s?) and 2nd relay 87 as in the video, they should not be grounded; so this wiring is different. The fact that the resistors show different value....can that really be the issue?
 
Joined
·
3,133 Posts
No that much probably and it can vary with temperature and how accurate your DVOM is...You should be able to just bypass it for what you are trying to do...Just connect the two eyelets on each end of the resistor...Jason
 

·
Registered
Joined
·
14 Posts
Discussion Starter #16
Found some kind of switch behind battery that has been installed, seems that it was related to fuel pumps. Removed it, reconnected the wires and seems like I got rid of my problem. Fuse is not blowing any more. At least now I know where all wiring to pumps are and how to remove the pumps.
 

·
Registered
Joined
·
446 Posts
Found some kind of switch behind battery that has been installed, seems that it was related to fuel pumps. Removed it, reconnected the wires and seems like I got rid of my problem. Fuse is not blowing any more. At least now I know where all wiring to pumps are and how to remove the pumps.
Glad you found your problem. It's amazing how many problems on cars come from the leftovers of installations of aftermarket electronics (audio, alarm, lighting, locating, etc.). I assume some previous owner did that to your car. Several of the cars I've bought I started with removing a box full of wiring and components that had been left behind from previous installations. When my next door neighbour saw the wiring and parts I took out of a Alfa Spider I bought he couldn't believe it...but the car ran fine and I never had a problem.
 

·
Performance Specialist
Joined
·
4,612 Posts
Very true, we had an electrical issue here from a used car dealership that installed a GPS to track a car that had financing (without the owners permission or knowledge). It wasn't a good install and now it's being corrected but caused a lot of problems for the owner.

Best Regards,
 
1 - 18 of 18 Posts
Top