cmking26

I have new injectors and a madz28 tune. My fuel pressure drops to 0 after it sits for awhile too. Is that normal? Im still at a loss and getting tired of screwing with this car.

Honda Hunter

Same here.

cmking26

Sounds like a pretty common problem. Im surprised no one has diagnosed it yet.

Guest47904

Since we are collectively talking to 4 people with the problem, let me ask all of you. Has anyone confirmed the PCM is seeing the correct temp? How about whether it goes into closed loop like it's supposed to? Last, has anyone confirmed all 8 are firing?

Start with the simplest, basic cause like not firing and then work your way to the harder items. Like Temp and closed loop. All Y'all need to check those 3 things at least.

I also find it interesting that everyone with the problem has heads, cams, headers and OBDI in common.

cmking26

Yes all cyl are firing. I need to get ahold of a scanner to check pcm. Thanks for the help

TransAm2k4

Having the same problem yes Heads/Cams Headers!!! But going to try and lean out the mixture with tunercat!! I tried using freescan and everything seems fine but the car doesn't.

Honda Hunter

The only code I'm getting is the high map sensor code but I only get it sometimes at start up and mabey sometimes at a light when idling. I'm pretty sure it has something to do with my cam size. I tried two new MAP sensors with the same results. Wires, plugs, o2 sensors, replaced fuel regulator, replaced injectors, replaced maf, cam was installed correctly, header gaskets, opti, any and everything ignition all has been replaced or checked out.
The only other thing I noticed was the coolant temp sensor wire on the drivers side got a little melted from the header but I dont think that's causing this.
My dyno showed me being extremly rich and I was told by the tuner mabey something was wrong with the ignition or whatever so I changed and or checked out whatever anyone said to look at. Hopefully (enshallah) Ill be able to get the car back on the dyno to see what the a/f ratio is. I'm not so much woried about the H.P but I would like to know that it's where it's suppose to be.
I have a LT1 KM still but it's tuned to pull no more than 6 or 7 and it's pulling the max. I'm 98.7% sure it's false knock. I did tell my tuner the best fuel we have here is 89 octane so I hope he tuned accordinglly. If it's pulling timing at WOT due to false knock would it also dump fuel to also protect the engine? If that's the case then I'm sure my problem can be solved. When I get to the dyno I want to datalog it at the same time using race fuel to check for knock. Only problem I see is if the computer is in that low octane mode or whatever it's called will it matter what fuel I add? Will I have to disconnect the battery then run a race fuel mixture? Another thing Im thinking I can do after that run is set all the Knock sensor values to zero and changing the low octane knock sensor values to zero. That should tell me alot about what's really going on and if my tune is any good.

MyZb383

I'm firing on all cylinders, though she's running so rich that I'm surprised I haven't fouled a plug at some point. I've run Datamaster and there are no codes being thrown. The car goes into closed loop as soon as it's warmed up a bit.

On another thread, I saw someone theorize that if the intake didn't fully seat and mate to the heads, it might cause this condition by allowing a slight amount of air to leak around the intake gaskets. That might also account for the gas smell in the oil. The theory was that if the block had been decked, and/or the heads had been milled down, a stock intake might not seat correctly. In my case, my block was decked and my heads are milled, so I would be a prime candidate if there's any reality to that theory. When I installed the intake, the angle on the intake bolts was right on the edge of not allowing me to get the threads to catch, so that idea really has me wondering now.

Anybody have a thought on that concept?

Oh, and BTW people, thanks for lending us a hand on figuring this one out. I had no idea this many of us were in the same boat.

cmking26

My block was decked and heads milled but there is actual gas in my oil, so I dont think an intake leak would do that. This is the second time my engine was rebuilt. First time it was running rich but I never caught it and it spun a bearing. So I am scared now to make sure I figure this out before I drive it. Would spending the money to put it on a dyno even help this problem?????

97HUGGER

Just did heads and cam swap and car smelled like it was running rich and it had low oil pressure after coming to a stop - my heads were milled and I used the Impala head gaskets for more compression I also am using 30# injectors and a mail order tune - I drove the car today and it had no power and didn't want to stay running when I slowed down - drained oil and found copper in it - spun a bearing I am assuming - I think it is to do with the engine running so rich - my car has a 160* stat also - I am very frustrated like you guys

Guest47904

The chances of that happening IMO are impossible without you seeing some other problem. More than likely an oil leak. Also if that where the case, you could easily push a 0.002 feeler gage into the gap between the intake and the heads. OR spraying a heavy lubricant on the gasket area would temporarily seal the leak just like we did when looking for leaks else where. YES?

Honda:
If you're getting a MAP high, look to the signal wiring. GM MAPS are bullett proof. Also, you don't just want to scan for codes. Look to see what things are being seen by the PCM like temp. etc.....

Transam2k4:
You're TB is way to big for a stock bottom end. Put your screen back in too!

I think you need to get injuneer back into the conversation. All y'all need to keep with this thread to help what appears to be a growing number of folks.

DiabloGT

ill add myself to the running rich problem, its happened after the long tubes, but right after the pcm tuning...

cammed_aro Z28

count me in for running too rich to drive, i have carbon buildup on my bumper, and last time i started my car i had tears running down my face from the fumes. after it warms up, it hesitates to rev really really bad, stutters until about 3 grand and then revs to 6000 and blows the biggest cloud of smoke i have ever seen. i have stock tune, slight exhaust leak and probably a sh*t load of false KR. i am trying to get ahold of a good scanner this weekend, i;ll let you know what i found out. also, tomorrow i am putting a resistor on the knock sensor to see if that helps at all.

Guest47904

You had best check the oil for fuel contamination.

MyZb383

How do you think fuel is getting into the oil?