P2138, won’t rev above 3000 rpms, lots of smoke

jsilva

jsilva

Greenie N00B Member
Greenie Member
I’ve been posting many questions and I appreciate your patience... :)

Yesterday I replaced the PCV valve and when it was back together I couldn’t rev the engine above 3000 rpms while in neutral and if I tried eventually the traction light would come on (!?) and it would stall. There is also a lot of smoke and it smells of fuel. I’m guessing it’s not getting enough air and running incredibly rich.

Error P2138.

I had removed the intake manifold yesterday and so I assumed maybe something with the throttle body. I happened to have another throttle body and so I just replaced it and there’s the same problem. I feel like it must be related to my work but I’m not sure where else to look.

Any ideas?
 
Throttle position sensor errors.
 
Thanks Raider. So what do I do about that? Perhaps I didn’t plug it back in properly?
 
Thanks Awafrican. I’m assuming the TPS is 18-9109 in the diagram? I do have two of those because I have two intake manifolds. I could swap it out...

I reseated the connector and no difference.

Regarding consolidating the thread, I understand. Though I chose to create different threads because I figure it’s a lot easier for someone experiencing the same problem to find it in a dedicated thread. And also someone perusing the forums may feel they can contribute in one area but not another and wouldn’t know from the title.
 
I replaced the what I think is the throttle position sensor (according to the part no. linked by Awafrican) and the problem persists. Still can’t rev above 3000rpm (approx) and there’s lots of smoke when trying followed by it eventually stalling. Some smoke when idling and I don’t think it’ll stall without reving the engine.

Here’s what I replaced.

2FCE611A-3BC0-41C0-ADC9-3552E06D66B1.jpeg
 
That is the position sensor for the VTCS in the intake manifold. It doesn't have anything to do with the throttle body.

The throttle body is drive-by-wire, so the motor and position sensors are all incorporated into one harness. So it's either not plugged in all the way, or the motor is going bad.

You could also check the actual accelerator pedal, since that has a sensor circuit that detects how far the pedal is moved. Check and make sure the plug is all the way on.
 
Thanks Mauro! I appreciate the clarification (some sellers are even calling the item above a throttle position sensor).

I replaced the throttle body a couple of days ago with another unit and the issue was the same. So I’m assuming it’s somewhere else. I’ll check out the accelerator pedal sensor but it seems to me the engine is trying to rev but is getting choked and can’t actually do it and then eventually stalls. Could that be the result of the accelerator sensor?
 
If you keep getting throttle issues and you have already swapped with another known good one, then it could be in the harness.

You might have a cut or break somewhere in the harness somewhere, including but not limited to, unplugged pigtail harnesses.

If all that is true then my suggestion is... keep checking all your harnesses around the front of the engine. Something is either penetrated or unplugged. Don't spend anymore money on parts until you 100% know your harness and connectors are good.
 
Thanks for the advice Mauro. That makes sense. I was hoping it’d be a wiring issue but then also dreading troubleshooting that...!

I wish I could more easily follow the wires to test points to test for continuity...doing this on a car is more bewildering to me than on an electrical component such as an amplifier!

I actually haven’t spent any money on this problem yet. A couple of weeks ago I bought a used intake manifold because on mine the EGR tube threads were messed up and causing a boost leak. That manifold came with everything attached to it including the throttle body (and an EGR tube) and so I’ve been swapping parts for testing this problem.
 
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If you can check voltage and continuity on an amplifier, you can check a wiring harness.

Really all you need to do is check continuity on each wire to the throttle body, also make sure all your throttle body pins are there and not bent. Also check and make sure the wires don't get pushed out when you plug the harness in. Yes, it can happen...
 
Yes I can check a harness, but at what point do I check it from? The throttle body connector groups in with other wires about 5” from the throttle body. I haven’t followed the bunch to see where it goes. If it goes to another connector then I can easily check that.

I did check for bent pins and cleaned the connectors, but I’ll do a more thorough check as you suggest and see what I can find about where the wires are going.

Thanks!
 
I could see that the wires from the throttle body connector are going to the fuse box:

A9F0ABFD-4695-40CE-98FE-83D38342FDC2.jpeg

So I tested for continuity of the 6 wires (two orange, two blue, and two white) from the little holes in the throttle body connector to the fuse box (as circled) and all wires made a connection. So if there’s a connection issue it’s not between the throttle body and fuse box.

The connector on the accelerator pedal is also secure.

Since this started after I replaced the PCV valve and one injector, and so had the intake manifold off, it seems reasonable to me that it’s related to taking off the manifold. No?

Is there anything that needs to come off when taking off the intake manifold which could cause this?
 
jsilva said:
I could see that the wires from the throttle body connector are going to the fuse box:

View attachment 13950

So I tested for continuity of the 6 wires (two orange, two blue, and two white) from the little holes in the throttle body connector to the fuse box (as circled) and all wires made a connection. So if there’s a connection issue it’s not between the throttle body and fuse box.
Click to expand...

Did you actually pull the connector at both ends and test continuity from the connecting side, or did you test from the back-side of one or more of the connectors? If you did the latter, there's always a chance that you've got a bent, corroded, or missing pin.

The likelihood is that something you disconnected, bent out of the way, or didn't fully reconnect is your problem here. I've had similar problems where one of the wires to one of my ignition coils backed part way out of the connector. It wasn't a visible problem, and when testing continuity and resistance from the back-side everything was fine, but I was still getting a cyl-3 misfire until I re-seated that pin in the connector.
 
I did test from the connecting side. The holes were tiny but my multimeter’s leads were just able to make contact.

I guess the only course of action is to take the manifold off again ... see what I missed. I was just hoping that maybe there was some other connector in the vicinity that might indirectly interfere with the accelerator sensors and cause the issues the car is having. So I could minimise what needs to come apart.
 
Ok...

I took off the intake manifold, cleaned all of the electrical connectors that would have come off during my last work, and put back in the original throttle body, and there was no improvement. Actually, it’s worse—after running for a while it just stopped. Now when I try to start it it’ll barely run before stalling.

I’m going to have to ask to see if a mechanic in the area is willing to come over and have a look. Any takers on this forum...? :)
 
Post up in the PA section of the forum. I'm sure there are locals that can help.
 
Thanks Mauro. I checked the regional sections and didn’t see PA. The closest was NJ/NY.
 
For whatever reason the forum format has it listed under "Mid-Atlantic." Which also lists New Jersey?!?

The section hasn't had a new thread in a while, but post up dude. You'd be surprised how locals may hang out on the forum and never start a thread.
 
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