My 1990 volvo 740 wagon will not start. For a whil, it would only start when cold, not when warm. NOw it won't start at all. I took it to one mechanic, and he said the MAF was out. My current mechanic did a vacuum check on the car, and when the car is starting there is no suction in the car, so he feels the diagnosis of a faulty MAF was incorrect; stating a lack of suctin would make the MAF look bad when it wasn't.
Fuel is not getting to the engine. Fo a while, I was using carborator fluid to start it up, and then it ran, but this isn't working anymore. The car idles badly, and my mechanic thinks it's a valve problem. He wants to do a compression check. Ignition is sparking. Any ideas?
Vacuum problems --car won't start
Hi Stan,
The symptomes could be caused by reduced valveplay. This can easily be checked with a feeler gauge. Act as following: dismount the valvecover and measure the valve play under the cams. Measure when the cams are pointing upwards. You can turn the engine by hand on the belts (watch your fingers). Gear handdle in free! The play should be between 0,25 and 0,35 (0,3 and 0,4 with warm engine). Altering the play is possible by changing the shims. They can be removed with a valvelifter. Note: lift the valves only in a safe position!! Otherwise the valve can be pushed in the piston. Good luck!!!
The symptomes could be caused by reduced valveplay. This can easily be checked with a feeler gauge. Act as following: dismount the valvecover and measure the valve play under the cams. Measure when the cams are pointing upwards. You can turn the engine by hand on the belts (watch your fingers). Gear handdle in free! The play should be between 0,25 and 0,35 (0,3 and 0,4 with warm engine). Altering the play is possible by changing the shims. They can be removed with a valvelifter. Note: lift the valves only in a safe position!! Otherwise the valve can be pushed in the piston. Good luck!!!
It would take a major event for the valve clerences to cause a no run situation.
An engine needs 3 things to run: compression, fuel, and spark. You say you have spark, but if there is no fuel .... You need to check fuel delivery, on a EFI system this requires a fuel pressure gauge. Common problems with Volvo's are the fuel pump relay, the fuel filter (if it has not been replaced for some time), and the fuel pumps.
Another possability which I would check first is that the timing belt has jumped a tooth. The timing belt should be replaced every 60,000 miles, with wear it can skip and will cause a misalignment of the camshaft with the pistons. When the camshaft does not open the valves at the correct time it will cause low or no compression, ignition timing will also be incorrect. If it has only skipped by one tooth I have seen the engine run but very poorly.
I would suggest that you follow a logical diagnostic sequence. Buy a service manual, the Hayes or Clinton will work. First check the ignition timing, if the timing belt has skipped this will show it right away, then follw what I have mentioned above, fuel pressure.
Let us know what you find out.
An engine needs 3 things to run: compression, fuel, and spark. You say you have spark, but if there is no fuel .... You need to check fuel delivery, on a EFI system this requires a fuel pressure gauge. Common problems with Volvo's are the fuel pump relay, the fuel filter (if it has not been replaced for some time), and the fuel pumps.
Another possability which I would check first is that the timing belt has jumped a tooth. The timing belt should be replaced every 60,000 miles, with wear it can skip and will cause a misalignment of the camshaft with the pistons. When the camshaft does not open the valves at the correct time it will cause low or no compression, ignition timing will also be incorrect. If it has only skipped by one tooth I have seen the engine run but very poorly.
I would suggest that you follow a logical diagnostic sequence. Buy a service manual, the Hayes or Clinton will work. First check the ignition timing, if the timing belt has skipped this will show it right away, then follw what I have mentioned above, fuel pressure.
Let us know what you find out.
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TheVellasr
I have an old 850 which has been excellent for the short period tha I have owned it.
The dreaded lambda light has always been lit but I have been told that this is quite common.
Three of the 4 back lights have failed whithin a couple of weeks of each other and I put this down to the force which my better half uses to close the boot.
A few weeks ago the service light illuminated but everything else worked fine. I was told that this is no indication of anything wrong just a service may be due.
I have noticed that if I fill her up the fule guage sometimes goes off the top and sometimes sticks at empty but this goes way after a few miles.
Then last week I drove somewhere and stopped. On trying to restart the car if refused for a few times but eventually did so.
The same happened on another occation. In between refusals and after starting it runs fine.
Now I have been unable to start for some time and am getting worried!
Any ideas?
The dreaded lambda light has always been lit but I have been told that this is quite common.
Three of the 4 back lights have failed whithin a couple of weeks of each other and I put this down to the force which my better half uses to close the boot.
A few weeks ago the service light illuminated but everything else worked fine. I was told that this is no indication of anything wrong just a service may be due.
I have noticed that if I fill her up the fule guage sometimes goes off the top and sometimes sticks at empty but this goes way after a few miles.
Then last week I drove somewhere and stopped. On trying to restart the car if refused for a few times but eventually did so.
The same happened on another occation. In between refusals and after starting it runs fine.
Now I have been unable to start for some time and am getting worried!
Any ideas?
First I would post this question in the correct Front Wheel Drive forum, more people in that forum may have expeience with this type of car.
Second, whenever a warning light comes on it is worth checking, very seldom a warning light will activate when there is no problem. These lights, triggered by the ECU, will warn of a sensor or reading being out of the normal or acceptable range. A sensor may be sending this "out of range" signal because of a fault in the sensor, or because of a problem within the system it is reading. In either case the engine is not running at its highest efficiency or reliability and should be checked before serious engine damage is done or the vehicle leaves you stranded..
When the warning light goes on a trouble code is set, this code can be read and the problem quickly identified.
Second, whenever a warning light comes on it is worth checking, very seldom a warning light will activate when there is no problem. These lights, triggered by the ECU, will warn of a sensor or reading being out of the normal or acceptable range. A sensor may be sending this "out of range" signal because of a fault in the sensor, or because of a problem within the system it is reading. In either case the engine is not running at its highest efficiency or reliability and should be checked before serious engine damage is done or the vehicle leaves you stranded..
When the warning light goes on a trouble code is set, this code can be read and the problem quickly identified.
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