Can't seem to adjust timing

[BojiBrent]

Working on my 97 Volvo 7.4L. I'm trying to adjust the timing, but when I put the timing light on it I don't see any movement of the line. I can move the distributor both ways until the engine dies but I node's see a change. What am I missing here?

 

[alldodge]

Howdy

Are you connecting the timing light pick up number one spark plug lead?

 

[bruceb58]

What model is your Volvo? If you have the EEM system like I do on my 7.4L LK, you can't adjust it. That is of course assuming nobody changed it out!

 

[bruceb58]

This system was only used for a couple years. I actually have a Delco Voyager distributor ready to drop in when I need it or even sooner!

 

[BojiBrent]

Thanks for the reply.

Believe I have the correct plug...port side closest to the bow. Even if it wasn't, I would expect to see some movement when I rotate the distributor.

Model is 7.4 GL PLKD

 

[bruceb58]

You have the EEM distributor. You can't adjust timing. The crank has sensors which tells the distributor when to fire. All you can do is make sure the timing is to spec to what is specified in the Service Manual. 12? or 13? at 1000 RPM. The 12? would be if the knock sensors weren't working properly.

Any reason you were trying to adjust timing other than what it is the thing normal people do during a tune up?

 

[BojiBrent]

Well, it's a long sad story, but the short version is the block froze> got a new long block> lots of screw-ups all around> now it runs (sort-of) but nobody wants to work on it due to the history. I'm not an engine guy, but I'm trying to get up to speed. Bought a timing light and vacuum gauge and have been tinkering.

Problem is at idle/low speed. Really rough, hard to keep it running. If I set the curb idle high enough to make it smooth it shifts really hard and leave a wake all the time.

Watched some youtube and thought step one was to get the timing set, then step two, on to the idle screws on the front sides of the carb. Have had some luck with step two but have been having trouble getting a vacuum reading. Haven't found a connection that shows any vacuum.

Thing is, the low speed performance overall is somewhat erratic. Once warmed up it will be really rough, and then other times not too bad. At higher speeds seems to run well.

Never had a ny issues like this prior to the engine work. Keep thinking there is a sensor somewhere with a loose connector or something, but I don't know what I don't know.

 

[bruceb58]

Problem is that your distributor uses knock sensors and a timing ring that sets the timing and is mounted near the flywheel. If that ring wasn't installed properly you are hosed.

Have you checked compression of this engine?

You can replace that distributor with Delco Voyager but you will have to do some wiring and you definitely need the OEM service manual as that that distributor was only used in 2 years of the Volvo 7.4L models.

There is a procedure in the service manual that needs to be followed exactly to set the distributor. When you do get a manual it is on page 7-23.

Here is a link to a soft copy:

http://boatinfo.no/lib/volvo/manuals/lk_elect.html#/136

 

[BojiBrent]

Problem is that your distributor uses knock sensors and a timing ring that sets the timing and is mounted near the flywheel. If that ring wasn't installed properly you are hosed. The guys who replaced the block do mostly hot rod stuff...not many boats and definitely no Volvo. Not a clue whether the timing ring is in properly. As I said it does fine at speed so I wouldn't think it's horribly off the mark.


Have you checked compression of this engine? No, but the 3rd(!) time they had to pull it out they broke it all the way down and checked everything

You can replace that distributor with Delco Voyager but you will have to do some wiring and you definitely need the OEM service manual as that that distributor was only used in 2 years of the Volvo 7.4L models. I'll take it in to a shop about 3 hours away before I get that brave. Thanks for the link, though.

One last thing... I can't get a vacuum reading on either of the crank case hoses. Is this normal?

 

[bruceb58]

This is what I would do. Follow the directions in the manual and set the distributor as described.

Check your timing over the RPM range as specified in the manual.

Once you have that done, you can explore other problems if they still exist.

One step at a time. Right now you are all over the place. Checking vacuum wouldn't be high on my list. What do you think you are going to tell with vacuum readings. Are you worried about something more serious like they don't have the cam set correctly?

 

[BojiBrent]

Then I will do likewise. As I said above, I don't know what I don't know, so I'll go through it with the manual as you suggest.

I intended to use the vacuum gauge to set the idle screws. Saw several vids on Holley carbs that showed adjusting those to max vacuum pressure was the way to go.

Bruce, thanks for your time and insights. Will give it another run-through this weekend.