New Comb is on/Dyno tune on Fri/ Funky Idle

[Venom351R]

well last night the #30 Injectors got swapped out for the #42's and the C&L is off and the PRO-M is on. W/ the previous combo it leaned out at 5,000 RPM's so I upped the injectors and replaced the C&L w/ a PRO M b/c Ive never tried a PRO-M before and b/c the C&L is notorious for leaning out combo's. Im going to Concord N.H for a dyno tune/Chip so after thats done the car should run alot better. The car so far loves the PRO-M and the 42's, w/ the extra fuel it seems to pull harder midrange through the RPM's and the idle is alot more smooth then the C&L was for the most part, but here is the kicker...... I know that at the dyno and w/ the chip they can fix this but Im just courious to see if anyone knows what might be causing this..

The car will not stay running when it is at a stop, The idle does not bounce up and down and then die out, it will be at say 800 RPM's and just stall like someone pulled a plug and everything shut off. The car drives mint I really like the PRO-M compared to the C&L so far. With the C&L the Idle would be really funky and bouce up and down but w/ the PRO-M its not doing that before it does just shut off the idle is very smooth and consistant but then for some unknown reason the car will just die and shut off. Anyone have any ideas on what could cause this?

Also anyone got any guess on what it will pull this time now that its not starving for fuel. Considering it pulled 370 last time and the HP/TQ lines on the graph had not even crossed yet Im hoping for a 390-400 RWHP pull w/ the addition of the PRO-M and the chip.

 

[wytstang]

It sound like what my car did when I first bought it. At every stop it would just die, it turned out to both my o2's. It also had a very weak fuel pump, I can't remember which one was causing it but I'm pretty sure it was the o2's that finally fixed it.

 

[Venom351R]

New 02's were put on last spring ( have been on just over a yr now, less then 15,000 Miles on them) and its got a 190 Fuel pump.

 

[wytstang]

I would run code and see what you get. My car (when first purchased) had 3 problems. 1) Both o2's where bad 2) very weak fuel pump 3)CCRM was bad. The car ran great while driving it ran like a champ until I came to a stop it would die without warning just like you discribe. It never pinged and never gave the CE light. Ran codes and sure enough lean bank 1&2 and the CCRM was throwing codes but no CE light. I'm assuming it starts right back up with no problems?

 

[Venom351R]

2) very weak fuel pump 3)CCRM was bad. The car ran great while driving it ran like a champ until I came to a stop it would die without warning just like you discribe. It never pinged and never gave the CE light. Ran codes and sure enough lean bank 1&2 and the CCRM was throwing codes but no CE light. I'm assuming it starts right back up with no problems?

Yeah it starts up and runs fine but at idle it just dies out. I would think that the fuel pump would be good, it is a 190 and only been on there a yr.

 

[final5-0]

Travis

If one uses a ProM maf with no chip or tuning interface, then they have no choice but to use ProM's cheat method of telling the pcm less air is flowing through the maf.

This is ok for 19's but as the size of the inj/maf grows this method becomes more and more inaccurate.

This method words kinda ok with 24's for some and not so good for others but when you move up to 30's then most peeps do have a few probs...if they would be truthful with the rest of us, lol.

A few of the most common areas where larger inj's cause probs are low pulse width driving conditions like idle, light throttle cruise, etc. Cold & Hot starts can cause probs as well.

Its just that 42's are so large that the matching inj/maf cal thing can't be accurate enough for ALL driving conditions. Thats why you are ok with part/wot driving conditions.

Your new tune should make things better again.

btw...if you have hot start probs...put the skinny pedal all the way to the floor before you turn on the key and crank the motor over...this shuts off the inj's.

Later
Grady

 

[Venom351R]

Thanks grady.

I'll post my results and how it runs after the chip when I get back tomorrow

 

[final5-0]

Thanks grady.

I'll post my results and how it runs after the chip when I get back tomorrow

I do remember your thread from a week or two and you said these guys have a good rep about tuning but If I was you ........ I'd be sure and tell them you not only expect good wot power but you have concerns about the 42's and any drivability probs they could cause with your street driven car.

Good luck tomorrow
Later
Grady