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I complete the timing belt and water pump on my 1990 928. I took for a short drive and the car felt a little underpowered.
I've uploaded the Crank location and photos of the two cams. I noticed that the large notch on the front of the cam is not aligned with the notch on the back side of the cam gear.
The cam gear timing looks about as close as you can get it, as far as the gears lining up anyway.
Meanwhile...
Make darn sure you have the coil wires connected at both distributor caps. Make sure the plug wires aren't mixed up. The former gives you sluggish performance because it's only running on four cylinders. It will still be pretty smooth on four cylinders but obviously down on power. If you have one, test each plug wire for spark using your inductive timing light.
The front-of-engine harness passes the Hall sensor behind the passenger-side cam gear where it's in that clamp at the front passenger side of the engine. When installed correctly, the clamp goes around the harness at the tougher angle for getting the bolt in, but the wire and connector for the Hall sensor is shielded by the bracket from the magnetic field around the primary conductor in the harness. Get it wrong, and the Hall sensor will be confused and the EZK will give up, and wind ignition timing back. Check your routing. I don't have a picture handy. I discovered this sort of the hard way, using a borrowed 928 code reader.
And I'm a little concerned about the backside of your belt -- looks like it has scrape marks on the back from dragging on something? I'm not sure how the backs of the Contitech belts look when new; the Gates and Porsche-by-Gates belts are smooth.
Thanks for the information. That sounds like it may be it. I am having trouble understanding what you are referring to in the wiring. I took a couple of photos, do you see anything in these?
In your last picture, the front harness is kind of draped across the front corner of he engine. When installed correctly, there's a clamp around that harness that's captive by the bolt that holds the ground wire to the lift bracket in your third picture. The harness passes back across the fender side of the lift bracket, secured by the clamp. The harness then makes a 180º turn back forward, and gets connected at the 14-pin and the jump post.
The plug wire routing wrapped around that same lift bracket looks wrong. I don't have my car close enough to me to get pics for you.
The connector for your Hall sensor also looks funny, but again it's hard for me to pick out the fault when I don't have a handy reference to share. Do make sure that the harness connector for that sensor is plugged in correctly, and that the sensor wire itself isn't damaged.
Housekeeping: The wiring for the injectors that continues across the to the front of the engine needs to be supported on the fuel rail. That fuel pressure gauge is a known fire hazard (See Randy V. vs Fuel Fire, et al). Those original fuel lines need to be replaced too. All Of Them.
As previously suggested, carefully check the connections and routing of the coil wires to the distro caps. This is a common known mistake, where the boot is on but the connector isn't engaged inside.
There's a protective relay that lives on the bracket for the two controllers in the passenger side footwell on the right, usually hidden by that carpet cover. The relay has a couple LED's on it that come on when the protection is active. Look for a red or green LED starting when the engine exhaust system gets warmed up following start-up. If one of them comes on, you have a fault in one of the ignition circuits. That relay helps prevent your car from catching fire from unburned fuel passing into the catalysts causing them to overheat.
First picture shows very top of Hall sensor connector - sender side - and you can't see the 'meaty' part of it.
The harness side is ... well... upside-down on the other side of that and its probably disconnected with the meaty part above broken off of the sender side.
The harness for this should be gray, branch from the LH harness in the vicinity of what, in yours is the pressure gauge, then run down the belt cover to the front main engine (FME) harness and then along with the FME under, behind and up. In your picture there appears to be a bunch of 'lectrical tape were the Hall sensor branch should emerge from the LH harness.
There are all kinds of pictures in many threads. Search for Hall Sensor and you will find.
For future reference
".... I noticed that the large notch on the front of the cam is not aligned with the notch on the back side of the cam gear."
Don't look at the Large notches on the front of the Gears, it's the small "V" on the back of the Gears that need to align with the "V" notch on the backing plates.
As far as the Hall sensor goes.. did you mess w/ it? If not and the car was running better before your T-Belt job, I'd start with the original suggestion of checking Ignition wires for proper connections and go from there.
What exactly was changed and or serviced along w/ the T-Belt and WP please, and how does the belt track on the gears when running (look through the vent holes)?
I did quite a lot over the winter. it started with a water pump, TB job. The timing belt is brand new from Roger, so are all the accessory belts. I did the filler neck baffle and gasket refresh, changed the motor mounts, replaced the fuel pressure regulators, and lots of other stuff on the rack and tie rods.
I did mark the ignition wires so I feel confident they are back in the correct location. I never touched the hall sensor, but I did have the engine on a chain lift from that lifter loop so i will examine tonight to see if there are any damaged wires in the vicinity.
I am confused regarding the routing of the wires. I did an initial triage on Rennlist to find photos, but most of the pictures are obscured by the cooling hoses.
If someone has the opportunity to post a photo of their wire routing in the front I would greatly appreciate it.
OK so you replaced the Water Pump, and all the rubber belts.
What did you do to the Stock Tensioner, did you dissemble it and clean it?
Did you clean & inspect/replace any of the belt rollers and the pivot arm plastic bushings?
Like Sean, I too am wondering why that "new" belt looks so old.
I should have been more specific, I completely rebuilt the tensioner arm and installed a new pulley and flushed and replaced the fluid.
I am starting to get a little worried about that belt. Since the rebuild I have let the engine idle twice for about 20 min each time, and one drive around the neighborhood (3 or 4 blocks).
It is almost impossible to do an '87+ timing belt job (assuming factory harness routing) without disturbing the connector to the Hall sensor. And even if you do, for an old Hall sensor connector the front main engine harness may be the only thing keeping it in position and connected.
I've also just finished replacing my water pump,TB and tensioner. The picture shows me dialing in the cams but the red arrows show the path of the wiring harness ( which loops under & behind the passenger side cambelt cover then forward to the connector plug). I can't really tell from your photos but I'd re-check the alignment of your timing marks, being one tooth out would explain the loss in power.
04-03-2017, 09:25 PM
Post Timing Belt Sluggish
