Tech, Repairs, Upgrades > Capri XR-2 89-94
SOLVED?? Misfiring or fuel cuts out under load?
boomingbeetle:
So since I fixed the overboosting issue I thought I better start a new thread. I've read about a lot of people having this issue, seems to be quite common, but I don't know of any definitive answers:
After a couple of minutes with the car running, it seems to cut out like there is no fuel. If you've ever run out of gas, you know what this feels like. This only happens while driving under a slight to moderate load, especially between 2000 and 4000 rpms. It revs smoothly and freely when not in gear, and has never stalled. Also, the problem does NOT happen if I floor it and go flat out. I can take off at wide open throttle and go all out through 3 gears and never a miss, but as soon as I lift the peddle off the floor and hold a steady cruise, it will start cutting and bucking. Makes a pain in the ass cruising on the highway... any ideas? I will troubleshoot the following items in this order, but the $$ will add up so I'd like to know if anyone else has solved this riddle before I get too far in the red with it:
1. just replaced the fuel filter, no change
2. new fuel pump on order, will install this coming weekend
3. replace plug wires (17k miles old)
4. replace cap and rotor (17k miles old)
5. injectors?
6. VAF?
7. O2 Sensor?
8. ECU?
#UPDATE# if you are having these problems, try cleaning the grounds at the thermostat housing including the bracket, connecting bolts, and the top bolt of the thermostat housing first!
boomingbeetle:
Update:
I started the car and unplugged the TPS, as others have done, and the car runs perfectly with no issue, as others have experienced. I think that rules out plugs, wires, injectors, or fuel pump. I believe I am now running in “safe mode”, but unplugging the TPS doesn’t mean that the TPS is necessarily faulty? It could be any other sensor/ECU that is faulty and I’ve just over-ridden it by unplugging the TPS? I will break out the multimeter and try testing the Unit this weekend, but could I still have a bad O2 sensor or VAF or other item? Can anyone chime in to tell me what others have found or am I going to keep replying to my own questions?
SHOwn:
I've noticed that traffic on the Capri sites dips in winter months, probably because a lot of owners park them in cold climates. I have not experienced the issues you have, so I've only read about this problem. Have you tried searching this site for TPS and reviewing all the posts that come up? I did and a preliminary scan looks promising. All I can say is in the absence of experienced people to reply, all we have to fall back on is searching. Actually, it is where we all should start, not saying that you didn't. Sometimes I fail to do that.
boomingbeetle:
Yes, lots of searching on this site and other boards... but it just leads to more questions :o
I'm not frustrated, so I hope it doesn't come across that way. It seems to me that this is a common enough issue that someone should have pinpointed it, but I don't think anyone has had a definite closure. It seems odd to me that the same problem could be caused by all of these separate items:
person 1 - bad ECU
person 2 - bad VAF
person 3 - bad TPS
person 4 - bad plug wires
person 5 - corroded wiring harness plugs near and/or involved with brake master cylinder swap
person 6 - corroded wiring harness plugs at ECU due to leaking heater core
person 7 - faulty engine ground
person 8 - vacuum leaks
Most people don't complete the thread with a "SOLVED" update, so I don't really know what has worked, and in many cases the threads are many years old and these people might have moved on from Capris long ago. Hopefully I will be able to narrow it down and document it, and I will post in other threads as well if I do find a solution.
SHOwn:
Thanks. Very good synopsis. I agree, most of us fail to report if an issue is solved, we just resume driving and forget to report. Many old posters have moved on. Most of these cars are no longer daily drivers like mine, so they sit a lot and many are just rarely used.
Hope you can find the smoking gun out of all those possibilities.
Navigation
[0] Message Index
[#] Next page
Go to full version