Just installed TFS Kit. now surging problem??

HO5POINTO1990 · Apr 15, 2006

Ok, so I ordered the TRICK FLOW KIT:
TFS-K514-350-370
for my 302 1990 mustang gt. I even got the radical cam too. We pressure tested it and everything was fine so when we went to fire it up the car wouldn't idle without the spout connector to adjust the timing.... So then we put it at top dead center and checked the timing and it was at about 12º. (the other way to adjust the timing) However, without the spout connector the car wont idle it just surges once and shuts off. So we put it back in and start the car and then the car has some problem idling there too.... So we test drove it and it dies whenever the rpm's drop from high back to idle everytime.
We then adjusted the throttle because when we did the new kit the throttle position had been loose and moved around a little. With it not being able to idle well we took the car for a spin around the block and I heard backfiring... He said that it was too retarded, but according to where it's set it's at a good advance. COULD this be because my computer can't handle the horsepower (like another buddy told me), or could my distriubutor be one notch off? I am thinking of just pulling out the distributor and turning it a hairline to the left so that i can advance it more... If anyone added this kit and had similar problems with idling please let me know.

txstang84 · Apr 15, 2006

the bit about the computer not being able to handle the power is a bunch of hooey-just look at some of the other folks on here that are running more radical setups...

I would put the timing at about 14-16*, ck the fuel pressure (39 is stock)...the backfire is probably a mixture issue.

If the dizzy was a tooth off, then you probably would be showing something way different than 12*.

What injectors are you running? what maf, what tb?

I'd disconnect the battery, make sure all the connections are correct, ck all your vacuum hoses for proper connection-they will cause MASSIVE idling problems-they allow unmetered air to enter the engine-which can cause a lean condition. After you've ck'd and double ck'd all your connectors, and hoses, then reconnect your battery, set your timing and see how it goes from there...

txstang84 · Apr 15, 2006

just to add real quick, with the dizzy on the correct tooth, you should still have plenty of adjustability for timing-anywhere between 0*-30* BTDC unless you're TFI hits the manifold right behind the thermostat housing...

If you want to make sure it's where it needs to be, rotate cylinder 1 to compression TDC, (you should be able to look at your balancer to do this), and when you drop in your dizzy, align it with the "1" on the cap just for a ruff estimate and go from there-remember counterclockwise will retard, clockwise will advance

HO5POINTO1990 · Apr 15, 2006

I have a 76mm C&L MAF calibrated for 30lb injectors with a 70mm TB. The only problem is that I can't turn the distributor any further to the right... The problem is that it stops turning with no room... The other thing is that we checked and there really isn't any vaccuum leaks anywhere, but someone was saying that if the IAC was bad it might not fire. and because that's connected directly to the computer that I could just chip it

HO5POINTO1990 · Apr 15, 2006

oh and the only way to check the timing is WITHOUT the gun but with the Distributor open and aligning it at top dead center. So checking it with the gun is impossible because it wont idle.

90lxfoxbody · Apr 15, 2006

i have had a similar problem before. i had two things wrong. the gasket between my upper & lower intake and spacer had developed a crack and i had a vacuum leak, and the iac valve was bad. i disconnected the iac valve and the car ran the same so i knew the valve was bad. i replaced the iac valve and the gasket and it has ran great since.

txstang84 · Apr 15, 2006

yes, the iac is a possibility, try jumping 12v directly to the iac, if you hear it "click" it works, it's quiet, so listen closely...it could also be clogged.

if the iac is bad, the engine will still try to start, but more that likely will fall right on it's face...during starting, the iac is commanded open until rpms rise, then it's commanded open/close based on duty cycle...

here's something else you can try, try inducing a vacuum leak, pull one of your vacuum hoses and see if it tries to idle on it's own...

txstang84 · Apr 15, 2006

just a thought, how are "checking" the timing without a gun-just lining up the rotor and cap based on what you see on the balancer is a decent guess at best, it doesn't take much movement to get a couple of degrees advanced or retarded. when the spout is in the computer believes the dizzy is set at 10* and takes over from there, but idling with the spout in, the timing is scarcely ever at 10...more like 18-22

1SLO306 · Apr 15, 2006

i think the injector are too big and are supplying to much start up full or somthing.

