head gasket job, now i have codes

[rocket455]

So i recently replaced the head gaskets on my car. Before I had torn it down, there were no codes, or electrical bugs. Now that I have it back together, the car has to be floored to get it to start. After it is started, if i touch the throttle the slightest, the car will stumble and die. I was able to get codes from the car with an OBD1 scanner. Codes are as follows:

118: ECT Sensor Circuit Above Maximum Voltage
157: Mass Air Flows Sensor Circuit Below Minimum Voltage (i have it unplugged, the car surges when its plugged in)
998: Hard Fault Present

I back probed the TPS to see if there is proper voltage, and there is. The car stumbles and dies at the touch of the throttle with and without the MAF plugged in. The ECT sensor is plugged in. Im at a loss of ideas. Assistance is needed

 

[SHOtimer]

You did something wrong, obviously.

When it runs, does it ever run smooth? When you do that much, you need to start at the basics.

1. Do you have the cams on each head timed right, do you have the heads timed correctly with the heads?

2. Do you have the crankshaft sensor gapped correctly?

3. The DIS grounded properly?

4. The ground strap from the motor to the firewall?

5. The plug wires routed correctly?

6. Vacuum leaks?

Did you pinch or damage the wiring harness anywhere?

Doug

 

[rocket455]

When I start it up, it idles smooth. The cams are timed correctly, along with the crank. I just replaced the CPS today and ensured that it was properly gapped. the DIS is grounded along with the strap on the backside of the intake. I routed the wires according to the sticky on the site. I took my sweet time routing the wiring harness and putting everything back on as not to pinch it anywhere.

I realized that I forgot to plug in the ECT on the housing that bolt to the head, so that issue is resolved along with the 998 (i reset the pcm). the issue at hand now, is why does it die when i even look at the throttle?

thank you for your quick reply

 

[Irish Pride]

Why did you replace the head gaskets?

 

[zach44102]

I would guess TPS or MAF but pull the codes

 

[rocket455]

I already pulled codes, they are listed in the first post. I also back probed the TPS and it operated correctly. The car dies when I touch the throttle with and without the MAF plugged in.

I replaced the head gaskets because it was consuming coolant and had low compression in 2 cylinders that were neighboring each other

 

[Irish Pride]

Looking at your sig you know what you're doing, but first question that comes to mind would be - you used 3.2 gaskets and not 3.0? Checked the failed head for damage or did you replace it all together? Recheck your wire routing. Even when you know what you are doing its easy to get one crossed. Do you have all the injectors installed correct and plugged in?

 

[rocket455]

yes, I used 3.2 gaskets. I sent the heads off to be resurfaced for minimal cleanup. One head cleaned up at .004" and the other at .006". I also had him check it for cracks, and they came back fine. I also ran a file across the surface of the block to knock off any potential high spots. I'm sure I did install all of the injectors correctly, but at this point, it doesn't hurt to go back and check again. Ill pull the intake off again tomorrow and double check the harness. Thank you so much guys

 

[SHOtimer]

Is the intake seated properly? Did you loosen all of the hose clamps prior to torquing down the intake and then re-tighten?

Doug

 

[Lorenr]

intake manifold

My first thought also was the intake manifold not seating properly.

Loosen all the intake fittings. I smeared a little silicone on the intake manifold gasket and seated it properly. Torque the manifold. Install everything else, then tighten the intake manifold hoses. Take your time. It doesn't take much to cause a vacuum leak and then they run about the way you describe.

:angelnot:

 

[LJRuddy]

When the engine is running rough, pump the brakes two or three times. Is your brake booster working properly? I had a similar issue when I first replaced my intake and I have a massive vac leak. Reinstalled the intake and all was well.