1998 S70 T5 - hard cold start

Post by **erikv11** » 02 Mar 2015, 08:39

I agree the MAF sounds fine. The behavoir you describe is typical, better to not do the plug/unplug while the car is running. Shut down, then restart, etc.

ECT is still a decent possibility, if it was only marginally bad before then it could be a little worse now. Did you at least look at the ECT connections? Sometimes they get crusty and corroded. It is only a guess but you don;t have a lot more to go with.

Cam position sensor and crank sensor are also decent guesses, especially cam sensor. Do you have a good CPS you can swap in?

shegarty · Post by **shegarty** » 03 Mar 2015, 10:49

So, I bit the bullet and ordered a new ECT sensor and an 87ºC thermostat as I have a feeling that a 90 or 92ºC is installed as the gauge reads slightly higher than 3 when warm. I also stumped for a cam sensor and will replace that as well. I already replaced the cam seal behind the distributor and figure if that was leaking the seal on the cam sensor is probably leaking too and will need to be replaced.

On a related note, since swapping out the MAF it seems to be running a bit smoother. Maybe its just me but previously there was often a shudder on deceleration coming to a stop as the revs dropped below about 5-600rpm and then jumped back up. This may have been around since purchasing the car but I only noticed it after replacing the upper engine mount. That shudder is now gone and the idle seems to be much more stable on deceleration ... then again maybe its just me

Will post back with update after new parts are installed or if she gives me more trouble - here's hoping for the former!

shegarty · Post by **shegarty** » 22 Mar 2015, 18:58

So, I replaced the ECT sensor two days ago and everything went smoothly. Put everything back together and she started and ran great yesterday when the temps were about 4ºC. We've hit another cold snap here and the temps dropped to about -8ºC today and when my wife went to go out this evening she refused to start ... again! Checking the ECU inputs from the new temp sensor indicate that it was reading slightly above ambient temp (by about º4C) ... could this be as a result of the repeated starting attempts? I was able to get her to turn over and fire but could not keep it running despite my best efforts at feathering the throttle. As a result of the repeated attempts I now have the charger on as I ended up draining the battery.

One thing of note that I talked to my wife about, she sometimes in her haste forgets to do a two count after hitting key position II before attempting to crank the engine. I am thinking that this might be contributing to my problem tonight by flooding the engine. I am going to let it sit while it charges and then try starting it again in a few hours.

BTW ... I also ordered a cam position sensor but have not had the time or warm enough weather yet to swap it out but that is next on my list.

shegarty · Post by **shegarty** » 05 Jan 2016, 05:33

So, back to this again. During the warmer months after replacing the ECT sensor I replaced the both the crank and cam position sensors. Still the same no start issue in -17°C weather. The hood latch is frozen shut as well so no chance of trying the swap the fuel pump relay! I'm pretty sure its not the fuel pump relay though as I remember trying that before ... any other ideas???

Post by **mecheng** » 05 Jan 2016, 06:53

Did you try bypassing the relay with a wire? Are all your ground wires tight/non corroded? Is the ECT Volvo blue box?
How old are the plugs?
BTW: I love port hope, beautiful little town.

shegarty · Post by **shegarty** » 05 Jan 2016, 08:55

ECT sensor was SWF brand which I was under the impression was OEM. I have a vague memory of doing the fuel relay bypass last year but that might have been when I was having trouble with another no start diagnosis. It is supposed to warm up here later today which means she will likely start with no problems. Temperatures are supposed to be around 0 for the next while so right now I am just collecting ideas. When it warms up I have a spare set of plugs that I'll try swapping. Thanks for the ideas ... anyone have any others?

Post by **cn90** » 05 Jan 2016, 09:06

- Hood cable and hood latch lubrication: move the car to a warm garage for consider cleaning the latches. At this age, I'd replace the hood cable (I posted a DIY for it in forum).
- Tune-up items: review all the ignition stuff (Bougicord, Bosch Cap/Rotor, spark plugs).
- Fuel Filter: how old?

- Consider adding some Techron stuff just in case there is some water in the fuel. tank.

Post by **mecheng** » 05 Jan 2016, 12:23

SWF is OEM, so you are good. Sometimes the connectors are corroded, mine were I sprayed them down with WD40 and a brass brush.
I don't replace spark plug wires until they fail the water arc test, I doubt yours are bad unless they are aftermarket.

It would be a good idea to inspect plugs to see what is happening to the engine and lubricate the threads. You could have a very large gap in them making them hard to fire. Cap and rotor may be excessively worn as well which I doubt but still good measure to check.

And yes, if you are handy you can open the relay and inspect for solder cracks using a magnifying glass. You will be surprised at what you will see. I reflowed all the large joints.

Post by **scot850** » 06 Jan 2016, 23:15

How is your battery? Have you had it tested at low temps to see if it is producing enough volts to start the car?

Also test your alternator at low temps to see if it is outputting sufficient power when really cold.

Check earths and battery/alternator/starter leads are all in good condition and no/minimal corrosion. Check the B+ cable up to the main fuse box and pay particular attention to the end in the fuse box. IT should be bright and shiny.

Have you checked the fuel pressure at low temps? Should be >43psi.

Remove the distributor cap and check for wear and corrosion on the cap and the rotor arm. Also check the cam seal is good behind the distributor and not leaking oil into the distributor.

Neil.

shegarty · Post by **shegarty** » 11 Jan 2016, 18:08

Got the hood latch lubricated and it is now working as it should. We had some wet weather and a cold snap during which time the car wasn't driven. I don't have a guage to measure fuel pressure but I did replace the filter just a few months ago. Also have relatively new cap and wires and a new cam seal behind the distributor as the old one caused a previous no start condition. Solenoid is also good. Battery is new this past fall as the old one was getting weak. Alternator puts out good charge even when cold, new serp belt with recent timing belt replacement too. Most of the connections look clean to me but I will check the cable up to the main fusebox and also try the fuel pump relay bypass if she acts up again now that I can get the hood open. Thanks for all the input folks

1998 S70 T5 - hard cold start

Re: 1998 S70 T5 - hard cold start