I have a 1995 volvo 850 (non turbo gas). Over the last few months it has been difficult to start. I crank it for about 5 seconds then stop and try again. It often will take three tries at this before I hear the engine start to catch. At this point I let go of the key and the engine catches and runs no problem. I have had no issues while driving with sputtering or stalling. Once the engine is warm it will start first try no hesitation. I do live in a cold climate but whether its warm or cold seemingly has no effect, the same procedure is required to start.

Today, after five tries the engine would not catch. Now it's time to start troubleshooting this issue.

Any suggestions on what these symptoms point to and some ways to troubleshoot them? Fuel pump relay, fuel injector relay? Does the fact that the car runs fine once started indicate fuel pumps are ok or might these be the culprit? Does this sound like a fuel problem rather than an ignition problem?

 

One way to quickly determine if it is a fuel or ignition problem is to let the car sit until it is cold, then spray a quick 2 second burst of starting fluid into the air intake tube and try to start the car. If it starts right away, you have a fuel delivery issue, if not it could be spark or air, or at worst timing (but since you said it runs well after starting I doubt it is timing.

When was the last time it had a full tune up..(oil and filter, air filter, fuel filter spark plugs and wires).

 

Does it start differently when the engine is warm vs cold? It sounds like you have trouble first thing in the AM from a cold start, how about when its been running and you restart after an errand? Its possible you have a temp sensor issue if so. Also, do you notice any black smoke from the exhaust immediately after a cold start (ie a small puff?) - this can be caused by a leaky fuel injector... Its also possible you are losing pressure in the fuel rail which needs the cranking time to build back up.

 

nice thread, This is very useful because I also have the same

 

It is a cold start issue, once the car has been driven and comes up to temperature it starts with no issues. Would this be a symptom of losing pressure in the fuel rail? If so, is this a fuel pump issue or maybe a cold climate issue?

I can't say I have noticed black smoke but if I did, it would be difficult to suspect only the fuel injectors for this because there is some oil consumption and lots of 20 year old seals around the engine.

I have only had the car for one year so don't know much about past maintenance. I changed the oil and oil filter 6 months ago (less than 5000km).

The car started today on the second try. Obviously this is still an issue but now it is a bit harder to troubleshoot since the car actually starts. Are the fuel system/fuel injector relays known to need replacement? Is it possible that the relays or pump can stick sometimes? I'm not sure if this would support the symptoms of a difficult cold start and a perfect warm start.

 

Is the check engine light on? If so, get the codes read at a local auto parts store and report back what they are. IF not, it might be a coolant temperature sensor issue. That is a small sensor located right below the thermostat on the thermostat housing flange. Very easy to change. I don't think it is a fuel pump or relay problem since the car runs fine once started and warm

 

Thanks for all the suggestions. I replaced the fuel pump relay first because it was the easiest thing to try and that has fixed the issue. She started on the first crank today despite the air temp being -10 celsius.

 

As a follow up, it turns out the problem is not solved. It is true that when we replaced the fuel pump relay the car started right up, but the next morning it was hard to start again.

We have replaced:
-fuel pump relay
-fuel pump
-fuel filter

The car runs great, very smooth since all the work to the fuel system. Now we are looking more closely at the ignition system.

When the engine is cold the starter cranks but the engine doesn't start until we release the key from the 'start' position. At this point the engine stutters to life then runs perfectly in idle and while driving. This is very consistent when the engine is cold.

When the engine is warm (after driving for a while) it will start perfectly.

We pulled the codes from the ECU OBD I. Nothing except for in the ignition port (6) we got one code 2-1-4 which is Vehicle Speed Sensor Intermittent. After clearing the code and going through the hard-to-start process we didn't get any codes, so not sure if the VSS code is related. Is this the same as engine speed sensor?

Is it possible to do further diagnostic with respect the the individual sensors in the ECU?

It seems like the Ignition Control Unit isn't sending signal for spark to the coil until the key is in the 'on' position as opposed to the 'start' position. Is it possible that the coil is not getting enough voltage when the starter motor is turning?

We don't have any other issues with the dash lights or accessories.

Previous suggestion was Engine Coolant Temp Sensor - is it possible to diagnose this? Or do we have to replace it to know for sure. The thermostat was replaced 2 years ago but the ECT sensor was not.

 

This is likely your problem. When they get real bad they will toss a code. There is a way to test the resistance but I'm not sure how. I would replace it if I were you.

 

If the ECT sensor is faulty, would the car run smoothly as soon as it starts? I would expect it to be rough until the engine gets up to temperature but this is not the case. As soon as it starts it idles perfectly.

I know this is relatively easy and cheap to fix but I will have to take it to a mechanic for this so I want to rule out or include other possibilities.

Is it possible to rule out crankshaft position sensor/vehicle speed sensor?

Does this definitely sound like a sensor issue?

 

Yes, you can find out the resistance limits and test it.

 

Is the ECT sensor responsible for the temp gauge readings as well? Our temp gauge reads normal and shows no signs of problems, does that rule out the temp sensor?

 

We replaced the spark plugs two weeks ago and this completely solved the problem of the car being hard to start when cold. She starts perfectly every time.

 

I am having a similar problem and my mechanic wants to replace the ignition control module but i havnt been able to find the part, have you had any luck with this?

 

I've never seen one go bad. Can't say. I will say, however, it is awfully easy to figure out if you have ignition events at the proper time or not. The ignition module is a timer only. These cars have a crazy low spark plug gap. lowest one I ever saw. That needs to be respected when you start questioning whether you have spark or not.

 

Genuine - you commented on a very old thread - are you talking about an 850 - if so what engine/year?

Cold start problems are usually related to one of a few things a) low fuel pressure at the rail. Normally some residual pressure should stay even overnight but a leaky injector or fuel pressure regulator can bleed it off - meaning the fuel pump needs to run a bit longer to build pressure back again. A simple test is to jumper the fuel pump relay to build pressure without running the engine, then try starting. If you can get access to the vacuum line on the fuel pressure regulator (not easy on the 850s as its under the intake manifold) - if you pop it off and fuel drips out, then you know you need a new regulator. b) weak spark. If you don't know when the rotor/cap/wires/plugs were done, that's a good place to start. These cars run best on copper core plugs gapped to.028 (.7mm or so). Check the date code on the wires - should be less than 5 years old and inspect the rotor/cap for corrosion (emory cloth or wet/dry sandpaper can clean up some of the corrosion). c) wonky engine coolant temp sensor. You can measure the resistance of the temp sensor by unplugging in and using a VOM. A cold sensor (ie 60-70F) should be in the 3000 ohms range (colder it is the higher the resistance). A warm engine (say 180F) would be under 300 ohms so anything in the ball park of 2500 ohms or more should tell the ECU the engine is cold. d) intake air leaks. If your car has a clogged PCV, that can start popping off vacuum lines. One place to start is to inspect the vacuum "tree" under the throttle cable spool cover. Next is to spray around with some carb cleaner to see if any gets sucked in.