Wooohoooo P0300!!!!!!!!!!!!!!! - Page 4 - DodgeIntrepid.Net Forums - Dodge Intrepid, Concorde, 300m and Eagle Vision chat

'87IROCZOWNER69 · 10-12-2012, 03:07 PM

Anyone have any ideas?

**mnitetrain** · 10-13-2012, 06:27 AM

Fuel pump going bad can also produce P0300. Fuel pressure should be almost 60 PSI and ROCK Steady no bouncing.

**Adpros** · 10-13-2012, 07:48 AM

Quote:

Originally Posted by '87IROCZOWNER69

I have the 3.5 in it. I also have no history on the engine because its a swapped motor. I also already did the ASD relay as well.

This being a swapped motor... Did you buy the car this way and, how long did the engine run until this code started popping up?

Misfire can be stated more complexly as anything that slows the crank down enough to be detected by the engine controller. Since a bad plug or coil is usually detected once in the firing order, the controller doesn't see the crank signal where it expects to see it. Therefore you can expect a P030 X to pop up.

In your case, P0300, these misfires are happening all over the firing order and not at regular times so the controller can't condemn any one single cylinder.

I have seen many times a vacuum leak through the EGR and, (Since this is a swap motor), cracks in he intake plenum near the side mounting bolts. In a few instances, I have seen leaks at the mating seals at the underside of the plenum. The seals on the intake to the head. And in some rare instances the throttle body seal.

If you have a can of carburetor cleaner handy, (And don't get too saturation happy), you can test for manifold and plenum leaks. If it's the EGR, you'll probably have to pull it and see if the plunger is sticking open with a light or vacuum pump.

'87IROCZOWNER69 · 10-13-2012, 06:57 PM

Quote:

Originally Posted by Adpros

This being a swapped motor... Did you buy the car this way and, how long did the engine run until this code started popping up?

Misfire can be stated more complexly as anything that slows the crank down enough to be detected by the engine controller. Since a bad plug or coil is usually detected once in the firing order, the controller doesn't see the crank signal where it expects to see it. Therefore you can expect a P030 X to pop up.

In your case, P0300, these misfires are happening all over the firing order and not at regular times so the controller can't condemn any one single cylinder.

I have seen many times a vacuum leak through the EGR and, (Since this is a swap motor), cracks in he intake plenum near the side mounting bolts. In a few instances, I have seen leaks at the mating seals at the underside of the plenum. The seals on the intake to the head. And in some rare instances the throttle body seal.

If you have a can of carburetor cleaner handy, (And don't get too saturation happy), you can test for manifold and plenum leaks. If it's the EGR, you'll probably have to pull it and see if the plunger is sticking open with a light or vacuum pump.

The engine ran just fine until about 1600 miles after I swapped it in when the code popped up.

I know that the throttle body gasket is fine ( I checked it when I had the plenum off plus it was put on brand new when I swapped the motors), I also changed out the intake to head gasket and the plenum to intake gasket during the swap. It is possible that there could be a leak at one of the four circle seals on the bottom of the plenum. I had it pulled off not too long ago and when I was looking at them one seemed to have a small gap in it. So it's possible that could be the problem? I'd rather deal with that again than do the egr. Other than the possible leak on the bottom everything else seemed all sealed up just fine.

**Adpros** · 10-13-2012, 07:45 PM

Quote:

Originally Posted by '87IROCZOWNER69

The engine ran just fine until about 1600 miles after I swapped it in when the code popped up.

I know that the throttle body gasket is fine ( I checked it when I had the plenum off plus it was put on brand new when I swapped the motors), I also changed out the intake to head gasket and the plenum to intake gasket during the swap. It is possible that there could be a leak at one of the four circle seals on the bottom of the plenum. I had it pulled off not too long ago and when I was looking at them one seemed to have a small gap in it. So it's possible that could be the problem? I'd rather deal with that again than do the egr. Other than the possible leak on the bottom everything else seemed all sealed up just fine.

Older 3.5L plenums also had a couple spring loaded doomaflotchies set into the sealing channel for the bottom PIP seal. I don't know offhand if 2nd gen plenums had this feature or not. Possibly had something to do with the manifold tuning valve circuit but, I haven't messed with any recently. If one of those fell out while you had the plenum off, you might have created a vacancy that the PIP seal is unable to cover. And as such, a vacuum leak.

I would pull the plenum and turn it over to look at the seal and also remove it and see if any of the inserts have fallen out. (Assuming yours is this type of plenum).

'87IROCZOWNER69 · 10-13-2012, 07:52 PM

Quote:

Originally Posted by Adpros

Older 3.5L plenums also had a couple spring loaded doomaflotchies set into the sealing channel for the bottom PIP seal. I don't know offhand if 2nd gen plenums had this feature or not. Possibly had something to do with the manifold tuning valve circuit but, I haven't messed with any recently. If one of those fell out while you had the plenum off, you might have created a vacancy that the PIP seal is unable to cover. And as such, a vacuum leak.

I would pull the plenum and turn it over to look at the seal and also remove it and see if any of the inserts have fallen out. (Assuming yours is this type of plenum).

Yeah the second gens had them too. I think mine had all of them but I will check again. I'll also go ahead and try and see if I can seal that circle thing if the seal is broken.

**Adpros** · 10-14-2012, 09:49 AM

Captain Morgan has put an older thread back in the hopper which has some nice pics of those inserts I was talking about...

http://www.dodgeintrepid.net/showthread.php?t=176230

'87IROCZOWNER69 · 10-15-2012, 01:40 PM

Quote:

Originally Posted by Adpros

Captain Morgan has put an older thread back in the hopper which has some nice pics of those inserts I was talking about...

http://www.dodgeintrepid.net/showthread.php?t=176230

Could the lack of RTV on the manifold itself also cause a vacuum leak? I never did put any on mine...

**Adpros** · 10-15-2012, 03:36 PM

I think the RTV was used in place of a gasket. In his case, he wanted to stick that spacer plate to the intake manifold and not use a conventional gasket. The top side of the spacer would then essentially become the top of the intake where the PIP seal in the plenum groove would seal.