Car won't start after intake manifold gasket replacement

Hello All,

I have a Pontiac grand prix GTP supercharged 3800 series 2 engine

This past weekend I had changed my intake manifold gasket because I was getting coolant mixing with the oil. So after I put everything back together the car started right up, I let it run for 15 minutes. Then I shut it off and now it's been 2 days since it was last turned on. I can't get it to start. Below I will list some things I changed, replaced, checked.

Changed:

Lower Intake Manifold gasket
Supercharger gasket
throttle body gasket
fuel injector "o" rings
PCV valve
oil filter
air filter
oil
coolant
spark plug wires

Checked:

Fluid levels - fine
Fuel pressure - fine
Spark plug gap - fine

Problems:

-I had originally put new spark plugs in but the car wouldn't start so I put the old ones in and it started right up for the first time
-Fuel injectors, when I was putting the fuel rail back on with the injectors I was pushing down on it to hard and the gasket at the tip by the O rings shattered. All of them did. Some of those little pieces fell into the engine but I know I got most of them out. Some still remain in the engine. To replace those gaskets I used nylon washes. It's what the put on the new injectors made today. So I went to a hardware store and bought some. Then I machined them to the correct size. I just don't know if these washers are heat resistant.
-A vacuum line fitting ripped on me while I was taking it off. I didn't have another one to replace it with so I put it back on, put some RTV silicone on it with a pipe clamp to hold it in place.
-I am getting the check engine light, low oil light, temperature light, and the battery light. I get these lights when I turn the key to the AUX position. I don't know if those lights always come on and stay on until the car starts but I did hook a battery charger up to the battery. Since then the starter seems to work faster. Without the charger it does not try to start as fast.
-Some of the codes I am getting with a scanner is P0123 and P0118.

With all of that said, I hope I provided enough information to help someone give me advice. Like I said, it won't start anymore but it started the before and ran for 15 minutes. It sounded great.

Thanks Guys. I hope you can help.

P0123 = TPS Sensor High Input

P0118 = Engine Temp Sensor high input

Sounds like you have a wire pinched or routed wrong and melted somehwere over by your throttle body. Check the ECT sensor wires that run down near the exhaust manifold crossover.

Otherwise, how did you attach the new nylon washers to the fuel injectors? Usually when they break off its best to replace the injector.

I know it's best to replace the washers but what I did was bore the inside diameter of the washer so that it was smaller then the the tip of the inject and I press fitted them on. They will nevre come off now unless you cut them off. Thanks for the advice, I will try that. Do you think what you described is enough to make the engine not start? A buddy of mine said to check the ground that goes from the engine to the frame.

P0118 Engine Coolant Temperature Circuit High Input

P0123 Throttle Position Sensor/Switch A Circuit High Input

Double check to insure you have the TPS plugged in and that none of the pins were bent over when you reconnected it. Also double check the coolant temp sensor located on the front cylinder head for the same. If the TPS is disconnected or the wiring is messed up, the PCM could be reverting to clear flood mode and shutting off injector fire.

thanks, i will try that and let you know how it goes

Well i did all that and the car wouldn't start so i hooked the battery charger up. it wouldn't start but it did start on the 2nd try. I let it run for 15 minutes, shut it off, and now it won't start again.

Here is an update.

Yesterday I came home and tried to start the car. It wouldn't start so I put the battery charger on it and it started right up. 2 times actually. Then I took the charger off and it wouldn't do anything. So I took the battery to 2 different stores and they told me the battery is fine and fully charger. I bought a new one anyway to try it out. So, I put the new battery in and it wouldn't start. I hooked the charger up to the new battery and it started right up. I let it run for 15 minutes and then I took it for a test drive. I didn't even make it 200 feet before the car just stalled. While I was driving the car it sounded great. So, I had to get a neighbor to jump me. I hooked the cables up and the car started right up, my buddies car wasn't even on when I started the car so I don't know if that makes a difference. Once the car was started something weird happened. The RPM's went all the way up to 3,000 and stayed there. So, I got in the car then put it in reverse and the RPM's dropped to normal. Once I started driving back to my house and once I was getting close I took my foot off the break and I could feel the RPM's still way up there as if my foot was on the pedal.

Another note I would like to mention, it doesn't matter what battery I have in the car whether it be the new or old one but the car does not try to start as fast as it does without the charger attached to it. I'm wondering if the starter is messed up, maybe the battery connections a loose or wet, the grounds are messed up, and I think the vacuum system is out of wack?

