Had to replace the water pump a few weeks ago. Since I was half way there, I decided to replace the timing chain & gear set (SA Gear). I also replaced the spark plugs (Bosch OE Fine Wire Platinum .040 gap), wires (Autolite Pro Series 7mm), distributor cap & rotor (BWD). Nothing I put on was high quality, but it wasn't my cheapest options.

When I put the new timing chain & gears on I made sure the timing marks were vertical with each other and I know the plug wires are on the distributor cap in the correct order.

The engine starts just fine and seems to idle without hesitation, but when the accelerator is applied, the engine sputters a little. I took it out on some back roads tonight and notice definite hesitation and quite a bit of backfire coming from the exhaust. This makes me believe the timing is off.

I believe the timing is electronically controlled, but am not positive. Maybe somebody could confirm? Can the timing be adjusted with an OBDII scanner? Or maybe rotation of the distributor or a sensor?

Any help is greatly appreciated!

 

any time you change the timing chain.. you rotate the engine 2 times around and recheck the timing marks..

it the timing marks ARE OFF.. the computer can not correct for it... as the electronics control the time of the spark... NOT the time the cam opens or closes the valves.. that is mechanical

 

Did the timing set you use have multiple key-ways on the crank gear?

If it's a tooth off, or on the wrong key-way, the computer can't adjust for that.

 

I did not rotate the engine to verify. The gears only have 1 key-way. I guess I made the mistake of thinking since there was only one way to put it on, it can't really go in wrong. So since the timing is electronically controlled, is there any other way to check it without taking things apart again to check the marks?

I have been doing some other research regarding this issue. Since it starts and seems to idle ok, could the fuel sync settings be off a few degrees?

 

You can remove your driver side valve cover and crank the engine over by hand until the timing marks line up on the timing cover. Look at the valve rockers on Cylinder #1 and confirm that they are both uncompressed. Before you do this, you'll also want to remove Spark Plug #1 so that you can confirm that Cylinder #1 is at the top of it's stroke when the timing marks are lined up. You'll want to do this by sticking an object, like a dowel rod in the hole, to tell when the piston is at the very top. Be careful to not let it break off in the hole, retrieving it would not be fun.

The fuel sync has to do with the Camshaft Position Sensor (build into the distributor housing) and the Crankshaft Position sensors being aligned. The way to adjust this is by turning the distributor. Did you turn the distributor while you did your timing chain? If so, your best bet is to let a dealership do it, or someone with the Snap On MT2500 scanner.

When I did the timing chain on my 5.9, I just took the old one off, and put the new one on. I was careful to not move anything, and hadn't had any problem with it.

 

All I did was remove the old gears & chain, then replace with a new set. I have 210,000 miles on this engine and expect they were original base on the amount of slack in the chain. I did not loosen or rotate the distributor. I only replaced the distributor rotor and cap. I made sure the rotor was at the #1 mark and the mark on the harmonic balancer lined up with TDC when I replaced it.

I'll pull the valve cover and take a look at the cylinder position. Is there a gasket or RTV on the covers that should be replaced?

Since it starts fine and seems to idle fine, I'm just kind of at a loss.

 

1997 I think you made an Error.. #1 on compression.. both valve springs should be uncompressed.. or all the way up.. Not compressed.. valves Closed on compression.

most likely you forgot to TYPE "UN" on compressed

 

Chuck, you're right! Springs should not be compressed. Missed a word...

You can replace the valve cover gasket, but I've re-used valve cover gaskets before without issue. If it's the original, I'd probably replace it though.

Coby, if your valve springs are uncompressed at TDC, then you're timing and fuel sync are probably fine. I'd reset the PCM by unhooking the battery for a half hour or so, and hook it back up. Let us know what you find out.

You might try asking over in the 2nd gen section, a lot of guys there are pretty familiar with the 5.9.

 

Thanks for all your help. I'll take a look and let you know.