98 V70 T5 - Starts and dies

neworleans · Post by **neworleans** » 11 May 2017, 06:46

Hello all,

I recently bought a 98 V70 T5 with 201K. It wasn't running when I got it and the seller told me that it needed a fuel pump and gave me the diagnose report from the mechanic. I replaced the fuel pump with a new after market cheap fuel pump for 33 bucks and also replaced the MAP sensor with a used one. Now the car starts but dies in 1-2 seconds. I am thinking that maybe the MAF sensor is bad because I had a similar issue with my 2000 S70 and I fixed it by replacing the MAF sensor. I am attaching the report from the mechanic, do you think replacing the MAF sensor would be a good shot? Any other ideas? Thanks in advance.

I forgot to add, I scanned the car with my OBD II scanner after replacing the fuel pump and during the replacement I had the battery disconnected and charged so I am thinking that disconnecting the battery may have reset the codes because I am not getting any codes now.

DrJammer · Post by **DrJammer** » 11 May 2017, 07:32

try starting with the MAF unplugged.

as far as fuel pumps and MAF sensors, this forum has taught me that OEM parts for these are critical.

Post by **theWIFES_S70** » 11 May 2017, 08:06

Wow, $33 for a fuel pump? I'm a cheap as they come, but man, that's cheap... I installed a Hella from FCP into our car. It was $65+.

How good is your fuel pressure? Have you tried super priming your fuel line before starting? (Just turn the ignition to the on side four, five times before starting.)

neworleans · Post by **neworleans** » 11 May 2017, 08:15

I usually buy my parts from FCP as well but this time I wanted to go with the cheapest way due to not running condition.
I don't know how to check the fuel pressure but I did it like you said, then it started, so I am assuming the fuel pump is working but not sure if the pressure is good enough.

Post by **Winnebago** » 11 May 2017, 08:18

so many possibilities... fuel pump relay? does upping the rpm right after start help?

Post by **theWIFES_S70** » 11 May 2017, 08:35

neworleans wrote: ↑11 May 2017, 08:15 I usually buy my parts from FCP as well but this time I wanted to go with the cheapest way due to not running condition.
I don't know how to check the fuel pressure but I did it like you said, then it started, so I am assuming the fuel pump is working but not sure if the pressure is good enough.

Glad you got it started! Yeah, fuel pumps are a tricky thing. It appears to be a little weak. Or it might just be a little shorter than the OE one. If you don't really care about the car too much, just make sure you super prime it before you drive and you should be good. Don't let that tank run low either. Cheap pumps burn out pretty easily.

Make sure you aren't leaking fuel from your fuel pressure damper. (Really easy to check, just look at the fuel rail, in between the first and second (or is it second and third?) fuel injector and see if there's any sign of fuel leaking.) They usually don't leak, but any sort of leak will give you a "sluggish" start and is dangerous!

There's a member on here who corrected a sluggish start condition by replacing (or cleaning out a a cheap plastic valve.) I think it was benpineapple, though I could be mistaken... I think it was this piece...

http://www.ebay.com/itm/322275082655?_t ... EBIDX%3AIT

It's a real good idea to check out the relay. The last two digits on it will tell you the year it was made. If it's a 98, 97, 96 relay, you really should put another one in there. There's probably someone on here who can sell you a junkyard one from the 00s for cheaper than an aftermarket relay. You're running a T5 so don't even think about putting a KAE relay in there!

Post by **cmblackburn** » 11 May 2017, 09:48

Definitely try replacing the fuel pump relay. I've cured so many cars with this same issue

Post by **cn90** » 11 May 2017, 10:37

- Search forum for photo of jumper on terminals 15 and 87 of the fuel relay socket. I posted some photos in the DIY.

- If that solves the problem, then the relay is bad.

- Aftermarket fuel pump is a crap shoot, I'd stick to Bosch 69693, about $80-$100 range but it is OEM quality that should give you some 150K-200K service.

neworleans · Post by **neworleans** » 11 May 2017, 11:42

Thank you guys, I have a 2000 S70 GLT SE also, same fuel pump relay? If yes, will I need to disconnect the battery while swapping the relays?

Post by **erikv11** » 11 May 2017, 12:36

Yes, 93-00 (i.e., all P80s) all use the same fuel pump relay. No need to disconnect the battery for a swap or a jumper wire.