Hello, I have a 1995 Volvo 850 GLT wagon with a 5 cyl. non-turbo 2.4. I went to start it one day and it sounded like it popped threw the throttle body. (I thought it broke the timing belt) I was told to try changing the plugs and it now it sounds like it wants to start. I checked the timing belt and turned it by hand to line up the marks according to the manual and the marks and the belt seem to be okay. Wondering if anyone had any ideas on if it is maybe ignition or fuel issues related with these cars.

Thanks for any help, Russ

 

Maybe something blew like the ignition coil or something. For a car to start you need fuel, air and fire. Do you have good fuel pressure? Do you have spark? Do you have any codes?

 

Do you have a good strong spark (snap) at the plug ? If you have carbon tracking or condensation inside the cap it can easily cause a backfire when trying to start. Take the cap off and inspect it carefully. If you see anything odd, dirty or signs of water get a new one. If you don't see anything but you're not sure last replacement pull the rotor too and get both. It's cheap insurance.

Inspect the wires too as the spark can jump from wire to wire when they get older and start to crack. Since they all get bundled together under the cover as they run to the plugs it's a perfect area for them to short out wire to wire. Pull the cover and in the evening when it's darker spray a little water (mist) on them and look for an arc. If they are shorting out you can hear them snap too.

These would be the logical choices as you say you've pulled the cover and lined up all three timing marks. Both of these could be causes of it popping back through the intake and making it difficult to start.

 

thanks for all the info, I'm going to try a cap and rotor then maybe a crank sensor. the plugs are new. I will also check fuel pressure, and the wires. Any other info would be helpful if any one has any other Ideas.

Thanks Russ

 

The wires have a date stap on them. It is week/year, so 27/06 is June of 2006. If the wires are newish, not older than 7 years, I would think they are fine. I really don't advise tossing parts at it. Check for fuel pressure, if you don't have good pressure, then jump the relay and see if the pump is putting out good pressure. All because you hear the pump doesn't mean it's sending the correct pressure to the injectors. If fuel pressure is good, check for spark. If you are getting spark to the plugs, it must be another issue like air control or timing.

The best way to check for spark is to pull a plug and lay it on the motor and have someone crank it over. You should see a spark at the tip of the spark plug. As it cranks the spark should happen every cycle. If you don't have spark, I would try the coil wire. If you have no spark off the coil wire, then I would replace it. If you do have spark from the coil wire but none at the plugs, I would replace the distributor and cap.

The thing is, you said that it sounded like something electrical exploded. If that happened it could easily take out more than one part but try to limit the parts by doing a little trouble shooting.

 

I'd hold off on that crank sensor unless you know you have no spark and you've done some diagnosis on the system and at least checked the resistance/voltage of the coil and ignition module. You can throw a lot of parts and not hit the problem.