3.5 Alero Cylinder Misfire [Archive] - GrandAmGT.com Forum

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slowalero
08-28-2012, 12:45 AM
Ok, so here goes my first post. I swapped an LX9 3.5 from a 2005 Malibu w/33k miles the end of last year in my 2001 57k mile Alero that had a blown 3400. I registered the car in June and have been driving it nearly every day since. Within the first 150 miles, the MIL set for a P0172, system rich. No noticeable driveabilty issue right away, other than what felt like a breaking coil @ 5500-6000 RPM. Soon, the rich code caught up and it's now giving me a hard misfire, P0304.

To help with any questions I'll break down first what is different than a stock setup, and what I've done to diag the problem.

OE PCM tuned by Milzy Motorsports
Delph 28# injectors from WOT-Tech
TCE 65mm TBC & TBC spacer/adapter
OE LX9 front rocker cover (w/fixed orifice PCV)
OE LX9 crankcase vent routing
OE LX9 CTS/MAP leads repinned into 3400 upper harness
OE LX9 MAP & CTS
OE LX9 CCP valve
TCE external 7x CKP sensor asm.

For those unfamiliar with these swaps, it's a 3400 PCM and sensors used to run the 3.5. The TPS and IAC motor were cores assembled on the TCE TB by Milzy. MAP is OE with the engine, both HO2S, MAF, and IAT are OE with the car itself. All other sensors (knock, CTS, both CKP, CMP, CCP valve, and OPS) are new (Duralast), as well as Bosch wires, AC Delco 41-101 irridium plugs, and OE (3400) ICM assembly.

I'm currently replacing a trans in an '01 GAGT, as well as a service and tune up. I temporarily swapped some parts from that car to help with diag, but came up short with every attempt.

Swapped Cyl. 4 plug wire
'' Cyl. 4 plug
'' MAF sensor
'' ICM assembly (from TWO 3400 cars)
'' CKP harness
'' MAP (from 2006 G6)

I also removed my LX9 plenum to determine a leaky injector and observe spray patterns. I found even patterns and no leaks. Fuel pressure sits @ 50 psi @ idle, 60 w/o vacuum, and the needle twitches from 45-55 when cracking the throttle quick. No even rise in pressure. Did not think to keep the gauge on the rail after shutting it off and observe vacuum loss.

Another thing is I'm using the LX9 CCP valve that is direct port, but mounted in the OE 3400 position. I was advised it was the same electronically by Milzy so using it wouldn't be an issue, however, during removal of the EVAP hose @ idle, there is audible evidence of CCP valve activity. An experienced friend told me there shouldn't be activity @ idle. Unpluging the CCP valve changes nothing. Upon scanning monitors, the EVAP system is NEVER ready.

Some techs have suggested a mechanical issue, but I'd be remiss if I didn't explain that it's an intermittent misfire. At no particular time will it light all six candles and give you some horsepower for a couple miles. I've also noticed I have random CTS inactivity. This doesn't affect the misfire, but shouldn't be happening. Like stated above, I've repinned the CTS and MAP leads from the OE LX9 upper (injector) harness into my OE 3400 upper harness. They (CTS/MAP) share a ground terminal in that harness bulkhead. Tried unplugging the MAP to duplicate an issue with that wiring but it's an obvious difference, one that I would notice when the CTS dies.

This has been going on for a couple days now and is scheduled for shop time at my friend's place this week where much better diag equipment exists. Is my fuel pressure too low? Is my charcoal canister flooded? The HO2S is OE and the blown OE 3400 dripped Yoo-Hoo from the exhaust tips. Is it possible the HO2S is damaged? Help! Some good words would be appreciated before I play doctor this week.

sleepyalero
08-28-2012, 01:47 AM
first my question is how did the 3.4 blow with only 57k miles?? :wtf

also, join aleromod.com ;)

slowalero
08-28-2012, 02:11 AM
I'm going to assume running it stupid low on oil. The rear cylinders were scored bad, bearings melted in their caps, and the pistons were burned up pretty good. The old lady I bought it from showed me all THREE oil change receipts in 57k miles. One of which was 22 months and 16,000 miles in between.

