Pinging and Code

[Paulinho11]

Hello guys, I was wondering if you could help me out. I have a 1994 Explorer with the automatic that has been pinging for 2 years. I just had the engine decarbonized, injectors cleaned and I also cleaned the maf sesor the way the instructions said on the website. Unfortunately, it still pings pretty bad when I get on it and the check engine lights up and evetually goes off when the pinging stops. The code I got was code 186 which is something about injector pulse width or maf not working correctly. I found out about the code becuase I took it to a trans shop because it would only go into OD intermittently and when they checked the computer that code was the only one in there. Unfortunately, I also just paid 2200 to rebuild the trans. at 93,000 and the OD still olnly works intermittently. But what I am wondering is if anyone knows why my car is pinging since I am getting this code. Any help is appreciated. Could my ECM be going bad since it pings, and it only shifts into OD when it wants? Thanks

 

[88vert]

Sounds like your lower intake gasket might be leaking

 

[MrShorty]

Tighten the lower intake manifold bolts and check for other vacuum leaks. The circuit test for code 186 says that a vacuum leak can cause this code to show up, and a vacuum leak is a probable cause of "ping."

 

[Paulinho11]

I also had both the top and bottom intake gaskets replaced just recently. As far as the lower intake bolts are converned I also had them check to make sure they were torqued down. Do you guys think it could be something else? I think the code was 186. It could have been 156.

 

[Webster3]

I have a 94 and I get a little pinging up hill in OD but it was horrible until I got the Mass Airflow Sensor completely replaced. Good luck!

Ed

 

[MrShorty]

I don't see a 156 listed. Still say check for other vacuum leaks (vacuum hoses cracked broken disconnected). One tricky place might be a "vacuum" leak through the transmission modulator. Check the hose to the transmission for ATF.
Another possibility might be bad/dirty/clogged fuel injectors causing a lean condition (which causes the ping). Low fuel pressure/bad fuel delivery could cause it.

 

[Runnin'OnEmpty]

Pauline, also check the vacuum "tree" at the rear of the engine (where all the vacuum lines plug into). A vacuum leak here would cause the pinging. Another possibility is the brake booster leaking vacuum.

I'm with MrShorty on this one. The code 186 shows a lean condition, in which the ECM is trying to compensate with higher injector pulsewidths. This is usually from a vacuum leak.

If all else fails, replace the MAF sensor.

 

[Paulinho11]

Hey guys, I know this sounds like a stupid question but how do I check for vacuum leaks? I have no idea how to check for vacuum leaks. thanks for the help.

Paul

 

[TPLYNCH]

You can try spraying WD-40. If theres a leak and it sucks it in, you should hear a change in the engine.