My perception of a daily driver was too messed up!

[Tfest]

http://forums.corral.net/forums/5-0-...rs-please.html

im sure you saw the same thing but this is all i can find.

[Jerd]

Turned the boost up to about 13 i noticed that towards 4,500rpm it starts to go back down 12 11 and as low as 10.5 before it hits that stupid stumble.

Asher and i both thought hey seems like a boost leak. A boost leak after the maf could cause the rich at wot and possibly this high rpm stumble thing. The concept is that the lean flash is unburnt fuel. So i whipped up a plug and hooked my air compressor up turned the regulator until m boost gauge read about 15psi.

I found 3 tiny leaks a very small pin hole in the coldside pipe where i welded the IAC nipple onto the ic pipe. The next leak was seeping from the threads of the boost gauge brass fittings. I fixed that now. And the third biggest but still tinny leak is from the throttle body. The throttle plate shaft that connects to the tps and the arm for the throttle spool. Where the shaft comes through the casting of the throttle body air is slowly seeping from there when the throttle is at wot.


EDIT: things to try

Ignition module
Stock ecu chip
Fuel Pressure Regulator
Bigger injectors

[MadDog_945]

Those tiny holes cannot create such a problem..

I drove around with open crankvent for a few days cause the flange broke and i wasnt able to fix it..

I did have some troubles on traffic lights with stalling but nothing in WOT..

[Jerd]

Tried stock fuel chip.

Okay so with the MBC on im now getting like 14psi around 3500 to 4,500 after that it starts to drop right around 5,000 its back down to like 10.5. Idk if this is an mbc related issue or if its a part of why im having the stumble at 5,500rpm.

What else could cause the boost to rise then fall ?

I tried the stock fuel chip it has corrected the afr in some area but still cuts at around 5,500 at wot.

Ignition module is next on my list.

I feel like a boost leak could easily be causing both the weird boost drop and the cutting out at higher rpm. The fact that the issue started right after i installed the intercooler also makes me think boost leak. Problem is i pressurized the system and only found a few small leaks. This is rather frustrating.

If the ignition module does nothing ill be forced to try larger injectors and a different fpr. If anything this will simply rule the "running out of fuel" theory out. If after having tried the larger injectors and a different ignition module the problem still exists do you guys have anymore ideas? Only thing i can thing of is check fuel pressure (hack into the fuel lines add a port and run a gauge out of the hood so i can make sure i have pressure when the car is cutting)

And also Asher mentioned the crank positioning sensor may be at fault for this weird high rpm cut.

Any more ideas would be GREATLY appreciated!

[klr142]

If you turn down the boost more, like 5-8psi, does it still cut out?

[Jerd]

Oddly enough the actuator wont allow for that i mean i suppose i could loosen it enough that it might regulate boost that low but it wont seal against the turbine housing and will spool super slow.

Are you thinking that with less boost, that the "running out of fuel" concept could be proven wrong if it still cuts? Seems like a good idea i may try doing it.

[towerymt]

stock throttle body? the 960 ones are known to come apart (screws loosen, plate wiggles around). I think that gave a whistle noise on my car at one time.

[iwannadrive]

Originally Posted by Jerd

Tried stock fuel chip.

Okay so with the MBC on im now getting like 14psi around 3500 to 4,500 after that it starts to drop right around 5,000 its back down to like 10.5. Idk if this is an mbc related issue or if its a part of why im having the stumble at 5,500rpm.

What else could cause the boost to rise then fall ?

I tried the stock fuel chip it has corrected the afr in some area but still cuts at around 5,500 at wot.

Ignition module is next on my list.

I feel like a boost leak could easily be causing both the weird boost drop and the cutting out at higher rpm. The fact that the issue started right after i installed the intercooler also makes me think boost leak. Problem is i pressurized the system and only found a few small leaks. This is rather frustrating.

