Running rough, sensor replaced, more problems.

[Toul]

I have the following codes:

511 EEC processor ROM test failure
116 Engine coolant sensor out of range
159 MAF sensor out of range
114 intake air temp sensor out of range
225 Knock sensor not tested (ignore if not pinging) - KS

A week ago I had:

543 Fuel pump secondary circuit
177 Rich
173 other cylinder bank Rich
511 EEC processor ROM test failure
225 Knock sensor
114 intake air temp sensor out of range

I concluded that the 511 was from my chip, and that the codes for Rich were caused by a bad IAT sensor sending flubbed numbers for air temp and screwing up the mixture. I replaced it with a 20 dollar IAT sensor from Advanced. Clearly my problem diid not go away, as in addition to still having a code for the IAT sensor, I now also have a code for the MAF sensor.

Does this sound like a ground problem? Was running fine up till about 2 weeks ago when it got cold if that helps at all. Also, is the coolant sensor anything I should worry about if I know there's coolant in the reservoir?

 

[shoff22]

it could be a ground make sure the motor has a good ground

 

[Toul]

Just cleaned my MAF, no change in how she runs. Pulled the sensor out of the housing and sprayed it down. It's an 80mm MAF that has at least 100k on it, it's been on her since I bought her.

I also sprayed down the new IAT sensor while I was there. I was really hoping it was just a gunked up MAF, as about a thousand miles ago I reoiled my filter.

When I'm driving theres a bit of stumbling, hesitation, and general sluggishness until I floor it. When I floor it she stumbles a bit more and kinda bogs down till the secondaries open, at which point I get pushed back into my seat and she takes off like a ***** ape like she should.

 

[St Louis SHO]

Replace the maf with another just to see.

 

[luigisho]

Or see if it improves by running it while it's unplugged. It'll throw a code but run in default.

 

[Toul]

Wiped codes and made sure car was at operating temp this time, I didnt remember that last time I checked. From a blank slate only codes that popped were the 511 and 225. Gonna leave the neg terminal disconnected for a few and hope that the comp resets, take her out and see what happens.

Side note, what is this connector? It's on the drivers side firewall, has 2 wires, connector is circled, where it melds back with other wires is arrowed. Couldnt find reconnection spot when I put intake back on last time, double checked on a parts SHO I had and couldnt find it.


Edit:

Wiped codes and reset comp after leaving neg terminal off for half hour. Took her out and did some hard runs down the interstate. On one of first hard runs had a very noticable stumble, and itermitantly had a dead spot in the 3000-4000 range till the secondaries kick in. Get her back home, pull codes and its a 543. I know everyone says ignore 543 if car runs, but could this be the problem?

I'll work on finding a replacement MAF, but I think swapping it out would also require new intake tubing since I've got the 80mm MAF.

 

[qiksho]

Wiped codes and made sure car was at operating temp this time, I didnt remember that last time I checked. From a blank slate only codes that popped were the 511 and 225. Gonna leave the neg terminal disconnected for a few and hope that the comp resets, take her out and see what happens.

Side note, what is this connector? It's on the drivers side firewall, has 2 wires, connector is circled, where it melds back with other wires is arrowed. Couldnt find reconnection spot when I put intake back on last time, double checked on a parts SHO I had and couldnt find it.


Edit:

Wiped codes and reset comp after leaving neg terminal off for half hour. Took her out and did some hard runs down the interstate. On one of first hard runs had a very noticable stumble, and itermitantly had a dead spot in the 3000-4000 range till the secondaries kick in. Get her back home, pull codes and its a 543. I know everyone says ignore 543 if car runs, but could this be the problem?

I'll work on finding a replacement MAF, but I think swapping it out would also require new intake tubing since I've got the 80mm MAF.

I have 2 good known working MAF's with tubes. PM me if you are interested in taking one off my hands...

 

[Toul]

Just went to drive out to an interview and she died on the interstate. No fuel pressure, fuel pump full on died. Ran codes with her on the side of the road, still just the 511 and 543. After sitting for 10 minutes or so she started back up, drove her back home and hit Autozone for a fuel pump, strainer, and filter.

Searching around on the forum though, I'm seeing some reference to CCRM issues screwing with the fuel pump. Also noted in one post someone asking if the CEL was dim. Mine is. It's dim when its on, when I paperclip to pull codes the CEL does a wierd dim flickering, then comes back full brightness while spitting out the codes. Is this indicative of anything?

Can a bad fuel pump go out so slowly and intermittently? The pumps always been kinda goofy, not always priming on first key turn, having to crank for 10 seconds or more, its died on me a couple times in the past 3 years, but it always comes back after sitting for 10-15 minutes.

Since cleaning the MAF and replacing the intake air temp sensor it did seem to run better. But now with the fuel pump acting up more at the same time, I'm wondering if it isn't an electrical issue.

Edit: Also recently had my low coolant sensor intermittently not work/register. I've got coolant in the reservoir, but after about 5 minutes of driving the low coolant light comes on, sometimes goes off, sometimes stays on. All the while with coolant in the reservoir.

