89 740 GL...help, no rotate

I was all wrong, (shows you how much I know), I got the wife to turn ignition key and watched, rather than listened. Although it sounds like the engine is not turning, it IS, all the accessories are rotating, and camshaft is rotating also. Since the crankshaft has to be turning, then the pistons are doing their up/down thing. Also I checked for a spark at plug wires, and that is good. But I have heard this car with dead ignition and seen how it sounds turning over, and it was not like this electric motor whirring sound. But if the pistons are doing their thing, camshaft turning, and there is spark...then it's maybe just not getting fuel? I don't have any troubleshooiting info on it so I am a bit in the dark on the fuel system.... like totally. thanks.

Well first of all, it's not a Bendix gear. The starter works by a solenoid pulling the pinnion into engagement. I think you probably understand this to be the case, but a Bendix gear works differently, and you are unlikely to see one on a car less than thirty years old. You will confuse the issue on end if you refer to something that your car hasn't got.

Try a jumper directly to the terminals of the starter. In theory, you can simply put a screwdriver from the big terminal on the solenoid that comes from the battery to the little one (or if access is difficult to do this carefully, use a flylead from the little terminal to the battery). This should both engage the pinnion in the flywheel, and then turn the starter motor, so make sure the car is in neutral or park when you do it - you will bypass any starter lockout. If you bridge the two big terminals on the solenoid, the starter should run without the pinnion engaging - it will just whir away. If you take off the main power lead (be careful, this is permanently live from the battery - avoid grounding it) and touch it to the solenoid connector you should clearly hear the pinnion moving (that loud click) without the motor turning.

If this produces the same result, take the starter off, and try it on the bench, so that you can see if the pinnion is moving properly and to its fullest extent.

I suppose that it's possible that what you are hearing is the engine turning over, but with a busted cam belt. It will turn quicker and sound different like this.

Stewart, Here is what I have found so far: There is not even the slightest amount of firing/ignition. The engine is definitely turning over with new starter....it doesn't really have anything to do with the starter. It doesn't at all sound like the normal crank noise, there is just that not-very-loud whirring of the starter motor, and you can see all the accessories turning. I have visually checked the camshaft by looking in the oil filler hole..it is turning. The timing belt is intact and turning. (The bottom of the timing belt cover has cracked off, so I could see a portion of the belt without taking the belts and pulleys off, or anything apart) I have spark at each spark wire boot. The spark is jumping about a

3/8 to 1/2 in gap to the block. I installed a new set of spark plugs, the old ones were in bad shape. Checked the forward piston, and it is indeed moving up/down. I cracked the fuel line nut loose where it connects to the fuel rail (figured out it is fuel-injected), and fuel was shooting out under high pressure when cranked. I put a DVM on the fuel injector connectors, (have no scope) and on the AC scale I could see *some* sort of a voltage pulse on each one when cranked, so the the injectors are being pulsed to open/close. So it looks like fuel delivery is probably OK. I have turned the engine over with a ratchet on the damper bolt, and it turns real easy....but there is *some* resistance there. I am not experienced enough to know whether it is a normal amount of resistance that you would have when you are working against cylinders with good compression or not. So what is making this engine DEAD? It's looking like I am going to have to get it towed to a shop and pay big $$$$ to get it fixed.

compression

Might be cheaper than starters you don't need. Maybe the battery is not so good even though it cranks, you could try jumping it just to eliminate that.

You are doing the right thing by checking all this. Some faults you only find by eliminating stuff. According to engine theory, if you have air + fuel, compression, spark and exhaust, then you have an engine, but all these things have to happen at the right time.

The following things occur to me:

Your comment that "It doesn't at all sound like the normal crank noise" is a bit of a worry. But I wonder if it is something simple like a poor battery not cranking very fast. Cranking the engine takes a lot of energy, and if the battery is failing, there may not be enough juice to make a good enough spark to withstand the rigours of compression.

You saying "..it turns real easy" is also a concern. If you can get hold of a compression tester, check the cylinder compressions.

Make sure the airways of the inlet tract are all clear.

Possibly the timing belt has slipped. Take off the top part of the belt cover, turn the engine to TDC. With piston 1 on its compression stroke you should be able to see a timing pip on the top sprocket line up with a mark behind it. If it has slipped you need to investigate why.

I'm guessing that you are in a part of the world that had some sort of engine management control by '89. If this goes wrong you may need specialist equipement to diagnose it, or a means of reading some fault codes.