If the ignition module does nothing ill be forced to try larger injectors and a different fpr. If anything this will simply rule the "running out of fuel" theory out. If after having tried the larger injectors and a different ignition module the problem still exists do you guys have anymore ideas? Only thing i can thing of is check fuel pressure (hack into the fuel lines add a port and run a gauge out of the hood so i can make sure i have pressure when the car is cutting)

And also Asher mentioned the crank positioning sensor may be at fault for this weird high rpm cut.

Any more ideas would be GREATLY appreciated!

Can't really help you with the stumble, I only really know K-jet so far, but what are you using as a boost reference port for the wastegate actuator? If it's before the IC it could be causing at least some of the pressure drop. Although, on second thought, you're running an ebay IC so I doubt you'd have anywhere near that much pressure drop. Hmm...

[Jerd]

Originally Posted by towerymt

stock throttle body? the 960 ones are known to come apart (screws loosen, plate wiggles around). I think that gave a whistle noise on my car at one time.

Stock. If the leak gets worse i may eventually replace it.

A friend mentioned to check grounds which got me thinking. My maf ground is ghetto when i get home ill double check resistance and make sure its a good ground.

[Jerd]

Originally Posted by iwannadrive

Can't really help you with the stumble, I only really know K-jet so far, but what are you using as a boost reference port for the wastegate actuator? If it's before the IC it could be causing at least some of the pressure drop. Although, on second thought, you're running an ebay IC so I doubt you'd have anywhere near that much pressure drop. Hmm...

Reference is off the compressor housing. I can verify that with the actuator and no mbc that the boost was a much more solid. And controlled. The mbc runs high then drops off. It might just be the mbc and not related to anything else.

[The Aspirator]

That sounds like an MBC issue for sure, some work steady, some creep, and some spike then drop off.

[klr142]

A lack of fuel flow issue would be more gradual, you'd see it lean out, I would expect. Not an immediate cut due to: lack of airflow(collapsed hose)/lack of spark(weak, because...?).

I don't think the FPR or throttle body are an issue. As far as the injectors off the t-bird, throw them in along with the stock tune(or at least a tune that has lambda correction on) to see how they do. It should do well enough once learning, and YES, it WILL be too fawkin rich when you first plug them in at higher rpm under boost.

It's odd that it seemed to work ok at one point with a different MAF in there. Definitely do go through your wiring to the MAF and see what that does.

I'm curious as to if it's flowing more air now than it did it before and that extra airflow is causing problems. Or, maybe there's some crap inside the intercooler that's moving and jamming something(not likely, but it's a thought). Like a hose or inlet something collapsing at some point, or airflow getting trapped somewhere as one of your hoses balloons up, or...?

And yeah, steady/solid boost is a good thing and will likely cause the AFRs to maybe do weird things if it isn't steady. Didn't you have issues with the boost going UP, before?

[Jerd]

Originally Posted by The Aspirator

That sounds like an MBC issue for sure, some work steady, some creep, and some spike then drop off.

Yah you cant really see that well in the video but it goes from 13-14psi back to like 11 before it cuts.

Originally Posted by klr142

A lack of fuel flow issue would be more gradual, you'd see it lean out, I would expect. Not an immediate cut due to: lack of airflow(collapsed hose)/lack of spark(weak, because...?).

Watching the video again and again shows that. low 11s 11.43 11.97 then the cut 31.16 and by the time it cuts the boost is back down.

Originally Posted by klr142

I don't think the FPR or throttle body are an issue. As far as the injectors off the t-bird, throw them in along with the stock tune(or at least a tune that has lambda correction on) to see how they do. It should do well enough once learning, and YES, it WILL be too fawkin rich when you first plug them in at higher rpm under boost.

Im running the stock tune now i can try the injectors tonight or if not tonight then tomorrow. The problem is watching the wideband i doubt im running out of fuel. i mean the fact that at 14psi its rich and then it leans out when the boost goes down.

Originally Posted by klr142

It's odd that it seemed to work ok at one point with a different MAF in there. Definitely do go through your wiring to the MAF and see what that does.

