Hey all. I've tried searching many times and can't seem to find anything that matches the problem I'm having so I'm going to chance getting flamed for not researching first and go ahead with a new thread...
I bought an 89 XR-7 for my son. Car is a little rough, and it sat for years, but I only paid $400 for it and after a fuel pump and filter change it started right up and runs surprisingly well...so I'm committed to finishing the mechanical work and then if he wants to restore it, that's up to him.
So here's the problem....it won't shift right. The first time I took it for a run it wouldn't shift at all but eventually it did....sort of. It will shift from 1st to 2nd but that's it.
There is a shudder that seems to come from the back end when accelerating around a corner and when downshifting from 2nd. I can't tell if it's a torque converter shudder, or the rear end, or a u-joint, or driveshaft issue, or what.
It has some instrumentation problems too, which I won't get into right now, that includes the speedo, tach and fuel gauge. There is power to the tach (it jumps when I turn the ignition on) and the fuel gauge (reading full but it's not full....and it's a new fuel pump/sender assembly). I can't be sure if there's power to the speedo or not (how can I tell?).
Based on the speedo not working and it not shifting, I assumed (despite the fact that the tach and fuel gauge aren't working right either) that it was the VSS causing the shift/speedo problem and the fuel gauge and tach are separate issues. However, I replaced the VSS and there hasn't been any change to the shifting or the speedo problem so maybe that was a foolish assumption. Is there actually some bigger that could cause the speedo, tach, fuel gauge AND shifting to misbehave? The temp and oil gauges DO work btw.
We had to change the ignition switch on the column (typical Ford problem...the switches on my 85 TC and even my 81 'bird wore out too), so I wondered if the boy had disturbed a ground somewhere and maybe that was part of the problem. So yesterday I took the entire dash apart and removed the cluster. I didn't find any unusual or loose grounds.
I haven't gone through each individual wire from the plug on the VSS all the way to the inside of the car with a meter yet (that's tomorrow's plan) but SOME of the wires are connecting because the car wouldn't start when I disconnected it (neutral safety sensor I assume?). I have all the electrical schematics for the car so I should be able to verify every connection (eventually).
The guy I bought the car from CLAIMED that it was driving until the fuel pump failed and that's when he parked it. If that's true (and it might not be) then the shifting problem is 'new' in the sense that many years ago (10+) the problem wasn't there.
Am I right in thinking that the transmission should still shift even without the cluster because the signal from the VSS is split BEFORE the speedo and the computer should still be telling the transmission to shift regardless of whether there is a speedo hooked up or not? Am I wrong to assume this?
Last time I checked for computer codes there weren't any...but my understanding of early OBD cars is that you don't get nearly the same amount of information from the computer that you do today. All I have for checking OBD1 codes is one of those cheap manufacturer-specific code readers, which I assume aren't that good.
So until I can update the thread with the results of some basic wiring traces, I would LOVE it if anyone has some a) troubleshooting tips/steps that I can follow, or b) some specific things to look at or try in order to isolate the issue.
I'm hoping this site is still frequented often and there's remains a good following of SCs (and XR-7s) out there. Around the same time I bought the XR7 for the boy I also found myself a 92 SC that's been stored indoors for several years and is in EXCELLENT shape. It's completely stock so I'm looking forward to updating and modding that one next year using info and help from this site.
Thx
K
I bought an 89 XR-7 for my son. Car is a little rough, and it sat for years, but I only paid $400 for it and after a fuel pump and filter change it started right up and runs surprisingly well...so I'm committed to finishing the mechanical work and then if he wants to restore it, that's up to him.
So here's the problem....it won't shift right. The first time I took it for a run it wouldn't shift at all but eventually it did....sort of. It will shift from 1st to 2nd but that's it.
There is a shudder that seems to come from the back end when accelerating around a corner and when downshifting from 2nd. I can't tell if it's a torque converter shudder, or the rear end, or a u-joint, or driveshaft issue, or what.
It has some instrumentation problems too, which I won't get into right now, that includes the speedo, tach and fuel gauge. There is power to the tach (it jumps when I turn the ignition on) and the fuel gauge (reading full but it's not full....and it's a new fuel pump/sender assembly). I can't be sure if there's power to the speedo or not (how can I tell?).
Based on the speedo not working and it not shifting, I assumed (despite the fact that the tach and fuel gauge aren't working right either) that it was the VSS causing the shift/speedo problem and the fuel gauge and tach are separate issues. However, I replaced the VSS and there hasn't been any change to the shifting or the speedo problem so maybe that was a foolish assumption. Is there actually some bigger that could cause the speedo, tach, fuel gauge AND shifting to misbehave? The temp and oil gauges DO work btw.
We had to change the ignition switch on the column (typical Ford problem...the switches on my 85 TC and even my 81 'bird wore out too), so I wondered if the boy had disturbed a ground somewhere and maybe that was part of the problem. So yesterday I took the entire dash apart and removed the cluster. I didn't find any unusual or loose grounds.
I haven't gone through each individual wire from the plug on the VSS all the way to the inside of the car with a meter yet (that's tomorrow's plan) but SOME of the wires are connecting because the car wouldn't start when I disconnected it (neutral safety sensor I assume?). I have all the electrical schematics for the car so I should be able to verify every connection (eventually).
The guy I bought the car from CLAIMED that it was driving until the fuel pump failed and that's when he parked it. If that's true (and it might not be) then the shifting problem is 'new' in the sense that many years ago (10+) the problem wasn't there.
Am I right in thinking that the transmission should still shift even without the cluster because the signal from the VSS is split BEFORE the speedo and the computer should still be telling the transmission to shift regardless of whether there is a speedo hooked up or not? Am I wrong to assume this?
Last time I checked for computer codes there weren't any...but my understanding of early OBD cars is that you don't get nearly the same amount of information from the computer that you do today. All I have for checking OBD1 codes is one of those cheap manufacturer-specific code readers, which I assume aren't that good.
So until I can update the thread with the results of some basic wiring traces, I would LOVE it if anyone has some a) troubleshooting tips/steps that I can follow, or b) some specific things to look at or try in order to isolate the issue.
I'm hoping this site is still frequented often and there's remains a good following of SCs (and XR-7s) out there. Around the same time I bought the XR7 for the boy I also found myself a 92 SC that's been stored indoors for several years and is in EXCELLENT shape. It's completely stock so I'm looking forward to updating and modding that one next year using info and help from this site.
Thx
K