Pull a plug and see if they are wet. If so dry them out, disconnect the coil, cover the fender and spin the motor with the starter to blow out any liquid fuel that is in the motor. Squirt some oil in the holes if the cylinders have washed down with gas . Spin the motor a few more times to distribute the oil on the cylinder walls. Notice if any gasoline is puffing out of the spark plug holes. If none comes out check the fuel injection relay.

Pull the ashtray to access the fuse panel. Pull off the cover the lighter, remove the two phillips screws. Pull the box out and disconnect the wire to the lighter and the wires to the bulb that is there. Remove the white relay on the left side of the electrical unit. Using a small screwdriver spread the bottom of the relay case and slide the relay out of of the case. Reinstall the relay, sans case, back in place. While touching the tops of the relay with your finger (you won't get shocked) turn on the key and notice which of the two relays on the common board clicks. The first will be power to the control unit, the second should latch when the motor is cranking. If it doesn't close pull it closed with your finger with the key in the run position and you should be able to hear the fuel pumps run. If you can make the fuel pumps run, try starting the car with the key while you hold the fuel pump relay shut with your finger. If it starts, the fuel pump relay is defective and you can either replace it or try to reflow all the solder joints on the circuit board the holds the relay coil assemblies inplace.

Bob

I agree - the description sounds like loss of compression, and the cracked lower timing belt cover makes me wonder if the belt has ever been changed.

The good news is that the engine is non-interference - if the belt is jumped you only need to replace it.

Mike

Fuel pump relay probably needs resoldering.

I mentioned that I had loosened the fuel line nut where it joins the fuel rail, cranked the engine, and fuel under high pressure spraayed out. So the fuel pump relay and pump must be working.

I am thinking that since the engine spins so easily, like there isn't the usual load on the starter (the load of cylinders under compression), that the timing has jumped way off. The timing belt is still intact and doesn't look loose....so I am not sure how that could have happened. I've had no luck locating a Haynes' manual for the car, so I am clueless as to how to check/set timing.

The timing belt won't be loose, they just strip teeth off the inside face and sit there as if nothing had happened. The pulleys might even still turn... a bit. And you might see some teeth down the bottom.

Open the hood & read off any DTC'S from A2 & A6 & post back so I might be able to assist you with your problem Glenn

Success!!!!! The starter had the unusual sound, like spininig with no load, because the timing belt somehow jumped way off. Its funny because all the teeth look fine, and it had plenty of tension. The harmonic balancer is still locked on to the crankshaft, so I don't know how it could have happened. It's time for a new belt anyway,so I am going to replace it as a precaution. Maybe the teeth have worn down form their original height.

Now I have another problem. The brake booster is not working. I figured I must have left a vacuum line loose or induced a leak. The brakes were working OK before the breakdown. Now you have to go all the way to the floor, and each time you depress the pedal, you hear a "woosh" sound of air. I pulled the vacuum line going into the booster out, and it has a good strong vacuum there. The idle seems a little rougher/ more unstable than it was before, could be a vacuum leak? Same leak that is messing up the brakes? So I am going to have to invest in a manual and get a vacuum tester, I guess. Any ideas what to check? Thanks to everyone who responded!!!!

Just a layman's guess, but sounds a bit like the belt is still wrong... maybe just one tooth, not sure what effect that has but then it might not pull enough vacuum at idle. Anyway I wouldn't trust it to the end of the driveway, they work fairly hard.

Well done for finding that out, though I have to say that you still need to be a little cautious - something caused it to slip; it didn't just happen. Replace the tensioner at the same time - it's cheap and easy.

Also be aware that the crank pulley is a composite unit, with a rubber insert between the metal inner and outer parts. If this starts to fail, the timing marks can mis-register.

Hmm. If the servo (booster) fails, the brakes become much harder work. The pedal will not descend further. If this happens there is a problem with the hydraulics, typically a failing master cylinder.

It could be. A common problem that affects idle is an induction leak from the injector seals.

I reckon it must be time for a full service to this car, including attention to all the parts that may be liable to fail after 15 years. Sort out all that is wrong with it, including all the parts that need regular service attention, and you should have a car with a few more years in it yet.

Excellent idea; it's a good investment.

The vacuum check valve on the booster is a flimsy (but not cheap!) plastic thing. Check around the back of the valve for cracks - mine popped all the way off and I epoxied a coin in place rather than spend the $35 US (IIRC) for a new one ;-}

It is also possible the brake booster is bad. Mine died with pretty much the same symptoms because the master cylinder quietly leaked fluid into it. The Volvo price was something outrageous, but they are plentiful at wrecking yards and an easy DIY job to change. IIRC there are only two styles from the

80s, differing by the mounting bolt pattern.

Mike