Code 542 and 327

Hi,
Code 542 is one that may be misleading, especially since you replaced 02’s, as it may cause a lean condition.
Motor ever get an intermittent Fuel Pump prime when you turn the key to start it?
First off, try these:
1) Check your Grounds, Battery to Chassis, Battery to Block, Block to Chassis. Make the connections all solid.
2) Check your Fuel Pressure at the Rail, 30lbs is what you want to see, if not- may be the Fuel filter, or Pump.

Hi,
No problem, happy to help you work this out. More details on the table, easier for expedited answers..Believe CCRM’s OK, prime occurs normally, engine doesn’t cut out, fans operate- correct? Then, so far, so good.. Grounds can wreak absolute havoc...
Code 327 is covered, below. Let’s dig in..
-How are you clearing Codes? Jumper on DX Connector, Obd-1 Scan-tool?
-Any other characteristics re: how she’s running, Hot, Cold, rough idle, hesitations, break up at RPM’s, others?
-When this began- what were the first signs.. things occur suddenly..over time?
-Any recently performed work, or aftermarket parts installed?
Any spark knock or ping under a load?
Do any issues manifest with heat, whether high outdoor temps, engine temp, different or less when cool?
The above answered in basic form will go a loooong way.!
Start with the item’s below to establish a baseline, paying closer attention to listed specifics .Do nce over, Pull the Plugs, something needs replacing, do it.
Will help now & later, you’ll automatically check what’s around you. That’ll help. A “Tune-up” , but only running the motions, unless obvious issues turn up.. Read/Clean Plugs, oil change if needed. Grab a can of CRC MAF Cleaner, AntiSeize packet for Plug threads. Dielectric grease for Connectors
You’ll be firing this between cleaning, resetting Codes, but you’ll locate the issue. & others that were on their way..
1) Clean your MAF & ACT (IAC) w/CRC MAF cleaner.
2) Run a CAI? Regardless, Check your Intake Connections for vacuum leaks & run through all the lines & Filter.
3) Verify the fuel pressure regulator is functioning correctly, Test Pressure with at the Schrader Valve. 30-40lbs, note the change with Reg. Disconnected....
4) Pull & clean out the EGR, ensure it’s properly operating, not sticking; evidence of the same. If it’s now cycling, check it, connections, the wiring associated with, Grounds.
5) With a VOM, Verify 4-6 Volts exists at the EGR Sensor, Both KOEO, Check Voltage at the TPS, Ground Blk lead, Red lead to Green wire- should be (0.75-98.DCV). Ensure your Plugs connect solidly. If a tab is broken- on any connector- replace it. Inexpensive Insurance.
6) Check your Salt & Pepper shaker Plugs for moisture free, Clean, low Resistance connections. Add Silicone Dielectric Grease to improve connections, inhibit corrosion, keep out moisuture.
Just an FYI: Q- Dizzy Stock or aftermarket? 94’-95’s appear to have OE Dizzy issues., i’d Relocated a TFI on a Well mounted Heat-Sink as one 95’ GT 302 I’d built w/ Broxix Hñ
Temp. margin of safety is non-existent.. After that, 3-4 94/5’s had 3+ TFI’s a YEAR.going & did the same relocate, Works excellent..
PIP’s are also vulnerable to early failure. Take a peek at things, clean anything up inside, blast the bowl clean with CRC MAF Cleaner.
.-I’ll adjust the list in terms of priority once I have that additional info from you-K?
Good luck!
-John

Hi,
No problem- happy to help!
This changes things, slightly, didn’t realize this occurred over time, and there was an overheating issue. If the Fuel was being run across 3 years while you were absent, & one started the car bi-weekly, that indicates it’s likely an issue sparked by fouled fuel. Volatility breaks down and fuel becomes gummy, then solidifies.
The aftermath is Sensors that are coated in this substance, CPU is fighting to run closed loop. The list if given you needs to be amended due to this, or prioritized.
Your CEL’s and specific’s regarding how it runs suggests a lean condition, which would likely be partially due to dirty Injectors.
How ithis is most effectively approached is based off
1) Is there still old fuel in the Tank?
2) Was the fuel ever topped off by the person that was running it for you?
3) Was any fuel stabilizer added to the fuel before you left?
4) How much fuel was left in the Car when you arrived back home?
5) How long was the.car run since you returned, did you add fresh fuel to top it off?
Once we have these answers, it’ll make an amended Hopefully, this can be addressed by a non-aggressive methods like using additives, Lucas Fuel Stabilizer, Injector Cleaner, cleaning up a few Sensors, Plugs, EGR & etc.
This lines up with some of the lean, rough idle, idle seeking, high idle conditions you’re experiencing, this is likely a major component of why things occurred. EGR c still be pulled & cleaned, function tested. Plugs should also be cleaned
Worst case is drmaining the system of fuel, pulling the injectors and cleaning, clearing anything out of the Tank.
Ok, talk to you soon
-John

