'98 5.7 PCM ignition timing procedure

[broke_not]

Hi,

New member here with a question on setting the initial ignition timing on an APEX 5.7 engine in a '98 Nautique. I just installed a fresh long block, and was wondering if anyone here has the procedure for setting the timing when the distributor is dropped back in?

I had the original engine at TDC on the number one cylinder compression stroke, and carefully marked the distributor body to intake manifold relationship. I also marked the distributor rotor position prior to removing the distributor from the original engine. This got me in the ballpark, (engine starts and runs fine), but I understand there's a procedure for correctly setting the "base" timing....since the engine ECM actually adjusts the timing on the fly while running.

The timing spec is in the owners and engine manuals, but the procedure isn't listed.

Anyone?

Thanks!!

[nms1991]

RE:

The only way I know of is to use the diacom system to set the base timing of the motor. If you have a dealer willing to set the timing for a reasonable price that may be your only way.

[AirTool]

RE:

The ignition timing is not adjustable in any way. It is all controlled by the ECM using information from the crank position sensor.

What turning the distributor changes is the camshaft retard....or in easier terms...the camshaft position sensor. Forget what the data is used for. Your question is how do you set it and and what is it set at? You have to use a scanner to set it and the range is + or - 2 degrees. (I believe from #1 top dead center.) If you marked the distributor, you are probably okay. On the autos, the check engine light comes on when it is out of spec. I don't know if that is the case for the boats.

What I did to set it in my truck was move the distributor in small increments until the light came on and marked that position. Then I went the other way until the light came back on and marked that. Then I put the distributor in the middle of the two marks and the light is out.

You should mark your current position (in case the light trick doesn't work) and give it a try. The camshaft test runs in the ECM just after starting the engine. The old code can't clear until the throttle position sensor reports throttle movement to the ECM. So if this trick works in the boats, you'll have to restart the engine and stroke the throttle after every move.

Try it if you can...I'm quite interested to know if this code is in the system.

I've read the symptoms (other than the light) if the distributor is out of spec is a rough idle and wear on the inside terminals of the distributor cap.

Please reply back with your plan/progress.

[AirTool]

RE:

Broke Not

Which distributor cap do you have?

1) http://www.skidim.com/prodinfo.asp?number=RP173081

2) http://www.skidim.com/prodinfo.asp?number=RA108009

Or a different one?

If you have the first one, there may be a base timing setting. Can you post a pic of your cap? I can't seem to figure it out on the web.

[broke_not]

RE:

Thanks for the replies!

AirTool, the procedure you listed for setting the camshaft retard is similar to one I read on a light truck forum....that will be the next step I'll try. This engine doesn't use a crankshaft sensor, there's a molded mounting point for one at the lower edge of the timing cover, but it's a blind hole. That was one of the questions they asked when I was ordering the long block. They only wanted to know so they could make sure the correct timing cover was one the engine when we received it.

The distributor is like the first one you linked to.....here are a couple of photos I took prior to pulling the engine:










The boat is in town, so I won't be able to get back to it until Monday evening. Once I got it ready to fire up on Friday, I called the Ski Nautique dealer and spoke to a customer service rep. He took down all of the info and was supposed to have a service tech call me back. Haven't heard anything yet....

I'll post back with the progress. If I do stumble across the official info from a service manual or get something from the dealer, I'll put that information up here as well. All of the manuals I've found so far online are for different setups than this one.

Yellow_Flash_Colorz:

[broke_not]

RE:

I spoke to a PCM tech and found out that the base timing could be set without a scan tool by starting the engine and then putting the system into timing mode by attaching a jumper across the A and B terminals at the diagnostic connector. The timing is then set to 10 degrees BTDC by using the old-fasioned timing light/rotating the distributor method.

I set it accordingly, and got in on the water today....all went well. Good power, no hesitation or detonation.

I also emailed the tech some other methods I'd read since I posted the same questions on a couple of other sites. Many of the processes for doing this are similar, but not exactly the same. Damage can easily result if things are done improperly. The information he provided me with only applies to '97 and '98 model Apex engines.

Always check with the manufacturer and/or service manual before jumpering anything out.

;-)

[AirTool]

RE:

Excellent news. You must have looked at the same sites as me. I couldn't find literature for your year model. I got to thinking about it and your setup should be similar to the 99 Mercruiser I used to operate and service (but not own) and my 93 Chevy pickup. On the truck, there is a plug to unplug to signal to the ECM that it is in timing mode. On the 99 Mercruise 5.0, I remember eighter a dangling wire that got grounded or a plug to separate. I was going to look that up for you but your problem is solved. I'll bet those systems are similar.

[T_Bone17]

Resurrecting an old thread here, but I am pretty much in the same situation. Trying to figure out proper instructions for setting base timing on my 2000 Super Air. PCM 5.7 Getting the same conflicting answers. Either jump A and B on diagnostics port, or need diacom or similiar to set cam retard.

I guess my main question is how do I know for sure which one it is? Does it depend on ECM I believe mine is the MEFI-3, but I am not sure, I could not find any marking on it.

Pics of Distributor and ignition coil