And thanks for reminding me of aleromod, my build thread is on 60V6 but it doesn't work on my phones browser anymore.

sleepyalero
08-28-2012, 03:08 AM
that is terrible! 3 oil changes in 57k miles..... what a shame......

atleast the car isnt sitting in a junk yard now! glad you decided to swap/fix the car.

other then that, i wish i could be some help to ya, but im honestly about as stumped as you are.

slowalero
11-24-2012, 06:13 PM
I guess I hadn't realized how much time past since I'd done anything with my car online, but one reason I haven't posted anything is cause not much has changed.

Like many discoveries in history, mine was an accident. I had robbed the proper, OE fuel pressure regulator vacuum elbow from a Grand Am I was storing, but when it had to go back I sacrificed a vacuum leak. Like most other things lately, it slipped through the cracks and I put on 1200 miles with a 1/16" vacuum leak. Somehow, that turned the light off. Most likely I now had enough air to match my fuel overload.

I also have no air filter. Not like, it has a stock air box with no filter, it's just the mass air hovering over the lower box. It's been like that for months, and after the 1200 mile clean slate, the light came back on for 4/500 miles. Today, it disappeared. Haven't done anything to the car. Still giant vacuum leak, and wide open MAF, 3k on an oil change.

Anyone? Harness glitch? This last time the light came on, the map light came on at exactly the same time. The button was popped out, but it wasn't on until it tweaked. Sometimes under full throttle in second gear mostly, during the pull it will tweak out for a quick second, like a loose connection. I do know I have a worn number one injector connector because it keeps coming loose causing a surging in overdrive, most notably, so I have to reach behind the steering pump and push down some and it goes away. It was the root of a misfire some months back. Weird.

Starglow
11-24-2012, 07:23 PM
My car has no tag and I can't get one with the P0172 code. I'm going to do a few tests and call Milzy regarding the PCM tune so I'll let you know if I find out anything.

I originally had stock Multec1 19# injectors on the 3400, so I upgraded to 28# Multec2 for the 3500 swap. But instead of just splicing the Multec2 connectors to the old harness, I pulled an FI Multec2 harness from an 02 Alero at the junk yard and rewired it to match my original harness since there were some minor differences.

I also just got an Elmscan5 OCDII code scanner and OBDwiz software that runs on a laptop to help me see what the PCM is reading. I have a lot to learn to use it properly but I'm working on it.

AaronGTR
11-24-2012, 08:38 PM
First off.... what the heck is a CCP and CTS? I'm not aware of any sensors on this car that are called out by those designations.

Second, there may be a problem with using the 3500 MAP sensor. I don't have specs on it, so I don't know it's voltage range... but it's possible that it's not on exactly the same scale as the stock 3400 MAP (same as different MAF sensors have different scales for reading air flow), and that might throw it off.

The fuel pressure might also be an issue. Your idle pressure should be 48psi and WOT should be 56 or 58 iirc. Sounds like you are 2psi high everywhere, which could cause it to run rich. In order to set the P0172 code for system rich though I think you have to max out the fuel trim adjustment, which shouldn't happen with only a 2psi fuel pressure increase. You'd have to have something else like and incorrect injector size or stuck injector. Did you ask Milzy to tune the PCM for the bigger injectors? If not, or if he forgot to do it or didn't enter the correct number... that would definitely cause it to run rich.

O1GAGT
11-24-2012, 09:59 PM
First off.... what the heck is a CCP and CTS? I'm not aware of any sensors on this car that are called out by those designations.

Second, there may be a problem with using the 3500 MAP sensor. I don't have specs on it, so I don't know it's voltage range... but it's possible that it's not on exactly the same scale as the stock 3400 MAP (same as different MAF sensors have different scales for reading air flow), and that might throw it off.

The fuel pressure might also be an issue. Your idle pressure should be 48psi and WOT should be 56 or 58 iirc. Sounds like you are 2psi high everywhere, which could cause it to run rich. In order to set the P0172 code for system rich though I think you have to max out the fuel trim adjustment, which shouldn't happen with only a 2psi fuel pressure increase. You'd have to have something else like and incorrect injector size or stuck injector. Did you ask Milzy to tune the PCM for the bigger injectors? If not, or if he forgot to do it or didn't enter the correct number... that would definitely cause it to run rich.

CCP Valve = Charcoal Canister Purge Valve

CTS = Coolant Temp Sensor

3500 MAP sensor works on the same principals and range as the 3400 MAP. There have been numerous people that use the 3500 MAP sensor with top end swaps and full 3500 swaps with out problem.