Hi,
If the EGR is functional, it doesn’t require replacement. If the EGR looks like it’s all of 25Yr’s old -internally & externally, once pulled, one might say it’s not counterproductive to replace it. It is a failure part that sees a lot of heat. If it was just idled while you were away, I’d think it’s likely stuck, it’s closed at an idle.
Roger that on the fuel system, Fuel of good Octane’s in & running through it. the original list should catch issues.
Glad there was stabilizer in it. So many people don’t. i’d keep going with the fuel injection treatment in the fuel, however.
I’d add running a Cylinder balance test to the list, and keep going down it. Issue(s) will show up as a weak cylinder. If you don’t know how to do one, just ask, I can send you a link.
Note aftermarket Ingition parts are also suspects, I trust you have old parts if you built it, if so, it’s great to swap out & try things, but I’d suggest not throwing money at it, keep it real as you have so far. Replace when required.
Good luck!
-John

+1 General karthief!
Hi Shelton,
Try the jumper-method to pull codes. Info on performing a cylinder balance test, if you haven’t yet run one:
http://sbftech.com/index.php/topic,2471.0.html
The 94’-95’ GT’s EEC’s (Obd-1 + Data) were setup in prep for Obd-2, but only the V-6 models actually utilized Obd-2 until 96’.
Sounds like you’re running to an idle issue when the Car jumps into closed loop, were the 02 Sensors you replaced OE? If not OE,
Sensors, IDT they were bad in the first place, just Carbonized. Could Clean & reinstall them & see how she runs.
Glad to hear you’re gaining ground... So, open items:
1)O2 Sensors, clean & retry.
2)Did you get a Fuel Pressure measurement, with/without Regulator?
3)How were the Plugs when you pulled them, 4)what color were the electrodes?
5)Not a bad idea double checking MAF, Intake piping, T.B., use CRC MAF Cleaner.
6) Pull the MAF plug, motor should run bad, or fall on its face & stall. What occurs?
7)Check your IACM for proper operation.
Check your Coolant levels & perform a specific Gravity test. Get it 50/50, 60/40.(W/C).
8)Verify proper operation of the Coolant temp. Sensor (CTS).
9)What CEL’s have been thrown besides 542, 327, 177..?
Since the issues presented are more a result of long term Wet storage, and it’s NOT overheating, keep running premium fuel with Injector Cleaner, or pull & clean the Injectors & clean, or have cleaned.
Fuel can be affected by breakdown after 1 Month.( I’ve seen it usable past a year)Stabilizer increases to near 2yrs. So, it ran Fuel for 1 yr. beyond that 26+ times, which is why I believe it’ll run better the more it’s run, or when cleaned.
Any questions or comments, please post. Apologies for the delay, had something come up I needed to address. i’ll get to you within a day, now.
Good luck!
-John

Shelton said:

I attempted to pull the codes again but I seem to have run into a little snag..the diagnostic port is no longer connecting to the obd-1 scanner. I was having trouble with this issue before but it would eventually connect after several attempts....I've been trying for quite sometime now and it will not connect. I'm at a loss...would you happen to have any suggestions?

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Shelton, Verify all your Socket Pins are straight & free on contaminants, as well as those on the Plug, sometimes a Battery reset will take care of Communication issues.
Utilizing the pin method will yield you the benefit of running the Cylinder balance test, this will catch a weak cylinder for whatever reason, whether Spark related, an injector that’s very clogged, Mechanical anomaly, etc.
If it’s available, why not utilize it- right?
Take care!
- John
Don’t trust those new O2’s, don’t know why..

Shelton said:

Hey John,

Thanks for the info, you’ve been a huge help. I am out of town so haven’t had the chance to work on the car. But before I left I was finally able to pull codes and it was throwing only code 542. But the additional codes in the continuous memory were codes 157..158..342..543

The CEL was still coming on intermittently and the idle was still jumping up at normal engine temperature and then leveling out. The O2s are NTK Performance O2s...different from what I had on previously.

I will run the cylinder balance test when I return and provide answers to your questions. Thanks.

Shelton

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Hi Shelton,
Happy to help. Happier once it’s done testing its CEL, lol.. Will be around when you’re back at it.
Cheers!
John