Question about 740 GL timing

  • Thread starter Thread starter Geronimo
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Geronimo

Its an 89 740 GL sedan, non-turbo, B230 F engine. Jetronic L
system. I am not sure I have it timed right. It idles rough
(erratic RPM....500-800 RPM), it has a strong miss every few seconds
(when the RPM dips).....but only when you have it in park! When put
into drive--- sitting still--- the idle RPM is perfectly stable,
roughness/missing is completely gone. And when moving, the miss is
still gone.
Went and spent a lot of $$ for new dist. cap & rotor, new plugs,
new spark plug wires. Now I notice that it is only running badly when
in PARK, so it wouldn't have been any of those parts! If not timed
right, can this cause the ign. control module to maybe set the advance
way off for PARK, but set it correctly when in DRIVE?
 
Does it run poorly in Neutral like in Park?


Geronimo said:
Its an 89 740 GL sedan, non-turbo, B230 F engine. Jetronic L
system. I am not sure I have it timed right. It idles rough
(erratic RPM....500-800 RPM), it has a strong miss every few seconds
(when the RPM dips).....but only when you have it in park! When put
into drive--- sitting still--- the idle RPM is perfectly stable,
roughness/missing is completely gone. And when moving, the miss is
still gone.
Went and spent a lot of $$ for new dist. cap & rotor, new plugs,
new spark plug wires. Now I notice that it is only running badly when
in PARK, so it wouldn't have been any of those parts! If not timed
right, can this cause the ign. control module to maybe set the advance
way off for PARK, but set it correctly when in DRIVE?
Click to expand...

__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"
 
Yea, runs poorly in neutral, also...same thing.


Does it run poorly in Neutral like in Park?




__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"
Click to expand...
 
Geronimo said:
Yea, runs poorly in neutral, also...same thing.
Click to expand...
Geronimo,

The ignition timing on that motor (if it's adjustable at all) needs to
be set, with the engine FULLY warmed up, as an ECU monitors the coolant
temperature, and gradually retards the ignition from an advanced
condition that exists with the coolant anything but fully warmed, this
allows the engine to run 'nicer' when cold.
The same ECU also monitors the status of the neutral start switch, very
slightly advancing the ignition timing if a gear is selected, helping to
prevent stalling while the engine is idling in gear.
I'm not sure if the ignition timing on the B230F is picked up from the
camshaft via a hall sensor in the distributor or the crank shaft via a
position sensor 'reading' the flywheel, if it's the later, AFAIK, you
can't actually change the timing, but, if you rotate the distributor too
far either way, then it's quite possible to have the ignition firing
sparks off, when the rotor arm is actually not close enough to a spark
lead, to actually get to a plug properly, hence causing a slight or not
so slight misfire.

Just my 2 pennies worth,

Ken Phillips
 
I determined crankshaft position by a crank position sensor mounted on
top of bell housing (reading the flywheel). I don't think the
distributor can be turned on this engine. All the Haynes manual says
to do is line up the mark behind the crankshaft pulley and line up the
mark on the camshaft pulley. It shows you how to position the idler
pulley...but it is only an idler, and it says it is not critical. The
camshaft mark is definitely lined up with the index mark (at 11
o'clock) and I verified that I had the crankshaft at TDC (firing) by
pulling the #1 spark plug and finding the highest level. But I think
my procedure is not right, and it is not timed right. Seems real
sluggish accelerating to 60 MPH, allthough as I said the
roughness/missing is gone when in any DRIVE gear, even if stopped.

If it smooths out in DRIVE because the computer advances the spark,
then would this indicate I have the timing too retarded?

Thanks!
 
I determined crankshaft position by a crank position sensor mounted on
top of bell housing (reading the flywheel). I don't think the
distributor can be turned on this engine. All the Haynes manual says
to do is line up the mark behind the crankshaft pulley and line up the
mark on the camshaft pulley. It shows you how to position the idler
pulley...but it is only an idler, and it says it is not critical. The
camshaft mark is definitely lined up with the index mark (at 11
o'clock) and I verified that I had the crankshaft at TDC (firing) by
pulling the #1 spark plug and finding the highest level. But I think
my procedure is not right, and it is not timed right. Seems real
sluggish accelerating to 60 MPH, allthough as I said the
roughness/missing is gone when in any DRIVE gear, even if stopped.

If it smooths out in DRIVE because the computer advances the spark,
then would this indicate I have the timing too retarded?
Click to expand...
If you don't have all the slack in the belt on the tensioner side of the
motor before you relase the tensioner, the belt pulls the crank wheel
clockwise. When you turn the motor over two times by hand to check the
tension, you will see that the cam has retarded one tooth. The trick is
to start the belt arounf the cam pulley and clip it with a clothspin
clamp and pull the belt snug around the crank pulley, then release the
tensioner.

Bob
 
Geronimo said:
I determined crankshaft position by a crank position sensor mounted on
top of bell housing (reading the flywheel). I don't think the
distributor can be turned on this engine.
Click to expand...

Since this engine has a crankshaft position sensor in the bellhousing, the
timing belt has nothing to do with ignition timing, which can not be
adjusted. The timing belt is only for the camshaft timing ( and the oil pump
which wont need timing ).
If the timing belt has been set incorrectly the engine will run poorly, but
again it's not an ignition problem.

I'm not sure what it means, the 11 o'clock position you refer to, but you
should have a look on theis website, and maybe it can be of some help to
you.
http://www.mikeponte.com/volvo/timing.htm


Regards

Per Hauge
 
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