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Roll Cage Installed loss power

Regi

New Member
Hello guys.

I need some help. I have a 1991 GT manual mustang convertible that was running just fine with the new 347 we put in. Since i was getting rattling sounds, I decided to put a roll cage in the car. Well since then the car runs like a stock 5,0L lacking a lot of Hp plus it runs hot and is hard on gas.

I am clueless as to why it lost all of its power. It ran like a rocket before but not it seems feels stock. 200 hp missing. The weird part is that the car starts and runs fine. If i didn’t knew what kind of power it was making before I wouldn’t know the car had a problem. This is how smooth it runs.

The only thing I can think of is that when going through the dash (through the front speakers opening to connect the cade to the floor)) I may of broken or damage a wire. I looked all over and under and i just don’t see whar wire I may have damaged.

But what wire would do that?? Wire that would connect to what?? I chechef and the TPS has all its voltages, EGR, MAF I check those too. What eire could do that?? If i knew then I would know where to look.
 

347HO

Active Member
If you have an IR temp gun, shoot each primary tube with engine running. The one that's cold, has a dead cylinder.
Start with that...
Good luck.
 

Regi

New Member
Hi thanks, the car is running well i.e. engine not hesitating it is just missing a lot of HP. When I drive it drives well but i know that it is missing a lot of HP. This car use to push me back in the seat now it feels less than a stock 5.0L.
 

347HO

Active Member
Hi thanks, the car is running well i.e. engine not hesitating it is just missing a lot of HP. When I drive it drives well but i know that it is missing a lot of HP. This car use to push me back in the seat now it feels less than a stock 5.0L.
lolz...
Maybe you'll understand after.
 

broncojunkie

Well-Known Member
I don't know that I would presume it's related to the cage install. It could just be coincidence. When someone describes a lack of power, I typically think timing or fuel delivery. But as 347HO said, make sure you're firing on all cylinders. You can have one or two cylinders not show up for the party and it still runs smoothly. Of course, on a 4 or 6 cylinder, the misfire would be more noticeable.

I'd then throw a fuel pressure gauge on it and check timing. Go from there.
 

Regi

New Member
Ok thanks, i wanted to do those tests and the car won’t start anymore. It cranks but won’t start. When I went to check the computer codes using the old method of flashing engine light I got no more code. The engine light does not flash anymire to give me any codes. So I think the computer is dead ??
 

broncojunkie

Well-Known Member
Ok thanks, i wanted to do those tests and the car won’t start anymore. It cranks but won’t start. When I went to check the computer codes using the old method of flashing engine light I got no more code. The engine light does not flash anymire to give me any codes. So I think the computer is dead ??
Possibly. I'd first figure out what's going on. It's probably not getting fuel or not getting spark. Have you checked those? If the issue is no fuel, find out if it's not getting fuel pressure at all or if it's due to injectors not firing.

When the ecm goes out, it's almost always because the capacitors are bad. They can be repaired pretty cheaply.
 

347HO

Active Member
Is/was the RC a weld in or bolt in?

Its recommended the ecu be isolated from the voltage and amperage during welding.

Also, a low voltage batt (10vdc or less) will take out integrated circuits in the ignition system.

At any rate... Its fairly simple to isolate if you have an "ignition" or "fuel delivery" issue, or both.
 
“Also, a low voltage batt (10vdc or less) will take out integrated circuits in the ignition system.”

Really?? I’ve been fighting with a dead battery/boosting etc and then lost all fire. Coil isn’t firing and the injectors aren’t firing. This could be because I was messing around with low voltages??
86 mustang lx with a 3.8/auto.

I was thinking distributor or tfi went bad or I zapped it… but I might of zapped the ecu??
 
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