Let me know what you think. I am posting these same questions on some internet forums and getting some responses back.

Any idea's?

-Dave

Thanks for the advice, I will try that. Do you think what you described is enough to make the engine not start?

In a word, yes. I would try and figure out why these sensors have high input especially if the ses light was off before you replaced the LIM gaskets.

If your car cranks over, I would say your problem is not with the battery or starting system. You need to find out what your car is missing fuel/air/or spark when it wont run.

Did you check all your sensor connections for a bent over tab like Rich mentioned. Its easy to do. I did it on my EVAP solonoid on top of the alternator bracket when I did my LIM gaskets. It kept setting the SES light for a circuit fault. When I unplugged the sensor I knew what happened right away. What is funny is with one tab bent over, the plug still fit just fine.

Otherwise, try unplugging your MAF sensor and starting your car.

Thanks for your posts man, I appreciate it.

Yes, I did check ALL the sensors.

What I found is shown in the pictures. One of the metal "prongs" inside the harness is missing. But I don't know if it is actually missing or not because I don't know what it is suppose to look like. I don't know what this connection is for but I posted a pic of it's location. maybe you could help me out with this.

Can anyone tell me what sensor this is? I pulled it out and the O ring on it was shredded. I wonder if that is enough to cause the problems I have been having.

David, that is not a sensor, it is just a vacuum source for your brake booster, FPR and EGR valve. The shredded o-ring would cause a massive vacuum leak which can cause issues, but shouldn't keep the car from starting.

I know you are new to AF, so I've been patient with you. I moved these posts to your thread, as again, the thread you originally posted this in is not related to your issue and was regarding a GT VIN-K not a GTP VIN-1 engine as in your car. The part you posted the pic of isn't even on a GT VIN-K's engine, so other forum members would be wondering what you took a pic of. Please keep your posts on this issue here in this thread rather than randomly posting everywhere, as it gets confusing for others and is harder to assist you.

Thanks for pointing that out buddy. My last post was posted in an area that was by a mistake. I started reading the thread and didn't realize which one I was in when I thought about posting. I'm not just randomly posting everywhere.

It would be nice if there was a catagory for specific motors so that questions like mine don't just hit readers that own pontiacs.

It would be nice if there was a catagory for specific motors so that questions like mine don't just hit readers that own pontiacs.

:confused:

I disagree and that doesn't make sense. Bad idea! :shakehead

Dave,

I just did this same job a couple days ago. I would take lots of pics of your engine and hope for the best! There are very knowledgeable guys on here, but they need good info to diagnose.

One thing I would check though. The Throttle Position Sensor connector on mine was definitely a stretch. The wiring seemed too short, but it barely reaches. I would check for pulled wires there. I will look at the wiring diagrams, but maybe these two sensors (TPS and Coolant temp sensor) share a common power or ground.

:confused:

I disagree and that doesn't make sense. Bad idea! :shakehead

x2. A GM 3.8 is much different than say a Ford 3.8 etc etc. Plus...there would be WAY to much congestion on the forums.

x2. A GM 3.8 is much different than say a Ford 3.8 etc etc. Plus...there would be WAY to much congestion on the forums.

I could be wrong but I think what he was saying is forums or subforums for specific engines but not relevant to the applicable make and model GM car. Like for example a general L67 Series II 3800 engine forum or a L36 N/A Series II 3800 engine forum. However, AF is primarily set up to cover makes and models.

Having unique forums on AF or here at Grand Prix that just address specific engines would be a no go. From my viewpoint it would be a moderating nightmare and way too much work to manage that type setup.

For example just think of how many different engines we would have to list or have forums on covering the Pontiac Grand Prix since it was first introduced by GM in 1962 up to the last (7th) generation to 2008. :screwy:

However, there are forums on the NET that address specifically engines like the GM LS series of V8 engines which I visit periodically but then you still get a bunch of replies from people that have no specific knowledge or expertise on that engine so where are you? :runaround:

I know this is an old thread but I just had the EXACT same problem with my 98 GTP - same codes and everything so I'm just commenting so other can know how to fix this problem if they have it.

The fix is very simple. GM decided that they would make 2 connectors with the same brown end that were both able to connect into the others locations. I believe its the coolant temp sensor and the manifold sensors. Make sure that they are plugged into the proper locations. I had the problem and only realized when i noticed that the sensor cables were stretched really tight when they weren't before. I hope this helps someone else.