Hello, i have a 97 s90 and did a tophead overhauling. After that i cant start the car. I have fuel pressure but due to age plug of wires r falling apart. Cant chk compression due to lack of tools. Checked ground off from coilpack and ground is not so solid. Could this be possibility of fail to start? It cranks.

 

I'd recheck the cam/crank timing just to be sure for starters. certainly any plug/coil issues will keep you from starting so you may want to do a freshen anyways. After that, if you cleaned the pistons/cylinder walls during you work, you may have washed off some of the oil so it may need to crank up some oil to build compression. Take a look at your spark plugs too. if they are oily/wet looking they may be fouled and need to be cleaned.

 

Use only plugs with the small gap (0.024 to 0.028") as recommended in the owners manual. A number of places sell surface gap plugs for the S90/960, but they will likely not work as the gaps are too large. The individual coils just have switched 12 V in the same fashion as older US cars, not the much higher voltages used in more modern electronic ignitions.

The coil connectors fail (rubber inside rots), but you can simply cut away the connector part and plug the individual wires into the coils (be careful not to change polarity). I eventually put on new plugs, but drove the car for many miles before that.

 

Thanks. I will check those aswell. After putting new cables, no more slow crank but still no start. Ifever what are the voltages goes into ignition coilpack.

 

It still wont start. By the way i read threads here and there, seems like even though same car if ecu is different trouble shoot testing procedures are also different except basic logical tests. Mine is motronic 4.4.

 

I tested crankshaft sensor and ohm came out 307. Not sure thats normal or not. How can i test camshaft sensor. And connector socket broke off long time ago and just want to make sure i got it correctly. How can i test which wire goes where. 3wires coming out from camshaft sensor red, green, blk. Color from engine wiring harness is different.