FirebatLT1

I redid the intake manifold gasket and changed oil and reconnected the battery. On the first run in idle i let in warm up to 180 degrees and blms were 112/115. Ran it again. About the third time i ran the car at idle it went to 108 on both sides. On the third run, the IAC was jumping between 13-22 and the engine was alternating between open and closed loop. When it went into open loop the iac would fall to 13-14and when it would go into closed loop it would increase. So, hopefully fixed the vacuum leak. It was going between open and closed loop before.

Could exhaust leaks at the headers cause blms at 108 on both sides? I kind of doubt it.

edit: Noticed the O2's are acting differently to each other. The right O2 mV values doesn't move as much as the left in closed loop. Don't know if open loop is important but when starting the engine when its cold, as the engine temp increases, the right O2 mV will increase also and the left O2 will stay about the same, about until closed loop happens.

FirebatLT1

Replaced all 16 Injector O-rings (a few didn't look good), measured resistance in spark plug wires, nothing unusual. Found out I had a bad Fuel pressure regulator b/c i smelled fuel on the vacuum line to it so I replaced that. Replaced the O2's b/c one of them was acting slow or something. Still getting 108s for BLMs.

In idle, After this I had about 10-14 for the IAC. After disconnecting the brake vacuum line and the opti vent lines and capping them, my IAC was at about 14-17 and the BLMs were at 108/109 in idle after running the car for 10-15 minutes. So, thinking I might have a small vacuum leak still? Taking off a few of the vacuum accessories made the car not have both blms at 108s. My map sensor is reading 10.47 Hg(35.4 Kpa) around 550 rpm when the car is warmed up. Might end up redoing the intake manifold gasket again...

Injuneer

Your MAP is fine.

The BLM's mean the PCM is removing fuel, because is thinks its running rich. That's not consistant with vacuum leaks. If you only had vacuum leaks as an issue, the BLM's would be above 128, and would DROP as you closed off the vacuum leaks.

Exhaust leaks cause HIGH BLM's, not low BLM's. Misfires cause HIGH BLM's, not low. The PCM sees the air from the leak or from the misfire, thinks the engine is running lean and raises the BLM's = "false" lean.

Seems to me you are looking in the wrong place for the problem. Either the engine is running extremely rich, or something is misleading the PCM into thinking it is running rich.

Have you checked your fuel pressure? Is the PCM tuned for the correct injector size? Is the MAF sensor accurate? Is there a possibility of an EGR leak? Is there a possibility of leaking injectors?

Are you still seeing large amounts of knock retard?

FirebatLT1

PCM is tuned correctly for stock injectors. 24.91lbs/hr. The Maf is reading 6-6.5. I did swap MAFs before with another car but that was before i changed the regulator and the O2s and fixed the intake leak.

I have no EGR but the block-off plates and gaskets are on tight.

I took off the rail and primed the pump to see if any injectors were leaking, none were.

Still having the knock retard show up when i rev the engine quickly.

Looked at fuel pressure today. With the Key on engine off, i got 42 psi. At idle i have 38, when i rev on it i have around 46. When i shut off the car I have about 37, then 5 minutes later I had 42???, then 25 minutes after that I had 42, then 20 minutes after that I had 32. 15 minutes after that I had 29 psi. An hour after that I had 25 psi. How do these fuel pressure readings look?

Guest47904

Is this a bad time to ask a simple question

What year components do you have in the KS and KM?

FirebatLT1

I have a 95 KS that i replaced and measured resistance to make sure. I have a LT4 KM at the moment. I've tried it with the LT1 KM, no difference.

Guest47904

Maybe I didn't catch this in your repsonse but correct me if I'm wrong. The 95 KS(OBDI) is gona read between 3.3K and 4.5K ohms to ground.

The LT4 KM is for OBDII (1996) and it expects to see an OBDII KM which should read between 93K and 107K ohms. THEREFORE if I'm correct, the LT4 KM should have an OBDII KS that reads higher. No?

Or is the beer I had since I got home

FirebatLT1

The KS have different resistance, but the LT4 KM is less sensitive to knock. I dont know how the KM circuitry works. I heard people swap them in and it helps on there obdi setup. For me, I notice no difference.

1SlowFormula

Like what was stated earlier, the KM nor KS would be the problem because this is an audible sound. Even if they were screwed up you would really feel the difference when it pulls timing and it will never pull enough to make any sort of audible noise.

However it does sound like the computer is leaning it out for some reason.

Guest47904

Check and see what DTC's are set and get back to us.

FirebatLT1

I have no diagnostic trouble codes being thrown.

FirebatLT1

I took another fuel pressure reading. Just primed the pump and didn't start the engine this time. It was at 42 psi and 10 minutes later it dropped to 35 psi. Do my fuel pressure readings look ok? Should i do a compression test? Any chance it could be the opti?

FirebatLT1

anybody?

FirebatLT1

Did a compression test. Warmed up engine. Had throttle blades wide open while testing. 4 strokes. All 8 were about the same. They were around 170-175.

Guest47904

Try getting the correct components for the knock circuit and see what happens.