2G P0110 and P0105 Problems

[funds]

I’ve been beating myself over the head with this, I need help with my 98 GST.

It started a few days ago on my way home from work on the freeway, when I started a nasty misfire and ended up stranded. It’ll idle at ~500rpm and wants to die if I’m not giving it gas, and it sounds like its running on 2 cylinders. After towing it home, I got codes P0110 and P0105. I swapped an old MAF I had laying around and it ran a little better, but still missing. My wires leading to the MAF were fine, but I wasn’t pulling any voltage on terminal 4 from the MFI. I have been googling and going through forms, but they’re old and people are getting more codes than I have. I only have P0110 and P0105

I WANT to say its my MFI relay because I don’t smell a fried ECU and I’m getting voltage from the connector, however I’m not good with electrics and I need someone’s second opinion before I start throwing money at it.

Its my daily driver, this is my last resort before I just take it to a shop

 

[pauleyman]

Have you done any basic tune up stuff? Plugs, wires. Etc?

 

[funds]

Recently I’ve done plugs & wires about 5k miles ago, injectors got serviced at the same time, transmission & oil flushed about 1k ago, and I got a new CAS thinking that would fix it. Probably good to mention it has an exhaust leak but its somewhere after the downpipe

 

[steve]

P0110 - Intake Air Temperature circuit malfunction
P0105 - Barometric Sensor circuit malfunction

Both point at the MAF but it's also possible you have a blown ECU sensor ground trace. blownsensorground [ECMTuning - wiki]

Usually you would have other fault codes too but it's worth looking into.

The car isn't going to run at all if you don't have power running to pin 4 of the MFI relay. It's common with pin 3 so not power would be going to the ECU either.

 

[funds]

P0110 - Intake Air Temperature circuit malfunction
P0105 - Barometric Sensor circuit malfunction

Both point at the MAF but it's also possible you have a blown ECU sensor ground trace. blownsensorground [ECMTuning - wiki]

Usually you would have other fault codes too but it's worth looking into.

The car isn't going to run at all if you don't have power running to pin 4 of the MFI relay. It's common with pin 3 so not power would be going to the ECU either.

I pulled my ECU, and the grounds look fine but the underside of my board looks trashed, and a lot of chips on my board look like they’ve melted. The case itself looks a bit melted/shiny inside too. Hoping this is my only problem

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[steve]

No it's not melting That is the conformal coating used to keep moisture at bay. The ECU is dipped in a waxy solution and allowed to drip off and dry.

I don't have any Black Box ECUs here in the mountains to trace out the sensor ground to display but I don't see any obvious places where something bad has happened to your ECU.

 

[funds]

I haven’t updated in a while and my car’s still dead:/

After waiting for a new MFI relay and MAF I finally got the chance to throw them on. It starts, but still has a rough misfire. For the little bit of time that the car starts, I got code P0100 along with the other two. Is there a way I can ohm out my ECU and see if my sensor grounds blew?

 

[luv2rallye]

Here: http://www.dsmlink.com/wiki/blownsensorground

 

[steve]

Here: http://www.dsmlink.com/wiki/blownsensorground

Sadly they don't have pictures of a Black Box ECU sensor ground. That's why I didn't post the link.

 

[funds]

So I finally sourced a good WORKING blackbox, and it’s still misfiring. I checked over my wiring harness, and everything looks good. I checked voltage to pin 4 of my MAF again, and I’m not getting anything but I get my 5v on other sensors. If I keep it at about 2k rpm the misfire starts to clear a bit, but it’ll only idle still at ~500. I checked my timing too, and my intake seems to be about a tooth off, so I’ll be compression checking ASAP. My car’s turning into yard art

 

[chrysler kid]

Does the car idles better with the mass air flow sensor unhooked?

If it idles better with the sensor unhooked you could have a large vacuum leak.

 

[luv2rallye]

I checked voltage to pin 4 of my MAF again, and I’m not getting anything but I get my 5v on other sensors.

If you didn't have +12v on pin 4 of MAF (larger red wire) you wouldn't have voltage to any sensors including CPS and CAS and the engine wouldn't run. Perhaps you counted from the other end and you're really on pin 5 (black) which is the sensors signal ground (goes to ECU pin 92).