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740 Ignition Timing

A

AMilli96

Member
Joined
Jul 22, 2015
Location
Michigan
I know I ask a lot of questions on this board, but its been so much help these past couple of months. Anyways. 87 740t, trying to set ignition timing. But my timing mark is pointing towards the waterpump pully, something like 25-30 degrees. Okay, I know that the rubber on the balancer could get loose and messed up, so I found true tdc with the long bolt in the cylinder, and I marked it with a paint pen. Now at idle its at something even worse. Just trying to time it right. Any help?
 
remove distributor cap...look for a mark at #1 top dead center at the distributor. the rotor should point directly to it...if not loosen the distributor retaining bolt and rotate to match...if your timing belt and auxiliary shaft are properly timed it should indicate proper mechanical correlation. go from there.
 
The outer ring of the balancer is probably so loose that it moved when you started the engine. This one turns easily by hand, yet it looked fine.

B230Balancer1.jpg


B230Balancer2.jpg
 
I marked the balancer with a paint pen, and it didn't move. When I did the timing belt I did it with the balancer and it was perfect. I'm just not sure where the issue could be. I don't know if its the ecu or what.
 
When you marked it with the paint pen, did the notch in the balancer line up with the 0 mark on the timing cover?
 
No, it didn't. But when I did my timing belt, could it have been off that many teeth and still run? it runs pretty well, but I hesitates. that's What I'm trying to get rid of.
 
Something must have slipped if the notch didn't line up. Either the balancer is slipping or the crank gear sheared it's locating key.
 
But even after I marked both the inner ring and the outer ring at tdc but taking #1 spark plug out and putting in a long bolt, it still didn't time right. I might have to throw in the towel and take it somewhere, I've been battling this for the last ten months.
 
So the marks on the inner and outer rings on the balancer lined up after you ran the engine? Are you sure the timing light isn't picking up the signal from another plug wire?

10 months is long time to be living with a hesitation.
 
Yes, the marks on the inner and outer rings matched. The timing light has done this since I bought the timing light. it must either be a ****ty timing light that's not shielded well, or something else. I've replaced almost every sensor on this car, and I'm getting tired of throwing stuff at it. ten months is a very long time, especially since it is my daily driver and I drive about 400+ miles a week, just in commute to school and to work and back.
 
Head mounted distributors can suffer from a number of maladies. Leaking oil seals, worn bushings, bare wires and broken connectors are all potential problems. Pull the cap and take a look inside. Grab the rotor and try to wiggle the shaft. Seals are available to repair oil leaks, but the shaft seal is a PITA to change.

You should still verify that the nub on the crank gear hasn't sheared off. You won't be able to set the timing if the balancer isn't located properly.
 
agreed, leaking oil can accumulate in the lower most point of the dizzy cap. Causing missfiring.

Another issue that 700 and 900 sometimes have is moisture between the black cover and the red cap. It is caused by rainwater dripping past the rubber seal that is fixed between paravan and hood.
This panelgap is positioned exactly overhead of the dizzycap so that rainwater drips directly on top of the dizzy cap.

When i still had my 940 i just removed that black cover completely and cleaned all debris of the red cap completely. I fixed the rubber seal on the paravan using bodypanel kit.
Never had any issue after that. Not even in a heavy rain shower.
 
Go back to square 1. Does the pulley at TDC match #1 at TDC? Is the cam indexed at the timing mark on the sprocket at TDC? The timing gets max timing and the knock sensor adjusts.
 
Well, three weeks ago or so, I replaced the distributor completely. I was trying to replace the hall sensor and my uncle punched two big holes in the plate. So all seals and shaft and cap and rotor are good. When I did my timing belt, I used the timing mark on the crank pulley. And since I now know that that mark isn't right, should I then use the mark that I made when I found true TDC? Ill have to redo my valve timing then. but it shouldn't run as good as it does if it skipped three, four or five teeth on the crank gear, right? usually if they skipped one tooth everything is messed up.
 
We are saying use the belt guide notch and the block to find true tdc! Disregard pulley mark at first, toss cover back on for a sec to see if it's correct or not.

Anyways, crank set tdc now verify auxiliary gear timing. Then carefully drop distributor in. Is your plastic still tgere? Drop distribution in so rotor points at notch. Adjustment bolt should be approx, or in correct position.
 
Aux shafts wouldn't matter in my case. I have the head mounted distributor. When I found true TDC with the bolt in the sparkplug hole, I did not check the camshaft or the Aux shafts for alignment.
 
Ill have to do that when I get home. At the moment in at school for a while. I'll check back later today or tomorrow. I hope it's just off a couple teeth. That would make my life easy.
 
Okay, so, a little update. Tonight I tore the car apart. Found TDC without the harmonic balancer. I Found it on the crank gear. Nothing sheared off. But I was off two teeth. Probably because I was going off of the old worn out balancer. Everything lined up and now I was doing ignition timing. It now read 12 degrees before tdc. Perfect! Except I'm still having the same problem I was having before. Which was a large hesitation right off idle. When I go to pull away, in a brisk fashion, it will hesitate, studder and wont rev past 1250 rpm no matter the position of the throttle. It will not do that with load on the engine. Until I get to about 15 or so mph when it will pick up and continue like nothing happened. It has done this for some time now, its not a new thing that just started. If I don't get the fix by Monday, I will be taking it to an indy shop, which I don't want to do. But it is my DD and I need it for Wednesday.
 
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