I am leaning toward a problem with the tune with injector flow rates.

AaronGTR
11-24-2012, 11:14 PM
Yeah, that's what had me confused. No one calls that the CCP. They call it the EVAP solenoid. Most people don't abbreviate the coolant temp sensor either, so I didn't even think of that.

Starglow
11-24-2012, 11:16 PM
First off.... what the heck is a CCP and CTS? I'm not aware of any sensors on this car that are called out by those designations.

Second, there may be a problem with using the 3500 MAP sensor. I don't have specs on it, so I don't know it's voltage range... but it's possible that it's not on exactly the same scale as the stock 3400 MAP (same as different MAF sensors have different scales for reading air flow), and that might throw it off.

The fuel pressure might also be an issue. Your idle pressure should be 48psi and WOT should be 56 or 58 iirc. Sounds like you are 2psi high everywhere, which could cause it to run rich. In order to set the P0172 code for system rich though I think you have to max out the fuel trim adjustment, which shouldn't happen with only a 2psi fuel pressure increase. You'd have to have something else like and incorrect injector size or stuck injector. Did you ask Milzy to tune the PCM for the bigger injectors? If not, or if he forgot to do it or didn't enter the correct number... that would definitely cause it to run rich.

I haven't talked to Mike yet, but I did provide him with a list of everything I was installing on the engine including the 28# fuel injectors. He doesn't provide any list or documentation of what changes he makes during a PCM tune, so I have no clue what the settings are.

I'm going to vacuum test the FPR and take fuel pressure readings on the fuel rail in addition to hooking up a vacuum gauge to the engine to see what it reads in case I have a vacuum leak by chance. The upper O2 sensor is fairly new and my research indicates that it's most likely not the cause anyway.

I bought the 28# fuel injectors new and will try listening to them with a stethoscope. Since I built the wiring harness and have the pin-out diagram I can measure resistance through the harness without pulling the UIM, but I'm not sure how accurate the readings would be with the extra wire resistance added.

Again I can check some things out in the PCM with the OBDwiz software if I know what to look for but I'm still researching to learn how to use the software and interpret the data.

sleepyalero
11-25-2012, 01:15 AM
he tuned my 3400 with the f40, mine seems to be doing well with it. most i know is that he tuned the fans to come on at 180*, stay on for an additional 2 or so minutes when the car is shut off on a very low setting, and changed the speed limiter. anything else idk what he did.

Starglow
11-25-2012, 11:34 AM
I do have a 180 degree T-stat, but the fans definitely don't turn on at 180 degrees.

AaronGTR
11-25-2012, 01:13 PM
I do have a 180 degree T-stat, but the fans definitely don't turn on at 180 degrees.


That's ok, you don't want them too anyway. I don't even recommend 180 t-stat's to people anymore. It's a waste of time. These cars aren't designed to run that cold. All you do is hurt your fuel mileage, and the engine runs dirtier and richer and you kill your O2 sensors and clog the cat faster.


They are designed to run over 200 degrees.

sleepyalero
11-25-2012, 02:41 PM
maybe its around 190-200 my temp gauge sits half way on the middle mark. (bottom half)

Starglow
11-25-2012, 07:22 PM
I did some diagnostics today to check out a few things as follows:

FPR vacuum test - good

Fuel pressure -
Steady @ 53 PSI key on, engine off
50-51 PSI engine running @ idle
54-56 PSI engine under throttle load
Steady @ 46 PSI engine off after run

Engine vacuum
Steady @ 20 Hg Idle

I listened to the fuel injectors with a stethoscope, at least the ones I could get access to, and they sounded good. I did not check for vacuum or exhaust leaks yet but it's on my list of things to check.

The PCM code scanner also showed a pending P1404 which is EGR related. I cleared the codes to see if they re-appear again but the exhaust smell is overpowering after a while. The gas in the tank is really old but I did add 5 gallons of fresh fuel and some Berryman's B12. Some are suggesting using Seafoam, but I'm not sure if I should do that on top of the Berryman's I already added.

Now I'm off to research how to interpret short fuel trim readings with the OBDwiz software. Lot's of information at my disposal but understanding what it means is a whole other skill.

slowalero
02-03-2013, 12:15 AM
Maybe my 180 t stat is causing the rich condition? Don't have the light on now, and hasn't been for quite some time. Either way, it's inspected so I have roughly a year to track it down. I've questioned the tune for a while, and I've heard sticky injector numerous times. British Car Conversions, not to mention The General, and many other professionals recognize the acronym CCP, and CTS.

