camshaft/idle help
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Junior User
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camshaft/idle help
its been awhile since ive been on lol ive been a busy little beaver. I currently have a 1994 f150 4wd with maybe 15 miles on my re-rebuilt 306 short block (machine shop put the wrong hone and ring gap on my rings n fried them) with KB115 flat top pistons, has Edelbrock Performer 1.90/1.60 heads, Hooker long tube headers, port matched stock intake, Trick flow 1" plenum spacer, Comp Cams 35-320-8 camshaft , and 2 1/2" dual exhaust. Right now my timing is set at 8 degrees BTDC. ive set it to the factory spec 10 degrees BTDC and up to 16 degrees BTDC had an issue of it surging off and on and when i put it in gear (AODE/W) she will drop so low in rpms (600 and lower) that if i dont step on the happy pedal she dies. i messed with it this evening and found she kind of likes 8 degrees BTDC and doesnt seem to drop terribly when i put her in gear but when i am fully stopped she idles down now to 600rpm. im kinda stumped on this timing issue. anyone have any info to throw at it? thanks
Fleet Owner
Joined: Oct 2005
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From: Kentucky
Is your truck using Mass Airflow (MAF) or Speed Density (SD)?
If the latter then you will more than likely need a custom tune for it to work with all changes as well as the cam that has a 112 degree LSA.
If you do have MAF you still may need a tune for the PCM to be happy.
If the latter then you will more than likely need a custom tune for it to work with all changes as well as the cam that has a 112 degree LSA.
If you do have MAF you still may need a tune for the PCM to be happy.
Senior User
Joined: Oct 2013
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From: wentzville MO
I think i am going down the exact same road you are. I am using a 351w on a 302 MAF computer. The cam I have is also a 112 so i think we need this;
http://www.summitracing.com/parts/mv...95/model/f-150
However I am not 100% and still doing my homework. if anyone knows if this is the fix let me know too.
http://www.summitracing.com/parts/mv...95/model/f-150
However I am not 100% and still doing my homework. if anyone knows if this is the fix let me know too.
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idk but i left the link up on my page. i do know the comp cam is built with a 4 degrees offset but im not sure what the F7TE cam had. i just went out and fired her up on a cold start and seemed ok and but still idled low for a cold start 1200rpm or so. ima talk to my post friend on here that brought my attention to the cam and see what he has to say later today or this evening, but i will say this its not a pig anymore lol she def has way more tq
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Laughing Gas
Joined: Dec 2007
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From: Imperial, MO
In that case, you'd likely be best served by a local dyno tuning facility. Tuning is accompanied by a relatively steep learning curve and a decent initial outlay of cash, but it's also very rewarding to be able to change just about any parameter you can think of.
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FTE Legend
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From: Ottawa, Ontario
X2 on that. Tuning is a steep learning curve but a system like this is easily worth the cost since it will likely take you quite a few tunes to get it running the way you want and that would cost you serious dollars at a dyno tune shop.
You low idle is likely a result of the lower idle vacuum this cam generates.. could be 14-16 in/hg where the stock cam produced 18-20 in/hg. Idle speed is something you can adjust with the tuning setup as is using a different MAF meter and larger injectors that would be better suited to all those high flow parts. Also note that the computer can't instantly adjust to these new parts it will take some time and many drive cycles.
You low idle is likely a result of the lower idle vacuum this cam generates.. could be 14-16 in/hg where the stock cam produced 18-20 in/hg. Idle speed is something you can adjust with the tuning setup as is using a different MAF meter and larger injectors that would be better suited to all those high flow parts. Also note that the computer can't instantly adjust to these new parts it will take some time and many drive cycles.
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Junior User
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when upgrading the flow meter and injectors wouldnt the computer need to be tuned to those new injectors and flow meter? it has 19# injectors and matching flow meter in it. i can get a set of 21# injectors and matching flow meter rather cheap or completely upgrade to 24# injectors and flow meter. would the 21# injectors need the tune cz if im not mistaken the 24# injectors would need to be tuned. and with the quarterhorse software would i need anything else? is it a plug and tune or is it a 1 chip burn at a time? and how would i build said tune to fit the motor? im completely new to building a tune
FTE Legend
Joined: Jun 2006
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From: Ottawa, Ontario
Yes when components are changed the computer needs to be tuned. With the Quarterhorse you have access to everything the computer uses to make calculations, so for example if you change to 24lb injectors you simply go in and change a few parameters to tell the computer about the new injectors and save the info. That is a "tune".
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ok sounds simple enough but beings as its a OBD1 MAF ecu will i have to install a new chip or does it plug in somewhere and use the exsisting chip that has the basic factory tune? will i need to purchase anything else besides the program like connection wires or additional software? just trying to figure out everything i will need to do this
FTE Legend
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From: Ottawa, Ontario
There is no removable "chip" in the OBD1 PCM, tuning systems like the Moates come with a module that plugs into the J3 port on the back of the PCM that overrides the onboard ROM, and this module connects to your laptop with a USB cable. Tunes are stored on the module so you don't need to have the laptop connected all the time.. just when you're making changes.
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there is a binary editor that is recommended for fords and is suggested for use with the quarterhorse. its a grand total of $340.00 which is way less than i have in components lol and it sounds like if i do drop in a 331 after awhile i can use it to tune for that as well 
does this come with instructions on what parameters to change to for the changes that have been made? like the cam, or the better flowing heads, or the diff injectors?
does this come with instructions on what parameters to change to for the changes that have been made? like the cam, or the better flowing heads, or the diff injectors?