347 Help Someone Please help me

[BlownSvt11]

This is the Problem
I just swapped over my 347 Stroker from the 85 5 Speed car to my 91 Gt Automatic Car.
The Engine has a Ford X-303 Cam. The car is Ideling Ruff, Not ruff as in Cam Ruff, But Ruff like the Computer is tring to Adjust something. When you get the car Higher in the RPM's it runs like a dream!! Only when it idles does it run Ruff... Is there something i have to do to the Computer to make this get better?? I had the Guy put it on the Computer and it said that the Cam is out of Adjustment?? He has never seen this before and said it was due to the Computer tring to adjust the cam but the cam is to big. Anyone know what i can do?? It might be something stupid.
Please help if you can
Thanks, Brian

 

[giddyup306]

If you have a loose timing chain the ECU will try and compensate for it as described above.

 

[BlownSvt11]

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[BlownSvt11]

the car ran good when it was in my 85 Gt 5 Speed. the car idled Awsome. just when i put it in the 91 Gt Automatic it runs like this. The only thing different is that the 91 has a MAF and a Computer and it Fuel Injected! This is a Brand New 347 it only has 200 Miles on it.
Its a Probe Racing 347 all forged with AFR 185 heads a Ford x-303 cam and 8:5:1 Compresion, 1.6 rockers. New Comp Cam Timing chain.. still think its the timing chain?? anything else it could be?

 

[giddyup306]

Disconnect the ground plug (as if you were setting timing). Then put a timing light on it. If it still bounces around it's your chain.

 

[giddyup306]

Also 8.5:1 sounds a little low to have a cam with 107* LSA. That may be part of your problem.

 

[BlownSvt11]

Ill give that a try. anyone else have any Sugestions?

 

[hllon4whls]

Disconnect the ground plug (as if you were setting timing). Then put a timing light on it. If it still bounces around it's your chain.

Not necessarily. A large duration camshaft can cause a vacuum/mechanical advance dist to move around at idle (the timing).

I suggest that the converter may be too tight and loading up the engine. What stall is the converter? If it runs the same in neutral as drive, then that is not the case.

 

[Xterminator03]

I had the same problem.
I fix it by going carburated.( Like you said this engine was once Carb and every thing was ok) But if you want to stick to Fuel Injection you need to make sure that you have the right injectors for your combination I think 24Ib would be good as well as what intake is the intake suppling enough air to the engine at idle then after all this recalibrate the computer.

 

[BlownSvt11]

The car is throwing These codes. 85, 41, 66, 91.
He told that the codes are Both o2's, MAF Malfunction and a weard 4 Letter Code meaning car running lean @ Idle. are these codes correct??

 

[BlownSvt11]

Not necessarily. A large duration camshaft can cause a vacuum/mechanical advance dist to move around at idle (the timing).

I suggest that the converter may be too tight and loading up the engine. What stall is the converter? If it runs the same in neutral as drive, then that is not the case.

No it's a stock Converter. I have not done anyhitng to the Tranny yet. Someone was telling me that if i have the stock 19# Injectors and the Stock MAF its not getting enought Air @ idle and running lean and that why the car does what it does. Does this sound right? Could that be the Problem?

 

[houstonstangguy]

you are running 19's still??? well that is a problem in itself but i dont think that is your problem. at idle it probably wouldnt be running lean, up high it would be. you said your problem was down low and up high it is good.......

you need bigger injectors anyway. what size is your fuel pump? that isn't stock too is it?

 

[BlownSvt11]

Yes im still running 19# and yes its a stock Pump in the tank. im not driving the car right now just building it for now but i just got it running and this problem came up. i have a set of 30# Injectors that came off my cobra im going to use, and im getting a bigger MAF and a Walbro 255 Intank here real soon.
Yea its just @ idle, up top it runs fine..

 

[vanzcorp]

Also 8.5:1 sounds a little low to have a cam with 107* LSA. That may be part of your problem.

doesnt the x303 cam have a 110 LSA?

 

[BlownSvt11]

Anyone else have any ideas?

 

[deftsound]

ok this is obvious, but first thing id do if i was throwing code 41 and 91 (which i am by the way) is check for vacuum leaks...