My advice is to always start with the basics. It's important to know that in a 90 Volvo, the engine can produce spark and run the pumps even if the timing belt breaks.

So, you need to check if the belt is ok. A visual check of the belt is not enough. Often the belt will remain intact, as in not parted, but it will strip teeth off at the crankshaft sprocket. The crank will turn, the cam will not. You can either look in the oil cap hole, or remove the distributor cap and observe the rotor, while someone cranks the engine over. Movement of the cam or rotor indicates an intact belt.

Now the belt could jump a couple teeth. This can happen if foreign objects fall into the belt. Recently fixed this on a similar car and saw evidence that it could happen again on my car and one other. The timing cover can break, losing chunks of plastic into the cam belt area- these pieces can make the belt walk over one or more teeth on the pulleys. At one tooth off, the engine will run poorly; at two teeth it's likely to die completely and never restart.

The crank pulley mark needs to be set to the zero line on the timing cover, then the upper mark is checked. There's a dot punched into the cam gear, and it should line up at about 11'o'clock with a little mark on the top of the back timing cover. If it's off 180° just turn the engine once over and recheck. If the cam is off significantly in either direction, this must be resolved.

If all that works out OK, you need to verify that strong spark is in fact reaching the plugs; that the plugs are clean; and that you have fuel system pressure.

The 90 is not exempt from problems with the -561 engine computer. Pull off the RF kick panel inside the passenger compartment to check the last 3 digits on the computer. If it's a -951 you should be in good shape. If it's a -561 it may be suspect.

While you're under there, look up on the firewall for a white relay about 1x2 inches. Part number should be 3523608 and it should have a date code. It's your fuel pump relay; if it's over 6 years old, replace it too. If that doesn't change anything, you'll have a spare. This is the #1 part that causes no-start conditions BUT it isn't the problem in your case, if you do in fact have running fuel pumps.

Good luck with the diagnosis!
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::: Rob Bareiss, New London CT ::: 92 244 M47 211K ::: 90 745GL M47 273K ::: 88 245DL AW70 190K ::: 84 242DL Project ::: 70 VW Bus ::: 70 VW Pickup Project ::: 71 VW Notchback :::