Cutting out problem Options

[TURBOWHT]

So my truck is still cutting out. If you guys done know its a 4g63 swapped dodge ram 50.

The truck was running good. never cut out. then one night. WOT the truck would creep alot and cut out. Fuel cut i assumed. Well the next day came and would cut out at 8psi. but would let me rev it from a stop just fine.

well started it up the next day and reved it up and now it cuts out from a stop. It shows im building 15psi just reving it up. Something is seriously not right. and i cant figure it out.

Here is what is done to the truck and what i have done.

The only aftermarket thing on the truck is a gm maft and greddy type s. and inline walbro fuel pump.

I put new plugs in it. bpr7es, thinking i fouled one and it cuts out high rpm. thats not the case.

I tightend down my intake manifold. for some reason the bolts backed out. So i thought that would fix it. nope. didnt still runs like crap. I checked the pipes and reseated them.but i havnt boost leak tested it since i dont have a tester.

Do you guys think its a boost leak? or something else? Could ecu cause it to cut out like this? because im pretty sure the caps were bad, it was smoking and smelled like ass one day. But i have no clue what the ecu does when it goes bad.

Anyhelp or something to check for would be great. thanks

[natedogg]

Definitely replace ECU. If it already smells bad then it might be too late to salvage just by replacing the caps. You'll probably have to put in a new one.

Do a boost leak test as well while you're at it. That's always a good thing to check.

[TURBOWHT]

So your thinking its prolly the ecu? I mean im going to replace it but just wondering what the problem really is.

Or do you think its a boost leak? regardless im going to do both anyways.

[turbohcar]

ECU's don't do anything particularly in common when they go out. Diagnosis is a crap shoot. It's hard to say if that's really your problem or not. Chances are good thought that it is the problem being as it smells like a burnt piece of plastic and the board is probably already burnt to a crisp.

Swap it out first and see if that doesn't help.

[turbohcar]

ECU's don't do anything particularly in common when they go out. Diagnosis is a crap shoot. It's hard to say if that's really your problem or not. Chances are good thought that it is the problem being as it smells like a burnt piece of plastic and the board is probably already burnt to a crisp.

Swap it out first and see if that doesn't help.

[TURBOWHT]

changed ecus. freaking car ran worse. changed back ecus. car is sputtering and stuff at idle now. and you can be at quarter throttle and it will go a little bit. but if you get into it at all it will cut out. driving me crazy.

[natedogg]

Make sure the ECU that you swapped into it was good...

This vfaq gives a good idea of where to look for bad caps. I'd check both ECU's
http://www.tmo.com/howto/ecu1g/caps.htm

And I'm sure it doesn't need to be said again, but I'll say it anyway...check for boost leaks.

[turbohcar]

Don't just look for the bad caps though. Check the entire board for burn marks. I had one that burnt up in my car and the caps looked perfect but the top of one of those aquamarine blocks was burnt pretty good. Just check the entire thing for burn marks or corrosion.

[TURBOWHT]

Cant find a freaking cap that will work to make a boost leak tester. But redone all my i/c pipes again. still cutting out.


DO you think my timing might of jumped?


I used to be able to sit from a stop rev it up and build 16 psi and then it would cut out.

Now if i rev it up full throttle. it will cut out at 6psi.

think its the timing or still a boost leak?

cause 1/4 throttle it will run fine. tell me what you think./

[natedogg]

Where are you checking for boost leak test caps? Any hardware store should be able to hook you up. Farm & Fleet has a good selection for example.

[TURBOWHT]

Do you think a boost leak would make me build boost like that from a stop? I mean i know i need to check for boost leaks but i havnt found a cap. so while im doing that just thought i would try to eliminate the possibilities with what i have. Till i can get a boost leak tester made.

[TURBOWHT]

stock turbo ecu. I swapped ecu's and it still cut out. so dont think its the ecu.

[natedogg]

The last 10 times Ive checked a dsm for boostleaks, I used a trash bag.. Get a black glad trashbag, fold it up until its a little square, put it over the inlet of the turbo, and use a hose clamp to sinch it down.

Ive had them hold 20psi of shop air.

That's a hell of an idea. You oughtta write that up, McGyver.

[natedogg]

Here's my reasoning for thinking its a boost leak. If you are cutting out at 8 psi, that tells me the turbo is working hard enough for the MAS to register enough air to trip fuel cut, but you are only building 8 psi so you aren't even tripping the WG actuator. That because a bunch of the air the MAS is sensing is escaping somewhere between the turbo and your engine. If you didn't have a boost leak your turbo would probably be building enough boost to trip the WG actuator.

Now as far as building that boost from a dead stop, I'm not quite as sure. Usually that means you are putting some kind of load on the engine. You using heavier than normal engine/transmission oil?

[TURBOWHT]

oil im running mobil 1 10w-30. and tranny fliud i just went with the penns synchromesh.

idk if maybe the actual timing jumped on the motor, it had 80k on it and who knows if anyone has ever touched the motor.



anyways. So about the trash bag. you fold it up and then cover the inlet. Im lost as to how to get the air in it. air compresser with just a blow valve on it?

[TURBOWHT]

Did the whole boost leak test. used a trash bag like said above. the bov is leaking a little and around the throttle body is leaking. would that cause it to act like that just those little leaks?

I guess ill have to check base timing now.

[natedogg]

Did the whole boost leak test. used a trash bag like said above. the bov is leaking a little and around the throttle body is leaking. would that cause it to act like that just those little leaks?

I guess ill have to check base timing now.

Its definitely possible. I'd get those leaks taken care of and like you said check your base timing.

[TURBOWHT]

So i took the timing cover off. Its off like 1- 2 teeth from lining up on the cam gears.

do you think that this is why its cutting out? Anyone have this problem? I have had my old 1g 2 teeth off and it was just doggy. never cutted out. just wondering if i still have something else wrong. Or if timing being off would cause the problem to cut out then slowely get worse.

[natedogg]

Having your cam timing off can definitely cause problems. I thought you were talking about your ignition timing. The markers in the cam gears should match up perfectly when your crank pulley marker shows it is at TDC on the timing belt cover. Your cam timing probably isn't off enough to damage the valves if you are still running stock pistons/valves, but it can cause the engine to run poorly.