Exactly idk why the hell it worked with brandons maf! I checked the wiring out a bit one pin had a solid ground, 2 had very high resistance to ground 950 ohms or so, then the rest where not grounded at all. I stoped by a local shop and talked to a friend he had some good ideas, we cut the tps wire that changed nothing and he handed me a big coil off a turbo car im going to try.

Originally Posted by klr142

I'm curious as to if it's flowing more air now than it did it before and that extra airflow is causing problems. Or, maybe there's some crap inside the intercooler that's moving and jamming something(not likely, but it's a thought). Like a hose or inlet something collapsing at some point, or airflow getting trapped somewhere as one of your hoses balloons up, or...?

Heres a concept, fuel cut. The issue is the same with the stock fuel chip and the beepee chip. I believe beepee mentioned he disabled a fuel cut. But i was thinking that the stock maf and chip would surely be at its limmits of fuel cut with this turbo at that rpm. Could beepee have accidentally not dissabled fuel cut on the chips i had?

Ill take a look inside the intercooler most of my pipes are all hard tubing couplers are good quality silicone.

Originally Posted by klr142

And yeah, steady/solid boost is a good thing and will likely cause the AFRs to maybe do weird things if it isn't steady. Didn't you have issues with the boost going UP, before?

That was a long time ago i had not ported the internal waste gate port on the ebay turbo big enough. When i went to an external wastegate i had solid boost 12psi throughout the entire range.

The so called ignition module i was referring too. Is the amplifier the guy at the shop said those either work or they dont. If its bad the car wont run.

Things left to try:

Continue checking wires and grounds
swap coils one more time
bigger injectors and a different fpr



Oh and heres the video!

[adrianpike]

Can't watch the video right now, but remember that rich misfires show up on a wideband as lean spikes.

[klr142]

Originally Posted by Jerd

Im running the stock tune now i can try the injectors tonight or if not tonight then tomorrow. The problem is watching the wideband i doubt im running out of fuel. i mean the fact that at 14psi its rich and then it leans out when the boost goes down.

I agree. I do NOT think you are running out of fuel, at least not to the point that it is causing this. It would not read 11s or 10s and then immediately be a cut. Unless a fuel pump was bad, MAYBE? But still not the issue here, I'm pretty sure of it.

Heres a concept, fuel cut. The issue is the same with the stock fuel chip and the beepee chip. I believe beepee mentioned he disabled a fuel cut. But i was thinking that the stock maf and chip would surely be at its limmits of fuel cut with this turbo at that rpm. Could beepee have accidentally not dissabled fuel cut on the chips i had?

This is what I've been thinking all along, other than the collapsed intake sort of idea... So, don't you have Mike's chips as well? they DON'T have fuel cut, correct? Does the car still do it with his fuel chip? DO IT! If you haven't. Do this before you do anything else. Injectors and FPR are very low on my likelihood list. The coil is also very down there, as you would get SOME improvement, or slight difference from just closing the spark plug gap which would indicate the spark being too weak.

See red.

On another note, you will like having an adjustable cam gear on there advanced 2-4 degrees. Grab a free one from somewhere and send it to Avalanche to have it drilled for $25 or whatever it is, or just buy one outright from them.

[nathaninwa]

Just a random thought here....I have missed a few pages. How about a fuel pump? Maybe a dirty sock? Week wiring? I say this because i had the same problem...come to find out the intank pump was not running and the inline 044 was having a hard time sucking through that pump and I would lean out near 15psi as well.

[Jerd]

Originally Posted by klr142

See red.

On another note, you will like having an adjustable cam gear on there advanced 2-4 degrees. Grab a free one from somewhere and send it to Avalanche to have it drilled for $25 or whatever it is, or just buy one outright from them.

I agree with a lot that you said. Im thinking that its less of a non functioning part and more of non functioning wiring or a set issue in the programming.

Fuel cut could be tested by turning boost down correct? I do not have mikes chip anymore. Except in the ignition computer. Ill turn the boost down as low as i can get it and ill see what changes.

Funny you should mention the cam gear i found one in my garage and i have been emailing dale. I should be picking one up at ipd....

