Car just Randomly dies with new setup

[bdazzgt]

I just rebuilt my motor with a new H/C/I trickflow junk, it runs great and idles fine but when i go to stop at a stoplight about 75% of the time it dies like someone cut the fuel off. The codes from the cpu are all just the EGR that was removed. I put a new 190lph fuel pump, and a newer filter <6 months ago. Any ideas what could cause this. sometimes it does it if i stop or turn abruptly? I cant find anything wrong with the motor after all new vacuum lines. and sensors im stumped. THANKS

 

[jrichker]

Tell us what all the codes were, Key On, Engine Off and Key On, Engine On. Sometimes there are clues to other problems hidden in to code dump.

 

[Icecold]

sometimes it does it if i stop or turn abruptly?

after checking the codes like JRichker suggested, next step is to check the baffles in the fuel tank.

Though not a real common problem, it does happen on older tanks. The baffles inside the tank come loss and usually when turning hard, slide around and block the fuel pick up.

Sometimes you can reattach the baffles, sometimes its just easier to spend $200 for a new fuel tank.

 

[bdazzgt]

so my baffle is loose....is this causing my problems? what is the next step can this be welded, bracket fixed ect? btw Jrichker you are the man

 

[281pony]

when the baffles break they no longer retain fuel for the fuel pump pickup. thus when there is force in any direction, it moves the fuel away from the pump and car dies/chokes out, ect.

you just need to buy a new tank.. or find another 5.0 tank and swap them out. a new tank was only like 140 i think at lmr when mine went. then i got one for free from a local.

 

[robo]

i have a super clean original 1991 mustang fuel tank. (no rust, dents, leaks etc...) only removed because i bought a sumped aeromotive tank for racing.

i will sell it to you if it helps you out.

pm me if you want.

have a good night, rob

 

[bdazzgt]

is there any glue expoxy that will work in the gas tank? this could explain my dying on deceleration without downshifting and randomly choking the motor out

 

[jrichker]

JB Weld is suitable to secure the baffle IF you clean the mating surfaces of the baffle and tank. Acetone is the recommended cleaning agent. Be sure to locate the baffle correctly and then epoxy it in place. Some strong magnets may be helpful to hold the baffle in place, and can even be left in place if you happen to cover them with the epoxy. Then let it sit overnight after putting gas back in it so that the epoxy has a chance to completely cure. Put the tank some place warm since this will speed the epoxy cure and strengthen the bond.

 

[87coupe50]

just an idea.... if you just put a bunch of new stuff on your engine did you propperly re-adjust the idle.

 

[bdazzgt]

yes the idle has been set, around 850 and idles great it just randomly dies when turning or decelerating, also jrichker how do i know when the baffle has been properly placed? and how much jb weld do i need to use?

 

[87coupe50]

question is: was it set properly? If the computer memory isn't cleared and idle screw set (without the IAC connected) the IAC will control the idle. Regular idle will work fine, but when you transition from one mode of driving to another it can cause the car to stall, especially with a manual. Lots of guys have issues with engine breaking (coasting in gear) and once they push in the clutch the car stalls.

just trying to help... and an quick easy check before you tear into the gas tank.

 

[4rdnut]

sounds like a bad vss sensor on the transmission or check the plug that goes into it, it usually gets transmission fluid and dirt inside the plug.

 

[bdazzgt]

i will go follow the idle setting checklist again before i go ripping out the gas tank, i just dont want to spend 150 on a new tank. Would it do it all the time if it wasnt correct though? thanks for the help guys

 

[87coupe50]

do you engine brake when coming to a stop or prior to turning? If so, then yes, it would happen all the time. The base idle needs to be adjusted to keep the engine running until the IAC takes over.

Did you change the throttle body along with the H/C/I install?
Did this start happening after you did the fuel pump or after the H/C/I?

 

[seijirou]

Does it do this even with a full tank?

If it's a baffling problem, it won't be a problem on a full tank.

I would check that out first to give further evidence for the real cause, so you're less likely to spend your time on the wrong thing.

 

[SMOKEDYA]

I'm going with the others and say it's most likely the baffles.But please keep us posted.peace







john

 

[bdazzgt]

do you engine brake when coming to a stop or prior to turning? If so, then yes, it would happen all the time. The base idle needs to be adjusted to keep the engine running until the IAC takes over.

Did you change the throttle body along with the H/C/I install?
Did this start happening after you did the fuel pump or after the H/C/I?

yes i changed it to a bbk 70mm,with the egr spacer, and i put a 190lph pump in at the same time as the motor. I used the nifty search button found how to set the base idle and readjusted the tps, it was around .75v, would that of mattered? i put all new vacuum lines and fittings, new gaskets and i followed all the things on the awesome surging idle checklist that i had not done yet. i also looked at the vss, the wires were broken so i fixed those, the actual idle is lower than it used to be but it doesn't surge or anything, it seems to run better also. it only died on me once when i first started it, and by engine brake do you mean downshifting? yes i downshift almost all the time but sometimes i just push in the clutch and coast to a stoplight. i cant wait to get this fixed so i can work on other fun projects

 

[4rdnut]

If your vss wires were broken or disconnected then you found the problem. The vehicle speed sensor is what gives the high hanging idle that everybody dreads, but you have to have it connected or your engine will stall when coming to a stop, now just fix the low idle by raising it up and dont forget to readjust the tps sensor after doing so and you should be good to go

 

[bdazzgt]

i hope it fixes it, the idle is great now i did the whole base setting the tps they are both set correctly now. i thought that some mustangs dont even run the VSS?

 

[87coupe50]

I don't have a VSS on mine, dont even have the wires for it. But it can contribute to the symptoms 4rdnut mentioned. THe VSS does have a lot of settings in the ECU that are controlled by MPH.

The TPS voltage shouldn't matter as long as it's not over 1.25v or below .20v (as these are the min and max settings in the ECU) . At each start up the lowest TPS voltage is measured, that voltage is what is used to determine the needed throttle position for WOT, OL and A/C cutoff.

By engine breaking I mean: downshifting or simply removing your foot from the gas while in gear. After doing this for a couple seconds and then pushing in the clutch the car wants to stall.