I have been working on my friends car for a bit now, and it seems like I can't possibly figure out what's going wrong.

Before she takes it to the dealers, want to check on your feedbacks.


Here is the story :

we've installed the walbro fuel pump on the he Evo, ran fine, then the next day he ran the auto-x.

After the fuel pump install, he could noticeably tell that the idle was a lot smoother and the car ran 5 runs at the auto-x without any sorta problems.

That night, he was coming home and he was trying to pass a car uphill, stayed in 5th gear, was'n't at WOT or going fast, then he heard this sound, "poof" like the upper to lower IC pipe comming undone.

There was no fuel cut or anything, he just lost all the boost and everytime he would give it gas it would backfire and would not boost at all.

Ok, at this point we think it's the IC pipe (RNR IC pipe + lower pipe) that came undone.

We check all the piping over and over and over again, it's lock tight. So we start to check the seals on the weldings, it's clean and good. He's running RNR FMIC. (This is not about RNR products)

We VTA his bov (OEM) to see if it holds air, it does. check the spring inside to see if it's good (comparison with another one).


So, we think it's the front 02 sensor (through researches on this site and in general asking mechanics) We buy one on here, slightly used, assuming it's good. Swap out the spark plugs, check all the sensor connections.

Swap it out, the car feels like crap, still can't boost, the car would just go into this dying mode whenever it tries to boost. we're at 0 boost, vac is normal on the gauge.

So here we check all the fuses, inside the car and in the engine bay, everything is good. (pulled everything out except for the ecu fuse, etc).

Then we change out the fuel pump with the stock fuel pump.

Here is where everything goes wrong. The car will crank, but will not start at all.

Before with the walbro, it would start but no boost, but now the car doesn't start.

We swap out the plugs again, crank it, still no go.

what the hell am I missing? This is driving me nutz, because the codes he threw when his car wasn't working properly were : p0134 (02 sensor), p0300 (mis-fire), p0179 (running too lean). These codes didn't come back when we cleared it without changing anything, before all the work to change things out.

All signs point to the 02 sensor, but man, I just don't know.

You think the 02 sensor we bought used might be bad? If not, you think there is something wrong with the fuel pump or any fuel related items?

any help will be great.

thanks.

 

Put the walbro back in. put the original o2 sensor on. anyother work done to the car? stock hoses? engine management? Mods?

 

is he still on the stock intake box? the two clips that hold it down on to the bumper might have come undone or could have been forgotten to put back on for what ever reason (if you ever removed it). when ever you push the car that box will lift up and choke the engine. happened to me once but i saw the problem right away.

goodluck. i have no idea why it wont start though. maybe you forgot to clip the switches back on during the pump install. that or the little ring that holds it on may have broken or fallen off.

 

why would he needs to put the old 02 sensor back and the walbro? did you not read the thread?


it's not simple as just the intake, the intake is aem. worked great for a long time.

I've installed more than my share of fuel pumps (about 10) and there is no problem with the installation.

I'm just trying to figure out what else it could be. It's not simple as clip here or switch here, i've triple checked everything.

I want to focus on the backfire and no boost...

 

the car should run fine without the front o2 sensor plugged in, check all your vacuum lines from the manifold

 

Did you touch the cam angle sensor? I had that same problem on my Vr4 once. It would sound like its boosting but go no where, check it out.

 

AAHhhh, OK, I guess that was my problem here, READING IT!!! take parts off, and back track to find the problem. I guess I am the a-hole here for trying to help. you blow ( this is not a THUMB, its the middle finger!) followed by what I think of your sarcastic answer:

 

I know you said you have triple checked everything but it's absolutely sounding like a leak somewhere in the intake (IC, IC piping, etc). Have you done a standing leak test?

 

As a matter of fact, I once had a similiar problem where there was a razor slit of the silicone coupler on the IC piping...car would make vacuum but would not boost properly because it started to open up under pressure. My 2c.

 

Can you hear the old fuel pump turning on with the key?

Did the pop come from the engine bay or out the exhaust?

If it came from the engine bay and the car was backfiring and running rich there is probably an IC leak somewere check the silicone unions to see if they split. How are you pressurizing the system to check it? The backfire is probably related to no boost becuase the boost is leaking out after the MAF before the cylinder and it is injecting way more fuel than it can burn. You might want to try changing the oil to make sure there is no evidence of metal shavings in it. That is probably overkill but, it would be a good idea if it has been flooding the cylinder and diluting the oil with fuel anyway.

