Broken timing belt leads to low idle?

[Brianmitchtay]

Hi guys, I've been trying to figure out why my 87 GL wagon has been idling at 1000-1250 for the last few months, with no real progress to speak of,

I've put on a new ignition coil, fuel filter, spark plugs and wires, and was able to get my hands on a new CTS as well, (the round plug version I couldn't find anywhere was listed under a GL-10 on rockauto, sold as a standard motors product, and had the Fuji heavy industries logo cast into the sensor when I got it so I think it might even be an OEM sensor) all of which made the car start and run a little nicer but made no noticeable difference to the idle speed, then last night driving home from an evening out with my lady, I had my driver's side timing belt snap on me - after only 21,000 miles! We left the car on the side of the road and this morning went back and swapped the old timing belts onto it, (glad I had kept them in the back as spares!) 

Curiously, after swapping the old belts back on, the car now idles between 500-650 rpms when it's warm, sputters, makes a sort of metallic buzzing when I'm coasting down hill in gear, and has basically no power. I had to downshift from second gear at 2400rpm, into first gear because I didn't have the power to make it up the slight incline back to the house.

I'm basically at a loss here, I was meticulous putting the old belts on and at worst the timing could only be off by one or two degrees, which I suppose could maybe account for some loss of power, but would that effect the idle speed so drastically?

At this point I've got a new timing component kit coming in the mail and I'm planning to replace both the tensioners and the idler sprocket when I put on the new belts, but would it hurt anything to just use the idle adjustment screw on the side of the throttle body to see if I can get it back to normal? That's the last thing I can think of considering I've now replaced the Battery, CTS, Ignition coil, Fuel Filter, plugs and wires etc.

Any thoughts? This is my daily driver and with winter on it's way I'm going to have to start browsing craigslist for another car if this keeps up. 

Edit: I know this was a long winded post but one last question, when the FSM says to rotate the crankshaft one full turn "Clockwise" between putting on the first and second belt, does that mean clockwise when you're in front of the car looking at the engine?(what I did)   or clockwise as viewed from the driver's seat? That's the only other thing I can think of

 

Edited September 15, 2018 by Brianmitchtay

[czny]

Clockwise one full turn looking from grill end at the engine.

Running engine rotates clockwise looking from grill so tension on belt is from crank pulley to bottom of oil pump across idler to cam sprocket. Drivers side belt has slack top - tension bottom.

Its talked about in this thread recently:

 

Edited September 15, 2018 by czny

[DaveT]

I've been running EA82s since 1988.  Not once has replacing a timing belt changed the timing enough to matter at all.  The idle screw is the last thing to touch.  Never had to turn one of those either.  Something else is wrong.

 

Vacuum leak. IAC valve.  Bad wire or connection.   CTS.

 

Does the CTS you have match the specs for resistance vs temperature of an OEM one?

 

[BEECHBM69]

Two things that come immediately to mind. Something in the rotating assembly is binding up causing a lot of drag, which may be what broke your timing belt in the first place. (Idler, tensioner, or possibly oil pump)

-or-

One of your belts could be off a tooth. It's easy to do if you've never done them before. Recheck all the marks and make sure they are dead on. That doesn't account for the belt breaking, but would account for the drivability issues. 

Good luck. 

Dan

[DaveT]

The one full revolution is as mentioned above.   Tighten the crank pulley bolt is another way to think of it.   I don't think it would mattter, it's just to get the drivers side belt to the corectangular position relative to the passenger side belt. 

 

After a short test fire, I like to re set the tensioners,  because the belts invariably walk into the positions they want to run in, and get a little loose.

 

But this wouldn't effect idle speed like you are experiencing either.  A couple degrees of timing is pretty subtle.   Also, you cannot get an accurate timing reading unless you connect the green test connectors, as the ECU is adjusting it.

[Brianmitchtay]

6 hours ago, BEECHBM69 said:

Two things that come immediately to mind. Something in the rotating assembly is binding up causing a lot of drag, which may be what broke your timing belt in the first place. (Idler, tensioner, or possibly oil pump)

-or-

One of your belts could be off a tooth. It's easy to do if you've never done them before. Recheck all the marks and make sure they are dead on. That doesn't account for the belt breaking, but would account for the drivability issues. 

Good luck. 

Dan

Ok, that actually sounds like it's pretty possible, I checked the idler sprocket but I can't believe I didn't think to make sure the tensioner pulleys were spinning freely! They're definitely pretty dirty, so maybe that has something to do with it. Although that still confuses me as to why the car would have been idling high before the first belt broke.

I'm about 99.99% positive the timing isn't off, I've had to do it about 10 times on this car now and have got the procedure down by this point (or so I thought!) as for the old belt, after I installed it there was a week where it consistently had coolant leaking onto it while I was driving and so I'm gonna say that's probably why it kicked the bucket so early.

7 hours ago, DaveT said:

Vacuum leak. IAC valve.  Bad wire or connection.   CTS.

Does the CTS you have match the specs for resistance vs temperature of an OEM one?

 

A Vacuum leak is the first thing I thought it was, but I traced all the lines and they seem connected and fine, maybe I''m missing one though? I've seen the IAC valve for the MPFI and Turbo ea82, but don't know where it is on the SPFI, I'll look and see what I can find there, although that seems odd to swing from one end to the other just like that.

