dies out at full boost

Okay so been having an issue with my wagon:
1987 Town and Country swapped to a 2.5L running on a flash able SBEC. Tune is one of the free BoostButton Stage 4 calls, modified for my specs.

If you watch this video and fast forward to the 3:29 mark, you can see what it's doing.
https://www.youtube.com/watch?v=Ivsxcif5SvY

Basically when I'm at the track, build boost and launch the car starts to go then the engine just shuts off. No sputter, no loss of power, just instant off.

It did this at SDAC when I tested the nitrous kit.

It will do this when driving down the road at say 30mph, and you punch it. When it really starts pulling hard, and wheels don't spin, the engine will just die. If I have enough engine speed you can still hear the engine spinning as the vehicle speed is turning the engine. Once I shift to neutral the engine stops completely. I then have to cycle the key to get the car to start. If I don't cycle the key, it will just crank, not start.

I'm thinking it could have something to do with when the engine torques back, possibly pinching a wire behind the intake manifold. BUT I moved that harness (just flipped it over the front of intake) and it still dies out. Now it doesn't do this every time. If you watch the video I made multiple passes without issues. When at SDAC the only time it did that was when I hit the nitrous.

I do have a solid front motor mount, and a brand new trans mount (old one was shot) I'm working on a drivers side mount, just have to find one. Trying to get the engine to not move. Wondering if anyone has any ideas? I've done visual check for wires that are worn, loose, tight, etc. Can't find anything. I'm thinking this could be in the tune somehow? Or a wiring issue. As I said in the first paragraph, the car has been converted to run SBEC, I presume this was done by Wallace, as it's his old car.


One last tid bit of information, I thought I might be starving the fuel pump. I filled the car up and test drove it....still dies out.


Looking forward to seeing some of those brainstorming ideas!!!

Thanks guys

Any codes?

There are 2 codes, I don't think they are relevant, but never know.

31 - purge control (Evap system long gone)

35 - Fan control relay

Have you hooked a FP gauge up and watched it DURING the episode? My Daytona had partially disconnected the pressure side line from the in tank fuel pump and had a weird intermittent stalling. Only other weird sometimes run condition I had on a TM was when the carbon 'button' came loose inside the distributor cap. The voltage would jump to the rotor without is but heavy loads would blow out the spark or increase resistance enough to stall. So there you have it, it's either fuel or electrical:lol:

Could try to tighten up the spark plug gap just to rule that out.

I'll admit it is a good idea to look at fuel pressure, just need to come up with a way to hook it up. With an aftermarket fuel rail, I'll have to tie into the fuel pressure regulator. Or I could just run it low on fuel and pull the pump and see what it looks like. It is a weird pump, like a walbro 480 or something huge like that and I have no idea how it was installed Spark plugs are gapped pretty tight all ready, I've gapped them at .020. My guts telling me it's either fuel or wiring issue.

So went out with JohnnyIroc last night and did some playing around. What we figured out is when less than 20 psi the wagon has no issues. Pull hard no issues.

When we cranked the boost up to 25 and when getting towards the top of 2nd gear I could feel just a very slight stumble, John said he didn't feel a thing so it was slight enough that only the driver could feel it, then the engine dies.

One last interesting piece of info, John reminded me when we got the car the fuel pump had its power supply coming right off the alternator. We rewired it to an unused power supply off the fuse panel in the engine bay.

So so basically we didn't eliminate anything. Could still be spark blow out, could be a fuel issue, could be wiring issue still.... Oh the joys of working on 30 year old cars.

I had something similarly weird with Slugmobile after i first got her back together for SDAC23. It would just shut off at high rpm. It turned out it was an issue with the cal version.
Can you attach your cal files?
The current version is v19.6 last i checked. But even if the updated version, could be something in the cal.

I don't think I have the ability to make attachments. I could email it to you? Becusee it's one of Robs staged cals when I compile the tune it requires version 3, it's an old staged cal, but for some reason the van and wagon have run best on these staged cals. my wife's going into the hosiptal for a 5 day study starting tomorrow so doubt I'll have time to get much done for at least a week.

