ibeljin

iTrader: (1)

I've tried searching for threads that might aid me in solving my problem but it's an interesting compound that is difficult to find. Here's the jist. Car is 1990 GXL and always runs slightly above operating temp. I replaced the rad with a bigger aftermarket one and replaced the thermostat. Clutchfan works great and the undertray is still installed in the car. When i drive the car around i dont notice the temps rising past the equilibrium point. I know s5 temp gauges weren't known for their accuracy so i accepted the possibility that this may be the characteristic of the car.

Here is where things get kinda weird.
Normal when i drive the car a while and park it, i notice that the engine bay is fairly warm, much warmer than my other cars. Recently we had a very hot day and as the car got up to temp, it hesitated and died. My fuel level gauge reset itself and the fuel pump died while i was driving. It happened to me a multiple occasions and i havent noticed a drop in voltage when the car dies. I have cleaned the grounds going to the fuel pump resistor relay and checked to make sure the resistances are within spec. I have cleaned the main ground on the passenger side strut tower as well but perhaps it might still be contributing?
the issue seems to be related to heat within the engine bay. Any insight is appreciated

texFCturboII

iTrader: (17)

How do you know that the fuel pump died?
What do you mean by the fuel gauge reset?

How does the main relay look?

As far as heat is concerned, have you checked the oil cooler and it's thermostat lately? The oil system is responsible for about 1/3 of the engine's cooling...


Sounds weird.

ibeljin

iTrader: (1)

The car stalls while driving, it doesnt seem like an ignition cut. When this happens my fuel gauge drops to zero which i find very odd. If i open the hood and wait a couple of minutes, the car will start up again and drive but ive had this issue happen before and the car just kept dieing. I was close enough to get home without a tow.
Oil cooler is evenly warm when the car is warmed up and i just replaced the thermostat with an OEM from mazda. None of the stant BS Radiator is an aftermarket Godspeed and is considerably larger than OEM.

I have not checked the main relay. And it just came to mind that the battery inside the car is 13 years old. I will also check the alternator although i havent noticed the power drop when the car stalls.

j9fd3s

iTrader: (3)

if the fuel gauge moves i'd suspect something electrical, like a 13 year old battery. the fuel pump and fuel gauge are completely separate, except that they live on the same bracket

RXSpeed16

iTrader: (41)

Take a look at the wiring connector near the fuel tank. It houses both the pump wiring and the fuel level signal. The S5 version is known to have more problems than the S4.

A 13 year old battery is like 184 in human years. You probably want to change that.

ibeljin

iTrader: (1)

changing out battery today, fuel pump was already changed to a new OEM equivalent. I will take a look at the connector going out of the fuel pump assy. When i replaced the fuel pump i didnt notice the connector was corroded or damaged but its worth a look

texFCturboII

iTrader: (17)

You might want to double check that Godspeed radiator too. I had one and it was fine, worked great and look good as well. However, I remember seeing something about some being fabricated without a key welded plate across the inside of the end tank. W/o that plate the water just flows from inlet to outlet without going through the heat-sinks.

ibeljin

iTrader: (1)

replaced the battery, drove around for a half hour and had no problems. I drove at night so im not entirely convinced that its reliable yet. Will post again if the problem arises again once the car is daily driven

ibeljin

iTrader: (1)

i took the car on a 250km road trip and had no issues untill the fuel level was below half. The car died on me while driving on the highway and the fuel gauge showed no gas again. I tried jumpering the fuel pump using that yellow connector near the passenger strut tower and the fuel pump did not come on. i sat there for a few minutes not knowing what to do and the car started again without me tinkering with anything. IT worked untill i got home when it died once again, and is now stuck that way. The fuel pump is brand new and i have no idea where to start looking

FührerTüner

iTrader: (5)

Jump ur fuel pump directly to a 12v source. If it works, try connecting a switch temporarily and drive around and see if you still have the problem.

ibeljin

iTrader: (1)

i ran the fuel pump fine off a powersupply for hours before putting it in the car. I was using the pump to clean some parts in kerosene. What bothers me is that when my fuel gauge doesnt work, neither does my pump. And this shouldnt be the case.
Are both s4 and s5 fuel systems wired the same? because i've only ever found wiring diagrams for the s4

bumpstart

sounds like an earthing issue if you lose indication and pump.. expect it the pump has a shitty earth it also may run hotter and trip out

ibeljin

iTrader: (1)

I cleaned the ground thats on the fuel pump assy but the car still wont start. I will look into it and report back once the whole car has been checked over.

misterstyx69

iTrader: (142)

Run a ground from the pump assembly to the car..see if that Helps ya Ivan.
If not pull the pump to see if the pump is grounded right inside the tank,on the assembly.I'm thinking #1 though.

ibeljin

iTrader: (1)

yup turns out its just a dumb grounding issue. I cleaned the chassis ground that both the fuel pump and fuel level sender ground to but it didnt solve anything. I guess something is wrong between the fuel assy and the ground itself. Just need to make myself some new solid grounds and that should do it. Thanks for the help guys

FührerTüner

iTrader: (5)

Yowsers!

Hazard15301

iTrader: (5)

Hey thanks for contributing to the thread!


OP: did you ever confirm it was a grounding issue? Did you ever try swapping the whole pump/sender out for a spare? My pump would cut out randomly while driving, but had good 12v and ground and would run forever straight off a battery. Swapped the whole thing out and never had another issue.

FührerTüner

iTrader: (5)

Always a pleasure to help!

ibeljin

iTrader: (1)

the issue is that this problem was always intermittent. It would only happen after long periods of driving. I ran into the issue again after driving for 250km and had absolutely no indication of any problem until it happened. After i parked the car at home, the problem stayed. I couldnt start it period. I cleaned all the grounds and still got nothing. Added a new ground that i knew myself would actually do its job, and the car starts.

I didnt swap out the sender unit but from my understanding the sender and the fuel pump arent related electrically other than the fact that they share the same connector. I really dont care if my fuel guage dies from time to time, but i F&@$ing hate it when the car leaves me stranded in the middle of nowhere.