HO5POINTO1990 · Apr 15, 2006

well my buddy who helped me put this together told me that this CAMSHAFT: TFS-51402000
Is not compatible with the stock computer. He did some research and somewhere through the web it says that you have to purchase an aftermarket computer. Could this be true or is this just speculation? I am going to work on it again tomorrow since I have to work all night, but I'll keep everyone posted and please give me your opinion on the cam????

jrichker · Apr 15, 2006

See the sticky "Help me create the Surging Idle Checklist" at the top of the forum for help with your idle problems. The first post in the sticky has almost all the details you need.

txstang84 · Apr 15, 2006

The part # you put up there says it's a TFS stage 1 cam...honestly, that's not big-my lunati 51014 is pretty close in 0.050" numbers, and in lift, but has almost 15* more total duration, and I've not had a problem with it yet, it cranks quick, holds a good steady idle, albeit lopey, but still good idle...

alot of cam grinders say that you should "upgrade" the computer, all they mean is you should get a tune to take full advantage of the setup, it doesn't mean you can't run your stock computer.

the fact that you're running 30 lb'ers with that setup probably has at least a little to do with it, evil88lxvert had them on his 306 w/edelbrock rpm heads, and the same cam i use, and it would gag you unless you were in a well ventilated area...and it fouled the plugs out super quick.

seriously, just try inducing a vacuum leak, and see if it tries to idle, if it does, chances are really good that either your iac is bad, you're running pig rich, or both...

but like jrichker said, ck the sticky first...

91lxttrim · Apr 15, 2006

Yes def go to jrichker's 'surging idle' sticky. I have the exact same set-up and had the exact same problem you are having. I pulled the codes, and tested each one until i was able to narrow it down to the sensor in the number 5 intake runner. Pulling the codes is a must.

I started by dremelling the AIC a little, cleaning the MAF, TB, and AIC, replacing the EGR valve, EGR sensor, adjusting the throttle stop, and TPS. Then replaced that ATC sensor in the #5 intake runner and that did it. Starts great, idles smooth and no surging!

Read the whole sticky and eliminate things one by one. Stay with it. I know how frustrating it can be.

Mustang5L5 · Apr 15, 2006

HO5POINTO1990 said:
well my buddy who helped me put this together told me that this CAMSHAFT: TFS-51402000
Is not compatible with the stock computer. He did some research and somewhere through the web it says that you have to purchase an aftermarket computer. Could this be true or is this just speculation? I am going to work on it again tomorrow since I have to work all night, but I'll keep everyone posted and please give me your opinion on the cam????

A TFS stage 1 cam is not that big. Plenty of guys run it.

I actually did the same thing and have the same problem today. Car is loping badly. All we did was install AL heads and roller rockers. WHen we slapped it back together car will just lope and lope. The TFS stage 1 cam has been in it for a year so it will run on that cam

RYC CUKR · Apr 15, 2006

I was having the same problems that you have after I did my HCI. GT40p heads, trackheat intake and TFS stage 1 cam. It ended up being that my timing was wayyyyyyyyyyyyyyy off.

What I did was have a buddy start the car and stay in the drivers seat. I pulled the spout out and had him just try to maintain about 700 rpm. Then I checked my timing and found out that it was way off. Reset it to 10* took it for a drive and then got it up to 14*. Every now and then it will surge a little when I pull the spout out to adjust my timing at the track for n2o.

Five that a shot and see how it works and if it solves your problems. My guess is it will since I had the same symptoms you have after my HCI.

My big problem is that now if I stop really hard or let off the gas after a burnout the car will stall out. I think its a converter/cam interaction issue. TFS stage 1 cam is by no means to radical for the stock computer in a 89-93 MAF car.

MustangGT92 · Apr 15, 2006

i had that same problem but with a little different setup...i had to pulled the distrubutor again and pulled the #1 spark plugto bring it to top dead center...then i checked on my harmonic balancer to see where it was at...after i got it to idle i advanced my timing and throttle...after idling fine i couldn't understand why no power...then after discussing it and reading it in this forum i realised it was my fuel pressure regulator<--- took time to do that...

Mustang5L5 · Apr 16, 2006

timing and fuel are fine

HO5POINTO1990 · Apr 16, 2006

thanks for all the input guys. i'll let you all know.

HO5POINTO1990 · Apr 17, 2006

Well we got it to idle. The idle is a little higher than usual. I figured that would be the case since it is a bigger cam. The idle is now around 900 rpms to 950rpms. Sometimes it will drop to 800. We cleaned out the IAC, and did a fuel pressure test to make sure it was getting 39lbs. It was. We also adjusted the throttle and the timing and it's set around 15.5º . I also purchased an aftermarket chip (from summit) because a lot of people tell me it will run a little nicer. I will be taking plenty of audio and video clips and I will post them. The car is running sweet with only minor problems like a little VAC leak, but it runs like a champ. Thanks for all your input.

HardmanGT · Apr 17, 2006

I'm willing to bet it is your timing. You NEED a gun to set your timing. If you can't get it set because the range is too limited on the dizzy than you have the dizzy off by at least a tooth. End of story

Get that squared away first.

Send back that chip and get the car properly tuned on a dyno by a professional tuner. Don't waste the cash. Put it to better use.

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