I have been trying to figure out this problem for a few months now. I have an '88 Bronco with a 351W and a C-6. When I "baby" the accelerator, the engine will run o.k. When I need to accelerate heavily, go up hills, or floor the accelerator, the enigine will go to about 4000 RPM and then go to about 1500 RPM. It has no power what so ever going up hills. I took it to ford, and they are now telling me they think that the timing chain has jumped two teeth. They say that this has put my timing off by more than 15 degrees. Is this possible?? I know that the fuel system is fine. I replaced both fuel pumps and have verified that there is plenty of fuel pressure. I have also replaced the spark plugs, wires, cap, rotor, coil, and tfi module. Can anyone tell me if this is possible?? Thanks.

 

[updated:LAST EDITED ON 02-Jan-03 AT 01:40 AM (EST)]It is possible but you would see drastic fuel economy changes not to mention knock and ping that you couldn't fix with the best fuels available. Jumpng time will happen to a very old or badly stretched timing chain and it will cause the symptoms you are describing but there will be more problems than that. You would have no power off the line, for passing, basically anything in the low end.
You can check this yourself if you want to be certain. If the chain has jumped time, you would most likely have very bad or zero compression with the #1 cylinder at TDC. So if you do a compression check of #1 @ TDC it would at least give you a good indication as to whether your Ford dealer has it right. You should be able to turn the engine by hand enough to get timin marks aligned and even turn it until you do get decent compression which would indicate just how far it has jumped time as well. I have no doubt that if I've screwed this one up, someone will be all to happy to tell me how wrong I am. But to the best of my knowledge, that procedure should at least help determine if you are looing in the right place for the problem.

 

Thanks a lot for your help. My truck is still at ford. They tore it down and I found out that whoever replaced the timing chain before, didn't do it correctly. The timing marks on the gears don't align! The chain is bad, there is more than a half inch of deflection. But it never jumped. It is so far out of time, and since the chain is bad, it makes the problem worse. The computer can't advance the timing enough for it to run correctly. Thanks so much for your feedback.

 

Yikes, glad they were able to get in there and fix it before something drastic happened. Best of luck.

 

My 89 EB 302 is doing the same thing, is this possible to be for mine, it has very slow throttle response, and it almost sounds like it misses a little bit too!! Would the timing be off this much, and how much do you think it will cost to be fixed??

 

hey all, i really need some help here on what to do about this bronco, its a hassle but i wouldn't trade it for the world, my g/f doesn't like it that much, but you know, i never really liked her much either acctually i love her to death, but will someone please give just a lil bit of help on what to look for, if you read the posts you have pretty good idea on whats going on!!

 

Pull your codes, do a compression test, and a vacuum test.
http://www.broncodata.com/tech/codes.htm
http://www.users.bigpond.com/ergoff/vac1.htm