Cmon SHO gods. Help me with your collective diagnostic genius:

Symptoms:

Intermittent fuel pump failure.
Low coolant sensor goofy
Dim CEL light when not pulling codes
Stumbling, stalling under 4k, pulls hard after.
bubbling popping backfire from exhaust (i think, could just be exhaust making contact with subframe connectors), but seems to get worse longer i drive it
Temp registering higher than usual (Used to stay at the A, now it hangs out around M, R, and sometimes O)
Needs new motor mounts, got rubbing on intake


Recent work:
New o2 sensors 5k ago, removed Y-pipe
New exhaust manifold to Y-pipe bolts (removed manifolds, removed intake to remove manifolds)
Re-oiled K&N filter (shoshop CAI)
New intake air temp sensor
Cleaned MAF
60k about 25k ago
Rod bearings 5k ago
Ground strap at rear passenger of intake tight.

 

[rubydist]

when pulling codes, the pcm does a quick dump of the codes for a code reader - this appears to the eye as a dim cel for a second or two while that happens. that is normal.

clean the bottom of the coolant sensor - after a while they get dirty and covered w/ crud and the sensor can't quite decide if it sees coolant or not.

sometimes the pump will work when cold and after running for a time will get hot enough to stop. that may be your issue.

 

[Toul]

Will try that.

Just went out to start thinking about changing the pump. While I was dead on the side of the road I checked the schrader valve for gas pressure and had none. When I just went out and checked it again, my schrader valve was leaking all over the place. A slow leak, not a stream, but definately enough. Don't know if its been doing this the whole time or not, first time I've noticed it. When it rains it pours.

I'm gonna try to tighten or replace it, borrow roomates car.

 

[Toul]

Tightened schrader valve, stopped leaking. Then noticed a fair amount of exhaust in the air. And water coming out the exhaust on the drivers side. Fair bit it seemed like, enough to puddle in the exhaust pipe some.

 

[rubydist]

water is a normal combustion byproduct, so you should get water from the tailpipe when first started up before the exhaust comes up to temp so it stays evaporated until out of the tailpipe.

best way to change pump is the "cut the floor under the rear seat" method - there is a write-up on here somewhere that is quite good.

 

[Toul]

That alleviates some worry, its cold out and it's STL, so there's plenty of water in the air. Can't tell if its really a lot of smoke or not since its night out and a flashlight lights it all up.

 

[freecop]

Cutout under the backseat worked awesome for me! My pump died at the gas station ( how ironic). Chopped a hole in the center of the backseat and there it was! Took 20 minutes with a Cutout tool. Be careful not to chop the fuel lines

 

[SHOZ123]

Check the small ground wire coming off the battery to the PCM if you have one.

 

[Toul]

Never fails I break something else when trying to fix anything. Cut the hole for the fuel pump with some tin snips since I dont have my dremmel with me. Knicked one of the vapor canister lines. I really, really dont want to have to replace it as well. I'm thinking about throwing some sort of tape over it. Teflon wrapping then some duct tape yah figure? Its just a small knick, don't even know that it punctured it. The thing buts RIGHT up to the floor pan at that ****.

 

[digeronimo34]

Knicked one of the vapor canister lines. I really, really dont want to have to replace it as well. I'm thinking about throwing some sort of tape over it. Teflon wrapping then some duct tape yah figure? Its just a small knick, don't even know that it punctured it. The thing buts RIGHT up to the floor pan at that ****.

On general principle i would Replace it. Gas vapors are not good to breath and can explode.

Sorry it's the firefighter in me. I would not be comfortable knowing that part of my fuel system mite be compromised. Tape won't be airtight. I don't know if that is some special type of line or if you can use generic by the foot line. But i'm sure that someone will chime in.

 

[e_clouser]

Two things...
1) In my 94 SHO.... it had a "chip" plugged in the back of the computer, had alot of the same problems you have. Mine kept getting worse, started out running rough, then just completely quit running. At that point, I could not even pull any codes. Most everyone on the forum said Ground issue. Made sense to me, but I never could find the problem. Someone on the forum told me to use a screw driver and tap the computer and see if that made a difference. It did....... Turned out to be the "chip" was falling out. I removed the chip and had no further problems.

2) In my current 92.... When I first got it, it smoked heavy, ran rough and had 1 code, 118. Replaced the coolant temp sensor, that cleared the 118 code but the car still ran like crap. This one turned out to be the thermostat stuck open. I would have never guessed that would cause all my problems but it did.

Hope this helps.

 

[Toul]

Welp, replaced the fuel pump yesterday. I left the seat out and it exposed so I could watch for leaks today. Sure enough, fuel pump cut out on me again tonight on the way home from a buddies, pulled into a bar parking lot and it came back on 10 minutes later. Only code in memory when I got home was 543. Gonna poke around at the computer tomorrow I guess.

What is the fuel pump secondary circuit to begin with? What would cause it to malfunction if it's not a bad fuel pump?

 

[SHOZ123]

I believe the secondary circuit code is left over from the Gen 1 days and does not mean anything. I'd be looking at the relay in the CCRM too.