Long drive + hot start = car dies EVERY TIME!

[whiplash306]

Hey guys...got a question. Just had my car tuned after a 2.3 Whipple install. Car runs great, boosts wonderfully, idles great after warmup, etc......but I have a weird problem. On a cold startup, the car fires right up, idles high for a sec appropriately, then slowly idles down and holds steady at around 800 RPM. However, if I drive the car for any length of time, then turn it off (say, to get gas or make a REAL QUICK run into a store), then come back out and try and restart the car, she'll fire up, stumble for a sec then die. It isn't unless I give 'er just a touch of gas on a hot start that she'll stay on. The car has the usual mods: 60 lb injectors, twin GT pumps, PPRV delete, Stage II FPDM, SCT 2800 MAF, stock TB :nonono:, head cooling mod, JLT high boost intake, etc, etc.

For the record, I've replaced the FRPS twice and have since placed the KB disc in there, so I don't believe I've got any FRPS issues.

Can anyone offer any guidance? This is a very frustrating issue that never seems to happen around my tuner.....it's like the car has "white coat syndrome" and knows that it best act right when around the doctor...! Ha

 

[whiplash306]

Since my first post, I've increased my idle RPM from 800-900 and after warming the car up on a short drive, I let 'er idle and disconnected the IAC motor and the car died....which tells me the IAC motor is fxning properly, correct? However, when getting back home and turning her off, it's still wants to stumble on hot start and die.....or, the engine will turn over and over and over, finally crank, stumble a bit and die.....

 

[wilderyzed]

Its more than likely the start/cranking fuel tables I had this issue once it ended up being a tuning glitch re-tuned the driveability and it straightened it out so its most likey in the tune since it didnt happen till after you put the blower on and retuned. OR you could have a vapor lock prob in the fuel rail and you get air bubbles in the FRPS making it stumble till you give it more throttle and it commands more Fuel Pressure. ORRRRR you could have a MAF issue. Plug in your handheld(if you have one) and make sure the MAFV or mass air voltage is steady and consistant at idle. If the voltage is for ex. .99 volts it shouldnt really variate more than .01 volts while idleing if its fluctuating all over the place the MAF is screwed up of the MAF table is not right in the tune. Run this stuff by your tuner see if you find something hope it helps since I just wrote a book:lol1:

 

[whiplash306]

Its more than likely the start/cranking fuel tables I had this issue once it ended up being a tuning glitch re-tuned the driveability and it straightened it out so its most likey in the tune since it didnt happen till after you put the blower on and retuned. OR you could have a vapor lock prob in the fuel rail and you get air bubbles in the FRPS making it stumble till you give it more throttle and it commands more Fuel Pressure. ORRRRR you could have a MAF issue. Plug in your handheld(if you have one) and make sure the MAFV or mass air voltage is steady and consistant at idle. If the voltage is for ex. .99 volts it shouldnt really variate more than .01 volts while idleing if its fluctuating all over the place the MAF is screwed up of the MAF table is not right in the tune. Run this stuff by your tuner see if you find something hope it helps since I just wrote a book:lol1:

Wow...great info. I'll be trying the handheld MAF voltage deal tomorrow. That seems the easiest variable/possibility to check out first. If you've got any other random thoughts or ideas, PLEASE feel free to share. This car is FRIGGIN' awesome and I really wanna hammer out these small little irritating obstacles in order to assure total enjoyment and above all, reliability.

 

[Tractionless1]

Wilderized,

And any ideas on fixing the vapor lock? I think that is my problem as mine does the same as the OP but only when my IAT2's are over 145*, ie hot top of motor.

 

[BlkCCSvt]

Hey guys...got a question. Just had my car tuned after a 2.3 Whipple install. Car runs great, boosts wonderfully, idles great after warmup, etc......but I have a weird problem. On a cold startup, the car fires right up, idles high for a sec appropriately, then slowly idles down and holds steady at around 800 RPM. However, if I drive the car for any length of time, then turn it off (say, to get gas or make a REAL QUICK run into a store), then come back out and try and restart the car, she'll fire up, stumble for a sec then die. It isn't unless I give 'er just a touch of gas on a hot start that she'll stay on. The car has the usual mods: 60 lb injectors, twin GT pumps, PPRV delete, Stage II FPDM, SCT 2800 MAF, stock TB :nonono:, head cooling mod, JLT high boost intake, etc, etc.

For the record, I've replaced the FRPS twice and have since placed the KB disc in there, so I don't believe I've got any FRPS issues.

Can anyone offer any guidance? This is a very frustrating issue that never seems to happen around my tuner.....it's like the car has "white coat syndrome" and knows that it best act right when around the doctor...! Ha

I have the same set up and my does the exact same thing!

 

[whiplash306]

Will be going on vacation for a couple of weeks beginning tomorrow. However, my tuner is now totally aware of this problem and this thread. We will be DILIGENTLY working on this issue when I return home and I'll report back with what we find out.........

 

[Jefe]

Has your tuner looked at "dashpot decay rate?" Do a search on this site for dashpot. Sounds like a similar problem

 

[metaman]

Mine was doing this and it turned out to be the EGR solenoid was sticking open when hot and killing the motor with exhaust at idle. It is not supposed to ever open at idle.

 

[triblk6spd]

Mine was doing the exact same thing when I got her. I had my tuner do a retune from scratch and the part throttle is perfect and has not stalled since. I dont know what he changed. PM me and I can get you his info if you need. He's in Austin once a month.

 

[svtleen]

I drove back from San Diego to Oakland approx 700 mile trip and it did that everytime I stop for gas or break. It would fire up fine and die 2 seconds later, so I had to gas it a little and drive off and it would be fine. I think its just the PPRV delete that 'we' have to help the hesitation between shifts when our Whipple kicks in. My 2cent.

 

[UFGatorGuy20]

Any reports to correct the problem? I've been experiencing the same thing. However, now my car wont start back up at all.

 

[whiplash306]

Any reports to correct the problem? I've been experiencing the same thing. However, now my car wont start back up at all.

Not a thing man. The only thing I've noticed that occasionally helps is to keep twisting the key in the ignition for like a split second longer after the cranks up. Sounds crazy, but it's somehow worked....a bit. My tuner actually thinks that some adjustments made to fuel delivery (add a bit more) during initial crank will help with the issue. We'll see. Either way, I'll report back if/when I know more....