So after a long line of trying to fix it..I finally caught something. I decided to look at the timing on my 98 4.0 and after getting the marker on the bearing to the 0 according to the manual and the rotor should be facing the #1 on the distributor cap. Well it wasn’t, it’s about 1 1/2” past it almost to the next post. I know the distributor is computer adjusted, so do I need to check my timing chain?
Do I need to check my timing chain?
- Thread starter Burch98
- Start date
Also I can’t really feel for the TDC with my finger as I have A/C and I really am trying to not tear everything down but am willing to open it up and look at the timing chain if anyone could chime in on it. It’s only got 156k miles but when it started it was 100+ outside and I was driving 70 down the turnpike
I don't know if you need to check it but it is really easy to. Just put a breaker bar on the crankshaft and move it back and forth. If the chain is really bad often you can hear it when you do this. You can also feel the play between the crank and the camshaft. It should be minimal. A shot chain will allow the crank to move before it starts to move the camshaft which has all those valve springs keeping it from moving easily. If you are really concerned you can pull the distributor cap or OPDA (sensor on top) and look at that when you move the crank. There should be very little play between them. In my Jeep a shot chain was really easy to feel this way. You do have to kinda think out what you are feeling as you rotate the engine but it isn't too difficult.
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Before, if you haven't already taken it apart. You can do what @pagrey was describing without taking anything apart on the front of the engine.
How do you know it isn't the distributor out of time? I'd be looking at that before I start pulling the front of the engine apart.
Had a CJ that I got cheap 'cause it ran so poorly. Would idle ok-ish, but like half the hp it should have. Any hill and I was down to 2nd gear. PO said his mechanic told him to change the carb. He wasn't going to spend the money.
So I went with it was the filthy neglected carb. Would backfire once thru the carb if the engine was up to temp when you turned it off.
Replaced the carb with really cheap auto zone carb. And then it would backfire thru carb when you let off the gas at a stoplight too. So, next cheap auto zone rebuilt carb. Same thing.
So I went back and started from the beginning.
All the spark plugs were soaked with huge carbon buildup. Checked the timing. Woah! Couldn't even find any Mark's with the light. Cranked the distributor a good 30-40 degrees to find any lines on the crank pulley. Got it dialed in and the thing ran great! Took a bit to blow all that carbon that had built up. Power galore! Able to fly up a hill like a jet!
Moral of the story...
Always start with the easy stuff first. If the distributor is that far off then it just might be that someone hooked the plug wires out of phase. I would never have thought an engine could run that far out of time, but the PO did for over a year. And who knows how long before him?
Had a CJ that I got cheap 'cause it ran so poorly. Would idle ok-ish, but like half the hp it should have. Any hill and I was down to 2nd gear. PO said his mechanic told him to change the carb. He wasn't going to spend the money.
So I went with it was the filthy neglected carb. Would backfire once thru the carb if the engine was up to temp when you turned it off.
Replaced the carb with really cheap auto zone carb. And then it would backfire thru carb when you let off the gas at a stoplight too. So, next cheap auto zone rebuilt carb. Same thing.
So I went back and started from the beginning.
All the spark plugs were soaked with huge carbon buildup. Checked the timing. Woah! Couldn't even find any Mark's with the light. Cranked the distributor a good 30-40 degrees to find any lines on the crank pulley. Got it dialed in and the thing ran great! Took a bit to blow all that carbon that had built up. Power galore! Able to fly up a hill like a jet!
Moral of the story...
Always start with the easy stuff first. If the distributor is that far off then it just might be that someone hooked the plug wires out of phase. I would never have thought an engine could run that far out of time, but the PO did for over a year. And who knows how long before him?
I tried adjusting the distributor. They’re computer controlled on the 98’s. It just wouldn’t go back to where it should. It was either backwards a hair or forwards an inch. And it wouldn’t even start in the other position. Couldn’t get it to go right where I wanted. That’s why i think it’s time to just look at the chain
I may be missing something but would think you should be able to pull your number one plug and rotate engine to located your #1 cylinder TDC compression stroke. Determine if the TDC timing alignment mark align with the mark on your harmonic balancer (may need to rotate slightly to align). Then check to see if your rotor is pointed to the #1 plug location on your distributer. If not you should be able to loosen the distributer hold down bolt and rotate the distributor to line it up. Wouldn't think your timing chain would be causing any of the issues you listed.
Distributor off by one tooth? Did the issue correspond with other repairs? Yes, the timing advance is ecu controlled, but it still depends on the distributor hall sensor and mechanical limits of the distributor. The ecu doesn't adjust the distributor, it can delay or advance the spark from the coil, but it has to be within the bounds of the mechanical components of the distributor. You still need perfect static timing on the distributor.
I'd start by checking ignition timing by the book. Follow the process for distributor R&R
I'd start by checking ignition timing by the book. Follow the process for distributor R&R
No I bought it over a year ago. It started about a month and a half, thought the fuel pump was going out. Changed it, all good. Gradually started feeling more and more gutless. I’ve checked tested and replaced anything that could possibly make it run this bad. Finally checked the timing and it’s pretty off. I tried adjusting the distributor but I couldn’t get it right where I wanted. It would either go right back where it started or right before the #1 peg. No matter where I turned the little slot that holds the distributor shaft in place to sit flush. Tried 11 o clock where it should be, and it was right back where it started. Basically it’s running really rough, feels powerless, and won’t run longer than 30 minutes without losing all power (won’t drive at all, give it any gas and it just dies, doesn’t even backfire or anything) until I shut it off for a bit.
Yeah...my catalytic converters and looked fine. Gonna sound dumb but I even took it off for a drive to see if it helped and it didnt