'98 S70 Jerky hesitation Topic is solved

Post by **dosbricks** » 13 Apr 2017, 17:41

Cn90, go back and read my initial post on page 1.

Post by **dosbricks** » 13 Apr 2017, 18:27

Bmdubya1198, you have 175k and my S70 has 229k, so very possible our fuel pumps have had the course.

Wondering what, in the forums collective experience, is the average life of these pumps?

Post by **bmdubya1198** » 13 Apr 2017, 20:42

dosbricks wrote: 13 Apr 2017, 18:27 Bmdubya1198, you have 175k and my S70 has 229k, so very possible our fuel pumps have had the course.

Wondering what, in the forums collective experience, is the average life of these pumps?

I'm thinking the same thing, I just passed 176k yesterday!
I have the same question. It's not bad yet *knock on wood* but it definitely feels like a quick loss of fuel when it misses every now and again.

Post by **misha** » 14 Apr 2017, 04:28

The main secret for long life of in tank fuel pumps is not to drive the car frequently when it's low on fuel.That said...when the needle drops to 12-15 liters,refill the tank and keep it always above that line.
That way will keep your fuel pump from overheating of it's inside elements since it is cooling itself with a petrol in the tank and will protect it from premature failure.

Post by **bmdubya1198** » 14 Apr 2017, 07:23

Good to know. I knew the fuel cooled the pump, but would the fuel being that low cause a quick loss of fuel?

Post by **misha** » 14 Apr 2017, 07:34

It shouldn't,except if you drive it a long after low fuel warning light turned on.
Could be that some ignition part is making problems...cap,rotor,spark plug/cable,wrong gap at spark plug....etc.

Post by **bmdubya1198** » 14 Apr 2017, 08:22

Yeah, my only guess is the wires since they aren't OEM. I know these cars are particular about wires. Otherwise, my plugs are correctly gapped (running NGK G Power platinums) and I have a new Bosch cap & rotor. Well new as in replaced in the past 4-5k miles.

Post by **erikv11** » 14 Apr 2017, 08:37

I also wondered about the wires, that's potentially troublesome. I've had a few fuel pumps go out on me, they always just stopped working, or were intermittently working or not. No intermediate stage of chugging. So I doubt it is the electrical portion, perhaps it could be the built in check valve though, if indeed the fuel pump is the problem.

The fuel pump relays are the same even past 2000. I don't know the full compatibility info but I have picked up newer ones at the JY and popped them in. My experience with P80 fuel pumps is anywhere from 100k to 200k. Probably depends a lot on fueling habits as suggested by misha.

Would be interested to hear your impression of the bargain priced Bosch fuel pump fro RockAuto.

Post by **cn90** » 14 Apr 2017, 08:55

dosbricks wrote: 13 Apr 2017, 17:41 Cn90, go back and read my initial post on page 1.

@dosbricks, You said "...I jumpered pins 15 & 87 in the fuel relay connector. The car started and ran great on a 5 mile test run."
Then the problem happened with the KAE relay.

My point is: leave the jumper wire in 15-87 for 1 week and see what happens.
If the car runs smooth for a week, then the relay is bad.

Post by **dosbricks** » 14 Apr 2017, 09:24

cn90 wrote: 14 Apr 2017, 08:55 @dosbricks, You said "...I jumpered pins 15 & 87 in the fuel relay connector. The car started and ran great on a 5 mile test run."
Then the problem happened with the KAE relay.

My point is: leave the jumper wire in 15-87 for 1 week and see what happens.
If the car runs smooth for a week, then the relay is bad.

OK, I'll put the jumper back in. I've had it in there twice now and the car runs good, but a more extensive test may be a good idea. But with 229k and the new pump insert in shipment, I plan to swap out the pump anyway as it's surely close to being due.