1997 V70 XC Hard Cold Start

T-HADLEY · Post by **T-HADLEY** » 22 Oct 2012, 12:17

The car is only hard to start after it sits all night, and the colder the out side temp gets the longer it takes to start.

I thought maybe a faulty fuel pump check valve, so I installed an in line one, on the incoming side, and no change...

I'm unsure what to check next?

No CEL
no smoke once it starts
no mis firing or rough runing
Runs fine after first start.
car runs great other than the hard cold start, takes up to 30 mins when really cold out.

Post by **jblackburn** » 22 Oct 2012, 12:21

Coolant temp sensor?

Does the temp gauge or heater take a long time to warm up even after 10+ minutes of driving?

T-HADLEY · Post by **T-HADLEY** » 22 Oct 2012, 12:33

no long warm ups

I replace the engine coolant temp sensor this past summer, I had the common fan running after the engine shuts off scenario.

T-HADLEY · Post by **T-HADLEY** » 23 Oct 2012, 11:59

so now I'm guessing this is not a common thing?

Post by **cn90** » 23 Oct 2012, 12:19

Hard COLD Start culprits:

1. You mentioned ECT, but what brand did you use?
OEM is SWF or Volvo.

2. Look into fuel relay. I posted some info on diagnostic guide last week.

3. MAF?

aamose · Post by **aamose** » 23 Oct 2012, 13:10

My V70 '98 won't start when there's cold weather, starts perfectly most of the year. Coolant temp. sensor and MAF did not make a difference when I changed them. I am next changing the starter relay. The way I found to make it start in the meantime was to get a small code reader/eraser and use it when it does not start. After reading and erasing codes, it starts right away, no matter the cold weather. I'll keep you posted about the starter relay. I'll change it this week.

T-HADLEY · Post by **T-HADLEY** » 23 Oct 2012, 13:36

cn90 wrote:Hard COLD Start culprits:

1. You mentioned ECT, but what brand did you use?
OEM is SWF or Volvo.

2. Look into fuel relay. I posted some info on diagnostic guide last week.

3. MAF?

Thanks for the reply, this is a very frustrating problem, because you can only make it repeat after it sits all night.

the ECT was from NAPA.

I could not find your info on the relay.
wouldn't a relay act up all the time?
How would the MAF effect cold start?, there is very little air flow at cranking speed

Post by **jblackburn** » 23 Oct 2012, 13:39

Ah, that sheds some light. These cars have had problems with aftermarket MAF and ECT sensors on this forum.

Do you have a voltmeter? On a cold start, unplug the ECT plug and test resistance (ohms) across the leads. You should see something between 7000-5000 ohms. If this value is too high (say, <3000 ohms), it won't put enough gas in the cylinders to get it to start on a cold engine. Kinda like not using the choke on a cold lawnmower.

T-HADLEY · Post by **T-HADLEY** » 23 Oct 2012, 13:50

jblackburn wrote:Ah, that sheds some light. These cars have had problems with aftermarket MAF and ECT sensors on this forum.

Do you have a voltmeter? On a cold start, unplug the ECT plug and test resistance (ohms) across the leads. You should see something between 7000-5000 ohms. If this value is too high (say, <3000 ohms), it won't put enough gas in the cylinders to get it to start on a cold engine. Kinda like not using the choke on a cold lawnmower.

yes I have VOM, I will check that.

Thanks T.

Post by **cn90** » 23 Oct 2012, 14:02

1. ECT: SWF is OEM, about $40.

2. Fuel Relay guide:

DIY: 1998 Volvo V70 Fuel System Troubleshooting Tips
https://www.matthewsvolvosite.com/forums ... =1&t=52252