Had just done a complete head rework recently. F3 Truck heads with Patriot performance Dual Gold springs,titanim retainers and hardened pushrods, Cop Cam 224-228--601-605 -112, LT Headers and a fresh tune thats putting down 400 horse at the rear wheels. Problem is car idles terribly, surges between 750 and 1100 RPM when cold and won't stay running unless water temp reaches 180 unless the RPM is kept in the 1200 range. Any suggestions!!

 

My guess would be tuning. Going thru some of the same things with my car and only have 115 LSA. There are several tuners in TX area who can probably take care of this for you. Good luck.

 

If you didn't retune it,,, hell yea it going to Idle poorly and have drive-ability issues! I bet your fuel efficiency sucks!

There are some good tuners there, just need to be pointed to the right ones

BC

 

It was tuned and Dynoed but a few days later it started idling badly when its cold. Its driveable but needs to warmup to about 180 before it quits surging and will idle below 1200 RPM without shutting down.

 

Terrible to hear, but been there myself. Pretty much the same setup 400-425rwhp range. Even after having a tuner or two look and give some advice and offer help for a few huindred bucks, I ordered my HPTuner myself. I did the ole school trick and drilled the throttleblade allowing more air to idle and lean out the a/f a bit. I had to adjust the idle up to 950 to get it to stop surging and dying with A/c on and coming to a stop.

I adjusted and played a little and eventually got it to be perfectly smooth and consistant at 800rpm with the A/C on or off and not surge or die at stops. It does have a bumpy idle(cam) but that's exactly what I wanted.

There will be all sorts of tuners and advice telling not to drill or you end up in Hell and carry the mark of the beast. BUT it's only a measure if you can't find a tuner who can fix it right. I'm still learning how to do it, but since my car runs so good and get's it when I want it(everyday) I'm still leaving it drilled. I have followed some advice but got tired of soldering that hole up only to have to redrill it so it would run right.

I'm NOT advocating drilling the throttlebody or suggesting that....I just wanted to provide you my results without paying a tuner hundreds of bucks...and my endeavor to learn to tune my own.

 

Look for any VACUUM leaks between the MAF and TB and any vacuum lines attached to the intake. Also make sure that the manifold bolts are tight REMEMBER,, there torqued to INCH POUNDS!

Tighten the intake manifold bolts. Tighten
Tighten the intake manifold bolts a first pass in sequence to 5 N·m (44 lb in).
Tighten the intake manifold bolts a final pass in sequence to 10 N·m (89 lb in).

 

I will NEVER drill my TB or anyone else's.

I have a NASTY cam and it idles and runs perfect. Its all in the tune and the tuner makes it happen... If a tuner needs to drill the TB,,, find another tuner. PERIOD!

It just needs more air and there are several PCM air tables that need to be adjusted to allow that to happen!

Drilling is a band-aid (and a poor one) used to provide the engine more air at idle. Adding air is easy if you adjust the right tables.

If you want an excellent tuner in TX,, call Stephen or Jason at ENGLANDGREEN PERFORMANCE in Houston. Its a hike but a well worth one.



Bill

 

Thanks guys for your inputs. Will need to wait a little while before I can afford another tune after all the cash put into the head work and previous tune.

 

Who GOOFED UP the tune you paid good cash for? That sux man!

 

Stephen and Jason at EnglandGreen, can fix that up no problem. You can even mail them your cam specs and PCM and I bet Stephen can nail it first try. I took him my PCM going from stone stock to forged, cammed, heads, blower, gears, nitrous, exhaust, basically a whole build, and it fired up on the first try, idles great, (with a pretty big cam) and runs perfectly. I have been driving it for a week, and it has not even hiccupped. I do alot of builds, and I wanted a professional shop to get me close so I can take over, and these guys are the ticket. Very professional, and are just regulalr old car guys to boot. Highly recommended. Save your money and take it to them. Good Luck, Steve

 

How about the Chuck Cow tune? You can log what is happening and e-mail it back to him. I would think he could get it to idle correctly.

 

Never drill your throttle body... and get a new Tuner. A cam that small should drive like stock.

Stephen

 

The LT's are more to blame than the cam---beacuse of the further back 02 locations on your headers than the stock manifolds--you get erroneous 02 readings and the car runs richer than the stock stoich of 14.68--In closed loop---Somewhere more in the low 14's -like 14.2
The cold start issue is from your cam--Beacuse of cam overlap and tigher LSA's the car also runs very rich at start up
Whenever started the ECM runs in "open loop"
When DEAD cold the coolant temp must reacl apprx 140* before the ECM swithes to "closed loop"
After warmed--It swithces over via a timer only--usually around 20 seconds
To correct all the cold starting over-rich mixture you should lean down the "commanded fuel in open loop normal" table
The stock AFR's in open loop for starting are very rich--from around 13.8 to 14.3 On my car with a .224/.224 @50 I had to lean it down to 16.12
So in the commmanded open loop table NORMAL in the start up fuel area and start-up temp area (say from 0 to 50 KPA and from 50* to 284*
lean it down to about 15.50 as a start---in the whole table area as mentioned---- start it up and see how it reacts---you may need more or less--a trial and error deal---
The fuel trims are turned OFF at start up even though the logger may show a % but it is meaningless--To check the dead cold start-up--you'll have to wait till the car is completly cold again to test---- I tune this way on every cammed car i tune-- to correct start issues---
PS: a C5 does not have an IAC (idle air control) like a camaro or truck)