My AFR gauge in my car has been reading rich the last few times I drove it. I never saw anything wrong with the car though.

Tonight I checked my oil and its thinned out and smells of gas.

-Fuel pressure while driving is fine, as per my gauge in my car. like 38-42 as always.
-Injectors all ohm at 12-13 hot
-No leaks from Pressure regulator with car on or off

What next?

 

compression (dry and wet) and leak down test.
washed out cylinders/ bad rings ?

 

im positive the motor is fine. I just need to find whats causing this condition.

Only things I can think of off te top of my head is bad cts, bad injectors or a bad injector wire lol

 

ok so I pressurized the system and clamped the feed and return line for about an hour with no change in pressure.

 

Intake gasket leak?

I was going to say bad fuel pump causing the gas in your oil, but you aren't running a mechanical unit.

 

check all your plugs.

 

ya it will probably need new plugs too

 

OK so everything scans fine. All sensors read perfect. Figured I might have an exhaust leak. No exhaust leaks to be found while I was under the car. Pulled the cap and rotor to check them




Look fine to me. The problem is definitely still there. Development though: When cold if I get on the gas too much it backfires through the intake. Once it warms up, it has this rich/stumble problem. I'm going to ohm the injectors cold tomorrow and see what they read. Its definitely running rich though...you can smell it at idle.

Changed the oil today too adn nope, no gas in the oil. Muhbad.

I'm at a loss as to what the problem is. Sensors, spark plugs, fuel pressure, everything seems fine. I guess I could throw a ignition module, coil, and cap/rotor at it but those are damn expensive being I need vortech parts.

Maybe bad injectors?

 

While idling I got these temps measured about 1" away from the header flange at the head

#1 160-175*F
#2 170ish*
#3 220-250*F
#4 230-240*F
#5 270ish*F
#6 270ish*F
#7 230-250*F
#8 230ish*F

 

this is with a TPIS Miniram, if that makes a difference. I also am using GM Multec 30lb injectors that were factory on the LT4 cars.

 

What do the plugs look like on one and two?

 

fine!

 

try moving the wires from three and four to those to plugs and see if the temp raises on one and two and lowers on the and four.

 

I see what youre wanting to do but the obd2 scanner is showing no misfires

 

Don't always believe the scanner.....we have a truck that shows false kr in the hptuners scanner when there is in fact none.

 

ok so in the morning im going to ohm the injectors cold, and swap plug wires.

 

when cold, all injectors ohm 12.0-12.3 with the exception of #7 that was 11.8

I swapped plug wires with 1/3 and 2/4 and cylinder 1 and 2 are still reading cold.

#1 150-180*F
#2 130-140*F
#3 200-230*F
#4 230-240*F
#5 230*F
#6 250*F
#7 220*F
#8 230*F

I guess next I swap injectors around.

 

is your distributor cap and rotor brass. if not I would replace and ohm your wires

 

They are not brass.

Swapped 1/3 and 2/4 injectors with no difference in temperature

 

bump

 

constant fan or electric fans for cooling

 

when we are racing I can pull no. 1 and no.2 plugs in about 1 minute after shutting down. my fans cool those cylinders very fast. might be they are cooling from the fan

 

HMM I hadn't thought of that but I'm kinda skeptical about that being the reason. I've had thoughts of header leaks sucking in cool air, or an intake leak.

Still need to pull those plugs and check em tho

 

ok so I've checked and double checked all the sensors and they are fine. compression check shows 160psi in each cylinder. even measured cam lift and the cam is fine.

Put in new plugs and cap and rotor and the car ran much better but is still running pig rich. The inevitable happened and running rich is playing hell on my new plugs and now its running the same.

Seems to be fine at idle and good at WOT (albeit I leave a LOT of smoke at WOT) but part throttle crusing is where the AF gauge reads like 11:1 afr. TEHFUX time to put it away for winter

 

SO it was fine a while ago and now running rich? Check your ignition module in the dizzy? backfiring thru the intake sounds like a timing problem.

Maybe the cold air just needs retune compared to summer time? You running open loop or closed?

 

how could it be a timing issue? Nothing was ever changed on the car and timing is all done through the pcm.

I wonder if I need a reflash?

I've driven the car in the cold before with no issues. I'm running closed loop

 

Well if a ignition component goes out, you could be seeing different timing at the engine. Hard to say.

You could try a reflash but its not likely that the ecm would go bad.

Now you are saying OBD-II....is this a 411 ecm swap car? Is the crank sensor good?

 

yeah its a 411 swap. I'm fairly certain that a bad crank sensor causes a no start condition, or at least a code of some sort. I have NO codes and not even any history of codes stored in the pcm.

I do have a chinese aluminum distributor in the car. I was kind of thinking maybe that went bad somehow. I'll check the easy stuff first lol

 

Justin, you have a 350/355. Did you ever think that 30lb injectors might be to big? Stock on a 350 is 22lb I belive. Just a thought

 

nah its fine. Its been fine almost 3 years now.....something has went south though

 

just pulled the car out of storage to mess with it again. Put a couple O2 sensors in it and it seems to be running much better