95' 7.4L TBI Problems

[tuff454]

Hi guys I have a 1995 7.4L engine with TBI and im having some major tuning issues.

 

The engine is in a '79 C20, the computer and all wiring have been hooked up. At the moment it runs, but idles very high and is running extremely rich at idle. When the engine is reving over about 1000rpm the air/fuel ratio drops to about 6:1 and the thing barely moves, maybe 20m/hr.

 

I have changed oil, plugs etc, installed a brand new injector assembly on the throttle body, and comp tested all the cylinders which are all approx 140. I have taken it to a mechanic but my problem being that im in Australia and I havent been able to find anyone that can even hook it up to a pc to get the error codes, so all im getting told is get MPI and a new computer.

 

I know it sounds like a bit of a mess but any info that anyone might have is greatly appreciated,

 

thanks

 

chris

[legionwagon]

Hi guys I have a 1995 7.4L engine with TBI and im having some major tuning issues.

 

The engine is in a '79 C20, the computer and all wiring have been hooked up. At the moment it runs, but idles very high and is running extremely rich at idle. When the engine is reving over about 1000rpm the air/fuel ratio drops to about 6:1 and the thing barely moves, maybe 20m/hr.

 

I have changed oil, plugs etc, installed a brand new injector assembly on the throttle body, and comp tested all the cylinders which are all approx 140. I have taken it to a mechanic but my problem being that im in Australia and I havent been able to find anyone that can even hook it up to a pc to get the error codes, so all im getting told is get MPI and a new computer.

 

I know it sounds like a bit of a mess but any info that anyone might have is greatly appreciated,

 

thanks

 

chris

 

<{POST_SNAPBACK}>

 

 

I'd check all the wiring, and sensor placement. I assume that you have the correct computer and all the sensors, correct? Using a stock or "painless" harness? Oxy sensor placed well? MAP sensor close to TBI, with no leaks, no other vacuum devices stealing vacuum?

I think that you can read the codes just with a jumper wire on the data connector, but a scanner is nice (I got one for about $60 US).

That help?

[c502cid]

I second the vacuum leak scenario. Do you have a check engine light hooked up to it, you can read codes off that.

[tuff454]

thanks guys, turns out the oxy sensor wasnt even hooked up so ill hook it up and see how she goes, thanks