XR7 did something weird yesterday

Ok, my 89 xr7 did something wierd yesterday. First when I was driving to work, everything was fine and then I looked down and saw that the tach wasn't reading. I got to work and shut the car off then restarted it. Still no tach. When I went to leave work for my lunch break, the tach was working again. I went home for lunch, then back to work, then home at the end of the day with no problems. After I showered and got changed I got in the car to go down to my girlfriends and it took a lot of cranking before it would start. When it did start, the tach was dead for a couple of seconds, then came up and was working fine. Then as I was getting on the highway, the car started bucking real bad, to the point where I wasn't sure if it was going to make it far enough to get off the highway. Out of gear, it would rev just fine, but in gear whenever you were on the gas, it just didn't want to go. I finally got it up to speed, and the car smoothed out and didn't give me any more problems since. I have driven it probably about 50 miles and started it up about 6 or 7 times, and every time everything was fine, but I'm just worried that something is starting to go that is going to leave me stranded. Anyone have any ideas what this might be? Thanks.

Mike

im not

100% on this but i think thats a sign of a dis module going bad. so look into buying a new one, or a used one offf ebay. $20-30 on ebay.

wont crank
tach no go
yeah im pretty sure its the dis.
well see what others think

Cam position sensor is the most likely cause of your problems. Easy fix..so long as you have a 5.5 mm socket to remove the two screws that hold the sensor on. The DIS module could also cause the problem, but it's much more expensive and the fact that your tach is not functioning properly make it more likely the cam position sensor is bad or has a bad wiring connection.

David

I am going to say the wiring problem or the DIS module. The tach will act funny when it goes out. Mine would jump all over the place and then when the engine would rev up, the tach would stay at like 2k rpms or so. The cam sensor could be bad too, but after it starts, if there is no oil in the sender, ON OCCASION you can drive it with no ill effects.

Chris

make sure the dis and cam sensor are

connected correctly too, one time mines became loose from the other day when i used artic silver didnt start so i popped the hood and made sure it was on tight. the connection on the dis.

Similiar Problem

I did have a similiar problem, with the bucking and surging, then in neutral it would rev fine, and my problem was

The Harmonic Balancer Bolt head sheared right off, cause the balancing to walk forward on the crankshaft, screwing with the crank sensor.

Pretty sure this is your worstcase scenario, as everyone else has good options to try first.

Mike

Pretty sure this is your worstcase scenario, as everyone else has good options to try first.

Click to expand...

If the balancer is the worst case scenario then I would suggest checking it first or else the scenario could become worser.

Kurt

The balancer was good when I checked it about a week ago. The car acted up again when I went to go back to work. It would crank over, but wouldn't fire. When it did fire, the tach stayed off all the way to work (only like a mile). Parked the car, and when I went to leave work to go home, it was fine again. Continued to be fine for the rest of the day. It seems like it doesn't like to be run for a short time then sit for 20 minutes then be started again. I did notice that the retaining tab on the cam sensor is broken, and after wiggling that connector was when the car finally started again. Maybe I should clean out that connector and zip tie it in place and see if that makes a difference.

Mike

I've had 3 DIS modules go out on me (two stock and one aftermarket) and all three times there were different symptoms. If you buy a DIS, I would suggest getting one from Advance Auto....they have a lifetime warranty! The lifetime warranty helped me save some dough once already. :-D

Fishbone