Sounds like cam, but NO cam!!!!!

[LEROYBLACK]

I have a 93 mustang GT that the motor blew in, so I put my motor out of my 91 GT in it. When the motor was in my 91 it ran fine, now that it is in my 93, whenever you crank it, it lopes and chops like its got a big cam in it...( sounds good< every thinks i got a cam) This sound last for like a minute, then it idles out perfect. Does not matter if cold/hot whatever. I do notice that when i get on it it is sluggish, kind of liek its bogging down. Both cars are 5 speeds. Its kind of like its relearning its timing....Can anyone please help.....

Thanks, Tim

 

[Daggar]

You done a code check? And my question to whomever knows the answer... are the computers between a 91 and 93 the same? Did you swap computers if they are not?

 

[LEROYBLACK]

I did not do a code check, because it is not throwing a check engine light, so i dont think that anything would show up...If wrong on that someone let me know please. Also I have been told the computers are not different, but didnt they drop the power rating in 93? Do ya think maybe it was a diffferent tune in the computer, and thats what is throwing it off?
Thanks, Tim

 

[Silver95Stint]

If it's sounds like a cam your harmonic balancer maybe off. At least that was my problem when I had a similiar sounding issue. GOOD LUCK.

 

[mob]

something could be wrong, dont take my word on this but i think someone on here posted a while ago about ther car sounding lopey like it had a cam, but something was wronng with it not sure at all tho what it is, but i dont think its too bad

 

[DTT92LX]

Mine recently sounded like it had a cam but it was a vacuum leak at the hose from the charcoal canister to the intake. Fix it and allllll smoothed out.

 

[LEROYBLACK]

DTT, but i would think that if it was a vacuum leak it would idle and sound like that at all times... My only does it for like the first minute i crank it up. I can run it for an hour and turn it off and crank right back up and it will run like that for a minute or so, then it idles out smooth. It does it no matter if its hot or cold.

QUESTION: While it was in my 91 (the motor) I advanced the timing to 15 degrees. The motor that was in my 93 ( the one i blew up) timing was set at stock. So the question i have is that do you think because i already had the timing at 15 degrees and just stuck it into my 93 and pluggged everything up the computer is still at stock timing.....maybe i need to retry doing the timing.
???

Thanks, Tim

 

[D347643]

wooooooah!!! mine is doing that too! god i hope someone knows how to fix that except i have a stage 1 cam. and its gets really lopey when you first start it up

 

[Jo_885o]

Does it lope and surge between 500 and say 1200? If so CLEAN ur tb. Mine did that when i was stock sounded like a mild cam, to make it stop i would hit the gas and it would smooth out.

 

[3022FST4U]

I had the same problem as well. It sounded almost like it was cammed mainly when cold or first started. It was a vacuum leak. Once its warmed up the computer does a good job of smoothing out the idle when its just a wee vacuum leak.
The timing and/or computer should not be an issue because you swapped motors or advanced the timing.

 

[LEROYBLACK]

Already cleaned throttle body, does it hot or cold, dont matter, and it takes the same amount of time to quit doing it wether its hot or cold, weither i give it some gas or anything, its almost kinda like its relearning its timing.

 

[92greenlx]

I had a vacum leak that was similiar to your problem. It was the hose to the canister and a small hose that ran from the passenger side firewall to the driver side. Then I advanced my timing and set my idle and I am ok now excpet for my cold start issue but thats another story. Oh and I set my timing and changed out my IAC.