Quote:

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Originally Posted by Joe_Van_Duno

I don't think I have the ability to make attachments. I could email it to you? Becusee it's one of Robs staged cals when I compile the tune it requires version 3, it's an old staged cal, but for some reason the van and wagon have run best on these staged cals. my wife's going into the hosiptal for a 5 day study starting tomorrow so doubt I'll have time to get much done for at least a week.

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Firstly, i hope everything turns out alright with the study.

If you are using the same version with success in the van, it may not be that unless there was some difference in the SBEC one.
What i was having was once the engine revved to a certain rpm, the ignition would just stop. The engine would die and you'd have to cycle the key to restart.
I can't remember if it would do the same in park and hitting the rpm, or if it only happened while driving.

Maybe we'll hear from Rob, or i'll have to try and find some old info if he described what was wrong with my cal version. I want to say something with the decel fuel cut but might have been domething else.

The flashable sbec's have had an issue with the emr routine shutting them down every so many miles. Shouldn't be related to your problem, but it could be.

Might also be a map sensor issue, or an incorrect overboost setting.

Try swapping out the coil to see if it makes a difference when you get a chance.

Quote:

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Originally Posted by Force Fed Mopar

The flashable sbec's have had an issue with the emr routine shutting them down every so many miles. Shouldn't be related to your problem, but it could be.

Might also be a map sensor issue, or an incorrect overboost setting.

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The wagon did have an intermittent stumble, but that was corrected by shutting off the purge controls. Jaren Niewinski (forget TM screen name) figured that one out on his car, it cured the wagons stumble also. I have triple checked my over boost settings, even raising them a more than the 30 psi they were set at, I put them up around 35 just to make sure the map wouldn't read it.

Quote:

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Originally Posted by wheming

Firstly, i hope everything turns out alright with the study.

If you are using the same version with success in the van, it may not be that unless there was some difference in the SBEC one.
What i was having was once the engine revved to a certain rpm, the ignition would just stop. The engine would die and you'd have to cycle the key to restart.
I can't remember if it would do the same in park and hitting the rpm, or if it only happened while driving.

Maybe we'll hear from Rob, or i'll have to try and find some old info if he described what was wrong with my cal version. I want to say something with the decel fuel cut but might have been domething else.

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Thank you Wayne, we are hoping that this study will finally help get some answers and allow my wife to get back to "normal" Have to put normal in quotes, after all she's a woman, NONE of them are normal....it's just her normal :)

I'm thinking the vans never had an issue because it's SMEC vs SBEC. If it's something in the tune I'm guessing there is some setting that is different and needs tweaking.

The car does nothing out of the ordinary when revving, buiding boost on the brake, or just driving around.....it's really strange.

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Quote:

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Originally Posted by black86glhs

Try swapping out the coil to see if it makes a difference when you get a chance.

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You know it's a good idea, just never know. I have like, 15-20 coils sitting around, might as well give it a shot.

I often do things like this to rule out stuff when you don't have the problem poking at you with a stick.....lol. Rather it be a small waste of time, rather than chasing stuff for weeks (and god knows I have done that often) only to find it was something simple. :mad::banghead::mecry:

Had the same thing happen with my van. The airtex pump would completely shut off if put under more than 60lbs of pressure. I found it while pinching off the return line and watching the fuel pressure. If the van was running the pressure would drop. You could also listen to the fuel pump and hear it shut off when I pinched the return line.

Heres a video of what the pump was doing under a load.

https://get.google.com/albumarchive/...MrDl9WQrqPU2wE

Quote:

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Originally Posted by Force Fed Mopar

The flashable sbec's have had an issue with the emr routine shutting them down every so many miles. Shouldn't be related to your problem, but it could be.

Might also be a map sensor issue, or an incorrect overboost setting.

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He has a flashable SBEC. So, my guess is it's the EMR thing. DL the latest T/SBEC v4 and re-compile the Stage cal.