surging 2000 RPM & below, fine up top???
 

when I take off it hesitates & surges until 2K then comes on like a shot of nitrous, what is going on? I have a new cap & rotor, wires, ignition, distributor, plugs, etc. I switched it back to stock ignition, and even took my chip out, what else could it be? could one of the sensors be the problem? IAC? maybe TPS? maybe a timing problem?I am running out of options here.

in reading your post, i have a couple of questions. what year is the car? what trans? what is the mileage on the car? what mods? if cam has been changed, which one? i might be able to assist with some more info.

Thanks Dave, any help would be greatly appreciated. This is the strangest problem I`ve ran into so far, on the dyno above 2K RPM it makes good power (315rwhp, 340rwtq) but on the street is where it is driven the most, so the power really doesn`t matter to me unless it runs good on the low end. Let me know what you think, or feel free to e-mail me @ bdhollie@aol.com

`90 LX Hatch
Keith Craft 306 (50 miles)(150K on car)
TFS Track Heat Heads
TFS Track heat Intake
75mm Pro-M (w/optimizer)
70mm Accufab TB
30lb. injectors
Anderson B-3 Cam
3.73
26X10.5 ET Streets
Draglites
4-point cage
Sub Frames
Lakewood 70/30 struts
Lakewood Drag Springs
Comp. Eng. Rear Shocks
Tremec 3550 w/ Hurst
255lph in-tank
T-Rex external
JMS Chip

Surging idle has been a problem to plaugue many stang owners, a lot of the time with no easy or simple solution. I had it, and the only thing that fixed it was to change the cam. I tried everything else, every trick, troubleshot every component. I R2'ed cam, problem solved.

Not saying this will help you, but something to keep in mind. I would suggest losing the "optimiser". I had one and it was a total piece of crap! It was an early model, and maybe pro-m has improved them since, but i wopuldnt take my chances. Send you meter back, tell them to remove the crapmiser and calibrate your meter for whatever injectors you are running.

good luck

I don`t think its the cam, at least I hope not. I have had the same cam in similar combos and it did fine , I also have a friend with the B-3 and a S-Trim and it runs great down low even without a chip, I do have 1.7RR`s on it and the cam is actually for 1.6`s,I wouldn`t think that more lift would be the problem. I am going to call Anderson Ford Motorsport tommorow and see what Rick thinks. I might also try a new mass air meter, I got that one used off the internet for 30lb injectors(supposedly)but I figured even if it wasn`t the right one I could calibrate the A/F ratio with the optimizer.

What's your TPS set at? Do you still have an egr valve installed? Have you tried to pull any codes?

Take care
~Chris

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Retired Moderator
MustangNet

My site: JimPorterRacing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!

the TPS is fine, I have an EGR but it is shut off with the chip in, even with the chip out it seems to make no difference with the vacuum lines connected or disconnected, I havent tried to pull any codes yet, I am going to try a new mass-air meter next weekend, I have a 94 maf electronics I can use on my `90 C&L with a 30lb sample tube, I just posted to see if they are the same. If I got a scanner and pulled the codes would one even show up without the check engine light on?

Sure. It keeps a record of problems it sees for 100 ignition cycles (every time you turn the key to the run position counts as an ignition cycle). Besides, after you do a KOEO test, do a KOER test. That way the ECM is specifically testing things while the engine is running. If you need help with this, let me know.

Take care
~Chris

------------------
Retired Moderator
MustangNet

My site: JimPorterRacing

RACECAR spelled backwards is RACECAR

HEY !!! Are you ASE Certified ??? If you are, ask me about iATN. The best tool you'll ever have, and it's free !!!

Well if you figure it out then let me know b/c mine does it up to 3000 rpm.

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89 LX Coupe
306, 10:1 compression, Holley Heads, Intake, and Cam package, 70 mm Throttle body and Mass Air, 30 lb injectors, 255 lph fuel pump, 1 5/8" full length headers, Flowmaster 2 1/2" American Thunder Cat back system, Centerforce dual friction clutch, 4.10 gears
50-175 hp Nitrous Works kit, 5" Auto Meter Shift Light