You have got to be missing something and it is probably something simple and easy to over look. Try making a check list so you don't get too busy going through possibilities and skip actually checking something.

Also, try not being a smarta*s to people who are trying to help you.

 

if you haven't read the thread, smoked mustang, and I know who you are in person, don't be a jerk.

I took out the fuel pump, ic piping out, in, out, in already. Fuel pumps swapped out 4 times, walbro to stock to walbro back to stock.

I will check the vacuum lines again this morning. We did the carb spray test and probably need to take it to somewhere to get it completely pressure tested.

intake, we took out twice to check it over and over. seems like there is no problem with the intake itself or the supporting hoses.

cam angle sensor's check, no problem with it, otherwise it'll throw 2 cel codes (i believe p0345 and 346? i had these before - cam angle and crank sensor both goes off).

we actually did change the oil a week before.

please, let's stay on topic without the off-topic pride games.


by the way, there was 02 sensor code and other codes. It can't just be the ic piping that's causing this... can it?

brb

 

Ok, then change the middle finger back to a thumb If you have an O2 sensor code, (I did) and it turned out to be a BAD MAF! the cone intake or the oil on the wire caused me to need a new MAF. Did you get that checked? Mine was reading 35ft. below sealevel, (Indiana) I probably should stop now and re-read the thread. Dont listen to me if I post past 8PM, as I get cranky, and dont read too well. accept my apology. I dont know what a PRIDE game is, I have none of that! Must have lost all those game pieces.

 

Did you check for shaft play in the turbo? is this car stock? what mods? any gagues in the car? I will be kind, and try to help you. need more meat in the sandwitch please. (mods, etc) MBC, the whole schmaole. This happens under large load. I will scratch my head and see what I come up with. This is a dumb question, did you remove the negative terminal and re-set? I always blew 2 IC hoses 1 at the throttle body, the other drivers side IC pipe where it connects to the IC. I recently blew on under the airbox (first time for that!) I checked the other 2 mentioned, and thought it WASN'T an IC pipe.

 

yeh, i forgot to mention that. The first thing we did was to check for shaft play. His car had less shaft play than mine, and I run mine 23psi everyday. He runs his at 20psi.

There are no scuff marks on the turbo lip either.

boost gauge is the only thing he got in his car.

this morning, we swapped out the fuel pump again to walbro, car started without any problem. idled fine, and ran fine. Apparently the stock fuel pump died after we took it out a while back when we installed the walbro for the first time.

For some reason, there is lifter tick, which is funny because he doesn't have cams.

here is the list of mods:

RNR Lower and upper IC piping, RNR FMIC, walbro fuel pump, hallman MBC, Buschur racing TBE, ACT Clutch, AEM intake, and everything else is stock.

We took the plugs out today and it seems to be real clean, no detonation, ceramic is clean.

This is the part that's killing me. Yes, usually the IC pipe comes off on the WOT and large load. But he wasn't flooring it or down shifting.

He was on 5th gear, just passing a real slow semi truck, uphill. Just cruising, not wot.

When I first heard about this problem, I said it's the IC pipe that goes from the throttle body to the lower pipe connecting to the FMIC.

Check the hose, and it's solid. No opening, or anything.

I thought it might be the lower IC pipe, and I looked. Apparently the shop who installed this did some serious clamping on this, since it blew out before.

They have clamps, then those expensive screw clamps on top of the clamps to clamp it to death.

anyway, pressure testing should be done monday. Car runs, but it's not boosting more than 1 or 2 psi. I hope it's not the MAF sensor, but really if MAF sensor malfunctions, wouldn't it throw a code?

At this point, after fuel pump examination, piping examination(took it apart, tightened it again), spark plugs, and 02 sensor swap outs, intake in and re-tightened out and in again, fuse check inside and in engine, and checking every vacuum hose that's in the engine bay, i don't know what else to do.

Pressure test will help. Only thing I could think of is that there is a leak in the FMIC or it blew a hole in it and that's what's causing it.

beause there is no problem with the fuel delievery, it's just the air not going in the engine, which is now causing the backfire and no boost.

 

doing a pressure test yourself? if not, try https://www.evolutionm.net/forums/sh...light=pressure

I hope his "lifter" tick isn't loud and you are just hearing the fuel injectors...