This is the CTS I bought https://www.rockauto.com/en/moreinfo.php?pk=39891&cc=1268478&jsn=415 When it arrived I was pleasantly surprised to see the Fuji Heavy industries logo cast into the metal head, but unfortunately I'm living in a tiny town and couldn't find a thermometer with the right temperature range at our little grocery store to check it before I installed it. That being said, I've had it installed for a week and the car ran exactly the same as it did with the old CTS (which I did check the resistance values for and they were fine)

[DaveT]

The IAC is a cylindrical thing on the front of the throttle body.   A hose ells out of the air boot, goes to the right,  turns 90 degrees down onto it.  Screws.hold the IAC valve to the throttle body. 

 

It is weird that it was idling high before, and now is more normal.  I don't recall the spec for idle with a stick shift.

[Brianmitchtay]

1 minute ago, DaveT said:

The IAC is a cylindrical thing on the front of the throttle body.   A hose ells out of the air boot, goes to the right,  turns 90 degrees down onto it.  Screws.hold the IAC valve to the throttle body. 

 

It is weird that it was idling high before, and now is more normal.  I don't recall the spec for idle with a stick shift.

The FSM says that with a manual SPFI the idle should be 700 exactly.

Ok I know what cylinder you're talking about. Can it be removed and adjusted like the MPFI ones? or is it a part that just has to be replaced? 

[czny]

5 minutes ago, DaveT said:

The IAC is a cylindrical thing on the front of the throttle body.   A hose ells out of the air boot, goes to the right,  turns 90 degrees down onto it.  Screws.hold the IAC valve to the throttle body. 

 

It is weird that it was idling high before, and now is more normal.  I don't recall the spec for idle with a stick shift.

700 rpm + / - 100 rpm. According to tuneup decal under my 87 5MT D/R GL hood. So 650 Rs is OK.

[Brianmitchtay]

2 minutes ago, czny said:

700 rpm + / - 100 rpm. According to tuneup decal under my 87 5MT D/R GL hood. So 650 Rs is OK.

Yeah, if it were idling at 650 at the lowest and had the power and pickup I'm used to I would be stoked! but with the total lack of power and the idle bottoming out at 500.. 

[czny]

Start with basics. Unplug, clean & re-connect your engine harness connectors a few times to make sure they are making good contact. 5V sensors can't have any resistance lowering signal voltages to ECM. Get undet the dash & make sure ECM connectors are good. Especially check that white translucent connector to left of ECM with all the shielded wires in it. That's your sensor nexus to ECM. Check all your chassis & engine grounds. Eliminate any poor electrical connections before you start swapping out MAFs, etc because I've been a victim of that myself.

Search for bucking, stalling problem thread.

Poor sensor connections can seem like failing sensors so any weak link in harness chain can cause a problem.

[Brianmitchtay]

Ok so I just checked my timing, lined the timing mark on the cam sprocket up with the seal in the rocker cover, (is that my best reference point with the belt covers off? That's the reference point he points out in the Miles Fox video and I hadn't thought or known to use that before so thanks for sharing that video czny.) and from there the timing marks on the flywheel were probably about 4-5 degrees off, so I'm gonna say I just didn't do as good of a job lining up the timing as I thought. I'll redo the belts before I do anything else, then go from there as far as how the idle is effected, etc. 

I wonder if I just had the timing off ever so slightly before and that's why it was idling high? seems odd but maybe?

[czny]

There are 3 marks on the FW for cam timing. Use the middle mark only for L or R cam timing setup. Ignition timing marks should be obvious. I painted my 20* & middle cam marks with a silver paint marker for clarity. Any light color paint will do.

Yup, the split where the VC meets the cam tower is a good reference for cam sprocket lineup.

Those videos kinda got buried in the last forum update I guess along with some great old threads about Frankensteinian transmission mods, etc. Time for new bookmarks.

[Brianmitchtay]

Alright, the timing was just off, I just re-did it by night after work (Since the forecast shows rain all this coming week and I don't have the luxury of a garage up here) and now I'm right back where I started, idling between 1000 and 1250, but with all the power I've ever had. Hmm..

Now with seeing how much the timing can effect the idle, next clear day I get I'm going to have to pull the distributor cap off and make sure that it's perfectly lined up on cylinder 1 at  20degrees BTDC.

Thanks as always for your help guys, someday I'll get this high idle figured out. Until then I guess 24-27 mpg is almost as good as the 30-34 I used to get.

[Steptoe]

On 9/16/2018 at 8:00 AM, czny said:

There are 3 marks on the FW for cam timing. Use the middle mark only for L or R cam timing setup. Ignition timing marks should be obvious. I painted my 20* & middle cam marks with a silver paint marker for clarity. Any light color paint will do.

Yup, the split where the VC meets the cam tower is a good reference for cam sprocket lineup.

Those videos kinda got buried in the last forum update I guess along with some great old threads about Frankensteinian transmission mods, etc. Time for new bookmarks.

I used to use traffic light colours on timing marks once worked out best....green for where it should be, red on next advanced mark and yellow on retard one mark back