Tax return may acquire WOT-Tech cam and heads. Hope the tranny holds a little longer...

klokworx
02-03-2013, 01:02 AM
Ok, so here goes my first post. I swapped an LX9 3.5 from a 2005 Malibu w/33k miles the end of last year in my 2001 57k mile Alero that had a blown 3400. I registered the car in June and have been driving it nearly every day since. Within the first 150 miles, the MIL set for a P0172, system rich. No noticeable driveabilty issue right away, other than what felt like a breaking coil @ 5500-6000 RPM. Soon, the rich code caught up and it's now giving me a hard misfire, P0304.

To help with any questions I'll break down first what is different than a stock setup, and what I've done to diag the problem.

OE PCM tuned by Milzy Motorsports
Delph 28# injectors from WOT-Tech
TCE 65mm TBC & TBC spacer/adapter
OE LX9 front rocker cover (w/fixed orifice PCV)
OE LX9 crankcase vent routing
OE LX9 CTS/MAP leads repinned into 3400 upper harness
OE LX9 MAP & CTS
OE LX9 CCP valve
TCE external 7x CKP sensor asm.

For those unfamiliar with these swaps, it's a 3400 PCM and sensors used to run the 3.5. The TPS and IAC motor were cores assembled on the TCE TB by Milzy. MAP is OE with the engine, both HO2S, MAF, and IAT are OE with the car itself. All other sensors (knock, CTS, both CKP, CMP, CCP valve, and OPS) are new (Duralast), as well as Bosch wires, AC Delco 41-101 irridium plugs, and OE (3400) ICM assembly.

I'm currently replacing a trans in an '01 GAGT, as well as a service and tune up. I temporarily swapped some parts from that car to help with diag, but came up short with every attempt.

Swapped Cyl. 4 plug wire
'' Cyl. 4 plug
'' MAF sensor
'' ICM assembly (from TWO 3400 cars)
'' CKP harness
'' MAP (from 2006 G6)

I also removed my LX9 plenum to determine a leaky injector and observe spray patterns. I found even patterns and no leaks. Fuel pressure sits @ 50 psi @ idle, 60 w/o vacuum, and the needle twitches from 45-55 when cracking the throttle quick. No even rise in pressure. Did not think to keep the gauge on the rail after shutting it off and observe vacuum loss.

Another thing is I'm using the LX9 CCP valve that is direct port, but mounted in the OE 3400 position. I was advised it was the same electronically by Milzy so using it wouldn't be an issue, however, during removal of the EVAP hose @ idle, there is audible evidence of CCP valve activity. An experienced friend told me there shouldn't be activity @ idle. Unpluging the CCP valve changes nothing. Upon scanning monitors, the EVAP system is NEVER ready.

Some techs have suggested a mechanical issue, but I'd be remiss if I didn't explain that it's an intermittent misfire. At no particular time will it light all six candles and give you some horsepower for a couple miles. I've also noticed I have random CTS inactivity. This doesn't affect the misfire, but shouldn't be happening. Like stated above, I've repinned the CTS and MAP leads from the OE LX9 upper (injector) harness into my OE 3400 upper harness. They (CTS/MAP) share a ground terminal in that harness bulkhead. Tried unplugging the MAP to duplicate an issue with that wiring but it's an obvious difference, one that I would notice when the CTS dies.

This has been going on for a couple days now and is scheduled for shop time at my friend's place this week where much better diag equipment exists. Is my fuel pressure too low? Is my charcoal canister flooded? The HO2S is OE and the blown OE 3400 dripped Yoo-Hoo from the exhaust tips. Is it possible the HO2S is damaged? Help! Some good words would be appreciated before I play doctor this week.

http://i32.photobucket.com/albums/d2/yukishirotora/diabeetus.jpg

2000GAGT
02-04-2013, 09:43 AM
I've been lucky with my 3500 swap, worked perfect the first time I turned it on. Been in there 4 years and drove 57k miles on it. Also supercharged it and then later on turbo. The only issue I ever had was it likes to blow ignition control modules. Had the original 3400 oem up to 157k miles and now im on my third one.