Bayou_Flyer

I replaced the burned/melted MAF sensor, and nothing has really changed. The CEL i can get is the “lean condition” after keeping it running until it warms up. Having replaced coils/plugs/wires/throttle body/MAF, I am going to see if I can troubleshoot the fuel pump itself….with 126k mi on the clock, I cant rule it out (and I know it hasn’t been changed).

it seems everything else would throw a code if it was sensor related. I hear the pump activate for a few seconds when I turn the key, but could it be that the car is running out of fuel under 2k RPM? The amount of surging/backfiring/popping that is happening on the low side makes me think that it could be. Once I get the RPM up around 3000 itll smooth out and run/rev. As soon as I start backing off, it falls off/stumbles/pops again.

i havent put much $$ into the car this far…but I feel like I need to rule these things out before considering the more expensive costs (like a new motor). That the PO told me the car shut off while driving on the interstate (after having the dealer do a comp test then recommending replacing ignition)….

Bayou_Flyer

I currently have the car idling at 1000rpm, warmed up.

i had to use just a little bit of throttle i put to get it going, but once I had it stabilized I put the pedal to the floor. Motor rev’d up to around 4500-5k rpm…stagnated there for a second or two…then rev’d up normally. Ii did that a few times with same result, producing some decent smoke, then it settled down to 800 rpm (roughly) before slowly rising to 1000k. Once in awhile, the idle will rise up to 1250 then settle back down. I put it in drive…and it died.

Bayou_Flyer

I took the fuel pump access panel off. I can hear/feel pump turn on when key it turned. However, the car acts the same when starting whether pump is plugged in or not. I did confirm the fuel gauge drops to zero with pump unplugged, so I guess the sender on the driver side is bad (gauge goes up to between 1/4-1/2 when plugged in). I also reached behind and held the fuel hose while trying to start…and I can feel the vibration from the pump. I guess next step will be to disconnect the fuel line in engine compartment to see if fuel actually comes out. Open to suggestions. Is it possible for the pressure regulator to go bad within the pump assembly? Being that it revs on the high end and stumbles on the low end…does the “circuit” relay handle that function on the S2 like on the S1?

Bayou_Flyer

Wow, five months already! Havent had a chance to hook up to a program to monitor the live data. I did replace the blue relays since they were damaged from the PO pulling and resetting them. I also put a solar trickle charger to keep it alive between days I feel like working on it.

Today, I figured I was a good day to see if it would do any better with the new relays installed. It fired up but inly by holding a little throttle input then would immediately stumble, backfire, then die. I unplugged the air pump (think that was in the troubleshooting tsb), got it to restart with a little pedal….fired up, was a little rough for a few minutes but then settled in around 800-1000rpm and it warmed up ro operating temp. I made the mistake of checking the AC (cold btw) and she died…could not get a good restart.

Would sonething like hp tuners read the data necessary? Any other areas to look since it wont start without a little bit of throttle input?

Oh, I also hear the TB open/test when the key is turned to run…so I abandoned the car at least knowing I havent thrown money away unnecessarily. Could the throttle itself be a factor here?

TeamRX8

iTrader: (25)

the rivets drilled out should have set off the alarm bells, maybe get your spiritual ears checked because that statement alone blew my ear drums out with the blaring loud booming of obviousness. just as it did for dannobre.

not sure if they’re the same but likely so; I can send you a used S1 TB to confirm.
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Bayou_Flyer

Yeah, when I saw the wire holding it together…I couldn’t believe it. That said, replacing it was just helping to alleviate a symptom and not the solution to the problem.

I need to tap into the obd and see what everything is doing.

TeamRX8

iTrader: (25)

What exactly are you asking then?

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Bayou_Flyer

I am asking if the actual throttle pedal assembly could be an issue? Just trying to think of other things to rule out.

I know it is DBW, but the car wants slight throttle input to stay running. I would assume there’d be a CEL if the throttle pedal assembly was failing, but just asking in a chance someone reads and says “try this to confirm….”

With it backfiring, popping, dying….and since the CEL doesnt show until after car has been idling…and with new coild/plugs/wires…and with 120k mikes without any record of change…my old school brain says “fuel pump”…but for now just working with the fact that the car will start, will rev, and (eventually) idle without needing throttle input.

Bayou_Flyer

Nearly a year….car has been a low priority for me. Today I went out and swapped fuel pumps. The one I pulled out was a 2017 unit…the one put in was dated 2018. Easy enough job.

Turned key and basically no change. However, i put a slight amount of input on the accelerator pedal and it started….then died. Repeated a few time than it came to life.

The PO told me he busted out the cat, but when it starts dying and backfires it sounds like the contents of said cat are in the muffler.

About 3-4th time starting up, I was able to get it to hold 3k rpm, then it felt like it came to life. I was able to rev freely up to about 5-6k where it would stop rev’ing. Let it come back to idle and it stumbled, died, and would not start again.

When I bought this S2, the PO said it died suddenly while accelerating and would only run by using the throttle. I replaced coils/plugs/wires, a heat damaged MAF and a broken throttle body. Also the two blue relays were broken from being removed, so I picked up two of those from Mazda.

It had a compression check from Mazda before it died on the PO…passed then. There are no CEL when it is running. I did pick up a new upper O2 sensor on a rock auto deal, reading on other posts that can cause issues, but I havent put that on yet.

TeamRX8

iTrader: (25)

you could unbolt the muffler pipe from the rear cat pipe to see how it starts & runs when open.