Originally Posted by Nathaninwa

Just a random thought here....I have missed a few pages. How about a fuel pump? Maybe a dirty sock? Week wiring? I say this because i had the same problem...come to find out the intank pump was not running and the inline 044 was having a hard time sucking through that pump and I would lean out near 15psi as well.

We have thought about it but i have done nothing to check. Checking the fuel pressure at the rail would be a great idea. But heres where im struggling to grasp that its a fuel pump or even remotely fuel related.

It goes from mid to high 11s to cutting out and flashing 30s or so. Seems like a random missfire. Its not aggressivly leaning out into the 12s 13s 14s then cutting. It just cuts.

I have covered most of the ignition stuff, plugs wires, cap,rotor, coil. Im trying another coil tonight or tomorrow. For it to be fuel related it would be fuel pump frp or injectors these three things are recently replaced the fuel pump is a walbro 255 the fpr and injectors where clean out of the junkyard and i cleaned them and installed them all worked flawlessly for a long time. When i installed the intercooler is when i ran into the issue. What keeps freaking me out is the idea that when i tried brandons MAF the car pulled to 6,500 without a hickup. Twice if i remember correctly. Thats when i assumed the maf was the problem. A few days later i had tried about 4 different mafs 2 off of running cars. All with the issue having not changed.

Brandons maf has yet to be tried again (working on it) I have checked all the wiring to the maf and as you can read above found 1 wire with a good ground 2 wires with a high resistance to ground and the rest where not grounded

Weird thing is if there are bad wires from the maf. Wouldnt there be a problem at all rpms???

[nathaninwa]

Looking back at my logs.....it only took about a half second for my to drop dead lean from an 11.6afr. I drove for like a week (50 miles maybe) with the internal pump not workin, then the car just quit....the 044 could not pull fuel even with a half tank gas....and in the initial fireup the tank was empty! When trying to replace the internal pump is when I figured out the pump was not getting any voltage.

[Jerd]

Originally Posted by Nathaninwa

Looking back at my logs.....it only took about a half second for my to drop dead lean from an 11.6afr. I drove for like a week (50 miles maybe) with the internal pump not workin, then the car just quit....the 044 could not pull fuel even with a half tank gas....and in the initial fireup the tank was empty! When trying to replace the internal pump is when I figured out the pump was not getting any voltage.

Interesting! Do you think i would be able to see this Half second with a fuel pressure gauge?

My pump setup is just a single intank walbro 255. Could i be running out of pump?

[nathaninwa]

I doubt your running out of pump....seeing FP would help. I have one that has a long hose on it for driving visibilty. I would maybe pull pump and check for clogged sock, maybe water in the sump....maybe even run a DVM from the pump wiring at the tank and watch it. It might not be the problem, but sure would awnser some unkowns. What about filter and line size?

You going to be at RSI as well?

[Jerd]

Originally Posted by Nathaninwa

I doubt your running out of pump....seeing FP would help. I have one that has a long hose on it for driving visibilty. I would maybe pull pump and check for clogged sock, maybe water in the sump....maybe even run a DVM from the pump wiring at the tank and watch it. It might not be the problem, but sure would awnser some unkowns. What about filter and line size?

You going to be at RSI as well?

Ill pop the pump out and take a look at everything If nothings obviously maybe ill finally hook up a fp gauge. Checking voltage at the pump when the car cuts out? seems like a long shot for trouble shooting but i suppose its always worth looking. I think its half inch from the pump to the filter then from the filter to the rail its oem.

Yes ill will, wouldnt miss it!

[TIPSP]

Are you sure the plugs are gapped correctly?

[nathaninwa]

Is the stock line the same as mine was where its like 3/16 inch on the ID at the flare fitting into the fuel rail?

[Jerd]

Originally Posted by TIPSP

Are you sure the plugs are gapped correctly?

Yes, old plugs where .028" new are .026" and i gap them all with feeler gauges not those stupid plug gappers from autozone.

Made not a single difference.

[nathaninwa]

go for broke and run 7's gapped at like .022 just to see. Im running a .024 gap but Im also wasted spark. Do you know how much air your turbo moves?