Engine dies under load after swap.

[thatblondechik]

I've searched and nothing covers my situation.

I've just finished a swap. New engine. 250 miles from the previous owner (which is well documented. Engine is in pristine condition and the quality isn't being questioned here). I've got a good base tune on it and it will idle just fine. When on a lift with the tires off the ground, it moves through the gears and spins just fine. No grinding or odd noises.

Now when I tried to back it out of the shop (the first time the car was attempting to move on its own and on the new engine in 5 months) I put it into reverse and it started to back up just fine...then just dies. I didn't stall it, I know that. It just died.

Now what I don't get, is why it would run through the gears on the lift just fine, but when actual load is put on the engine and tranny...it runs for a second and then dies.

Any ideas?

 

[thatblondechik]

**UPDATE**
Attempted to start and move the car again today. It sounds like it has a nice lumpy cam in it, very lopey. Ran and moved fine for about 15 seconds before it died again. This has seriously got me stumped.

Double checked my grounds, they're all fine.

 

[Tyeler18]

have you checked engine and tranny mounts? bad mounts could possibly be causing a misalignment under load and throwing off the gears causing the car to stall out on you

 

[thatblondechik]

Brand new poly mounts. And I'm not too sure I understand how mounts can cause a misalignment...

 

[Tyeler18]

well if the engine shifts while the tranny stays in place, it can cause the gear spindles to line up properly and jam causing a stall

 

[thatblondechik]

Now wouldn't I hear a grind of some sort? No grinding at all, the idle just falls straight down and ...pffft. And I would think I'd also feel some kind of jerk or something if it had something to do with tranny. But it's smooth as butter.

 

[92AWDHX40]

MMM did you put the dowels in, just curious had the problem when i didnt, i also had a tob that was giving me problems.

 

[Nicks2319]

When you try to drive it, it stalls when you let off the gas, or even when you have the pedal down?

 

[thatblondechik]

The dowels are all in, tranny has all of about 10k on it. I had a TOB explode on me so everything in the tranny has 10k or less on it.

And it doesn't matter if I hold the gas or not, it still dies. Sometimes it will sputter a bit on the throttle like it WANTS to rev...but then nothing. And it's never been "driven" on the engine, we couldn't get it to move 15 feet without stalling.

 

[rbwtrans]

Hi. I am a factory trained transmission tech. I've never heard of the mounts causing the trans gears to incorrectly mesh. The trans moves with the engine (it's bolted to it.) Bad mounts can cause the the cables to pull the trans out of gear under extreme circumstances. Leaving the dowel pins out can cause a bind on the input shaft, but it would seems to be that the trans would make a lot of noise on the rack. Is the the car making noise in the bellhousing area while in neutral? Is the small rear bolt, under the starter, in place and tight? Is the car dieing with your foot on the clutch or are you trying to give the car the gas? Also, your fuel may have gotten somewhat crappy over the 5 months that it was down?

 

[92AWDHX40]

So idoes it feels like a shifting issue, causing you to stall?

 

[thatblondechik]

Like I said, there are absolutely no odd noises/feelings/shiftings/anything. Everything is smooth as butter.

 

[Nicks2319]

Well start with the basics. Boost leak test, check timing, check for correct fuel pressure.

 

[thatblondechik]

Check, check, and check. Brand new afpr hovering around 43-45psi, brand new piping, tested no leaks, and good compression across all 4

 

[92AWDHX40]

MMMM sounds like maybe wiseman question? Anyone want to help her out?

 

[forcefed4]

MAS plugged in?

EDIT just read your mod list.

MAF and Translator plugged in? SAFC setting still ok?

 

[Nicks2319]

Brand new afpr hovering around 43-45psi

This is with the vac line off, correct? Also, are you 6bolt swapped?

 

[ekanddsm]

Check the harness. Does the engine light come on when it stalls.
What does the logger rpm say when it stalls.
What does the " " mas reading when it stalls?
It free revs fine, but under load it stalls?
Can you roll the car by hand in nuetral with the engine running e-brake off?
Does the mil come on after it stalls? or do you have to cycle the key?


Please give us info on whether it is a mechanical stall or electrical stall?

 

[thatblondechik]

Alright, to answer a few questions.

Yes MAFT is all hooked up and working.
7-bolt not a 6.
Yes, PSI is with VAC lines off.
No engine lights after the stall.
I didn't have a logger hooked up during the stalls, but on the tach, it just falls straight down and I haven't payed attention to the AFC so I'm not sure what the mas is reading, I'll check that tomorrow and give an update.
It free revs just fine, and runs just fine while on the lift with the wheels off the ground.
It will roll with the engine on and ebrake off in neutral.
What is "mil?"

 

[gendestruction8]

Mine was doing the same thing after it sit for awhile it looked at all of that stuff at first too i had to clean out the maf sensor and my filter. i was really irritated because i spent like a week looking at big stuff and it was something little like that

 

[4g64fiero]

Check the fuel pressure while its failing. I suspect lack of fuel during failure.

 

[EVO_THREE]

Did you find out what the problem was?

I have the same issue..

Cold start ok, idles fine for as long as you want it to..

Go for a drive and then splutters and dies. Won't atart again for ages.. Cranks over and when it does start, it's like the timing is way off and it has huge cams AND an air leak!!

no air leaks in mine..

????

Cheers.